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• Moving data files failing

  - by Miles Hayler

  Trying to migrate data from C: to D: via the SBS console is failing. The wizard starts running but drops out in the first few seconds. I'll post the full logs, but the important lines appear to be as follows: An exception of type 'Type: System.IO.FileNotFoundException, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' has occurred. Message: The system cannot find the file specified. (Exception from HRESULT: 0x80070002) Stack: at TaskScheduler.TaskSchedulerClass.GetFolder(String Path) at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) BaseException: Microsoft.WindowsServerSolutions.Storage.Common.StorageException: GetServerBackupTaskStatus: fail to find the task --- ErrorCode:0 I've been googling for days with no luck. I have found that mscorlib is a component of .net, and I've discovered multiple instances of the file in %windir%, %windir%\winsxs, %windir%\Microsoft.net Anyone come across and fixed this one before? --------------------------------------------------------- [1516] 110315.190856.1105: Storage: Initializing...C:\Program Files\Windows Small Business Server\Bin\MoveData.exe [1516] 110315.190856.2875: Storage: Data Store to be moved: Exchange [1516] 110315.190856.5305: TaskScheduler: Exception System.IO.FileNotFoundException: [1516] 110315.190856.5605: Exception: --------------------------------------- An exception of type 'Type: System.IO.FileNotFoundException, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' has occurred. Timestamp: 03/15/2011 19:08:56 Message: The system cannot find the file specified. (Exception from HRESULT: 0x80070002) Stack: at TaskScheduler.TaskSchedulerClass.GetFolder(String Path) at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) [1516] 110315.190856.5625: Storage: Exception Microsoft.WindowsServerSolutions.Common.WindowsTaskSchedulerException: [1516] 110315.190856.5635: Exception: --------------------------------------- [b]An exception of type 'Type: Microsoft.WindowsServerSolutions.Common.WindowsTaskSchedulerException, Common, Version=6.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' has occurred.[/b] Timestamp: 03/15/2011 19:08:56 Message: Failed to find the task path Stack: at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) at Microsoft.WindowsServerSolutions.Storage.Common.ServerBackupUtility.GetServerBackupTaskStatus() --------------------------------------- An exception of type 'Type: System.IO.FileNotFoundException, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' has occurred. Timestamp: 03/15/2011 19:08:56 Message: The system cannot find the file specified. (Exception from HRESULT: 0x80070002) Stack: at TaskScheduler.TaskSchedulerClass.GetFolder(String Path) at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) [1516] 110315.190856.5665: Storage: Error Retrieving Server Backup Task Status: ErrorCode:0 BaseException: Microsoft.WindowsServerSolutions.Storage.Common.StorageException: GetServerBackupTaskStatus: fail to find the task ---> ErrorCode:0 BaseException: Microsoft.WindowsServerSolutions.Common.WindowsTaskSchedulerException: Failed to find the task path ---> System.IO.FileNotFoundException: The system cannot find the file specified. (Exception from HRESULT: 0x80070002) at TaskScheduler.TaskSchedulerClass.GetFolder(String Path) at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) --- End of inner exception stack trace --- at Microsoft.WindowsServerSolutions.Common.WindowsTaskScheduler..ctor(String taskPath, String taskName) at Microsoft.WindowsServerSolutions.Storage.Common.ServerBackupUtility.GetServerBackupTaskStatus() --- End of inner exception stack trace --- at Microsoft.WindowsServerSolutions.Storage.Common.ServerBackupUtility.GetServerBackupTaskStatus() at Microsoft.WindowsServerSolutions.Storage.MoveData.Helper.get_ServerBackupTaskState() [1516] 110315.190857.6216: Storage: Backup Task State: Unknown [1516] 110315.190857.9347: Storage: Launching the Move Data Wizard! [1516] 110315.190857.9397: Wizard: Admin:QueryNextPage(null) = Storage.MoveDataWizard.GettingStartedPage [1516] 110315.190857.9417: Wizard: TOC Storage.MoveDataWizard.GettingStartedPage is on ExpectedPath [1516] 110315.190857.9577: Wizard: Storage.MoveDataWizard.GettingStartedPage entered [1516] 110315.190857.9657: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.GettingStartedPage) = Storage.MoveDataWizard.DiagnoseDataStorePage [1516] 110315.190857.9657: Wizard: TOC Storage.MoveDataWizard.DiagnoseDataStorePage is on ExpectedPath [1516] 110315.190857.9657: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.DiagnoseDataStorePage) = Storage.MoveDataWizard.NewDataStoreLocationPage [1516] 110315.190857.9657: Wizard: TOC Storage.MoveDataWizard.NewDataStoreLocationPage is on ExpectedPath [1516] 110315.190857.9657: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.NewDataStoreLocationPage) = null [1516] 110315.190857.9697: Wizard: ---------------------------------- [1516] 110315.190857.9697: Wizard: The pages visted: [1516] 110315.190857.9697: Wizard: Current Page := [TOC Storage.MoveDataWizard.GettingStartedPage] [1516] 110315.190857.9697: Wizard: [TOC] : TOC Storage.MoveDataWizard.DiagnoseDataStorePage [1516] 110315.190857.9697: Wizard: [TOC] : TOC Storage.MoveDataWizard.NewDataStoreLocationPage [1516] 110315.190857.9697: Wizard: Step 1 of 3 [1516] 110315.190907.0406: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.GettingStartedPage) = Storage.MoveDataWizard.DiagnoseDataStorePage [1516] 110315.190907.0416: Wizard: Storage.MoveDataWizard.GettingStartedPage exited with the button: Next [1516] 110315.190907.0416: WizardChainEngine Next Clicked: Going to page {0}.: Storage.MoveDataWizard.DiagnoseDataStorePage [1516] 110315.190907.0496: Wizard: Storage.MoveDataWizard.DiagnoseDataStorePage entered [1516] 110315.190907.0606: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.DiagnoseDataStorePage) = Storage.MoveDataWizard.NewDataStoreLocationPage [1516] 110315.190907.0606: Wizard: Admin:QueryNextPage(Storage.MoveDataWizard.NewDataStoreLocationPage) = null [1516] 110315.190907.0606: Wizard: ---------------------------------- [1516] 110315.190907.0606: Wizard: The pages visted: [1516] 110315.190907.0606: Wizard: [TOC] visited: TOC Storage.MoveDataWizard.GettingStartedPage [1516] 110315.190907.0606: Wizard: Current Page := [TOC Storage.MoveDataWizard.DiagnoseDataStorePage] [1516] 110315.190907.0616: Wizard: [TOC] : TOC Storage.MoveDataWizard.NewDataStoreLocationPage [1516] 110315.190907.0616: Wizard: Step 2 of 3 [19772] 110315.190907.0656: Storage: Starting System Diagnosis [19772] 110315.190907.0656: Storage: Getting Data Store Information [19772] 110315.190907.1086: Storage: Create the list of storage and DB directory path [19772] 110315.190907.1246: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingTasks..ctor [19772] 110315.190907.1546: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingTasks.Initialize [19772] 110315.190907.1596: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.Initialize [19772] 110315.190907.1606: Messaging: Exchange install path: C:\Program Files\Microsoft\Exchange Server\bin [19772] 110315.190908.4157: Messaging: E12 Monad runspace created ID: Microsoft.PowerShell [19772] 110315.190908.4237: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190908.4287: Messaging: Executed management shell command: get-exchangeserver [19772] 110315.190910.2369: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190910.2369: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.Initialize [19772] 110315.190910.5699: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingTasks.GatherAdminInfo [19772] 110315.190910.5699: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190910.5719: Messaging: Executed management shell command: get-user -Identity "dmagroup.local\Administrator" [19772] 110315.190911.0870: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.0880: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.0880: Messaging: Executed management shell command: get-mailbox -Identity "d2ae2bf0-48a7-4ce9-9e72-bb3c765454ac" [19772] 110315.190911.1300: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.1310: Messaging: User Administrator is mail enabled and can use MessagingManagement to send mail. [19772] 110315.190911.1310: Messaging: Email address used for user: [email protected] [19772] 110315.190911.1440: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.1440: Messaging: Executed management shell command: get-group -Identity "Domain Admins" [19772] 110315.190911.1630: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.1640: Messaging: User Administrator is a member of Domain Admins and can use MessagingManagement to manage Exchange. [19772] 110315.190911.1640: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingTasks.GatherAdminInfo [19772] 110315.190911.1640: Messaging: MessagingManagement enabled for Exchange management: True [19772] 110315.190911.1640: Messaging: MessagingManagement enabled for mail submission: True [19772] 110315.190911.1640: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingTasks.Initialize [19772] 110315.190911.1640: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Tasks.TaskMoveExchangeData.CreateDataStoreDriveList [19772] 110315.190911.1670: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.Initialize [19772] 110315.190911.1670: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.1670: Messaging: Executed management shell command: get-storagegroup -Server "SERVER01" [19772] 110315.190911.2990: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.3070: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.Initialize [19772] 110315.190911.3070: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.3070: Messaging: Executed management shell command: get-mailboxdatabase -Server "SERVER01" [19772] 110315.190911.4440: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.4520: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.Initialize [19772] 110315.190911.4520: Messaging: Begin Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.4520: Messaging: Executed management shell command: get-publicfolderdatabase -Server "SERVER01" [19772] 110315.190911.5240: Messaging: End Microsoft.WindowsServerSolutions.Messaging.Management.MessagingRunspace.StaticExecute [19772] 110315.190911.5510: Storage: Data Store Drive/s Details:Name=C:\,Size=12675712420 [19772] 110315.190911.5510: Storage: Data Store Size Details: Current Total Size=12675712420 Required Size=12675712420 [19772] 110315.190911.5510: Storage: MoveData Task can move the Data Store=True [19772] 110315.190911.8401: Storage: An error was encountered when performing system diagnosis : ErrorCode:0 BaseException: Microsoft.WindowsServerSolutions.Storage.Common.StorageException: WMI error occurred while accessing drive ---> System.Management.ManagementException: Not found at System.Management.ManagementException.ThrowWithExtendedInfo(ManagementStatus errorCode) at System.Management.ManagementObjectCollection.ManagementObjectEnumerator.MoveNext() at Microsoft.WindowsServerSolutions.Storage.Common.DriveUtil.IsDriveRemovable(String drive) --- End of inner exception stack trace --- at Microsoft.WindowsServerSolutions.Storage.Common.DriveUtil.IsDriveRemovable(String drive) at Microsoft.WindowsServerSolutions.Storage.Common.DataStoreInfo.LoadAvailableDrives() at Microsoft.WindowsServerSolutions.Storage.Common.MoveDataUtil.CanMoveData(DataStoreInfo storeInfo, MoveDataError& error) at Microsoft.WindowsServerSolutions.Storage.MoveData.DiagnoseDataStorePagePresenter.DiagnoseDataStore(Object sender, DoWorkEventArgs args) [1516] 110315.190912.0331: Storage: An error occured during the execution: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> ErrorCode:0 BaseException: Microsoft.WindowsServerSolutions.Storage.Common.StorageException: Diagnosing the Data Store failed (see the inner exception) ---> ErrorCode:0 BaseException: Microsoft.WindowsServerSolutions.Storage.Common.StorageException: WMI error occurred while accessing drive ---> System.Management.ManagementException: Not found at System.Management.ManagementException.ThrowWithExtendedInfo(ManagementStatus errorCode) at System.Management.ManagementObjectCollection.ManagementObjectEnumerator.MoveNext() at Microsoft.WindowsServerSolutions.Storage.Common.DriveUtil.IsDriveRemovable(String drive) --- End of inner exception stack trace --- at Microsoft.WindowsServerSolutions.Storage.Common.DriveUtil.IsDriveRemovable(String drive) at Microsoft.WindowsServerSolutions.Storage.Common.DataStoreInfo.LoadAvailableDrives() at Microsoft.WindowsServerSolutions.Storage.Common.MoveDataUtil.CanMoveData(DataStoreInfo storeInfo, MoveDataError& error) at Microsoft.WindowsServerSolutions.Storage.MoveData.DiagnoseDataStorePagePresenter.DiagnoseDataStore(Object sender, DoWorkEventArgs args) at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument) --- End of inner exception stack trace --- at Microsoft.WindowsServerSolutions.Storage.MoveData.DiagnoseDataStorePagePresenter.backgroundWorker_RunWorkerCompleted(Object sender, RunWorkerCompletedEventArgs e) --- End of inner exception stack trace --- at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) at System.Delegate.DynamicInvokeImpl(Object[] args) at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme) at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj) at System.Threading.ExecutionContext.runTryCode(Object userData) at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry tme) at System.Windows.Forms.Control.InvokeMarshaledCallbacks() at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at Microsoft.WindowsServerSolutions.Common.Wizards.Framework.WizardFrameView.Create() at Microsoft.WindowsServerSolutions.Common.Wizards.Framework.WizardChainEngine.Launch() at Microsoft.WindowsServerSolutions.Storage.MoveData.MainClass.LaunchMoveDataWizard() at Microsoft.WindowsServerSolutions.Storage.MoveData.MainClass.Main(String[] args)

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• OpenVPN Client timing out

  - by Austin

  I recently installed OpenVPN on my Ubuntu VPS. Whenenver I try to connect to it, I can establish a connection just fine. However, everything I try to connect to times out. If I try to ping something, it will resolve the IP, but will time out after resolving the IP. (So DNS Server seems to be working correctly) My server.conf has this relevant information (At least I think it's relevant. I'm not sure if you need more or not) # Which local IP address should OpenVPN # listen on? (optional) ;local a.b.c.d # Which TCP/UDP port should OpenVPN listen on? # If you want to run multiple OpenVPN instances # on the same machine, use a different port # number for each one. You will need to # open up this port on your firewall. port 1194 # TCP or UDP server? ;proto tcp proto udp # "dev tun" will create a routed IP tunnel, # "dev tap" will create an ethernet tunnel. # Use "dev tap0" if you are ethernet bridging # and have precreated a tap0 virtual interface # and bridged it with your ethernet interface. # If you want to control access policies # over the VPN, you must create firewall # rules for the the TUN/TAP interface. # On non-Windows systems, you can give # an explicit unit number, such as tun0. # On Windows, use "dev-node" for this. # On most systems, the VPN will not function # unless you partially or fully disable # the firewall for the TUN/TAP interface. ;dev tap dev tun # Windows needs the TAP-Win32 adapter name # from the Network Connections panel if you # have more than one. On XP SP2 or higher, # you may need to selectively disable the # Windows firewall for the TAP adapter. # Non-Windows systems usually don't need this. ;dev-node MyTap # SSL/TLS root certificate (ca), certificate # (cert), and private key (key). Each client # and the server must have their own cert and # key file. The server and all clients will # use the same ca file. # # See the "easy-rsa" directory for a series # of scripts for generating RSA certificates # and private keys. Remember to use # a unique Common Name for the server # and each of the client certificates. # # Any X509 key management system can be used. # OpenVPN can also use a PKCS #12 formatted key file # (see "pkcs12" directive in man page). ca ca.crt cert server.crt key server.key # This file should be kept secret # Diffie hellman parameters. # Generate your own with: # openssl dhparam -out dh1024.pem 1024 # Substitute 2048 for 1024 if you are using # 2048 bit keys. dh dh1024.pem # Configure server mode and supply a VPN subnet # for OpenVPN to draw client addresses from. # The server will take 10.8.0.1 for itself, # the rest will be made available to clients. # Each client will be able to reach the server # on 10.8.0.1. Comment this line out if you are # ethernet bridging. See the man page for more info. server 10.8.0.0 255.255.255.0 # Maintain a record of client <-> virtual IP address # associations in this file. If OpenVPN goes down or # is restarted, reconnecting clients can be assigned # the same virtual IP address from the pool that was # previously assigned. ifconfig-pool-persist ipp.txt # Configure server mode for ethernet bridging. # You must first use your OS's bridging capability # to bridge the TAP interface with the ethernet # NIC interface. Then you must manually set the # IP/netmask on the bridge interface, here we # assume 10.8.0.4/255.255.255.0. Finally we # must set aside an IP range in this subnet # (start=10.8.0.50 end=10.8.0.100) to allocate # to connecting clients. Leave this line commented # out unless you are ethernet bridging. ;server-bridge 10.8.0.4 255.255.255.0 10.8.0.50 10.8.0.100 # Configure server mode for ethernet bridging # using a DHCP-proxy, where clients talk # to the OpenVPN server-side DHCP server # to receive their IP address allocation # and DNS server addresses. You must first use # your OS's bridging capability to bridge the TAP # interface with the ethernet NIC interface. # Note: this mode only works on clients (such as # Windows), where the client-side TAP adapter is # bound to a DHCP client. ;server-bridge # Push routes to the client to allow it # to reach other private subnets behind # the server. Remember that these # private subnets will also need # to know to route the OpenVPN client # address pool (10.8.0.0/255.255.255.0) # back to the OpenVPN server. ;push "route 192.168.10.0 255.255.255.0" ;push "route 192.168.20.0 255.255.255.0" # To assign specific IP addresses to specific # clients or if a connecting client has a private # subnet behind it that should also have VPN access, # use the subdirectory "ccd" for client-specific # configuration files (see man page for more info). # EXAMPLE: Suppose the client # having the certificate common name "Thelonious" # also has a small subnet behind his connecting # machine, such as 192.168.40.128/255.255.255.248. # First, uncomment out these lines: ;client-config-dir ccd ;route 192.168.40.128 255.255.255.248 # Then create a file ccd/Thelonious with this line: # iroute 192.168.40.128 255.255.255.248 # This will allow Thelonious' private subnet to # access the VPN. This example will only work # if you are routing, not bridging, i.e. you are # using "dev tun" and "server" directives. # EXAMPLE: Suppose you want to give # Thelonious a fixed VPN IP address of 10.9.0.1. # First uncomment out these lines: ;client-config-dir ccd ;route 10.9.0.0 255.255.255.252 # Then add this line to ccd/Thelonious: # ifconfig-push 10.9.0.1 10.9.0.2 # Suppose that you want to enable different # firewall access policies for different groups # of clients. There are two methods: # (1) Run multiple OpenVPN daemons, one for each # group, and firewall the TUN/TAP interface # for each group/daemon appropriately. # (2) (Advanced) Create a script to dynamically # modify the firewall in response to access # from different clients. See man # page for more info on learn-address script. ;learn-address ./script # If enabled, this directive will configure # all clients to redirect their default # network gateway through the VPN, causing # all IP traffic such as web browsing and # and DNS lookups to go through the VPN # (The OpenVPN server machine may need to NAT # or bridge the TUN/TAP interface to the internet # in order for this to work properly). push "redirect-gateway def1 bypass-dhcp" push "dhcp-option DNS 8.8.8.8" # Certain Windows-specific network settings # can be pushed to clients, such as DNS # or WINS server addresses. CAVEAT: # http://openvpn.net/faq.html#dhcpcaveats # The addresses below refer to the public # DNS servers provided by opendns.com. ;push "dhcp-option DNS 8.8.8.8" push "dhcp-option DNS 8.8.4.4" # Uncomment this directive to allow different # clients to be able to "see" each other. # By default, clients will only see the server. # To force clients to only see the server, you # will also need to appropriately firewall the # server's TUN/TAP interface. ;client-to-client # Uncomment this directive if multiple clients # might connect with the same certificate/key # files or common names. This is recommended # only for testing purposes. For production use, # each client should have its own certificate/key # pair. # # IF YOU HAVE NOT GENERATED INDIVIDUAL # CERTIFICATE/KEY PAIRS FOR EACH CLIENT, # EACH HAVING ITS OWN UNIQUE "COMMON NAME", # UNCOMMENT THIS LINE OUT. ;duplicate-cn # The keepalive directive causes ping-like # messages to be sent back and forth over # the link so that each side knows when # the other side has gone down. # Ping every 10 seconds, assume that remote # peer is down if no ping received during # a 120 second time period. keepalive 10 120 # For extra security beyond that provided # by SSL/TLS, create an "HMAC firewall" # to help block DoS attacks and UDP port flooding. # # Generate with: # openvpn --genkey --secret ta.key # # The server and each client must have # a copy of this key. # The second parameter should be '0' # on the server and '1' on the clients. ;tls-auth ta.key 0 # This file is secret # Select a cryptographic cipher. # This config item must be copied to # the client config file as well. ;cipher BF-CBC # Blowfish (default) ;cipher AES-128-CBC # AES ;cipher DES-EDE3-CBC # Triple-DES # Enable compression on the VPN link. # If you enable it here, you must also # enable it in the client config file. comp-lzo # The maximum number of concurrently connected # clients we want to allow. ;max-clients 100 # It's a good idea to reduce the OpenVPN # daemon's privileges after initialization. # # You can uncomment this out on # non-Windows systems. ;user nobody ;group nogroup # The persist options will try to avoid # accessing certain resources on restart # that may no longer be accessible because # of the privilege downgrade. persist-key persist-tun # Output a short status file showing # current connections, truncated # and rewritten every minute. status openvpn-status.log # By default, log messages will go to the syslog (or # on Windows, if running as a service, they will go to # the "\Program Files\OpenVPN\log" directory). # Use log or log-append to override this default. # "log" will truncate the log file on OpenVPN startup, # while "log-append" will append to it. Use one # or the other (but not both). ;log openvpn.log ;log-append openvpn.log # Set the appropriate level of log # file verbosity. # # 0 is silent, except for fatal errors # 4 is reasonable for general usage # 5 and 6 can help to debug connection problems # 9 is extremely verbose verb 3 # Silence repeating messages. At most 20 # sequential messages of the same message # category will be output to the log. ;mute 20 I've tried on multiple computers by the way. The same result on all of them. What could be wrong? Thanks in advance, and if you need other information I'll gladly post it. Information for new comments root@vps:~# iptables -L -n -v Chain INPUT (policy ACCEPT 862K packets, 51M bytes) pkts bytes target prot opt in out source destination Chain FORWARD (policy ACCEPT 3 packets, 382 bytes) pkts bytes target prot opt in out source destination 0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED 4641 298K ACCEPT all -- * * 10.8.0.0/24 0.0.0.0/0 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable Chain OUTPUT (policy ACCEPT 1671K packets, 2378M bytes) pkts bytes target prot opt in out source destination And root@vps:~# iptables -t nat -L -n -v Chain PREROUTING (policy ACCEPT 17937 packets, 2013K bytes) pkts bytes target prot opt in out source destination Chain POSTROUTING (policy ACCEPT 8975 packets, 562K bytes) pkts bytes target prot opt in out source destination 1579 103K SNAT all -- * * 10.8.0.0/24 0.0.0.0/0 to:SERVERIP Chain OUTPUT (policy ACCEPT 8972 packets, 562K bytes) pkts bytes target prot opt in out source destination

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• How and where to implement basic authentication in Kibana 3

  - by Jabb

  I have put my elasticsearch server behind a Apache reverse proxy that provides basic authentication. Authenticating to Apache directly from the browser works fine. However, when I use Kibana 3 to access the server, I receive authentication errors. Obviously because no auth headers are sent along with Kibana's Ajax calls. I added the below to elastic-angular-client.js in the Kibana vendor directory to implement authentication quick and dirty. But for some reason it does not work. $http.defaults.headers.common.Authorization = 'Basic ' + Base64Encode('user:Password'); What is the best approach and place to implement basic authentication in Kibana? /*! elastic.js - v1.1.1 - 2013-05-24 * https://github.com/fullscale/elastic.js * Copyright (c) 2013 FullScale Labs, LLC; Licensed MIT */ /*jshint browser:true */ /*global angular:true */ 'use strict'; /* Angular.js service wrapping the elastic.js API. This module can simply be injected into your angular controllers. */ angular.module('elasticjs.service', []) .factory('ejsResource', ['$http', function ($http) { return function (config) { var // use existing ejs object if it exists ejs = window.ejs || {}, /* results are returned as a promise */ promiseThen = function (httpPromise, successcb, errorcb) { return httpPromise.then(function (response) { (successcb || angular.noop)(response.data); return response.data; }, function (response) { (errorcb || angular.noop)(response.data); return response.data; }); }; // check if we have a config object // if not, we have the server url so // we convert it to a config object if (config !== Object(config)) { config = {server: config}; } // set url to empty string if it was not specified if (config.server == null) { config.server = ''; } /* implement the elastic.js client interface for angular */ ejs.client = { server: function (s) { if (s == null) { return config.server; } config.server = s; return this; }, post: function (path, data, successcb, errorcb) { $http.defaults.headers.common.Authorization = 'Basic ' + Base64Encode('user:Password'); console.log($http.defaults.headers); path = config.server + path; var reqConfig = {url: path, data: data, method: 'POST'}; return promiseThen($http(angular.extend(reqConfig, config)), successcb, errorcb); }, get: function (path, data, successcb, errorcb) { $http.defaults.headers.common.Authorization = 'Basic ' + Base64Encode('user:Password'); path = config.server + path; // no body on get request, data will be request params var reqConfig = {url: path, params: data, method: 'GET'}; return promiseThen($http(angular.extend(reqConfig, config)), successcb, errorcb); }, put: function (path, data, successcb, errorcb) { $http.defaults.headers.common.Authorization = 'Basic ' + Base64Encode('user:Password'); path = config.server + path; var reqConfig = {url: path, data: data, method: 'PUT'}; return promiseThen($http(angular.extend(reqConfig, config)), successcb, errorcb); }, del: function (path, data, successcb, errorcb) { $http.defaults.headers.common.Authorization = 'Basic ' + Base64Encode('user:Password'); path = config.server + path; var reqConfig = {url: path, data: data, method: 'DELETE'}; return promiseThen($http(angular.extend(reqConfig, config)), successcb, errorcb); }, head: function (path, data, successcb, errorcb) { $http.defaults.headers.common.Authorization = 'Basic ' + Base64Encode('user:Password'); path = config.server + path; // no body on HEAD request, data will be request params var reqConfig = {url: path, params: data, method: 'HEAD'}; return $http(angular.extend(reqConfig, config)) .then(function (response) { (successcb || angular.noop)(response.headers()); return response.headers(); }, function (response) { (errorcb || angular.noop)(undefined); return undefined; }); } }; return ejs; }; }]); UPDATE 1: I implemented Matts suggestion. However, the server returns a weird response. It seems that the authorization header is not working. Could it have to do with the fact, that I am running Kibana on port 81 and elasticsearch on 8181? OPTIONS /solar_vendor/_search HTTP/1.1 Host: 46.252.46.173:8181 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:25.0) Gecko/20100101 Firefox/25.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3 Accept-Encoding: gzip, deflate Origin: http://46.252.46.173:81 Access-Control-Request-Method: POST Access-Control-Request-Headers: authorization,content-type Connection: keep-alive Pragma: no-cache Cache-Control: no-cache This is the response HTTP/1.1 401 Authorization Required Date: Fri, 08 Nov 2013 23:47:02 GMT WWW-Authenticate: Basic realm="Username/Password" Vary: Accept-Encoding Content-Encoding: gzip Content-Length: 346 Connection: close Content-Type: text/html; charset=iso-8859-1 UPDATE 2: Updated all instances with the modified headers in these Kibana files root@localhost:/var/www/kibana# grep -r 'ejsResource(' . ./src/app/controllers/dash.js: $scope.ejs = ejsResource({server: config.elasticsearch, headers: {'Access-Control-Request-Headers': 'Accept, Origin, Authorization', 'Authorization': 'Basic XXXXXXXXXXXXXXXXXXXXXXXXXXXXX=='}}); ./src/app/services/querySrv.js: var ejs = ejsResource({server: config.elasticsearch, headers: {'Access-Control-Request-Headers': 'Accept, Origin, Authorization', 'Authorization': 'Basic XXXXXXXXXXXXXXXXXXXXXXXXXXXXX=='}}); ./src/app/services/filterSrv.js: var ejs = ejsResource({server: config.elasticsearch, headers: {'Access-Control-Request-Headers': 'Accept, Origin, Authorization', 'Authorization': 'Basic XXXXXXXXXXXXXXXXXXXXXXXXXXXXX=='}}); ./src/app/services/dashboard.js: var ejs = ejsResource({server: config.elasticsearch, headers: {'Access-Control-Request-Headers': 'Accept, Origin, Authorization', 'Authorization': 'Basic XXXXXXXXXXXXXXXXXXXXXXXXXXXXX=='}}); And modified my vhost conf for the reverse proxy like this <VirtualHost *:8181> ProxyRequests Off ProxyPass / http://127.0.0.1:9200/ ProxyPassReverse / https://127.0.0.1:9200/ <Location /> Order deny,allow Allow from all AuthType Basic AuthName “Username/Password” AuthUserFile /var/www/cake2.2.4/.htpasswd Require valid-user Header always set Access-Control-Allow-Methods "GET, POST, DELETE, OPTIONS, PUT" Header always set Access-Control-Allow-Headers "Content-Type, X-Requested-With, X-HTTP-Method-Override, Origin, Accept, Authorization" Header always set Access-Control-Allow-Credentials "true" Header always set Cache-Control "max-age=0" Header always set Access-Control-Allow-Origin * </Location> ErrorLog ${APACHE_LOG_DIR}/error.log </VirtualHost> Apache sends back the new response headers but the request header still seems to be wrong somewhere. Authentication just doesn't work. Request Headers OPTIONS /solar_vendor/_search HTTP/1.1 Host: 46.252.26.173:8181 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:25.0) Gecko/20100101 Firefox/25.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3 Accept-Encoding: gzip, deflate Origin: http://46.252.26.173:81 Access-Control-Request-Method: POST Access-Control-Request-Headers: authorization,content-type Connection: keep-alive Pragma: no-cache Cache-Control: no-cache Response Headers HTTP/1.1 401 Authorization Required Date: Sat, 09 Nov 2013 08:48:48 GMT Access-Control-Allow-Methods: GET, POST, DELETE, OPTIONS, PUT Access-Control-Allow-Headers: Content-Type, X-Requested-With, X-HTTP-Method-Override, Origin, Accept, Authorization Access-Control-Allow-Credentials: true Cache-Control: max-age=0 Access-Control-Allow-Origin: * WWW-Authenticate: Basic realm="Username/Password" Vary: Accept-Encoding Content-Encoding: gzip Content-Length: 346 Connection: close Content-Type: text/html; charset=iso-8859-1 SOLUTION: After doing some more research, I found out that this is definitely a configuration issue with regard to CORS. There are quite a few posts available regarding that topic but it appears that in order to solve my problem, it would be necessary to to make some very granular configurations on apache and also make sure that the right stuff is sent from the browser. So I reconsidered the strategy and found a much simpler solution. Just modify the vhost reverse proxy config to move the elastisearch server AND kibana on the same http port. This also adds even better security to Kibana. This is what I did: <VirtualHost *:8181> ProxyRequests Off ProxyPass /bigdatadesk/ http://127.0.0.1:81/bigdatadesk/src/ ProxyPassReverse /bigdatadesk/ http://127.0.0.1:81/bigdatadesk/src/ ProxyPass / http://127.0.0.1:9200/ ProxyPassReverse / https://127.0.0.1:9200/ <Location /> Order deny,allow Allow from all AuthType Basic AuthName “Username/Password” AuthUserFile /var/www/.htpasswd Require valid-user </Location> ErrorLog ${APACHE_LOG_DIR}/error.log </VirtualHost>

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• dynamic multiple instance of swfupload (firefox vs IE)

  - by jean27

  We have this dynamic uploader which creates a new instance of swfupload. I'm a little bit confused with the outputs produced by firefox and ie. Firefox have the same output as chrome, safari and opera. Whenever I clicked a button for adding a new instance, the previous instances of swfupload in firefox refresh while IE don't. I have this debug information: For Firefox: SWF DEBUG OUTPUT IN FIREFOX ---SWFUpload Instance Info--- Version: 2.2.0 2009-03-25 Movie Name: SWFUpload_0 Settings: upload_url: /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== flash_url: /content/swfupload.swf?preventswfcaching=1272512466022 use_query_string: false requeue_on_error: false http_success: assume_success_timeout: 0 file_post_name: Filedata post_params: [object Object] file_types: .jpg;.gif;.png;.bmp file_types_description: Image Files file_size_limit: 1MB file_upload_limit: 1 file_queue_limit: 1 debug: true prevent_swf_caching: true button_placeholder_id: file-1_swf button_placeholder: Not Set button_image_url: /content/images/blankButton.png button_width: 109 button_height: 22 button_text: button_text_style: color: #000000; font-size: 16pt; button_text_top_padding: 1 button_text_left_padding: 30 button_action: -110 button_disabled: false custom_settings: [object Object] Event Handlers: swfupload_loaded_handler assigned: true file_dialog_start_handler assigned: true file_queued_handler assigned: true file_queue_error_handler assigned: true upload_start_handler assigned: true upload_progress_handler assigned: true upload_error_handler assigned: true upload_success_handler assigned: true upload_complete_handler assigned: true debug_handler assigned: true SWF DEBUG: SWFUpload Init CompleteSWF DEBUG: SWF DEBUG: ----- SWF DEBUG OUTPUT ---- SWF DEBUG: Build Number: SWFUPLOAD 2.2.0 SWF DEBUG: movieName: SWFUpload_0 SWF DEBUG: Upload URL: /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== SWF DEBUG: File Types String: .jpg;.gif;.png;.bmp SWF DEBUG: Parsed File Types: jpg,gif,png,bmp SWF DEBUG: HTTP Success: 0 SWF DEBUG: File Types Description: Image Files (.jpg;.gif;.png;.bmp) SWF DEBUG: File Size Limit: 1048576 bytes SWF DEBUG: File Upload Limit: 1 SWF DEBUG: File Queue Limit: 1 SWF DEBUG: Post Params: SWF DEBUG: ----- END SWF DEBUG OUTPUT ---- SWF DEBUG: SWF DEBUG: Event: fileDialogStart : Browsing files. Multi Select. Allowed file types: .jpg;.gif;.png;.bmpSWF DEBUG: Select Handler: Received the files selected from the dialog. Processing the file list...SWF DEBUG: Event: fileQueued : File ID: SWFUpload_0_0SWF DEBUG: Event: fileDialogComplete : Finished processing selected files. Files selected: 1. Files Queued: 1---SWFUpload Instance Info--- Version: 2.2.0 2009-03-25 Movie Name: SWFUpload_1 Settings: upload_url: /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== flash_url: /content/swfupload.swf?preventswfcaching=1272512476357 use_query_string: false requeue_on_error: false http_success: assume_success_timeout: 0 file_post_name: Filedata post_params: [object Object] file_types: .jpg;.gif;.png;.bmp file_types_description: Image Files file_size_limit: 1MB file_upload_limit: 1 file_queue_limit: 1 debug: true prevent_swf_caching: true button_placeholder_id: file-2_swf button_placeholder: Not Set button_image_url: /content/images/blankButton.png button_width: 109 button_height: 22 button_text: button_text_style: color: #000000; font-size: 16pt; button_text_top_padding: 1 button_text_left_padding: 30 button_action: -110 button_disabled: false custom_settings: [object Object] Event Handlers: swfupload_loaded_handler assigned: true file_dialog_start_handler assigned: true file_queued_handler assigned: true file_queue_error_handler assigned: true upload_start_handler assigned: true upload_progress_handler assigned: true upload_error_handler assigned: true upload_success_handler assigned: true upload_complete_handler assigned: true debug_handler assigned: true SWF DEBUG: SWFUpload Init CompleteSWF DEBUG: SWF DEBUG: ----- SWF DEBUG OUTPUT ---- SWF DEBUG: Build Number: SWFUPLOAD 2.2.0 SWF DEBUG: movieName: SWFUpload_1 SWF DEBUG: Upload URL: /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== SWF DEBUG: File Types String: .jpg;.gif;.png;.bmp SWF DEBUG: Parsed File Types: jpg,gif,png,bmp SWF DEBUG: HTTP Success: 0 SWF DEBUG: File Types Description: Image Files (.jpg;.gif;.png;.bmp) SWF DEBUG: File Size Limit: 1048576 bytes SWF DEBUG: File Upload Limit: 1 SWF DEBUG: File Queue Limit: 1 SWF DEBUG: Post Params: SWF DEBUG: ----- END SWF DEBUG OUTPUT ---- SWF DEBUG: SWF DEBUG: SWFUpload Init CompleteSWF DEBUG: SWF DEBUG: ----- SWF DEBUG OUTPUT ---- SWF DEBUG: Build Number: SWFUPLOAD 2.2.0 SWF DEBUG: movieName: SWFUpload_0 SWF DEBUG: Upload URL: /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== SWF DEBUG: File Types String: .jpg;.gif;.png;.bmp SWF DEBUG: Parsed File Types: jpg,gif,png,bmp SWF DEBUG: HTTP Success: 0 SWF DEBUG: File Types Description: Image Files (.jpg;.gif;.png;.bmp) SWF DEBUG: File Size Limit: 1048576 bytes SWF DEBUG: File Upload Limit: 1 SWF DEBUG: File Queue Limit: 1 SWF DEBUG: Post Params: SWF DEBUG: ----- END SWF DEBUG OUTPUT ---- SWF DEBUG: SWF DEBUG: Event: fileDialogStart : Browsing files. Multi Select. Allowed file types: .jpg;.gif;.png;.bmpSWF DEBUG: Select Handler: Received the files selected from the dialog. Processing the file list...SWF DEBUG: Event: fileQueued : File ID: SWFUpload_1_0SWF DEBUG: Event: fileDialogComplete : Finished processing selected files. Files selected: 1. Files Queued: 1SWF DEBUG: StartUpload: First file in queueSWF DEBUG: StartUpload(): No files found in the queue.SWF DEBUG: StartUpload: First file in queueSWF DEBUG: Event: uploadStart : File ID: SWFUpload_1_0SWF DEBUG: ReturnUploadStart(): File accepted by startUpload event and readied for upload. Starting upload to /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== for File ID: SWFUpload_1_0SWF DEBUG: Event: uploadProgress (OPEN): File ID: SWFUpload_1_0SWF DEBUG: Event: uploadProgress: File ID: SWFUpload_1_0. Bytes: 30218. Total: 30218SWF DEBUG: Event: uploadSuccess: File ID: SWFUpload_1_0 Response Received: true Data: 65-AddClassification.pngSWF DEBUG: Event: uploadComplete : Upload cycle complete. For IE: SWF DEBUG OUTPUT IN IE ---SWFUpload Instance Info--- Version: 2.2.0 2009-03-25 Movie Name: SWFUpload_0 Settings: upload_url: /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== flash_url: /content/swfupload.swf?preventswfcaching=1272512200531 use_query_string: false requeue_on_error: false http_success: assume_success_timeout: 0 file_post_name: Filedata post_params: [object Object] file_types: .jpg;.gif;.png;.bmp file_types_description: Image Files file_size_limit: 1MB file_upload_limit: 1 file_queue_limit: 1 debug: true prevent_swf_caching: true button_placeholder_id: file-1_swf button_placeholder: Not Set button_image_url: /content/images/blankButton.png button_width: 109 button_height: 22 button_text: Browse... button_text_style: color: #000000; font-size: 16pt; button_text_top_padding: 1 button_text_left_padding: 30 button_action: -110 button_disabled: false custom_settings: [object Object] Event Handlers: swfupload_loaded_handler assigned: true file_dialog_start_handler assigned: true file_queued_handler assigned: true file_queue_error_handler assigned: true upload_start_handler assigned: true upload_progress_handler assigned: true upload_error_handler assigned: true upload_success_handler assigned: true upload_complete_handler assigned: true debug_handler assigned: true SWF DEBUG: SWFUpload Init CompleteSWF DEBUG: SWF DEBUG: ----- SWF DEBUG OUTPUT ---- SWF DEBUG: Build Number: SWFUPLOAD 2.2.0 SWF DEBUG: movieName: SWFUpload_0 SWF DEBUG: Upload URL: /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== SWF DEBUG: File Types String: .jpg;.gif;.png;.bmp SWF DEBUG: Parsed File Types: jpg,gif,png,bmp SWF DEBUG: HTTP Success: 0 SWF DEBUG: File Types Description: Image Files (.jpg;.gif;.png;.bmp) SWF DEBUG: File Size Limit: 1048576 bytes SWF DEBUG: File Upload Limit: 1 SWF DEBUG: File Queue Limit: 1 SWF DEBUG: Post Params: SWF DEBUG: ----- END SWF DEBUG OUTPUT ---- SWF DEBUG: Removing Flash functions hooks (this should only run in IE and should prevent memory leaks)SWF DEBUG: Event: fileDialogStart : Browsing files. Multi Select. Allowed file types: .jpg;.gif;.png;.bmpSWF DEBUG: Select Handler: Received the files selected from the dialog. Processing the file list...SWF DEBUG: Event: fileQueued : File ID: SWFUpload_0_0SWF DEBUG: Event: fileDialogComplete : Finished processing selected files. Files selected: 1. Files Queued: 1---SWFUpload Instance Info--- Version: 2.2.0 2009-03-25 Movie Name: SWFUpload_1 Settings: upload_url: /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== flash_url: /content/swfupload.swf?preventswfcaching=1272512222093 use_query_string: false requeue_on_error: false http_success: assume_success_timeout: 0 file_post_name: Filedata post_params: [object Object] file_types: .jpg;.gif;.png;.bmp file_types_description: Image Files file_size_limit: 1MB file_upload_limit: 1 file_queue_limit: 1 debug: true prevent_swf_caching: true button_placeholder_id: file-2_swf button_placeholder: Not Set button_image_url: /content/images/blankButton.png button_width: 109 button_height: 22 button_text: Browse... button_text_style: color: #000000; font-size: 16pt; button_text_top_padding: 1 button_text_left_padding: 30 button_action: -110 button_disabled: false custom_settings: [object Object] Event Handlers: swfupload_loaded_handler assigned: true file_dialog_start_handler assigned: true file_queued_handler assigned: true file_queue_error_handler assigned: true upload_start_handler assigned: true upload_progress_handler assigned: true upload_error_handler assigned: true upload_success_handler assigned: true upload_complete_handler assigned: true debug_handler assigned: true SWF DEBUG: SWFUpload Init CompleteSWF DEBUG: SWF DEBUG: ----- SWF DEBUG OUTPUT ---- SWF DEBUG: Build Number: SWFUPLOAD 2.2.0 SWF DEBUG: movieName: SWFUpload_1 SWF DEBUG: Upload URL: /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== SWF DEBUG: File Types String: .jpg;.gif;.png;.bmp SWF DEBUG: Parsed File Types: jpg,gif,png,bmp SWF DEBUG: HTTP Success: 0 SWF DEBUG: File Types Description: Image Files (.jpg;.gif;.png;.bmp) SWF DEBUG: File Size Limit: 1048576 bytes SWF DEBUG: File Upload Limit: 1 SWF DEBUG: File Queue Limit: 1 SWF DEBUG: Post Params: SWF DEBUG: ----- END SWF DEBUG OUTPUT ---- SWF DEBUG: Removing Flash functions hooks (this should only run in IE and should prevent memory leaks)SWF DEBUG: ExternalInterface reinitializedSWF DEBUG: Event: fileDialogStart : Browsing files. Multi Select. Allowed file types: .jpg;.gif;.png;.bmpSWF DEBUG: Select Handler: Received the files selected from the dialog. Processing the file list...SWF DEBUG: Event: fileQueued : File ID: SWFUpload_1_0SWF DEBUG: Event: fileDialogComplete : Finished processing selected files. Files selected: 1. Files Queued: 1SWF DEBUG: StartUpload: First file in queueSWF DEBUG: Event: uploadStart : File ID: SWFUpload_0_0SWF DEBUG: StartUpload: First file in queueSWF DEBUG: Event: uploadStart : File ID: SWFUpload_1_0SWF DEBUG: ReturnUploadStart(): File accepted by startUpload event and readied for upload. Starting upload to /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== for File ID: SWFUpload_0_0SWF DEBUG: ReturnUploadStart(): File accepted by startUpload event and readied for upload. Starting upload to /86707/listing/asynchronousuploadphoto/87085/15/E1ptdReNMwcU/cUkx4p689ChPRZYMKkLZQ== for File ID: SWFUpload_1_0SWF DEBUG: Event: uploadProgress (OPEN): File ID: SWFUpload_0_0SWF DEBUG: Event: uploadProgress: File ID: SWFUpload_0_0. Bytes: 29151. Total: 29151SWF DEBUG: Event: uploadProgress (OPEN): File ID: SWFUpload_1_0SWF DEBUG: Event: uploadProgress: File ID: SWFUpload_1_0. Bytes: Total: 30218SWF DEBUG: Event: uploadSuccess: File ID: SWFUpload_0_0 Response Received: true Data: 62-Greenwich_-_Branches.pngSWF DEBUG: Event: uploadComplete : Upload cycle complete.

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• Spork servers super slow (>3m) to start for RSpec & Cucumber BDD

  - by Eric M.

  I recently installed a fresh development setup on my laptop and now notice that my instances of spork take several minutes to start up. This is also most likely of the RSpec and Cucumber tests start up times running super slow. I ran in diagnostic mode with the -d flag and received the output below. Anyone have a clue why this is suddenly happening? Spork Diagnosis - -- Summary -- config/boot.rb config/environment.rb config/initializers/backtrace_silencers.rb config/initializers/devise.rb config/initializers/hoptoad.rb config/initializers/inflections.rb config/initializers/mime_types.rb config/initializers/new_rails_defaults.rb config/initializers/session_store.rb spec/spec_helper.rb -- Detail -- --- config/boot.rb --- config/environment.rb:7 /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:inrequire' spec/spec_helper.rb:9 /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/bin/../lib/spork.rb:23:in `prefork' spec/spec_helper.rb:7 --- config/environment.rb --- spec/spec_helper.rb:9 /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/bin/../lib/spork.rb:23:in `prefork' spec/spec_helper.rb:7 --- config/initializers/backtrace_silencers.rb --- /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:147:in load' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:622:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:in each' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:176:in process' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:insend' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:in run_without_spork' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/lib/spork/app_framework/rails.rb:18:inrun' config/environment.rb:9 /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:inrequire' spec/spec_helper.rb:9 /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/bin/../lib/spork.rb:23:in `prefork' spec/spec_helper.rb:7 --- config/initializers/devise.rb --- /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:147:in load' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:622:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:in each' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:176:in process' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:insend' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:in run_without_spork' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/lib/spork/app_framework/rails.rb:18:inrun' config/environment.rb:9 /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:inrequire' spec/spec_helper.rb:9 /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/bin/../lib/spork.rb:23:in `prefork' spec/spec_helper.rb:7 --- config/initializers/hoptoad.rb --- /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:147:in load' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:622:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:in each' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:176:in process' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:insend' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:in run_without_spork' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/lib/spork/app_framework/rails.rb:18:inrun' config/environment.rb:9 /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:inrequire' spec/spec_helper.rb:9 /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/bin/../lib/spork.rb:23:in `prefork' spec/spec_helper.rb:7 --- config/initializers/inflections.rb --- /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:147:in load' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:622:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:in each' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:176:in process' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:insend' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:in run_without_spork' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/lib/spork/app_framework/rails.rb:18:inrun' config/environment.rb:9 /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:inrequire' spec/spec_helper.rb:9 /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/bin/../lib/spork.rb:23:in `prefork' spec/spec_helper.rb:7 --- config/initializers/mime_types.rb --- /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:147:in load' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:622:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:in each' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:176:in process' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:insend' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:in run_without_spork' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/lib/spork/app_framework/rails.rb:18:inrun' config/environment.rb:9 /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:inrequire' spec/spec_helper.rb:9 /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/bin/../lib/spork.rb:23:in `prefork' spec/spec_helper.rb:7 --- config/initializers/new_rails_defaults.rb --- /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:147:in load' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:622:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:in each' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:176:in process' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:insend' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:in run_without_spork' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/lib/spork/app_framework/rails.rb:18:inrun' config/environment.rb:9 /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:inrequire' spec/spec_helper.rb:9 /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/bin/../lib/spork.rb:23:in `prefork' spec/spec_helper.rb:7 --- config/initializers/session_store.rb --- /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:147:in load' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:622:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:in each' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:621:inload_application_initializers' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:176:in process' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:insend' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/rails-2.3.5/lib/initializer.rb:113:in run_without_spork' /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/lib/spork/app_framework/rails.rb:18:inrun' config/environment.rb:9 /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' /Users/Eric/.rvm/rubies/ruby-1.8.7-p249/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:inrequire' spec/spec_helper.rb:9 /Users/Eric/.rvm/gems/ruby-1.8.7-p249@33n/gems/spork-0.8.2/bin/../lib/spork.rb:23:in `prefork' spec/spec_helper.rb:7 --- spec/spec_helper.rb ---

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• MVC 2 Entity Framework View Model Insert

  - by cannibalcorpse

  This is driving me crazy. Hopefully my question makes sense... I'm using MVC 2 and Entity Framework 1 and am trying to insert a new record with two navigation properties. I have a SQL table, Categories, that has a lookup table CategoryTypes and another self-referencing lookup CategoryParent. EF makes two nav properties on my Category model, one called Parent and another called CategoryType, both instances of their respective models. On my view that creates the new Category, I have two dropdowns, one for the CategoryType and another for the ParentCategory. When I try and insert the new Category WITHOUT the ParentCategory, which allows nulls, everything is fine. As soon as I add the ParentCategory, the insert fails, and oddly (or so I think) complains about the CategoryType in the form of this error: 0 related 'CategoryTypes' were found. 1 'CategoryTypes' is expected. When I step through, I can verifiy that both ID properties coming in on the action method parameter are correct. I can also verify that when I go to the db to get the CategoryType and ParentCategory with the ID's, the records are being pulled fine. Yet it fails on SaveChanges(). All that I can see is that my CategoryParent dropdownlistfor in my view, is somehow causing the insert to bomb. Please see my comments in my httpPost Create action method. My view model looks like this: public class EditModel { public Category MainCategory { get; set; } public IEnumerable<CategoryType> CategoryTypesList { get; set; } public IEnumerable<Category> ParentCategoriesList { get; set; } } My Create action methods look like this: // GET: /Categories/Create public ActionResult Create() { return View(new EditModel() { CategoryTypesList = _db.CategoryTypeSet.ToList(), ParentCategoriesList = _db.CategorySet.ToList() }); } // POST: /Categories/Create [HttpPost] public ActionResult Create(Category mainCategory) { if (!ModelState.IsValid) return View(new EditModel() { MainCategory = mainCategory, CategoryTypesList = _db.CategoryTypeSet.ToList(), ParentCategoriesList = _db.CategorySet.ToList() }); mainCategory.CategoryType = _db.CategoryTypeSet.First(ct => ct.Id == mainCategory.CategoryType.Id); // This db call DOES get the correct Category, but fails on _db.SaveChanges(). // Oddly the error is related to CategoryTypes and not Category. // Entities in 'DbEntities.CategorySet' participate in the 'FK_Categories_CategoryTypes' relationship. // 0 related 'CategoryTypes' were found. 1 'CategoryTypes' is expected. //mainCategory.Parent = _db.CategorySet.First(c => c.Id == mainCategory.Parent.Id); // If I just use the literal ID of the same Category, // AND comment out the CategoryParent dropdownlistfor in the view, all is fine. mainCategory.Parent = _db.CategorySet.First(c => c.Id == 2); _db.AddToCategorySet(mainCategory); _db.SaveChanges(); return RedirectToAction("Index"); } Here is my Create form on the view : <% using (Html.BeginForm()) {%> <%= Html.ValidationSummary(true) %> <fieldset> <legend>Fields</legend> <div> <%= Html.LabelFor(model => model.MainCategory.Parent.Id) %> <%= Html.DropDownListFor(model => model.MainCategory.Parent.Id, new SelectList(Model.ParentCategoriesList, "Id", "Name")) %> <%= Html.ValidationMessageFor(model => model.MainCategory.Parent.Id) %> </div> <div> <%= Html.LabelFor(model => model.MainCategory.CategoryType.Id) %> <%= Html.DropDownListFor(model => model.MainCategory.CategoryType.Id, new SelectList(Model.CategoryTypesList, "Id", "Name"))%> <%= Html.ValidationMessageFor(model => model.MainCategory.CategoryType.Id)%> </div> <div> <%= Html.LabelFor(model => model.MainCategory.Name) %> <%= Html.TextBoxFor(model => model.MainCategory.Name)%> <%= Html.ValidationMessageFor(model => model.MainCategory.Name)%> </div> <div> <%= Html.LabelFor(model => model.MainCategory.Description)%> <%= Html.TextAreaFor(model => model.MainCategory.Description)%> <%= Html.ValidationMessageFor(model => model.MainCategory.Description)%> </div> <div> <%= Html.LabelFor(model => model.MainCategory.SeoName)%> <%= Html.TextBoxFor(model => model.MainCategory.SeoName, new { @class = "large" })%> <%= Html.ValidationMessageFor(model => model.MainCategory.SeoName)%> </div> <div> <%= Html.LabelFor(model => model.MainCategory.HasHomepage)%> <%= Html.CheckBoxFor(model => model.MainCategory.HasHomepage)%> <%= Html.ValidationMessageFor(model => model.MainCategory.HasHomepage)%> </div> <p><input type="submit" value="Create" /></p> </fieldset> <% } %> Maybe I've just been staying up too late playing with MVC 2? :) Please let me know if I'm not being clear enough.

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• WebLogic job scheduling

  - by XpiritO

  Hello, overflowers :) I'm trying to implement a WebLogic job scheduling example, to test my cluster capabilities of fail-over on scheduled tasks (to ensure that these tasks are executed on fail over scenario). With this in mind, I've been following this example and trying to configure everything accordingly. Here are the steps I've done so far: Configured a cluster with 1 admin server (AdminServer) and 2 managed instances (Noddy and Snoopy); Set up database tables (using Oracle XE): ACTIVE and WEBLOGIC_TIMERS; Set up data source to access DB and associated it to the scheduling tasks under "Settings for cluster" "Scheduling"; Implemented a job (TimerListener) and a servlet to initialize the job scheduling, as follows: . package timedexecution; import java.io.IOException; import java.io.PrintWriter; import java.io.Serializable; import java.text.SimpleDateFormat; import java.util.Date; import javax.naming.InitialContext; import javax.naming.NamingException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import commonj.timers.Timer; import commonj.timers.TimerListener; import commonj.timers.TimerManager; public class TimerServlet extends HttpServlet { private static final long serialVersionUID = 1L; protected static void logMessage(String message, PrintWriter out){ out.write("<p>"+ message +"</p>"); System.out.println(message); } @Override public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { PrintWriter out = response.getWriter(); // out.println("<html>"); out.println("<head><title>TimerServlet</title></head>"); // try { // logMessage("service() entering try block to intialize the timer from JNDI", out); // InitialContext ic = new InitialContext(); TimerManager jobScheduler = (TimerManager)ic.lookup("weblogic.JobScheduler"); // logMessage("jobScheduler reference " + jobScheduler, out); // jobScheduler.schedule(new ExampleTimerListener(), 0, 30*1000); // logMessage("Timer scheduled!", out); // //execute this job every 30 seconds logMessage("service() started the timer", out); // logMessage("Started the timer - status:", out); // } catch (NamingException ne) { String msg = ne.getMessage(); logMessage("Timer schedule failed!", out); logMessage(msg, out); } catch (Throwable t) { logMessage("service() error initializing timer manager with JNDI name weblogic.JobScheduler " + t,out); } // out.println("</body></html>"); out.close(); } private static class ExampleTimerListener implements Serializable, TimerListener { private static final long serialVersionUID = 8313912206357147939L; public void timerExpired(Timer timer) { SimpleDateFormat sdf = new SimpleDateFormat(); System.out.println( "timerExpired() called at " + sdf.format( new Date() ) ); } } } Then I executed the servlet to start the scheduling on the first managed instance (Noddy server), which returned as expected: (Servlet execution output) service() entering try block to intialize the timer from JNDI jobScheduler reference weblogic.scheduler.TimerServiceImpl@43b4c7 Timer scheduled! service() started the timer Started the timer - status: Which resulted in the creation of 2 rows in my DB tables: WEBLOGIC_TIMERS table state after servlet execution: "EDIT"; "TIMER_ID"; "LISTENER"; "START_TIME"; "INTERVAL"; "TIMER_MANAGER_NAME"; "DOMAIN_NAME"; "CLUSTER_NAME"; ""; "Noddy_1268653040156"; "[datatype]"; "1268653040156"; "30000"; "weblogic.JobScheduler"; "myCluster"; "Cluster" ACTIVE table state after servlet execution: "EDIT"; "SERVER"; "INSTANCE"; "DOMAINNAME"; "CLUSTERNAME"; "TIMEOUT"; ""; "service.SINGLETON_MASTER"; "6382071947583985002/Noddy"; "QRENcluster"; "Cluster"; "10.03.15" Although, the job is not executed as scheduled. It should print a message on the server's log output (Noddy.out file) with a timestamp, saying that the timer had expired. It doesn't. My log files state as follows: Admin server log (myCluster.log file): ####<15/Mar/2010 10H45m GMT> <Warning> <Cluster> <test-ad> <Noddy> <[STANDBY] ExecuteThread: '1' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <> <> <1268649925727> <BEA-000192> <No currently living server was found that could host TimerMaster. The server will retry in a few seconds.> Noddy server log (Noddy.out file): service() entering try block to intialize the timer from JNDI jobScheduler reference weblogic.scheduler.TimerServiceImpl@43b4c7 Timer scheduled! service() started the timer Started the timer - status: <15/Mar/2010 10H45m GMT> <Warning> <Cluster> <BEA-000192> <No currently living server was found that could host TimerMaster. The server will retry in a few seconds.> (Noddy.log file): ####<15/Mar/2010 11H24m GMT> <Info> <Common> <test-ad> <Noddy> <[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <> <> <1268652270128> <BEA-000628> <Created "1" resources for pool "TxDataSourceOracle", out of which "1" are available and "0" are unavailable.> ####<15/Mar/2010 11H37m GMT> <Info> <Cluster> <test-ad> <Noddy> <[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <<anonymous>> <> <> <1268653040226> <BEA-000182> <Job Scheduler created a job with ID Noddy_1268653040156 for TimerListener with description timedexecution.TimerServlet$ExampleTimerListener@2ce79a> ####<15/Mar/2010 11H39m GMT> <Info> <JDBC> <test-ad> <Noddy> <[ACTIVE] ExecuteThread: '3' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <> <> <1268653166307> <BEA-001128> <Connection for pool "TxDataSourceOracle" closed.> Can anyone help me out discovering what's wrong with my configuration? Thanks in advance for your help!

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• Hosted bug tracking system with mercurial repositories (Summary of options & request for opinions)

  - by Mark Booth

  The Question What hosted mercurial repository/bug tracking system or systems have you used? Would you recommend it to others? Are there serious flaws, either in the repository hosting or the bug tracking features that would make it difficult to recommend it? Do you have any other experiences with it or opinions of it that you would like to share? If you have used other non mercurial hosted repository/bug tracking systems, how does it compare? (If I understand correctly, the best format for this type of community-wiki style question is one answer per option, if you have experienced if several) Background I have been looking into options for setting up a bug/issue tracking database and found some valuable advice in this thread and this. But then I got to thinking that a hosted solution might not only solve the problem of tracking bugs, but might also solve the problem we have accessing our mercurial source code repositories while at customer sites around the world. Since we currently have no way to serve mercurial repositories over ssl, when I am at a customer site I have to connect my laptop via VPN to my work network and access the mercurial repositories over a samba share (even if it is just to synce twice a day). This is excruciatingly slow on high latency networks and can be impossible with some customers' firewalls. Even if we could run a TRAC or Redmine server here (thanks turnkey), I'm not sure it would be much quicker as our internet connection is over-stretched as it is. What I would like is for developers to be able to be able to push/pull to/from a remote repository, servicing engineers to be able to pull from a remote repository and for customers (both internal and external) to be able to submit bug/issue reports. Initial options The two options I found were Assembla and Jira. Looking at Assembla I thought the 'group' price looked reasonable, but after enquiring, found that each workspace could only contain a single repository. Since each of our products might have up to a dozen repositories (mostly for libraries) which need to be managed seperately for each product, I could see it getting expensive really quickly. On the plus side, it appears that 'users' are just workspace members, so you can have as many client users (people who can only submit support tickets and track their own tickets) without using up your user allocation. Jira only charges based on the number of users, unfortunately client users also count towards this, if you want them to be able to track their tickets. If you only want clients to be able to submit untracked issues, you can let them submit anonymously, but that doesn't feel very professional to me. More options Looking through MercurialHosting page that @Paidhi suggested, I've added the options which appear to offer private repositories, along with another that I found with a web search. Prices are as per their website today (29th March 2010). Corrections welcome in the future. Anyway, here is my summary, according to the information given on their websites: Assembla, http://www.assembla.com/, looks to be a reasonable price, but suffers only one repository per workspace, so three projects with 6 repos each would use up most of the spaces associated with a $99/month professional account (20 spaces). Bug tracking is based on Trac. Mercurial+Trac support was announced in a blog entry in 2007, but they only list SVN and Git on their Features web page. Cost: $24, $49, $99 & $249/month for 40, 40, unlimited, unlimited users and 1, 10, 20, 100 workspaces. SSL based push/pull? Website https login. BitBucket, http://bitbucket.org/plans/, is primarily a mercurial hosting site for open source projects, with SSL support, but they have an integrated bug tracker and they are cheap for private repositories. It has it’s own issues tracker, but also integrates with Lighthouse & FogBugz. Cost: $0, $5, $12, $50 & $100/month for 1, 5, 15, 25 & 150 private repositories. SSL based push/pull. No https on website login, but supports OpenID, so you can chose an OpenID provider with https login. Codebase HQ, http://www.codebasehq.com/, supports Hg and is almost as cheap as BitBucket. Cost: £5, £13, £21 & £40/month for 3, 15, 30 & 60 active projects, unlimited repositories, unlimited users (except 10 users at £5/month) and 0.5, 2, 4 & 10GB. SSL based push/pull? Website https login? Firefly, http://www.activestate.com/firefly/, by ActiveState looks interesting, but the website is a little light on details, such as whether you can only have one repository per project or not. Cost: $9, $19, & £39/month for 1, 5 & 30 private projects, with a 0.5, 1.5 & 3 GB storage limit. SSL based push/pull? Website https login. Jira, http://www.atlassian.com/software/jira/, isn’t limited by the number of repositories you can have, but by ‘user’. It could work out quite expensive if we want client users to be able to track their issues, since they would need a full user account to be created for them. Also, while there is a Mercurial extension to support jira, there is no ‘Advanced integration’ for Mercurial from Atlassian Fisheye. Cost: $150, $300, $400, $500, $700/month for 10, 25, 50, 100, 100+ users. SSL based push/pull? Website https login. Kiln & FogBugz On Demand, http://fogcreek.com/Kiln/IntrotoOnDemand.html, integrates Kilns mercurial DVCS features with FogBugz, where the combined package is much cheaper than the component parts. Also, the Fogbugz integration is supposedly excellent. *8’) Cost: £30/developer/month ($5/d/m more than either on their own). SSL based push/pull? SourceRepo, http://sourcerepo.com/, also supports HG and is even cheaper than BitBucket & Codebase. Cost: $4, $7 & $13/month for 1, unlimited & unlimited repositories/trac/redmine instances and 500MB, 1GB & 3GB storage. SSL based push/pull. Website https login. Edit: 29th March 2010 & Bounty I split this question into sections, made the questions themselves more explicit, added other options from the research I have done since my first posting and made this community wiki, since I now understand what CW is for. *8') Also, I've added a bounty to encourage people to offer their opinions. At the end of the bounty period, I will award the bounty to whoever writes the best review (good or bad), irrespective of the number of up/down votes it gets. Given that it's probably more important to avoid bad providers than find the absolute best one, 'bad reviews' could be considered more important than good ones.

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• problem solving [closed]

  - by Suresh S

  Problem Statement The Sports Associations in India (SAI) wants to choose 2 teams of 4 people each to send to Asian games. There are 13 people who want to be members of the teams. The SAI tries grouping them in various ways to see which athletes perform well together. Each grouping gets one test run on the test track and their time is recorded. Your task is to help the SAI choose two disjoint teams of 4 such that the sum of their practice times is minimal. Input There will be several input instances. The first line of each instance gives the total number of practice runs. This will be followed by n lines. Each of those lines will contain 5 numbers: p1 p2 p3 p4 t t is the time taken (in milliseconds) by the team consisting of p1, p2, p3 and p4. The time taken will not be more than 2 minutes. The end of the input will be indicated by a line with n=0. Output Output the best total and the two teams that you choose. If it is impossible to choose two disjoint teams from the test runs given, output -1. Sample Input 6 1 2 3 4 30000 10 11 12 13 15000 5 6 7 8 37800 1 5 10 12 20000 5 6 9 11 43000 1 9 12 13 11000 3 1 4 7 9 10000 3 5 7 11 17890 6 7 12 13 20000 0 Sample Output 45000 -1 Input to the problem 40 2 8 11 9 15532 1 13 11 9 57629 10 12 1 5 43406 6 10 1 2 43904 8 3 4 11 12473 6 12 5 11 19826 3 9 10 11 48347 6 12 13 1 45854 5 4 9 7 34452 9 8 12 2 5596 4 10 2 7 6778 3 6 8 5 32858 13 12 8 6 42457 12 9 2 5 49530 6 8 10 7 51453 1 3 11 9 18620 6 2 5 11 5153 4 1 9 8 37336 10 5 1 12 59524 4 5 3 2 1318 2 13 6 8 7839 12 4 9 5 30697 4 10 13 1 25249 4 2 9 13 52359 8 11 1 9 36437 7 5 11 6 58522 9 1 12 6 58837 7 6 8 5 37826 13 1 11 3 1841 11 3 5 13 50000 2 8 7 12 10137 1 4 12 5 32558 8 5 6 7 39021 1 7 10 13 5979 9 2 11 6 29661 13 12 9 7 7219 12 1 11 9 37354 5 1 10 9 47948 8 1 2 10 11071 2 11 1 8 3074 80 3 5 8 10 37873 1 2 3 5 27633 10 13 3 11 8645 13 1 9 6 2167 5 11 13 8 30862 8 7 9 6 47591 3 11 13 8 33823 2 13 7 5 36668 12 3 11 6 53711 6 13 3 7 52412 3 6 7 5 3850 1 5 11 12 35483 1 7 6 10 50943 11 3 6 8 40191 12 8 13 7 4529 4 10 5 1 43280 4 12 10 5 35142 12 4 5 10 37242 9 7 13 2 2661 3 9 2 10 453 3 8 12 9 12479 3 10 11 5 30047 9 1 11 2 40883 6 5 1 2 8774 11 7 9 1 37701 8 3 4 6 32970 4 12 7 10 55109 8 11 13 12 44713 2 10 8 5 37763 13 10 12 2 53628 7 2 5 10 53197 3 2 1 11 14916 1 2 3 10 50756 3 13 5 6 6959 10 6 1 4 2948 4 7 13 9 14146 8 13 10 2 16784 3 2 6 5 30337 1 6 7 8 14239 2 6 11 5 13749 12 1 10 5 30827 4 6 11 8 18780 9 10 8 5 6336 7 9 1 3 3101 10 3 4 13 56678 7 6 3 8 8258 11 7 12 6 19046 13 6 9 8 46356 9 5 11 13 56570 9 1 10 5 6193 8 6 9 11 16854 3 7 4 9 53573 8 12 10 1 28135 10 3 8 4 31411 11 1 3 12 34534 8 6 4 13 3527 1 6 10 9 52307 11 7 1 12 2886 12 11 1 6 17659 13 5 6 8 48834 11 2 1 10 52951 3 9 13 7 21054 1 5 11 9 14507 11 5 12 4 42040 1 6 12 7 46414 5 12 3 10 26239 6 10 7 8 40762 8 11 6 10 38538 13 1 10 7 31140 9 10 13 4 34164 13 6 7 12 49696 6 13 3 5 36003 8 9 13 6 58409 3 10 7 9 20693 2 1 11 12 22653 5 8 4 7 49888 5 3 2 11 29911 8 12 6 9 30964 8 3 13 6 23597 4 1 6 7 31657 4 6 8 7 13 33639 13 8 10 3 27863 5 2 1 12 1408 4 11 1 12 59010 63 10 11 9 8 23611 10 8 6 11 12410 4 6 7 9 44390 8 4 1 6 16543 1 2 8 10 37452 11 12 6 13 28968 11 12 2 8 59617 1 9 11 2 28631 11 6 5 1 27251 2 7 10 4 42503 7 8 10 3 13673 9 13 11 7 30308 6 1 12 9 4888 13 1 9 8 19475 8 7 3 5 34187 8 1 12 3 46266 6 10 12 5 32855 3 7 13 1 38427 2 5 13 3 59487 6 11 1 13 2098 1 4 13 6 22239 13 7 12 3 28703 12 3 7 4 32 9 8 2 13 35271 10 13 6 12 36422 12 6 9 8 44303 1 9 13 11 22962 11 13 6 12 39518 5 6 13 11 47909 4 13 1 8 10654 11 8 12 4 31956 7 12 9 13 35923 4 9 3 2 34736 13 2 10 1 22945 7 10 8 13 36947 1 4 12 13 19432 7 12 13 4 48718 9 5 13 11 18827 11 2 1 12 45444 8 12 6 13 33175 4 2 11 13 56186 2 9 3 11 33218 12 13 8 1 50727 13 1 8 2 48138 7 1 5 3 1926 6 4 10 1 40997 11 3 1 4 26033 6 10 13 1 40988 11 12 5 4 25199 4 3 1 10 23498 3 6 12 7 24306 13 10 12 3 53255 3 13 4 12 14517 7 10 9 3 29925 9 11 12 13 28333 3 5 13 6 13602 13 12 9 6 10394 8 4 12 6 57471 9 3 4 7 34723 11 9 5 3 38480 12 9 10 11 48048 4 3 6 7 31884 2 10 4 5 57654 86 1 6 5 13 56577 6 8 2 5 20429 11 13 9 3 2243 3 1 10 12 55231 9 5 7 8 29964 5 11 8 1 29624 6 9 3 1 43055 12 13 10 8 52132 10 8 4 1 5729 7 3 6 8 53097 11 12 7 1 18711 12 7 6 13 44397 10 12 5 7 53574 5 3 4 13 27078 11 2 5 10 43623 3 7 1 8 57350 10 12 4 9 19752 5 13 9 3 59380 4 7 13 6 32575 7 5 6 11 13593 13 7 12 6 38282 13 7 6 2 45430 6 2 5 10 38082 2 11 13 7 53557 10 6 7 13 40461 6 11 7 1 22007 4 7 2 3 22386 9 7 11 10 35337 2 6 11 7 4129 6 13 5 3 31813 1 11 6 9 11749 5 11 8 13 21858 5 12 9 11 2470 13 10 6 11 14503 8 4 1 3 10783 1 10 12 7 47116 11 1 8 10 25034 8 1 4 9 23350 3 10 1 9 56717 13 2 8 12 5825 12 3 13 7 35628 10 6 1 12 26901 2 13 3 5 2775 1 8 9 7 1294 7 13 12 2 48170 11 9 13 1 34311 9 6 3 13 30663 8 3 10 6 5853 1 10 2 4 19880 9 2 3 12 48990 3 7 11 4 51558 8 13 2 4 9698 9 4 5 1 6834 3 4 12 2 20941 11 3 9 7 40108 13 11 2 4 2594 8 9 10 13 12242 1 8 10 5 42413 7 1 11 3 17779 1 5 8 3 6934 4 9 8 11 10235 8 11 10 2 18879 11 4 8 2 12691 9 7 5 2 44947 3 2 5 4 30042 2 7 12 4 27185 6 5 10 1 28695 12 9 1 5 53813 8 12 9 3 24719 6 1 4 11 22716 1 13 10 8 39981 12 11 5 2 22412 6 11 2 4 14457 4 11 5 3 39658 10 11 2 1 33056 1 3 6 9 16958 6 11 12 7 50779 8 10 6 13 24824 7 10 1 13 35692 13 4 8 9 32885 7 6 4 3 10948 4 5 7 1 36875 5 10 6 7 58746 10 7 8 12 39453 8 4 12 1 46674 11 3 1 8 48103 0

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• Out of memory exception during scrolling of listview

  - by user1761316

  I am using facebook data like postedpicture,profile picture,name,message in my listview.I am getting an OOM error while doing fast scrolling of listview. I am also having scrollviewlistener in my application that loads more data when the scrollbar reaches the bottom of the screen.I just want to know whether I need to change anything in this class. imageLoader.DisplayImage(postimage.get(position).replace(" ", "%20"), postimg) ; I am using the above line to call the method in this imageloader class to set the bitmap to imageview. Here is my imageloader class import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; import java.util.Collections; import java.util.Map; import java.util.Stack; import java.util.WeakHashMap; import com.stellent.beerbro.Wall; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Bitmap.Config; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.PorterDuff.Mode; import android.graphics.PorterDuffXfermode; import android.graphics.Rect; import android.graphics.RectF; import android.graphics.drawable.BitmapDrawable; import android.util.Log; import android.widget.ImageView; public class ImageLoader { MemoryCache memoryCache=new MemoryCache(); FileCache fileCache; private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>()); public ImageLoader(Context context){ //Make the background thead low priority. This way it will not affect the UI performance photoLoaderThread.setPriority(Thread.NORM_PRIORITY-1); fileCache=new FileCache(context); } // final int stub_id=R.drawable.stub; public void DisplayImage(String url,ImageView imageView) { imageViews.put(imageView, url); System.gc(); // Bitmap bitmap=createScaledBitmap(memoryCache.get(url), 100,100,0); Bitmap bitmap=memoryCache.get(url); // Bitmap bitmaps=bitmap.createScaledBitmap(bitmap, 0, 100, 100); if(bitmap!=null) { imageView.setBackgroundDrawable(new BitmapDrawable(bitmap)); // imageView.setImageBitmap(getRoundedCornerBitmap( bitmap, 10,70,70)); // imageView.setImageBitmap(bitmap); // Log.v("first", "first"); } else { queuePhoto(url, imageView); // Log.v("second", "second"); } } private Bitmap createScaledBitmap(Bitmap bitmap, int i, int j, int k) { // TODO Auto-generated method stub return null; } private void queuePhoto(String url, ImageView imageView) { //This ImageView may be used for other images before. So there may be some old tasks in the queue. We need to discard them. photosQueue.Clean(imageView); PhotoToLoad p=new PhotoToLoad(url, imageView); synchronized(photosQueue.photosToLoad){ photosQueue.photosToLoad.push(p); photosQueue.photosToLoad.notifyAll(); } //start thread if it's not started yet if(photoLoaderThread.getState()==Thread.State.NEW) photoLoaderThread.start(); } public Bitmap getBitmap(String url) { File f=fileCache.getFile(url); //from SD cache Bitmap b = decodeFile(f); if(b!=null) return b; //from web try { Bitmap bitmap=null; URL imageUrl = new URL(url); HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection(); conn.setConnectTimeout(30000); conn.setReadTimeout(30000); InputStream is=conn.getInputStream(); OutputStream os = new FileOutputStream(f); Utils.CopyStream(is, os); os.close(); bitmap = decodeFile(f); return bitmap; } catch (Exception ex){ ex.printStackTrace(); return null; } }//Lalit //decodes image and scales it to reduce memory consumption private Bitmap decodeFile(File f){ try { //decode image size BitmapFactory.Options o = new BitmapFactory.Options(); o.inJustDecodeBounds = true; BitmapFactory.decodeStream(new FileInputStream(f),null,o); //Find the correct scale value. It should be the power of 2. final int REQUIRED_SIZE=Wall.width; final int REQUIRED_SIZE1=Wall.height; // final int REQUIRED_SIZE=250; // int width_tmp=o.outWidth, height_tmp=o.outHeight; int scale=1; // while(o.outWidth/scale/2>=REQUIRED_SIZE && o.outHeight/scale/2>=REQUIRED_SIZE) //// scale*=2; while(true){ if(width_tmp/2<REQUIRED_SIZE && height_tmp/2<REQUIRED_SIZE1) break; width_tmp/=2; height_tmp/=2; scale*=2; } //decode with inSampleSize BitmapFactory.Options o2 = new BitmapFactory.Options(); o2.inSampleSize=scale; // o2.inSampleSize=2; return BitmapFactory.decodeStream(new FileInputStream(f), null, o2); } catch (FileNotFoundException e) {} return null; } //Task for the queue private class PhotoToLoad { public String url; public ImageView imageView; public PhotoToLoad(String u, ImageView i){ url=u; imageView=i; } } PhotosQueue photosQueue=new PhotosQueue(); public void stopThread() { photoLoaderThread.interrupt(); } //stores list of photos to download class PhotosQueue { private Stack<PhotoToLoad> photosToLoad=new Stack<PhotoToLoad>(); //removes all instances of this ImageView public void Clean(ImageView image) { for(int j=0 ;j<photosToLoad.size();){ if(photosToLoad.get(j).imageView==image) photosToLoad.remove(j); else ++j; } } } class PhotosLoader extends Thread { public void run() { try { while(true) { //thread waits until there are any images to load in the queue if(photosQueue.photosToLoad.size()==0) synchronized(photosQueue.photosToLoad){ photosQueue.photosToLoad.wait(); } if(photosQueue.photosToLoad.size()!=0) { PhotoToLoad photoToLoad; synchronized(photosQueue.photosToLoad){ photoToLoad=photosQueue.photosToLoad.pop(); } Bitmap bmp=getBitmap(photoToLoad.url); memoryCache.put(photoToLoad.url, bmp); String tag=imageViews.get(photoToLoad.imageView); if(tag!=null && tag.equals(photoToLoad.url)){ BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad.imageView); Activity a=(Activity)photoToLoad.imageView.getContext(); a.runOnUiThread(bd); } } if(Thread.interrupted()) break; } } catch (InterruptedException e) { //allow thread to exit } } } PhotosLoader photoLoaderThread=new PhotosLoader(); //Used to display bitmap in the UI thread class BitmapDisplayer implements Runnable { Bitmap bitmap; ImageView imageView; public BitmapDisplayer(Bitmap b, ImageView i){bitmap=b;imageView=i;} public void run() { if(bitmap!=null) imageView.setBackgroundDrawable(new BitmapDrawable(bitmap)); } } public void clearCache() { memoryCache.clear(); fileCache.clear(); } public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, int pixels,int width,int height) { Bitmap output = Bitmap.createBitmap(width,height, Config.ARGB_8888); Canvas canvas = new Canvas(output); final int color = 0xff424242; final Paint paint = new Paint(); final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); final RectF rectF = new RectF(rect); final float roundPx = pixels; paint.setAntiAlias(true); canvas.drawARGB(0, 0, 0, 0); paint.setColor(color); canvas.drawRoundRect(rectF, roundPx, roundPx, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); canvas.drawBitmap(bitmap, rect, rect, paint); return output; } }

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• Create a class that inherets DrawableGameComponent in XNA as a CLASS with custom functions

  - by user3675013

  using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Media; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Content; namespace TileEngine { class Renderer : DrawableGameComponent { public Renderer(Game game) : base(game) { } SpriteBatch spriteBatch ; protected override void LoadContent() { base.LoadContent(); } public override void Draw(GameTime gameTime) { base.Draw(gameTime); } public override void Update(GameTime gameTime) { base.Update(gameTime); } public override void Initialize() { base.Initialize(); } public RenderTarget2D new_texture(int width, int height) { Texture2D TEX = new Texture2D(GraphicsDevice, width, height); //create the texture to render to RenderTarget2D Mine = new RenderTarget2D(GraphicsDevice, width, height); GraphicsDevice.SetRenderTarget(Mine); //set the render device to the reference provided //maybe base.draw can be used with spritebatch. Idk. We'll see if the order of operation //works out. Wish I could call base.draw here. return Mine; //I'm hoping that this returns the same instance and not a copy. } public void draw_texture(int width, int height, RenderTarget2D Mine) { GraphicsDevice.SetRenderTarget(null); //Set the renderer to render to the backbuffer again Rectangle drawrect = new Rectangle(0, 0, width, height); //Set the rendering size to what we want spriteBatch.Begin(); //This uses spritebatch to draw the texture directly to the screen spriteBatch.Draw(Mine, drawrect, Color.White); //This uses the color white spriteBatch.End(); //ends the spritebatch //Call base.draw after this since it doesn't seem to recognize inside the function //maybe base.draw can be used with spritebatch. Idk. We'll see if the order of operation //works out. Wish I could call base.draw here. } } } I solved a previous issue where I wasn't allowed to access GraphicsDevice outside the main Default 'main' class Ie "Game" or "Game1" etc. Now I have a new issue. FYi no one told me that it would be possible to use GraphicsDevice References to cause it to not be null by using the drawable class. (hopefully after this last bug is solved it doesn't still return null) Anyways at present the problem is that I can't seem to get it to initialize as an instance in my main program. Ie Renderer tileClipping; and I'm unable to use it such as it is to be noted i haven't even gotten to testing these two steps below but before it compiled but when those functions of this class were called it complained that it can't render to a null device. Which meant that the device wasn't being initialized. I had no idea why. It took me hours to google this. I finally figured out the words I needed.. which were "do my rendering in XNA in a seperate class" now I haven't used the addcomponent function because I don't want it to only run these functions automatically and I want to be able to call the custom ones. In a nutshell what I want is: *access to rendering targets and graphics device OUTSIDE default class *passing of Rendertarget2D (which contain textures and textures should automatically be passed with a rendering target? ) *the device should be passed to this function as well OR the device should be passed to this function as a byproduct of passing the rendertarget (which is automatically associated with the render device it was given originally) *I'm assuming I'm dealing with abstracted pointers here so when I pass a class object or instance, I should be recieving the SAME object , I referenced, and not a copy that has only the lifespan of the function running. *the purpose for all these options: I want to initialize new 2d textures on the fly to customize tileclipping and even the X , y Offsets of where a WHOLE texture will be rendered, and the X and Y offsets of where tiles will be rendered ON that surface. This is why. And I'll be doing region based lighting effects per tile or even per 8X8 pixel spaces.. we'll see I'll also be doing sprite rotations on the whole texture then copying it again to a circular masked texture, and then doing a second copy for only solid tiles for masked rotated collisions on sprites. I'll be checking the masked pixels for my collision, and using raycasting possibly to check for collisions on those areas. The sprite will stay in the center, when this rotation happens. Here is a detailed diagram: http://i.stack.imgur.com/INf9K.gif I'll be using texture2D for steps 4-6 I suppose for steps 1 as well. Now ontop of that, the clipping size (IE the sqaure rendered) will be able to be shrunk or increased, on a per frame basis Therefore I can't use the same static size for my main texture2d and I can't use just the backbuffer Or we get the annoying flicker. Also I will have multiple instances of the renderer class so that I can freely pass textures around as if they are playing cards (in a sense) layering them ontop of eachother, cropping them how i want and such. and then using spritebatch to simply draw them at the locations I want. Hopefully this makes sense, and yes I will be planning on using alpha blending but only after all tiles have been drawn.. The masked collision is important and Yes I am avoiding using math on the tile rendering and instead resorting to image manipulation in video memory which is WHY I need this to work the way I'm intending it to work and not in the default way that XNA seems to handle graphics. Thanks to anyone willing to help. I hate the code form offered, because then I have to rely on static presence of an update function. What if I want to kill that update function or that object, but have it in memory, but just have it temporarily inactive? I'm making the assumption here the update function of one of these gamecomponents is automatic ? Anyways this is as detailed as I can make this post hopefully someone can help me solve the issue. Instead of tell me "derrr don't do it this wayyy" which is what a few people told me (but they don't understand the actual goal I have in mind) I'm trying to create basically a library where I can copy images freely no matter the size, i just have to specify the size in the function then as long as a reference to that object exists it should be kept alive? right? :/ anyways.. Anything else? I Don't know. I understand object oriented coding but I don't understand this XNA It's beggining to feel impossible to do anything custom in it without putting ALL my rendering code into the draw function of the main class tileClipping.new_texture(GraphicsDevice, width, height) tileClipping.Draw_texture(...)

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• A free standing ASP.NET Pager Web Control

  - by Rick Strahl

  Paging in ASP.NET has been relatively easy with stock controls supporting basic paging functionality. However, recently I built an MVC application and one of the things I ran into was that I HAD TO build manual paging support into a few of my pages. Dealing with list controls and rendering markup is easy enough, but doing paging is a little more involved. I ended up with a small but flexible component that can be dropped anywhere. As it turns out the task of creating a semi-generic Pager control for MVC was fairly easily. Now I’m back to working in Web Forms and thought to myself that the way I created the pager in MVC actually would also work in ASP.NET – in fact quite a bit easier since the whole thing can be conveniently wrapped up into an easily reusable control. A standalone pager would provider easier reuse in various pages and a more consistent pager display regardless of what kind of 'control’ the pager is associated with. Why a Pager Control? At first blush it might sound silly to create a new pager control – after all Web Forms has pretty decent paging support, doesn’t it? Well, sort of. Yes the GridView control has automatic paging built in and the ListView control has the related DataPager control. The built in ASP.NET paging has several issues though: Postback and JavaScript requirements If you look at paging links in ASP.NET they are always postback links with javascript:__doPostback() calls that go back to the server. While that works fine and actually has some benefit like the fact that paging saves changes to the page and post them back, it’s not very SEO friendly. Basically if you use javascript based navigation nosearch engine will follow the paging links which effectively cuts off list content on the first page. The DataPager control does support GET based links via the QueryStringParameter property, but the control is effectively tied to the ListView control (which is the only control that implements IPageableItemContainer). DataSource Controls required for Efficient Data Paging Retrieval The only way you can get paging to work efficiently where only the few records you display on the page are queried for and retrieved from the database you have to use a DataSource control - only the Linq and Entity DataSource controls  support this natively. While you can retrieve this data yourself manually, there’s no way to just assign the page number and render the pager based on this custom subset. Other than that default paging requires a full resultset for ASP.NET to filter the data and display only a subset which can be very resource intensive and wasteful if you’re dealing with largish resultsets (although I’m a firm believer in returning actually usable sets :-}). If you use your own business layer that doesn’t fit an ObjectDataSource you’re SOL. That’s a real shame too because with LINQ based querying it’s real easy to retrieve a subset of data that is just the data you want to display but the native Pager functionality doesn’t support just setting properties to display just the subset AFAIK. DataPager is not Free Standing The DataPager control is the closest thing to a decent Pager implementation that ASP.NET has, but alas it’s not a free standing component – it works off a related control and the only one that it effectively supports from the stock ASP.NET controls is the ListView control. This means you can’t use the same data pager formatting for a grid and a list view or vice versa and you’re always tied to the control. Paging Events In order to handle paging you have to deal with paging events. The events fire at specific time instances in the page pipeline and because of this you often have to handle data binding in a way to work around the paging events or else end up double binding your data sources based on paging. Yuk. Styling The GridView pager is a royal pain to beat into submission for styled rendering. The DataPager control has many more options and template layout and it renders somewhat cleaner, but it too is not exactly easy to get a decent display for. Not a Generic Solution The problem with the ASP.NET controls too is that it’s not generic. GridView, DataGrid use their own internal paging, ListView can use a DataPager and if you want to manually create data layout – well you’re on your own. IOW, depending on what you use you likely have very different looking Paging experiences. So, I figured I’ve struggled with this once too many and finally sat down and built a Pager control. The Pager Control My goal was to create a totally free standing control that has no dependencies on other controls and certainly no requirements for using DataSource controls. The idea is that you should be able to use this pager control without any sort of data requirements at all – you should just be able to set properties and be able to display a pager. The Pager control I ended up with has the following features: Completely free standing Pager control – no control or data dependencies Complete manual control – Pager can render without any data dependency Easy to use: Only need to set PageSize, ActivePage and TotalItems Supports optional filtering of IQueryable for efficient queries and Pager rendering Supports optional full set filtering of IEnumerable<T> and DataTable Page links are plain HTTP GET href Links Control automatically picks up Page links on the URL and assigns them (automatic page detection no page index changing events to hookup) Full CSS Styling support On the downside there’s no templating support for the control so the layout of the pager is relatively fixed. All elements however are stylable and there are options to control the text, and layout options such as whether to display first and last pages and the previous/next buttons and so on. To give you an idea what the pager looks like, here are two differently styled examples (all via CSS):   The markup for these two pagers looks like this: <ww:Pager runat="server" id="ItemPager" PageSize="5" PageLinkCssClass="gridpagerbutton" SelectedPageCssClass="gridpagerbutton-selected" PagesTextCssClass="gridpagertext" CssClass="gridpager" RenderContainerDiv="true" ContainerDivCssClass="gridpagercontainer" MaxPagesToDisplay="6" PagesText="Item Pages:" NextText="next" PreviousText="previous" /> <ww:Pager runat="server" id="ItemPager2" PageSize="5" RenderContainerDiv="true" MaxPagesToDisplay="6" /> The latter example uses default style settings so it there’s not much to set. The first example on the other hand explicitly assigns custom styles and overrides a few of the formatting options. Styling The styling is based on a number of CSS classes of which the the main pager, pagerbutton and pagerbutton-selected classes are the important ones. Other styles like pagerbutton-next/prev/first/last are based on the pagerbutton style. The default styling shown for the red outlined pager looks like this: .pagercontainer { margin: 20px 0; background: whitesmoke; padding: 5px; } .pager { float: right; font-size: 10pt; text-align: left; } .pagerbutton,.pagerbutton-selected,.pagertext { display: block; float: left; text-align: center; border: solid 2px maroon; min-width: 18px; margin-left: 3px; text-decoration: none; padding: 4px; } .pagerbutton-selected { font-size: 130%; font-weight: bold; color: maroon; border-width: 0px; background: khaki; } .pagerbutton-first { margin-right: 12px; } .pagerbutton-last,.pagerbutton-prev { margin-left: 12px; } .pagertext { border: none; margin-left: 30px; font-weight: bold; } .pagerbutton a { text-decoration: none; } .pagerbutton:hover { background-color: maroon; color: cornsilk; } .pagerbutton-prev { background-image: url(images/prev.png); background-position: 2px center; background-repeat: no-repeat; width: 35px; padding-left: 20px; } .pagerbutton-next { background-image: url(images/next.png); background-position: 40px center; background-repeat: no-repeat; width: 35px; padding-right: 20px; margin-right: 0px; } Yup that’s a lot of styling settings although not all of them are required. The key ones are pagerbutton, pager and pager selection. The others (which are implicitly created by the control based on the pagerbutton style) are for custom markup of the ‘special’ buttons. In my apps I tend to have two kinds of pages: Those that are associated with typical ‘grid’ displays that display purely tabular data and those that have a more looser list like layout. The two pagers shown above represent these two views and the pager and gridpager styles in my standard style sheet reflect these two styles. Configuring the Pager with Code Finally lets look at what it takes to hook up the pager. As mentioned in the highlights the Pager control is completely independent of other controls so if you just want to display a pager on its own it’s as simple as dropping the control and assigning the PageSize, ActivePage and either TotalPages or TotalItems. So for this markup: <ww:Pager runat="server" id="ItemPagerManual" PageSize="5" MaxPagesToDisplay="6" /> I can use code as simple as: ItemPagerManual.PageSize = 3; ItemPagerManual.ActivePage = 4;ItemPagerManual.TotalItems = 20; Note that ActivePage is not required - it will automatically use any Page=x query string value and assign it, although you can override it as I did above. TotalItems can be any value that you retrieve from a result set or manually assign as I did above. A more realistic scenario based on a LINQ to SQL IQueryable result is even easier. In this example, I have a UserControl that contains a ListView control that renders IQueryable data. I use a User Control here because there are different views the user can choose from with each view being a different user control. This incidentally also highlights one of the nice features of the pager: Because the pager is independent of the control I can put the pager on the host page instead of into each of the user controls. IOW, there’s only one Pager control, but there are potentially many user controls/listviews that hold the actual display data. The following code demonstrates how to use the Pager with an IQueryable that loads only the records it displays: protected voidPage_Load(objectsender, EventArgs e) {     Category = Request.Params["Category"] ?? string.Empty;     IQueryable<wws_Item> ItemList = ItemRepository.GetItemsByCategory(Category);     // Update the page and filter the list down     ItemList = ItemPager.FilterIQueryable<wws_Item>(ItemList); // Render user control with a list view Control ulItemList = LoadControl("~/usercontrols/" + App.Configuration.ItemListType + ".ascx"); ((IInventoryItemListControl)ulItemList).InventoryItemList = ItemList; phItemList.Controls.Add(ulItemList); // placeholder } The code uses a business object to retrieve Items by category as an IQueryable which means that the result is only an expression tree that hasn’t execute SQL yet and can be further filtered. I then pass this IQueryable to the FilterIQueryable() helper method of the control which does two main things: Filters the IQueryable to retrieve only the data displayed on the active page Sets the Totaltems property and calculates TotalPages on the Pager and that’s it! When the Pager renders it uses those values, plus the PageSize and ActivePage properties to render the Pager. In addition to IQueryable there are also filter methods for IEnumerable<T> and DataTable, but these versions just filter the data by removing rows/items from the entire already retrieved data. Output Generated and Paging Links The output generated creates pager links as plain href links. Here’s what the output looks like: <div id="ItemPager" class="pagercontainer"> <div class="pager"> <span class="pagertext">Pages: </span><a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=1" class="pagerbutton" />1</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=2" class="pagerbutton" />2</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=3" class="pagerbutton" />3</a> <span class="pagerbutton-selected">4</span> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=5" class="pagerbutton" />5</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=6" class="pagerbutton" />6</a> <a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=20" class="pagerbutton pagerbutton-last" />20</a>&nbsp;<a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=3" class="pagerbutton pagerbutton-prev" />Prev</a>&nbsp;<a href="http://localhost/WestWindWebStore/itemlist.aspx?Page=5" class="pagerbutton pagerbutton-next" />Next</a></div> <br clear="all" /> </div> </div> The links point back to the current page and simply append a Page= page link into the page. When the page gets reloaded with the new page number the pager automatically detects the page number and automatically assigns the ActivePage property which results in the appropriate page to be displayed. The code shown in the previous section is all that’s needed to handle paging. Note that HTTP GET based paging is different than the Postback paging ASP.NET uses by default. Postback paging preserves modified page content when clicking on pager buttons, but this control will simply load a new page – no page preservation at this time. The advantage of not using Postback paging is that the URLs generated are plain HTML links that a search engine can follow where __doPostback() links are not. Pager with a Grid The pager also works in combination with grid controls so it’s easy to bypass the grid control’s paging features if desired. In the following example I use a gridView control and binds it to a DataTable result which is also filterable by the Pager control. The very basic plain vanilla ASP.NET grid markup looks like this: <div style="width: 600px; margin: 0 auto;padding: 20px; "> <asp:DataGrid runat="server" AutoGenerateColumns="True" ID="gdItems" CssClass="blackborder" style="width: 600px;"> <AlternatingItemStyle CssClass="gridalternate" /> <HeaderStyle CssClass="gridheader" /> </asp:DataGrid> <ww:Pager runat="server" ID="Pager" CssClass="gridpager" ContainerDivCssClass="gridpagercontainer" PageLinkCssClass="gridpagerbutton" SelectedPageCssClass="gridpagerbutton-selected" PageSize="8" RenderContainerDiv="true" MaxPagesToDisplay="6" /> </div> and looks like this when rendered: using custom set of CSS styles. The code behind for this code is also very simple: protected void Page_Load(object sender, EventArgs e) { string category = Request.Params["category"] ?? ""; busItem itemRep = WebStoreFactory.GetItem(); var items = itemRep.GetItemsByCategory(category) .Select(itm => new {Sku = itm.Sku, Description = itm.Description}); // run query into a DataTable for demonstration DataTable dt = itemRep.Converter.ToDataTable(items,"TItems"); // Remove all items not on the current page dt = Pager.FilterDataTable(dt,0); // bind and display gdItems.DataSource = dt; gdItems.DataBind(); } A little contrived I suppose since the list could already be bound from the list of elements, but this is to demonstrate that you can also bind against a DataTable if your business layer returns those. Unfortunately there’s no way to filter a DataReader as it’s a one way forward only reader and the reader is required by the DataSource to perform the bindings.  However, you can still use a DataReader as long as your business logic filters the data prior to rendering and provides a total item count (most likely as a second query). Control Creation The control itself is a pretty brute force ASP.NET control. Nothing clever about this other than some basic rendering logic and some simple calculations and update routines to determine which buttons need to be shown. You can take a look at the full code from the West Wind Web Toolkit’s Repository (note there are a few dependencies). To give you an idea how the control works here is the Render() method: /// <summary> /// overridden to handle custom pager rendering for runtime and design time /// </summary> /// <param name="writer"></param> protected override void Render(HtmlTextWriter writer) { base.Render(writer); if (TotalPages == 0 && TotalItems > 0) TotalPages = CalculateTotalPagesFromTotalItems(); if (DesignMode) TotalPages = 10; // don't render pager if there's only one page if (TotalPages < 2) return; if (RenderContainerDiv) { if (!string.IsNullOrEmpty(ContainerDivCssClass)) writer.AddAttribute("class", ContainerDivCssClass); writer.RenderBeginTag("div"); } // main pager wrapper writer.WriteBeginTag("div"); writer.AddAttribute("id", this.ClientID); if (!string.IsNullOrEmpty(CssClass)) writer.WriteAttribute("class", this.CssClass); writer.Write(HtmlTextWriter.TagRightChar + "\r\n"); // Pages Text writer.WriteBeginTag("span"); if (!string.IsNullOrEmpty(PagesTextCssClass)) writer.WriteAttribute("class", PagesTextCssClass); writer.Write(HtmlTextWriter.TagRightChar); writer.Write(this.PagesText); writer.WriteEndTag("span"); // if the base url is empty use the current URL FixupBaseUrl(); // set _startPage and _endPage ConfigurePagesToRender(); // write out first page link if (ShowFirstAndLastPageLinks && _startPage != 1) { writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, (1).ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-first"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write("1"); writer.WriteEndTag("a"); writer.Write("&nbsp;"); } // write out all the page links for (int i = _startPage; i < _endPage + 1; i++) { if (i == ActivePage) { writer.WriteBeginTag("span"); if (!string.IsNullOrEmpty(SelectedPageCssClass)) writer.WriteAttribute("class", SelectedPageCssClass); writer.Write(HtmlTextWriter.TagRightChar); writer.Write(i.ToString()); writer.WriteEndTag("span"); } else { writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, i.ToString()).TrimEnd('&'); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(i.ToString()); writer.WriteEndTag("a"); } writer.Write("\r\n"); } // write out last page link if (ShowFirstAndLastPageLinks && _endPage < TotalPages) { writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, TotalPages.ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-last"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(TotalPages.ToString()); writer.WriteEndTag("a"); } // Previous link if (ShowPreviousNextLinks && !string.IsNullOrEmpty(PreviousText) && ActivePage > 1) { writer.Write("&nbsp;"); writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, (ActivePage - 1).ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-prev"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(PreviousText); writer.WriteEndTag("a"); } // Next link if (ShowPreviousNextLinks && !string.IsNullOrEmpty(NextText) && ActivePage < TotalPages) { writer.Write("&nbsp;"); writer.WriteBeginTag("a"); string pageUrl = StringUtils.SetUrlEncodedKey(BaseUrl, QueryStringPageField, (ActivePage + 1).ToString()); writer.WriteAttribute("href", pageUrl); if (!string.IsNullOrEmpty(PageLinkCssClass)) writer.WriteAttribute("class", PageLinkCssClass + " " + PageLinkCssClass + "-next"); writer.Write(HtmlTextWriter.SelfClosingTagEnd); writer.Write(NextText); writer.WriteEndTag("a"); } writer.WriteEndTag("div"); if (RenderContainerDiv) { if (RenderContainerDivBreak) writer.Write("<br clear=\"all\" />\r\n"); writer.WriteEndTag("div"); } } As I said pretty much brute force rendering based on the control’s property settings of which there are quite a few: You can also see the pager in the designer above. unfortunately the VS designer (both 2010 and 2008) fails to render the float: left CSS styles properly and starts wrapping after margins are applied in the special buttons. Not a big deal since VS does at least respect the spacing (the floated elements overlay). Then again I’m not using the designer anyway :-}. Filtering Data What makes the Pager easy to use is the filter methods built into the control. While this functionality is clearly not the most politically correct design choice as it violates separation of concerns, it’s very useful for typical pager operation. While I actually have filter methods that do something similar in my business layer, having it exposed on the control makes the control a lot more useful for typical databinding scenarios. Of course these methods are optional – if you have a business layer that can provide filtered page queries for you can use that instead and assign the TotalItems property manually. There are three filter method types available for IQueryable, IEnumerable and for DataTable which tend to be the most common use cases in my apps old and new. The IQueryable version is pretty simple as it can simply rely on on .Skip() and .Take() with LINQ: /// <summary> /// <summary> /// Queries the database for the ActivePage applied manually /// or from the Request["page"] variable. This routine /// figures out and sets TotalPages, ActivePage and /// returns a filtered subset IQueryable that contains /// only the items from the ActivePage. /// </summary> /// <param name="query"></param> /// <param name="activePage"> /// The page you want to display. Sets the ActivePage property when passed. /// Pass 0 or smaller to use ActivePage setting. /// </param> /// <returns></returns> public IQueryable<T> FilterIQueryable<T>(IQueryable<T> query, int activePage) where T : class, new() { ActivePage = activePage < 1 ? ActivePage : activePage; if (ActivePage < 1) ActivePage = 1; TotalItems = query.Count(); if (TotalItems <= PageSize) { ActivePage = 1; TotalPages = 1; return query; } int skip = ActivePage - 1; if (skip > 0) query = query.Skip(skip * PageSize); _TotalPages = CalculateTotalPagesFromTotalItems(); return query.Take(PageSize); } The IEnumerable<T> version simply  converts the IEnumerable to an IQuerable and calls back into this method for filtering. The DataTable version requires a little more work to manually parse and filter records (I didn’t want to add the Linq DataSetExtensions assembly just for this): /// <summary> /// Filters a data table for an ActivePage. /// /// Note: Modifies the data set permanently by remove DataRows /// </summary> /// <param name="dt">Full result DataTable</param> /// <param name="activePage">Page to display. 0 to use ActivePage property </param> /// <returns></returns> public DataTable FilterDataTable(DataTable dt, int activePage) { ActivePage = activePage < 1 ? ActivePage : activePage; if (ActivePage < 1) ActivePage = 1; TotalItems = dt.Rows.Count; if (TotalItems <= PageSize) { ActivePage = 1; TotalPages = 1; return dt; } int skip = ActivePage - 1; if (skip > 0) { for (int i = 0; i < skip * PageSize; i++ ) dt.Rows.RemoveAt(0); } while(dt.Rows.Count > PageSize) dt.Rows.RemoveAt(PageSize); return dt; } Using the Pager Control The pager as it is is a first cut I built a couple of weeks ago and since then have been tweaking a little as part of an internal project I’m working on. I’ve replaced a bunch of pagers on various older pages with this pager without any issues and have what now feels like a more consistent user interface where paging looks and feels the same across different controls. As a bonus I’m only loading the data from the database that I need to display a single page. With the preset class tags applied too adding a pager is now as easy as dropping the control and adding the style sheet for styling to be consistent – no fuss, no muss. Schweet. Hopefully some of you may find this as useful as I have or at least as a baseline to build ontop of… Resources The Pager is part of the West Wind Web & Ajax Toolkit Pager.cs Source Code (some toolkit dependencies) Westwind.css base stylesheet with .pager and .gridpager styles Pager Example Page © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• Building applications with WPF, MVVM and Prism(aka CAG)

  - by skjagini

  In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab).  The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen to engage the cab and roam around and calculating the total fare Metered Rate of Fare The meter is required to be engaged when a cab is occupied by anyone $3.00 upon entry $0.35 for each additional unit The unit fare is: one-fifth of a mile, when the cab is traveling at 6 miles an hour or more; or 60 seconds when not in motion or traveling at less than 12 miles per hour. Night surcharge of $.50 after 8:00 PM & before 6:00 AM Peak hour Weekday Surcharge of $1.00 Monday - Friday after 4:00 PM & before 8:00 PM New York State Tax Surcharge of $.50 per ride. Example: Friday (2010-10-08) 5:30pm Start at Lexington Ave & E 57th St End at Irving Pl & E 15th St Start = $3.00 Travels 2 miles at less than 6 mph for 15 minutes = $3.50 Travels at more than 12 mph for 5 minutes = $1.75 Peak hour Weekday Surcharge = $1.00 (ride started at 5:30 pm) New York State Tax Surcharge = $0.50 Before we dive into the app, I would like to give brief description about the framework.  If you want to jump on to the source code, scroll all the way to the end of the post. MVVM MVVM pattern is in no way related to the usage of PRISM in your application and should be considered if you are using WPF irrespective of PRISM or not. Lets say you are not familiar with MVVM, your typical UI would involve adding some UI controls like text boxes, a button, double clicking on the button,  generating event handler, calling a method from business layer and updating the user interface, it works most of the time for developing small scale applications. The problem with this approach is that there is some amount of code specific to business logic wrapped in UI specific code which is hard to unit test it, mock it and MVVM helps to solve the exact problem. MVVM stands for Model(M) – View(V) – ViewModel(VM),  based on the interactions with in the three parties it should be called VVMM,  MVVM sounds more like MVC (Model-View-Controller) so the name. Why it should be called VVMM: View – View Model - Model WPF allows to create user interfaces using XAML and MVVM takes it to the next level by allowing complete separation of user interface and business logic. In WPF each view will have a property, DataContext when set to an instance of a class (which happens to be your view model) provides the data the view is interested in, i.e., view interacts with view model and at the same time view model interacts with view through DataContext. Sujith, if view and view model are interacting directly with each other how does MVVM is helping me separation of concerns? Well, the catch is DataContext is of type Object, since it is of type object view doesn’t know exact type of view model allowing views and views models to be loosely coupled. View models aggregate data from models (data access layer, services, etc) and make it available for views through properties, methods etc, i.e., View Models interact with Models. PRISM Prism is provided by Microsoft Patterns and Practices team and it can be downloaded from codeplex for source code,  samples and documentation on msdn.  The name composite implies, to compose user interface from different modules (views) without direct dependencies on each other, again allowing  loosely coupled development. Well Sujith, I can already do that with user controls, why shall I learn another framework?  That’s correct, you can decouple using user controls, but you still have to manage some amount of coupling, like how to do you communicate between the controls, how do you subscribe/unsubscribe, loading/unloading views dynamically. Prism is not a replacement for user controls, provides the following features which greatly help in designing the composite applications. Dependency Injection (DI)/ Inversion of Control (IoC) Modules Regions Event Aggregator  Commands Simply put, MVVM helps building a single view and Prism helps building an application using the views There are other open source alternatives to Prism, like MVVMLight, Cinch, take a look at them as well. Lets dig into the source code.  1. Solution The solution is made of the following projects Framework: Holds the common functionality in building applications using WPF and Prism TaxiClient: Start up project, boot strapping and app styling TaxiCommon: Helps with the business logic TaxiModules: Holds the meat of the application with views and view models TaxiTests: To test the application 2. DI / IoC Dependency Injection (DI) as the name implies refers to injecting dependencies and Inversion of Control (IoC) means the calling code has no direct control on the dependencies, opposite of normal way of programming where dependencies are passed by caller, i.e inversion; aside from some differences in terminology the concept is same in both the cases. The idea behind DI/IoC pattern is to reduce the amount of direct coupling between different components of the application, the higher the dependency the more tightly coupled the application resulting in code which is hard to modify, unit test and mock.  Initializing Dependency Injection through BootStrapper TaxiClient is the starting project of the solution and App (App.xaml)  is the starting class that gets called when you run the application. From the App’s OnStartup method we will invoke BootStrapper.   namespace TaxiClient { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e);   (new BootStrapper()).Run(); } } } BootStrapper is your contact point for initializing the application including dependency injection, creating Shell and other frameworks. We are going to use Unity for DI and there are lot of open source DI frameworks like Spring.Net, StructureMap etc with different feature set  and you can choose a framework based on your preferences. Note that Prism comes with in built support for Unity, for example we are deriving from UnityBootStrapper in our case and for any other DI framework you have to extend the Prism appropriately   namespace TaxiClient { public class BootStrapper: UnityBootstrapper { protected override IModuleCatalog CreateModuleCatalog() { return new ConfigurationModuleCatalog(); } protected override DependencyObject CreateShell() { Framework.FrameworkBootStrapper.Run(Container, Application.Current.Dispatcher);   Shell shell = new Shell(); shell.ResizeMode = ResizeMode.NoResize; shell.Show();   return shell; } } } Lets take a look into  FrameworkBootStrapper to check out how to register with unity container. namespace Framework { public class FrameworkBootStrapper { public static void Run(IUnityContainer container, Dispatcher dispatcher) { UIDispatcher uiDispatcher = new UIDispatcher(dispatcher); container.RegisterInstance<IDispatcherService>(uiDispatcher);   container.RegisterType<IInjectSingleViewService, InjectSingleViewService>( new ContainerControlledLifetimeManager());   . . . } } } In the above code we are registering two components with unity container. You shall observe that we are following two different approaches, RegisterInstance and RegisterType.  With RegisterInstance we are registering an existing instance and the same instance will be returned for every request made for IDispatcherService   and with RegisterType we are requesting unity container to create an instance for us when required, i.e., when I request for an instance for IInjectSingleViewService, unity will create/return an instance of InjectSingleViewService class and with RegisterType we can configure the life time of the instance being created. With ContaienrControllerLifetimeManager, the unity container caches the instance and reuses for any subsequent requests, without recreating a new instance. Lets take a look into FareViewModel.cs and it’s constructor. The constructor takes one parameter IEventAggregator and if you try to find all references in your solution for IEventAggregator, you will not find a single location where an instance of EventAggregator is passed directly to the constructor. The compiler still finds an instance and works fine because Prism is already configured when used with Unity container to return an instance of EventAggregator when requested for IEventAggregator and in this particular case it is called constructor injection. public class FareViewModel:ObservableBase, IDataErrorInfo { ... private IEventAggregator _eventAggregator;   public FareViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; InitializePropertyNames(); InitializeModel(); PropertyChanged += OnPropertyChanged; } ... 3. Shell Shells are very similar in operation to Master Pages in asp.net or MDI in Windows Forms. And shells contain regions which display the views, you can have as many regions as you wish in a given view. You can also nest regions. i.e, one region can load a view which in itself may contain other regions. We have to create a shell at the start of the application and are doing it by overriding CreateShell method from BootStrapper From the following Shell.xaml you shall notice that we have two content controls with Region names as ‘MenuRegion’ and ‘MainRegion’.  The idea here is that you can inject any user controls into the regions dynamically, i.e., a Menu User Control for MenuRegion and based on the user action you can load appropriate view into MainRegion.    <Window x:Class="TaxiClient.Shell" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Regions="clr-namespace:Microsoft.Practices.Prism.Regions;assembly=Microsoft.Practices.Prism" Title="Taxi" Height="370" Width="800"> <Grid Margin="2"> <ContentControl Regions:RegionManager.RegionName="MenuRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" />   <ContentControl Grid.Row="1" Regions:RegionManager.RegionName="MainRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" /> <!--<Border Grid.ColumnSpan="2" BorderThickness="2" CornerRadius="3" BorderBrush="LightBlue" />-->   </Grid> </Window> 4. Modules Prism provides the ability to build composite applications and modules play an important role in it. For example if you are building a Mortgage Loan Processor application with 3 components, i.e. customer’s credit history,  existing mortgages, new home/loan information; and consider that the customer’s credit history component involves gathering data about his/her address, background information, job details etc. The idea here using Prism modules is to separate the implementation of these 3 components into their own visual studio projects allowing to build components with no dependency on each other and independently. If we need to add another component to the application, the component can be developed by in house team or some other team in the organization by starting with a new Visual Studio project and adding to the solution at the run time with very little knowledge about the application. Prism modules are defined by implementing the IModule interface and each visual studio project to be considered as a module should implement the IModule interface.  From the BootStrapper.cs you shall observe that we are overriding the method by returning a ConfiguratingModuleCatalog which returns the modules that are registered for the application using the app.config file  and you can also add module using code. Lets take a look into configuration file.   <?xml version="1.0"?> <configuration> <configSections> <section name="modules" type="Microsoft.Practices.Prism.Modularity.ModulesConfigurationSection, Microsoft.Practices.Prism"/> </configSections> <modules> <module assemblyFile="TaxiModules.dll" moduleType="TaxiModules.ModuleInitializer, TaxiModules" moduleName="TaxiModules"/> </modules> </configuration> Here we are adding TaxiModules project to our solution and TaxiModules.ModuleInitializer implements IModule interface   5. Module Mapper With Prism modules you can dynamically add or remove modules from the regions, apart from that Prism also provides API to control adding/removing the views from a region within the same module. Taxi Information Screen: Engage the Taxi Screen: The sample application has two screens, ‘Taxi Information’ and ‘Engage the Taxi’ and they both reside in same module, TaxiModules. ‘Engage the Taxi’ is again made of two user controls, FareView on the left and TotalView on the right. We have created a Shell with two regions, MenuRegion and MainRegion with menu loaded into MenuRegion. We can create a wrapper user control called EngageTheTaxi made of FareView and TotalView and load either TaxiInfo or EngageTheTaxi into MainRegion based on the user action. Though it will work it tightly binds the user controls and for every combination of user controls, we need to create a dummy wrapper control to contain them. Instead we can apply the principles we learned so far from Shell/regions and introduce another template (LeftAndRightRegionView.xaml) made of two regions Region1 (left) and Region2 (right) and load  FareView and TotalView dynamically.  To help with loading of the views dynamically I have introduce an helper an interface, IInjectSingleViewService,  idea suggested by Mike Taulty, a must read blog for .Net developers. using System; using System.Collections.Generic; using System.ComponentModel;   namespace Framework.PresentationUtility.Navigation {   public interface IInjectSingleViewService : INotifyPropertyChanged { IEnumerable<CommandViewDefinition> Commands { get; } IEnumerable<ModuleViewDefinition> Modules { get; }   void RegisterViewForRegion(string commandName, string viewName, string regionName, Type viewType); void ClearViewFromRegion(string viewName, string regionName); void RegisterModule(string moduleName, IList<ModuleMapper> moduleMappers); } } The Interface declares three methods to work with views: RegisterViewForRegion: Registers a view with a particular region. You can register multiple views and their regions under one command.  When this particular command is invoked all the views registered under it will be loaded into their regions. ClearViewFromRegion: To unload a specific view from a region. RegisterModule: The idea is when a command is invoked you can load the UI with set of controls in their default position and based on the user interaction, you can load different contols in to different regions on the fly.  And it is supported ModuleViewDefinition and ModuleMappers as shown below. namespace Framework.PresentationUtility.Navigation { public class ModuleViewDefinition { public string ModuleName { get; set; } public IList<ModuleMapper> ModuleMappers; public ICommand Command { get; set; } }   public class ModuleMapper { public string ViewName { get; set; } public string RegionName { get; set; } public Type ViewType { get; set; } } } 6. Event Aggregator Prism event aggregator enables messaging between components as in Observable pattern, Notifier notifies the Observer which receives notification it is interested in. When it comes to Observable pattern, Observer has to unsubscribes for notifications when it no longer interested in notifications, which allows the Notifier to remove the Observer’s reference from it’s local cache. Though .Net has managed garbage collection it cannot remove inactive the instances referenced by an active instance resulting in memory leak, keeping the Observers in memory as long as Notifier stays in memory.  Developers have to be very careful to unsubscribe when necessary and it often gets overlooked, to overcome these problems Prism Event Aggregator uses weak references to cache the reference (Observer in this case)  and releases the reference (memory) once the instance goes out of scope. Using event aggregator is very simple, declare a generic type of CompositePresenationEvent by inheriting from it. using Microsoft.Practices.Prism.Events; using TaxiCommon.BAO;   namespace TaxiCommon.CompositeEvents { public class TaxiOnMoveEvent:CompositePresentationEvent<TaxiOnMove> { } }   TaxiOnMove.cs includes the properties which we want to exchange between the parties, FareView and TotalView. using System;   namespace TaxiCommon.BAO { public class TaxiOnMove { public TimeSpan MinutesAtTweleveMPH { get; set; } public double MilesAtSixMPH { get; set; } } }   Lets take a look into FareViewodel (Notifier) and how it raises the event.  Here we are raising the event by getting the event through GetEvent<..>() and publishing it with the payload private void OnAddMinutes(object obj) { TaxiOnMove payload = new TaxiOnMove(); if(MilesAtSixMPH != null) payload.MilesAtSixMPH = MilesAtSixMPH.Value; if(MinutesAtTweleveMPH != null) payload.MinutesAtTweleveMPH = new TimeSpan(0,0,MinutesAtTweleveMPH.Value,0);   _eventAggregator.GetEvent<TaxiOnMoveEvent>().Publish(payload); ResetMinutesAndMiles(); } And TotalViewModel(Observer) subscribes to notifications by getting the event through GetEvent<..>() namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { .... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; ... }   private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>() .Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>() .Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>() .Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   ... private void OnTaxiMove(TaxiOnMove taxiOnMove) { OnMoveFare fare = new OnMoveFare(taxiOnMove); Fares.Add(fare); SetTotalFare(new []{fare}); }   .... 7. MVVM through example In this section we are going to look into MVVM implementation through example.  I have all the modules declared in a single project, TaxiModules, again it is not necessary to have them into one project. Once the user logs into the application, will be greeted with the ‘Engage the Taxi’ screen which is made of two user controls, FareView.xaml and TotalView.Xaml. As you can see from the solution explorer, each of them have their own code behind files and  ViewModel classes, FareViewMode.cs, TotalViewModel.cs Lets take a look in to the FareView and how it interacts with FareViewModel using MVVM implementation. FareView.xaml acts as a view and FareViewMode.cs is it’s view model. The FareView code behind class   namespace TaxiModules.Views { /// <summary> /// Interaction logic for FareView.xaml /// </summary> public partial class FareView : UserControl { public FareView(FareViewModel viewModel) { InitializeComponent(); this.Loaded += (s, e) => { this.DataContext = viewModel; }; } } } The FareView is bound to FareViewModel through the data context  and you shall observe that DataContext is of type Object, i.e. the FareView doesn’t really know the type of ViewModel (FareViewModel). This helps separation of View and ViewModel as View and ViewModel are independent of each other, you can bind FareView to FareViewModel2 as well and the application compiles just fine. Lets take a look into FareView xaml file  <UserControl x:Class="TaxiModules.Views.FareView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Toolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" xmlns:Commands="clr-namespace:Microsoft.Practices.Prism.Commands;assembly=Microsoft.Practices.Prism"> <Grid Margin="10" > ....   <Border Style="{DynamicResource innerBorder}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="11" Grid.ColumnSpan="2" Panel.ZIndex="1"/>   <Label Grid.Row="0" Content="Engage the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="1" Content="Select the State"/> <ComboBox Grid.Row="1" Grid.Column="1" ItemsSource="{Binding States}" Height="auto"> <ComboBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Name}"/> </DataTemplate> </ComboBox.ItemTemplate> <ComboBox.SelectedItem> <Binding Path="SelectedState" Mode="TwoWay"/> </ComboBox.SelectedItem> </ComboBox> <Label Grid.Row="2" Content="Select the Date of Entry"/> <Toolkit:DatePicker Grid.Row="2" Grid.Column="1" SelectedDate="{Binding DateOfEntry, ValidatesOnDataErrors=true}" /> <Label Grid.Row="3" Content="Enter time 24hr format"/> <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding TimeOfEntry, TargetNullValue=''}"/> <Button Grid.Row="4" Grid.Column="1" Content="Start the Meter" Commands:Click.Command="{Binding StartMeterCommand}" />   <Label Grid.Row="5" Content="Run the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="6" Content="Number of Miles &lt;@6mph"/> <TextBox Grid.Row="6" Grid.Column="1" Text="{Binding MilesAtSixMPH, TargetNullValue='', ValidatesOnDataErrors=true}"/> <Label Grid.Row="7" Content="Number of Minutes @12mph"/> <TextBox Grid.Row="7" Grid.Column="1" Text="{Binding MinutesAtTweleveMPH, TargetNullValue=''}"/> <Button Grid.Row="8" Grid.Column="1" Content="Add Minutes and Miles " Commands:Click.Command="{Binding AddMinutesCommand}"/> <Label Grid.Row="9" Content="Other Operations" Style="{DynamicResource innerHeader}"/> <Button Grid.Row="10" Grid.Column="1" Content="Reset the Meter" Commands:Click.Command="{Binding ResetCommand}"/>   </Grid> </UserControl> The highlighted code from the above code shows data binding, for example ComboBox which displays list of states has it’s ItemsSource bound to States property, with DataTemplate bound to Name and SelectedItem  to SelectedState. You might be wondering what are all these properties and how it is able to bind to them.  The answer lies in data context, i.e., when you bound a control, WPF looks for data context on the root object (Grid in this case) and if it can’t find data context it will look into root’s root, i.e. FareView UserControl and it is bound to FareViewModel.  Each of those properties have be declared on the ViewModel for the View to bind correctly. To put simply, View is bound to ViewModel through data context of type object and every control that is bound on the View actually binds to the public property on the ViewModel. Lets look into the ViewModel code (the following code is not an exact copy of FareViewMode.cs, pasted relevant code for this section)   namespace TaxiModules.ViewModels { public class FareViewModel:ObservableBase, IDataErrorInfo { public List<USState> States { get { return USStates.StateList; } }   public USState SelectedState { get { return _selectedState; } set { _selectedState = value; RaisePropertyChanged(_selectedStatePropertyName); } }   public DateTime? DateOfEntry { get { return _dateOfEntry; } set { _dateOfEntry = value; RaisePropertyChanged(_dateOfEntryPropertyName); } }   public TimeSpan? TimeOfEntry { get { return _timeOfEntry; } set { _timeOfEntry = value; RaisePropertyChanged(_timeOfEntryPropertyName); } }   public double? MilesAtSixMPH { get { return _milesAtSixMPH; } set { _milesAtSixMPH = value; RaisePropertyChanged(_distanceAtSixMPHPropertyName); } }   public int? MinutesAtTweleveMPH { get { return _minutesAtTweleveMPH; } set { _minutesAtTweleveMPH = value; RaisePropertyChanged(_minutesAtTweleveMPHPropertyName); } }   public ICommand StartMeterCommand { get { if(_startMeterCommand == null) { _startMeterCommand = new DelegateCommand<object>(OnStartMeter, CanStartMeter); } return _startMeterCommand; } }   public ICommand AddMinutesCommand { get { if(_addMinutesCommand == null) { _addMinutesCommand = new DelegateCommand<object>(OnAddMinutes, CanAddMinutes); } return _addMinutesCommand; } }   public ICommand ResetCommand { get { if(_resetCommand == null) { _resetCommand = new DelegateCommand<object>(OnResetCommand); } return _resetCommand; } }   } private void OnStartMeter(object obj) { _eventAggregator.GetEvent<TaxiStartedEvent>().Publish( new TaxiStarted() { EngagedOn = DateOfEntry.Value.Date + TimeOfEntry.Value, EngagedState = SelectedState.Value });   _isMeterStarted = true; OnPropertyChanged(this,null); } And views communicate user actions like button clicks, tree view item selections, etc using commands. When user clicks on ‘Start the Meter’ button it invokes the method StartMeterCommand, which calls the method OnStartMeter which publishes the event to TotalViewModel using event aggregator  and TaxiStartedEvent. namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { ... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator;   InitializePropertyNames(); InitializeModel(); SubscribeToEvents(); }   public decimal? TotalFare { get { return _totalFare; } set { _totalFare = value; RaisePropertyChanged(_totalFarePropertyName); } } .... private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>().Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>().Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>().Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   private void OnTaxiStarted(TaxiStarted taxiStarted) { Fares.Add(new EntryFare()); Fares.Add(new StateTaxFare(taxiStarted)); Fares.Add(new NightSurchargeFare(taxiStarted)); Fares.Add(new PeakHourWeekdayFare(taxiStarted));   SetTotalFare(Fares); }   private void SetTotalFare(IEnumerable<IFare> fares) { TotalFare = (_totalFare ?? 0) + TaxiFareHelper.GetTotalFare(fares); } ....   } }   TotalViewModel subscribes to events, TaxiStartedEvent and rest. When TaxiStartedEvent gets invoked it calls the OnTaxiStarted method which sets the total fare which includes entry fee, state tax, nightly surcharge, peak hour weekday fare.   Note that TotalViewModel derives from ObservableBase which implements the method RaisePropertyChanged which we are invoking in Set of TotalFare property, i.e, once we update the TotalFare property it raises an the event that  allows the TotalFare text box to fetch the new value through the data context. ViewModel is communicating with View through data context and it has no knowledge about View, helping in loose coupling of ViewModel and View.   I have attached the source code (.Net 4.0, Prism 4.0, VS 2010) , download and play with it and don’t forget to leave your comments.  

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• An Introduction to ASP.NET Web API

  - by Rick Strahl

  Microsoft recently released ASP.NET MVC 4.0 and .NET 4.5 and along with it, the brand spanking new ASP.NET Web API. Web API is an exciting new addition to the ASP.NET stack that provides a new, well-designed HTTP framework for creating REST and AJAX APIs (API is Microsoft’s new jargon for a service, in case you’re wondering). Although Web API ships and installs with ASP.NET MVC 4, you can use Web API functionality in any ASP.NET project, including WebForms, WebPages and MVC or just a Web API by itself. And you can also self-host Web API in your own applications from Console, Desktop or Service applications. If you're interested in a high level overview on what ASP.NET Web API is and how it fits into the ASP.NET stack you can check out my previous post: Where does ASP.NET Web API fit? In the following article, I'll focus on a practical, by example introduction to ASP.NET Web API. All the code discussed in this article is available in GitHub: https://github.com/RickStrahl/AspNetWebApiArticle [republished from my Code Magazine Article and updated for RTM release of ASP.NET Web API] Getting Started To start I’ll create a new empty ASP.NET application to demonstrate that Web API can work with any kind of ASP.NET project. Although you can create a new project based on the ASP.NET MVC/Web API template to quickly get up and running, I’ll take you through the manual setup process, because one common use case is to add Web API functionality to an existing ASP.NET application. This process describes the steps needed to hook up Web API to any ASP.NET 4.0 application. Start by creating an ASP.NET Empty Project. Then create a new folder in the project called Controllers. Add a Web API Controller Class Once you have any kind of ASP.NET project open, you can add a Web API Controller class to it. Web API Controllers are very similar to MVC Controller classes, but they work in any kind of project. Add a new item to this folder by using the Add New Item option in Visual Studio and choose Web API Controller Class, as shown in Figure 1. Figure 1: This is how you create a new Controller Class in Visual Studio   Make sure that the name of the controller class includes Controller at the end of it, which is required in order for Web API routing to find it. Here, the name for the class is AlbumApiController. For this example, I’ll use a Music Album model to demonstrate basic behavior of Web API. The model consists of albums and related songs where an album has properties like Name, Artist and YearReleased and a list of songs with a SongName and SongLength as well as an AlbumId that links it to the album. You can find the code for the model (and the rest of these samples) on Github. To add the file manually, create a new folder called Model, and add a new class Album.cs and copy the code into it. There’s a static AlbumData class with a static CreateSampleAlbumData() method that creates a short list of albums on a static .Current that I’ll use for the examples. Before we look at what goes into the controller class though, let’s hook up routing so we can access this new controller. Hooking up Routing in Global.asax To start, I need to perform the one required configuration task in order for Web API to work: I need to configure routing to the controller. Like MVC, Web API uses routing to provide clean, extension-less URLs to controller methods. Using an extension method to ASP.NET’s static RouteTable class, you can use the MapHttpRoute() (in the System.Web.Http namespace) method to hook-up the routing during Application_Start in global.asax.cs shown in Listing 1.using System; using System.Web.Routing; using System.Web.Http; namespace AspNetWebApi { public class Global : System.Web.HttpApplication { protected void Application_Start(object sender, EventArgs e) { RouteTable.Routes.MapHttpRoute( name: "AlbumVerbs", routeTemplate: "albums/{title}", defaults: new { symbol = RouteParameter.Optional, controller="AlbumApi" } ); } } } This route configures Web API to direct URLs that start with an albums folder to the AlbumApiController class. Routing in ASP.NET is used to create extensionless URLs and allows you to map segments of the URL to specific Route Value parameters. A route parameter, with a name inside curly brackets like {name}, is mapped to parameters on the controller methods. Route parameters can be optional, and there are two special route parameters – controller and action – that determine the controller to call and the method to activate respectively. HTTP Verb Routing Routing in Web API can route requests by HTTP Verb in addition to standard {controller},{action} routing. For the first examples, I use HTTP Verb routing, as shown Listing 1. Notice that the route I’ve defined does not include an {action} route value or action value in the defaults. Rather, Web API can use the HTTP Verb in this route to determine the method to call the controller, and a GET request maps to any method that starts with Get. So methods called Get() or GetAlbums() are matched by a GET request and a POST request maps to a Post() or PostAlbum(). Web API matches a method by name and parameter signature to match a route, query string or POST values. In lieu of the method name, the [HttpGet,HttpPost,HttpPut,HttpDelete, etc] attributes can also be used to designate the accepted verbs explicitly if you don’t want to follow the verb naming conventions. Although HTTP Verb routing is a good practice for REST style resource APIs, it’s not required and you can still use more traditional routes with an explicit {action} route parameter. When {action} is supplied, the HTTP verb routing is ignored. I’ll talk more about alternate routes later. When you’re finished with initial creation of files, your project should look like Figure 2.   Figure 2: The initial project has the new API Controller Album model   Creating a small Album Model Now it’s time to create some controller methods to serve data. For these examples, I’ll use a very simple Album and Songs model to play with, as shown in Listing 2. public class Song { public string AlbumId { get; set; } [Required, StringLength(80)] public string SongName { get; set; } [StringLength(5)] public string SongLength { get; set; } } public class Album { public string Id { get; set; } [Required, StringLength(80)] public string AlbumName { get; set; } [StringLength(80)] public string Artist { get; set; } public int YearReleased { get; set; } public DateTime Entered { get; set; } [StringLength(150)] public string AlbumImageUrl { get; set; } [StringLength(200)] public string AmazonUrl { get; set; } public virtual List<Song> Songs { get; set; } public Album() { Songs = new List<Song>(); Entered = DateTime.Now; // Poor man's unique Id off GUID hash Id = Guid.NewGuid().GetHashCode().ToString("x"); } public void AddSong(string songName, string songLength = null) { this.Songs.Add(new Song() { AlbumId = this.Id, SongName = songName, SongLength = songLength }); } } Once the model has been created, I also added an AlbumData class that generates some static data in memory that is loaded onto a static .Current member. The signature of this class looks like this and that's what I'll access to retrieve the base data:public static class AlbumData { // sample data - static list public static List<Album> Current = CreateSampleAlbumData(); /// <summary> /// Create some sample data /// </summary> /// <returns></returns> public static List<Album> CreateSampleAlbumData() { … }} You can check out the full code for the data generation online. Creating an AlbumApiController Web API shares many concepts of ASP.NET MVC, and the implementation of your API logic is done by implementing a subclass of the System.Web.Http.ApiController class. Each public method in the implemented controller is a potential endpoint for the HTTP API, as long as a matching route can be found to invoke it. The class name you create should end in Controller, which is how Web API matches the controller route value to figure out which class to invoke. Inside the controller you can implement methods that take standard .NET input parameters and return .NET values as results. Web API’s binding tries to match POST data, route values, form values or query string values to your parameters. Because the controller is configured for HTTP Verb based routing (no {action} parameter in the route), any methods that start with Getxxxx() are called by an HTTP GET operation. You can have multiple methods that match each HTTP Verb as long as the parameter signatures are different and can be matched by Web API. In Listing 3, I create an AlbumApiController with two methods to retrieve a list of albums and a single album by its title .public class AlbumApiController : ApiController { public IEnumerable<Album> GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); return albums; } public Album GetAlbum(string title) { var album = AlbumData.Current .SingleOrDefault(alb => alb.AlbumName.Contains(title)); return album; }} To access the first two requests, you can use the following URLs in your browser: http://localhost/aspnetWebApi/albumshttp://localhost/aspnetWebApi/albums/Dirty%20Deeds Note that you’re not specifying the actions of GetAlbum or GetAlbums in these URLs. Instead Web API’s routing uses HTTP GET verb to route to these methods that start with Getxxx() with the first mapping to the parameterless GetAlbums() method and the latter to the GetAlbum(title) method that receives the title parameter mapped as optional in the route. Content Negotiation When you access any of the URLs above from a browser, you get either an XML or JSON result returned back. The album list result for Chrome 17 and Internet Explorer 9 is shown Figure 3. Figure 3: Web API responses can vary depending on the browser used, demonstrating Content Negotiation in action as these two browsers send different HTTP Accept headers.   Notice that the results are not the same: Chrome returns an XML response and IE9 returns a JSON response. Whoa, what’s going on here? Shouldn’t we see the same result in both browsers? Actually, no. Web API determines what type of content to return based on Accept headers. HTTP clients, like browsers, use Accept headers to specify what kind of content they’d like to see returned. Browsers generally ask for HTML first, followed by a few additional content types. Chrome (and most other major browsers) ask for: Accept: text/html, application/xhtml+xml,application/xml; q=0.9,*/*;q=0.8 IE9 asks for: Accept: text/html, application/xhtml+xml, */* Note that Chrome’s Accept header includes application/xml, which Web API finds in its list of supported media types and returns an XML response. IE9 does not include an Accept header type that works on Web API by default, and so it returns the default format, which is JSON. This is an important and very useful feature that was missing from any previous Microsoft REST tools: Web API automatically switches output formats based on HTTP Accept headers. Nowhere in the server code above do you have to explicitly specify the output format. Rather, Web API determines what format the client is requesting based on the Accept headers and automatically returns the result based on the available formatters. This means that a single method can handle both XML and JSON results.. Using this simple approach makes it very easy to create a single controller method that can return JSON, XML, ATOM or even OData feeds by providing the appropriate Accept header from the client. By default you don’t have to worry about the output format in your code. Note that you can still specify an explicit output format if you choose, either globally by overriding the installed formatters, or individually by returning a lower level HttpResponseMessage instance and setting the formatter explicitly. More on that in a minute. Along the same lines, any content sent to the server via POST/PUT is parsed by Web API based on the HTTP Content-type of the data sent. The same formats allowed for output are also allowed on input. Again, you don’t have to do anything in your code – Web API automatically performs the deserialization from the content. Accessing Web API JSON Data with jQuery A very common scenario for Web API endpoints is to retrieve data for AJAX calls from the Web browser. Because JSON is the default format for Web API, it’s easy to access data from the server using jQuery and its getJSON() method. This example receives the albums array from GetAlbums() and databinds it into the page using knockout.js.$.getJSON("albums/", function (albums) { // make knockout template visible $(".album").show(); // create view object and attach array var view = { albums: albums }; ko.applyBindings(view); }); Figure 4 shows this and the next example’s HTML output. You can check out the complete HTML and script code at http://goo.gl/Ix33C (.html) and http://goo.gl/tETlg (.js). Figu Figure 4: The Album Display sample uses JSON data loaded from Web API.   The result from the getJSON() call is a JavaScript object of the server result, which comes back as a JavaScript array. In the code, I use knockout.js to bind this array into the UI, which as you can see, requires very little code, instead using knockout’s data-bind attributes to bind server data to the UI. Of course, this is just one way to use the data – it’s entirely up to you to decide what to do with the data in your client code. Along the same lines, I can retrieve a single album to display when the user clicks on an album. The response returns the album information and a child array with all the songs. The code to do this is very similar to the last example where we pulled the albums array:$(".albumlink").live("click", function () { var id = $(this).data("id"); // title $.getJSON("albums/" + id, function (album) { ko.applyBindings(album, $("#divAlbumDialog")[0]); $("#divAlbumDialog").show(); }); }); Here the URL looks like this: /albums/Dirty%20Deeds, where the title is the ID captured from the clicked element’s data ID attribute. Explicitly Overriding Output Format When Web API automatically converts output using content negotiation, it does so by matching Accept header media types to the GlobalConfiguration.Configuration.Formatters and the SupportedMediaTypes of each individual formatter. You can add and remove formatters to globally affect what formats are available and it’s easy to create and plug in custom formatters.The example project includes a JSONP formatter that can be plugged in to provide JSONP support for requests that have a callback= querystring parameter. Adding, removing or replacing formatters is a global option you can use to manipulate content. It’s beyond the scope of this introduction to show how it works, but you can review the sample code or check out my blog entry on the subject (http://goo.gl/UAzaR). If automatic processing is not desirable in a particular Controller method, you can override the response output explicitly by returning an HttpResponseMessage instance. HttpResponseMessage is similar to ActionResult in ASP.NET MVC in that it’s a common way to return an abstract result message that contains content. HttpResponseMessage s parsed by the Web API framework using standard interfaces to retrieve the response data, status code, headers and so on[MS2] . Web API turns every response – including those Controller methods that return static results – into HttpResponseMessage instances. Explicitly returning an HttpResponseMessage instance gives you full control over the output and lets you mostly bypass WebAPI’s post-processing of the HTTP response on your behalf. HttpResponseMessage allows you to customize the response in great detail. Web API’s attention to detail in the HTTP spec really shows; many HTTP options are exposed as properties and enumerations with detailed IntelliSense comments. Even if you’re new to building REST-based interfaces, the API guides you in the right direction for returning valid responses and response codes. For example, assume that I always want to return JSON from the GetAlbums() controller method and ignore the default media type content negotiation. To do this, I can adjust the output format and headers as shown in Listing 4.public HttpResponseMessage GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); // Create a new HttpResponse with Json Formatter explicitly var resp = new HttpResponseMessage(HttpStatusCode.OK); resp.Content = new ObjectContent<IEnumerable<Album>>( albums, new JsonMediaTypeFormatter()); // Get Default Formatter based on Content Negotiation //var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); resp.Headers.ConnectionClose = true; resp.Headers.CacheControl = new CacheControlHeaderValue(); resp.Headers.CacheControl.Public = true; return resp; } This example returns the same IEnumerable<Album> value, but it wraps the response into an HttpResponseMessage so you can control the entire HTTP message result including the headers, formatter and status code. In Listing 4, I explicitly specify the formatter using the JsonMediaTypeFormatter to always force the content to JSON.  If you prefer to use the default content negotiation with HttpResponseMessage results, you can create the Response instance using the Request.CreateResponse method:var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); This provides you an HttpResponse object that's pre-configured with the default formatter based on Content Negotiation. Once you have an HttpResponse object you can easily control most HTTP aspects on this object. What's sweet here is that there are many more detailed properties on HttpResponse than the core ASP.NET Response object, with most options being explicitly configurable with enumerations that make it easy to pick the right headers and response codes from a list of valid codes. It makes HTTP features available much more discoverable even for non-hardcore REST/HTTP geeks. Non-Serialized Results The output returned doesn’t have to be a serialized value but can also be raw data, like strings, binary data or streams. You can use the HttpResponseMessage.Content object to set a number of common Content classes. Listing 5 shows how to return a binary image using the ByteArrayContent class from a Controller method. [HttpGet] public HttpResponseMessage AlbumArt(string title) { var album = AlbumData.Current.FirstOrDefault(abl => abl.AlbumName.StartsWith(title)); if (album == null) { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found")); return resp; } // kinda silly - we would normally serve this directly // but hey - it's a demo. var http = new WebClient(); var imageData = http.DownloadData(album.AlbumImageUrl); // create response and return var result = new HttpResponseMessage(HttpStatusCode.OK); result.Content = new ByteArrayContent(imageData); result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg"); return result; } The image retrieval from Amazon is contrived, but it shows how to return binary data using ByteArrayContent. It also demonstrates that you can easily return multiple types of content from a single controller method, which is actually quite common. If an error occurs - such as a resource can’t be found or a validation error – you can return an error response to the client that’s very specific to the error. In GetAlbumArt(), if the album can’t be found, we want to return a 404 Not Found status (and realistically no error, as it’s an image). Note that if you are not using HTTP Verb-based routing or not accessing a method that starts with Get/Post etc., you have to specify one or more HTTP Verb attributes on the method explicitly. Here, I used the [HttpGet] attribute to serve the image. Another option to handle the error could be to return a fixed placeholder image if no album could be matched or the album doesn’t have an image. When returning an error code, you can also return a strongly typed response to the client. For example, you can set the 404 status code and also return a custom error object (ApiMessageError is a class I defined) like this:return Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found") );   If the album can be found, the image will be returned. The image is downloaded into a byte[] array, and then assigned to the result’s Content property. I created a new ByteArrayContent instance and assigned the image’s bytes and the content type so that it displays properly in the browser. There are other content classes available: StringContent, StreamContent, ByteArrayContent, MultipartContent, and ObjectContent are at your disposal to return just about any kind of content. You can create your own Content classes if you frequently return custom types and handle the default formatter assignments that should be used to send the data out . Although HttpResponseMessage results require more code than returning a plain .NET value from a method, it allows much more control over the actual HTTP processing than automatic processing. It also makes it much easier to test your controller methods as you get a response object that you can check for specific status codes and output messages rather than just a result value. Routing Again Ok, let’s get back to the image example. Using the original routing we have setup using HTTP Verb routing there's no good way to serve the image. In order to return my album art image I’d like to use a URL like this: http://localhost/aspnetWebApi/albums/Dirty%20Deeds/image In order to create a URL like this, I have to create a new Controller because my earlier routes pointed to the AlbumApiController using HTTP Verb routing. HTTP Verb based routing is great for representing a single set of resources such as albums. You can map operations like add, delete, update and read easily using HTTP Verbs. But you cannot mix action based routing into a an HTTP Verb routing controller - you can only map HTTP Verbs and each method has to be unique based on parameter signature. You can't have multiple GET operations to methods with the same signature. So GetImage(string id) and GetAlbum(string title) are in conflict in an HTTP GET routing scenario. In fact, I was unable to make the above Image URL work with any combination of HTTP Verb plus Custom routing using the single Albums controller. There are number of ways around this, but all involve additional controllers.  Personally, I think it’s easier to use explicit Action routing and then add custom routes if you need to simplify your URLs further. So in order to accommodate some of the other examples, I created another controller – AlbumRpcApiController – to handle all requests that are explicitly routed via actions (/albums/rpc/AlbumArt) or are custom routed with explicit routes defined in the HttpConfiguration. I added the AlbumArt() method to this new AlbumRpcApiController class. For the image URL to work with the new AlbumRpcApiController, you need a custom route placed before the default route from Listing 1.RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); Now I can use either of the following URLs to access the image: Custom route: (/albums/rpc/{title}/image)http://localhost/aspnetWebApi/albums/PowerAge/image Action route: (/albums/rpc/action/{title})http://localhost/aspnetWebAPI/albums/rpc/albumart/PowerAge Sending Data to the Server To send data to the server and add a new album, you can use an HTTP POST operation. Since I’m using HTTP Verb-based routing in the original AlbumApiController, I can implement a method called PostAlbum()to accept a new album from the client. Listing 6 shows the Web API code to add a new album.public HttpResponseMessage PostAlbum(Album album) { if (!this.ModelState.IsValid) { // my custom error class var error = new ApiMessageError() { message = "Model is invalid" }; // add errors into our client error model for client foreach (var prop in ModelState.Values) { var modelError = prop.Errors.FirstOrDefault(); if (!string.IsNullOrEmpty(modelError.ErrorMessage)) error.errors.Add(modelError.ErrorMessage); else error.errors.Add(modelError.Exception.Message); } return Request.CreateResponse<ApiMessageError>(HttpStatusCode.Conflict, error); } // update song id which isn't provided foreach (var song in album.Songs) song.AlbumId = album.Id; // see if album exists already var matchedAlbum = AlbumData.Current .SingleOrDefault(alb => alb.Id == album.Id || alb.AlbumName == album.AlbumName); if (matchedAlbum == null) AlbumData.Current.Add(album); else matchedAlbum = album; // return a string to show that the value got here var resp = Request.CreateResponse(HttpStatusCode.OK, string.Empty); resp.Content = new StringContent(album.AlbumName + " " + album.Entered.ToString(), Encoding.UTF8, "text/plain"); return resp; } The PostAlbum() method receives an album parameter, which is automatically deserialized from the POST buffer the client sent. The data passed from the client can be either XML or JSON. Web API automatically figures out what format it needs to deserialize based on the content type and binds the content to the album object. Web API uses model binding to bind the request content to the parameter(s) of controller methods. Like MVC you can check the model by looking at ModelState.IsValid. If it’s not valid, you can run through the ModelState.Values collection and check each binding for errors. Here I collect the error messages into a string array that gets passed back to the client via the result ApiErrorMessage object. When a binding error occurs, you’ll want to return an HTTP error response and it’s best to do that with an HttpResponseMessage result. In Listing 6, I used a custom error class that holds a message and an array of detailed error messages for each binding error. I used this object as the content to return to the client along with my Conflict HTTP Status Code response. If binding succeeds, the example returns a string with the name and date entered to demonstrate that you captured the data. Normally, a method like this should return a Boolean or no response at all (HttpStatusCode.NoConent). The sample uses a simple static list to hold albums, so once you’ve added the album using the Post operation, you can hit the /albums/ URL to see that the new album was added. The client jQuery code to call the POST operation from the client with jQuery is shown in Listing 7. var id = new Date().getTime().toString(); var album = { "Id": id, "AlbumName": "Power Age", "Artist": "AC/DC", "YearReleased": 1977, "Entered": "2002-03-11T18:24:43.5580794-10:00", "AlbumImageUrl": http://ecx.images-amazon.com/images/…, "AmazonUrl": http://www.amazon.com/…, "Songs": [ { "SongName": "Rock 'n Roll Damnation", "SongLength": 3.12}, { "SongName": "Downpayment Blues", "SongLength": 4.22 }, { "SongName": "Riff Raff", "SongLength": 2.42 } ] } $.ajax( { url: "albums/", type: "POST", contentType: "application/json", data: JSON.stringify(album), processData: false, beforeSend: function (xhr) { // not required since JSON is default output xhr.setRequestHeader("Accept", "application/json"); }, success: function (result) { // reload list of albums page.loadAlbums(); }, error: function (xhr, status, p3, p4) { var err = "Error"; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); The code in Listing 7 creates an album object in JavaScript to match the structure of the .NET Album class. This object is passed to the $.ajax() function to send to the server as POST. The data is turned into JSON and the content type set to application/json so that the server knows what to convert when deserializing in the Album instance. The jQuery code hooks up success and failure events. Success returns the result data, which is a string that’s echoed back with an alert box. If an error occurs, jQuery returns the XHR instance and status code. You can check the XHR to see if a JSON object is embedded and if it is, you can extract it by de-serializing it and accessing the .message property. REST standards suggest that updates to existing resources should use PUT operations. REST standards aside, I’m not a big fan of separating out inserts and updates so I tend to have a single method that handles both. But if you want to follow REST suggestions, you can create a PUT method that handles updates by forwarding the PUT operation to the POST method:public HttpResponseMessage PutAlbum(Album album) { return PostAlbum(album); } To make the corresponding $.ajax() call, all you have to change from Listing 7 is the type: from POST to PUT. Model Binding with UrlEncoded POST Variables In the example in Listing 7 I used JSON objects to post a serialized object to a server method that accepted an strongly typed object with the same structure, which is a common way to send data to the server. However, Web API supports a number of different ways that data can be received by server methods. For example, another common way is to use plain UrlEncoded POST  values to send to the server. Web API supports Model Binding that works similar (but not the same) as MVC's model binding where POST variables are mapped to properties of object parameters of the target method. This is actually quite common for AJAX calls that want to avoid serialization and the potential requirement of a JSON parser on older browsers. For example, using jQUery you might use the $.post() method to send a new album to the server (albeit one without songs) using code like the following:$.post("albums/",{AlbumName: "Dirty Deeds", YearReleased: 1976 … },albumPostCallback); Although the code looks very similar to the client code we used before passing JSON, here the data passed is URL encoded values (AlbumName=Dirty+Deeds&YearReleased=1976 etc.). Web API then takes this POST data and maps each of the POST values to the properties of the Album object in the method's parameter. Although the client code is different the server can both handle the JSON object, or the UrlEncoded POST values. Dynamic Access to POST Data There are also a few options available to dynamically access POST data, if you know what type of data you're dealing with. If you have POST UrlEncoded values, you can dynamically using a FormsDataCollection:[HttpPost] public string PostAlbum(FormDataCollection form) { return string.Format("{0} - released {1}", form.Get("AlbumName"),form.Get("RearReleased")); } The FormDataCollection is a very simple object, that essentially provides the same functionality as Request.Form[] in ASP.NET. Request.Form[] still works if you're running hosted in an ASP.NET application. However as a general rule, while ASP.NET's functionality is always available when running Web API hosted inside of an  ASP.NET application, using the built in classes specific to Web API makes it possible to run Web API applications in a self hosted environment outside of ASP.NET. If your client is sending JSON to your server, and you don't want to map the JSON to a strongly typed object because you only want to retrieve a few simple values, you can also accept a JObject parameter in your API methods:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } There quite a few options available to you to receive data with Web API, which gives you more choices for the right tool for the job. Unfortunately one shortcoming of Web API is that POST data is always mapped to a single parameter. This means you can't pass multiple POST parameters to methods that receive POST data. It's possible to accept multiple parameters, but only one can map to the POST content - the others have to come from the query string or route values. I have a couple of Blog POSTs that explain what works and what doesn't here: Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API   Handling Delete Operations Finally, to round out the server API code of the album example we've been discussin, here’s the DELETE verb controller method that allows removal of an album by its title:public HttpResponseMessage DeleteAlbum(string title) { var matchedAlbum = AlbumData.Current.Where(alb => alb.AlbumName == title) .SingleOrDefault(); if (matchedAlbum == null) return new HttpResponseMessage(HttpStatusCode.NotFound); AlbumData.Current.Remove(matchedAlbum); return new HttpResponseMessage(HttpStatusCode.NoContent); } To call this action method using jQuery, you can use:$(".removeimage").live("click", function () { var $el = $(this).parent(".album"); var txt = $el.find("a").text(); $.ajax({ url: "albums/" + encodeURIComponent(txt), type: "Delete", success: function (result) { $el.fadeOut().remove(); }, error: jqError }); }   Note the use of the DELETE verb in the $.ajax() call, which routes to DeleteAlbum on the server. DELETE is a non-content operation, so you supply a resource ID (the title) via route value or the querystring. Routing Conflicts In all requests with the exception of the AlbumArt image example shown so far, I used HTTP Verb routing that I set up in Listing 1. HTTP Verb Routing is a recommendation that is in line with typical REST access to HTTP resources. However, it takes quite a bit of effort to create REST-compliant API implementations based only on HTTP Verb routing only. You saw one example that didn’t really fit – the return of an image where I created a custom route albums/{title}/image that required creation of a second controller and a custom route to work. HTTP Verb routing to a controller does not mix with custom or action routing to the same controller because of the limited mapping of HTTP verbs imposed by HTTP Verb routing. To understand some of the problems with verb routing, let’s look at another example. Let’s say you create a GetSortableAlbums() method like this and add it to the original AlbumApiController accessed via HTTP Verb routing:[HttpGet] public IQueryable<Album> SortableAlbums() { var albums = AlbumData.Current; // generally should be done only on actual queryable results (EF etc.) // Done here because we're running with a static list but otherwise might be slow return albums.AsQueryable(); } If you compile this code and try to now access the /albums/ link, you get an error: Multiple Actions were found that match the request. HTTP Verb routing only allows access to one GET operation per parameter/route value match. If more than one method exists with the same parameter signature, it doesn’t work. As I mentioned earlier for the image display, the only solution to get this method to work is to throw it into another controller. Because I already set up the AlbumRpcApiController I can add the method there. First, I should rename the method to SortableAlbums() so I’m not using a Get prefix for the method. This also makes the action parameter look cleaner in the URL - it looks less like a method and more like a noun. I can then create a new route that handles direct-action mapping:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); As I am explicitly adding a route segment – rpc – into the route template, I can now reference explicit methods in the Web API controller using URLs like this: http://localhost/AspNetWebApi/rpc/SortableAlbums Error Handling I’ve already done some minimal error handling in the examples. For example in Listing 6, I detected some known-error scenarios like model validation failing or a resource not being found and returning an appropriate HttpResponseMessage result. But what happens if your code just blows up or causes an exception? If you have a controller method, like this:[HttpGet] public void ThrowException() { throw new UnauthorizedAccessException("Unauthorized Access Sucka"); } You can call it with this: http://localhost/AspNetWebApi/albums/rpc/ThrowException The default exception handling displays a 500-status response with the serialized exception on the local computer only. When you connect from a remote computer, Web API throws back a 500  HTTP Error with no data returned (IIS then adds its HTML error page). The behavior is configurable in the GlobalConfiguration:GlobalConfiguration .Configuration .IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Never; If you want more control over your error responses sent from code, you can throw explicit error responses yourself using HttpResponseException. When you throw an HttpResponseException the response parameter is used to generate the output for the Controller action. [HttpGet] public void ThrowError() { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.BadRequest, new ApiMessageError("Your code stinks!")); throw new HttpResponseException(resp); } Throwing an HttpResponseException stops the processing of the controller method and immediately returns the response you passed to the exception. Unlike other Exceptions fired inside of WebAPI, HttpResponseException bypasses the Exception Filters installed and instead just outputs the response you provide. In this case, the serialized ApiMessageError result string is returned in the default serialization format – XML or JSON. You can pass any content to HttpResponseMessage, which includes creating your own exception objects and consistently returning error messages to the client. Here’s a small helper method on the controller that you might use to send exception info back to the client consistently:private void ThrowSafeException(string message, HttpStatusCode statusCode = HttpStatusCode.BadRequest) { var errResponse = Request.CreateResponse<ApiMessageError>(statusCode, new ApiMessageError() { message = message }); throw new HttpResponseException(errResponse); } You can then use it to output any captured errors from code:[HttpGet] public void ThrowErrorSafe() { try { List<string> list = null; list.Add("Rick"); } catch (Exception ex) { ThrowSafeException(ex.Message); } }   Exception Filters Another more global solution is to create an Exception Filter. Filters in Web API provide the ability to pre- and post-process controller method operations. An exception filter looks at all exceptions fired and then optionally creates an HttpResponseMessage result. Listing 8 shows an example of a basic Exception filter implementation.public class UnhandledExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { HttpStatusCode status = HttpStatusCode.InternalServerError; var exType = context.Exception.GetType(); if (exType == typeof(UnauthorizedAccessException)) status = HttpStatusCode.Unauthorized; else if (exType == typeof(ArgumentException)) status = HttpStatusCode.NotFound; var apiError = new ApiMessageError() { message = context.Exception.Message }; // create a new response and attach our ApiError object // which now gets returned on ANY exception result var errorResponse = context.Request.CreateResponse<ApiMessageError>(status, apiError); context.Response = errorResponse; base.OnException(context); } } Exception Filter Attributes can be assigned to an ApiController class like this:[UnhandledExceptionFilter] public class AlbumRpcApiController : ApiController or you can globally assign it to all controllers by adding it to the HTTP Configuration's Filters collection:GlobalConfiguration.Configuration.Filters.Add(new UnhandledExceptionFilter()); The latter is a great way to get global error trapping so that all errors (short of hard IIS errors and explicit HttpResponseException errors) return a valid error response that includes error information in the form of a known-error object. Using a filter like this allows you to throw an exception as you normally would and have your filter create a response in the appropriate output format that the client expects. For example, an AJAX application can on failure expect to see a JSON error result that corresponds to the real error that occurred rather than a 500 error along with HTML error page that IIS throws up. You can even create some custom exceptions so you can differentiate your own exceptions from unhandled system exceptions - you often don't want to display error information from 'unknown' exceptions as they may contain sensitive system information or info that's not generally useful to users of your application/site. This is just one example of how ASP.NET Web API is configurable and extensible. Exception filters are just one example of how you can plug-in into the Web API request flow to modify output. Many more hooks exist and I’ll take a closer look at extensibility in Part 2 of this article in the future. Summary Web API is a big improvement over previous Microsoft REST and AJAX toolkits. The key features to its usefulness are its ease of use with simple controller based logic, familiar MVC-style routing, low configuration impact, extensibility at all levels and tight attention to exposing and making HTTP semantics easily discoverable and easy to use. Although none of the concepts used in Web API are new or radical, Web API combines the best of previous platforms into a single framework that’s highly functional, easy to work with, and extensible to boot. I think that Microsoft has hit a home run with Web API. Related Resources Where does ASP.NET Web API fit? Sample Source Code on GitHub Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API Creating a JSONP Formatter for ASP.NET Web API Removing the XML Formatter from ASP.NET Web API Applications© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Capturing and Transforming ASP.NET Output with Response.Filter

  - by Rick Strahl

  During one of my Handlers and Modules session at DevConnections this week one of the attendees asked a question that I didn’t have an immediate answer for. Basically he wanted to capture response output completely and then apply some filtering to the output – effectively injecting some additional content into the page AFTER the page had completely rendered. Specifically the output should be captured from anywhere – not just a page and have this code injected into the page. Some time ago I posted some code that allows you to capture ASP.NET Page output by overriding the Render() method, capturing the HtmlTextWriter() and reading its content, modifying the rendered data as text then writing it back out. I’ve actually used this approach on a few occasions and it works fine for ASP.NET pages. But this obviously won’t work outside of the Page class environment and it’s not really generic – you have to create a custom page class in order to handle the output capture. [updated 11/16/2009 – updated ResponseFilterStream implementation and a few additional notes based on comments] Enter Response.Filter However, ASP.NET includes a Response.Filter which can be used – well to filter output. Basically Response.Filter is a stream through which the OutputStream is piped back to the Web Server (indirectly). As content is written into the Response object, the filter stream receives the appropriate Stream commands like Write, Flush and Close as well as read operations although for a Response.Filter that’s uncommon to be hit. The Response.Filter can be programmatically replaced at runtime which allows you to effectively intercept all output generation that runs through ASP.NET. A common Example: Dynamic GZip Encoding A rather common use of Response.Filter hooking up code based, dynamic  GZip compression for requests which is dead simple by applying a GZipStream (or DeflateStream) to Response.Filter. The following generic routines can be used very easily to detect GZip capability of the client and compress response output with a single line of code and a couple of library helper routines: WebUtils.GZipEncodePage(); which is handled with a few lines of reusable code and a couple of static helper methods: /// <summary> ///Sets up the current page or handler to use GZip through a Response.Filter ///IMPORTANT:  ///You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() {     HttpResponse Response = HttpContext.Current.Response;     if(IsGZipSupported())     {         stringAcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"];         if(AcceptEncoding.Contains("deflate"))         {             Response.Filter = newSystem.IO.Compression.DeflateStream(Response.Filter,                                        System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "deflate");         }         else        {             Response.Filter = newSystem.IO.Compression.GZipStream(Response.Filter,                                       System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "gzip");                            }     }     // Allow proxy servers to cache encoded and unencoded versions separately    Response.AppendHeader("Vary", "Content-Encoding"); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } GZipStream and DeflateStream are streams that are assigned to Response.Filter and by doing so apply the appropriate compression on the active Response. Response.Filter content is chunked So to implement a Response.Filter effectively requires only that you implement a custom stream and handle the Write() method to capture Response output as it’s written. At first blush this seems very simple – you capture the output in Write, transform it and write out the transformed content in one pass. And that indeed works for small amounts of content. But you see, the problem is that output is written in small buffer chunks (a little less than 16k it appears) rather than just a single Write() statement into the stream, which makes perfect sense for ASP.NET to stream data back to IIS in smaller chunks to minimize memory usage en route. Unfortunately this also makes it a more difficult to implement any filtering routines since you don’t directly get access to all of the response content which is problematic especially if those filtering routines require you to look at the ENTIRE response in order to transform or capture the output as is needed for the solution the gentleman in my session asked for. So in order to address this a slightly different approach is required that basically captures all the Write() buffers passed into a cached stream and then making the stream available only when it’s complete and ready to be flushed. As I was thinking about the implementation I also started thinking about the few instances when I’ve used Response.Filter implementations. Each time I had to create a new Stream subclass and create my custom functionality but in the end each implementation did the same thing – capturing output and transforming it. I thought there should be an easier way to do this by creating a re-usable Stream class that can handle stream transformations that are common to Response.Filter implementations. Creating a semi-generic Response Filter Stream Class What I ended up with is a ResponseFilterStream class that provides a handful of Events that allow you to capture and/or transform Response content. The class implements a subclass of Stream and then overrides Write() and Flush() to handle capturing and transformation operations. By exposing events it’s easy to hook up capture or transformation operations via single focused methods. ResponseFilterStream exposes the following events: CaptureStream, CaptureString Captures the output only and provides either a MemoryStream or String with the final page output. Capture is hooked to the Flush() operation of the stream. TransformStream, TransformString Allows you to transform the complete response output with events that receive a MemoryStream or String respectively and can you modify the output then return it back as a return value. The transformed output is then written back out in a single chunk to the response output stream. These events capture all output internally first then write the entire buffer into the response. TransformWrite, TransformWriteString Allows you to transform the Response data as it is written in its original chunk size in the Stream’s Write() method. Unlike TransformStream/TransformString which operate on the complete output, these events only see the current chunk of data written. This is more efficient as there’s no caching involved, but can cause problems due to searched content splitting over multiple chunks. Using this implementation, creating a custom Response.Filter transformation becomes as simple as the following code. To hook up the Response.Filter using the MemoryStream version event: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformStream += filter_TransformStream; Response.Filter = filter; and the event handler to do the transformation: MemoryStream filter_TransformStream(MemoryStream ms) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = encoding.GetString(ms.ToArray()); output = FixPaths(output); ms = new MemoryStream(output.Length); byte[] buffer = encoding.GetBytes(output); ms.Write(buffer,0,buffer.Length); return ms; } private string FixPaths(string output) { string path = HttpContext.Current.Request.ApplicationPath; // override root path wonkiness if (path == "/") path = ""; output = output.Replace("\"~/", "\"" + path + "/").Replace("'~/", "'" + path + "/"); return output; } The idea of the event handler is that you can do whatever you want to the stream and return back a stream – either the same one that’s been modified or a brand new one – which is then sent back to as the final response. The above code can be simplified even more by using the string version events which handle the stream to string conversions for you: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; and the event handler to do the transformation calling the same FixPaths method shown above: string filter_TransformString(string output) { return FixPaths(output); } The events for capturing output and capturing and transforming chunks work in a very similar way. By using events to handle the transformations ResponseFilterStream becomes a reusable component and we don’t have to create a new stream class or subclass an existing Stream based classed. By the way, the example used here is kind of a cool trick which transforms “~/” expressions inside of the final generated HTML output – even in plain HTML controls not HTML controls – and transforms them into the appropriate application relative path in the same way that ResolveUrl would do. So you can write plain old HTML like this: <a href=”~/default.aspx”>Home</a>  and have it turned into: <a href=”/myVirtual/default.aspx”>Home</a>  without having to use an ASP.NET control like Hyperlink or Image or having to constantly use: <img src=”<%= ResolveUrl(“~/images/home.gif”) %>” /> in MVC applications (which frankly is one of the most annoying things about MVC especially given the path hell that extension-less and endpoint-less URLs impose). I can’t take credit for this idea. While discussing the Response.Filter issues on Twitter a hint from Dylan Beattie who pointed me at one of his examples which does something similar. I thought the idea was cool enough to use an example for future demos of Response.Filter functionality in ASP.NET next I time I do the Modules and Handlers talk (which was great fun BTW). How practical this is is debatable however since there’s definitely some overhead to using a Response.Filter in general and especially on one that caches the output and the re-writes it later. Make sure to test for performance anytime you use Response.Filter hookup and make sure it' doesn’t end up killing perf on you. You’ve been warned :-}. How does ResponseFilterStream work? The big win of this implementation IMHO is that it’s a reusable  component – so for implementation there’s no new class, no subclassing – you simply attach to an event to implement an event handler method with a straight forward signature to retrieve the stream or string you’re interested in. The implementation is based on a subclass of Stream as is required in order to handle the Response.Filter requirements. What’s different than other implementations I’ve seen in various places is that it supports capturing output as a whole to allow retrieving the full response output for capture or modification. The exception are the TransformWrite and TransformWrite events which operate only active chunk of data written by the Response. For captured output, the Write() method captures output into an internal MemoryStream that is cached until writing is complete. So Write() is called when ASP.NET writes to the Response stream, but the filter doesn’t pass on the Write immediately to the filter’s internal stream. The data is cached and only when the Flush() method is called to finalize the Stream’s output do we actually send the cached stream off for transformation (if the events are hooked up) and THEN finally write out the returned content in one big chunk. Here’s the implementation of ResponseFilterStream: /// <summary> /// A semi-generic Stream implementation for Response.Filter with /// an event interface for handling Content transformations via /// Stream or String. /// <remarks> /// Use with care for large output as this implementation copies /// the output into a memory stream and so increases memory usage. /// </remarks> /// </summary> public class ResponseFilterStream : Stream { /// <summary> /// The original stream /// </summary> Stream _stream; /// <summary> /// Current position in the original stream /// </summary> long _position; /// <summary> /// Stream that original content is read into /// and then passed to TransformStream function /// </summary> MemoryStream _cacheStream = new MemoryStream(5000); /// <summary> /// Internal pointer that that keeps track of the size /// of the cacheStream /// </summary> int _cachePointer = 0; /// <summary> /// /// </summary> /// <param name="responseStream"></param> public ResponseFilterStream(Stream responseStream) { _stream = responseStream; } /// <summary> /// Determines whether the stream is captured /// </summary> private bool IsCaptured { get { if (CaptureStream != null || CaptureString != null || TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Determines whether the Write method is outputting data immediately /// or delaying output until Flush() is fired. /// </summary> private bool IsOutputDelayed { get { if (TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Event that captures Response output and makes it available /// as a MemoryStream instance. Output is captured but won't /// affect Response output. /// </summary> public event Action<MemoryStream> CaptureStream; /// <summary> /// Event that captures Response output and makes it available /// as a string. Output is captured but won't affect Response output. /// </summary> public event Action<string> CaptureString; /// <summary> /// Event that allows you transform the stream as each chunk of /// the output is written in the Write() operation of the stream. /// This means that that it's possible/likely that the input /// buffer will not contain the full response output but only /// one of potentially many chunks. /// /// This event is called as part of the filter stream's Write() /// operation. /// </summary> public event Func<byte[], byte[]> TransformWrite; /// <summary> /// Event that allows you to transform the response stream as /// each chunk of bytep[] output is written during the stream's write /// operation. This means it's possibly/likely that the string /// passed to the handler only contains a portion of the full /// output. Typical buffer chunks are around 16k a piece. /// /// This event is called as part of the stream's Write operation. /// </summary> public event Func<string, string> TransformWriteString; /// <summary> /// This event allows capturing and transformation of the entire /// output stream by caching all write operations and delaying final /// response output until Flush() is called on the stream. /// </summary> public event Func<MemoryStream, MemoryStream> TransformStream; /// <summary> /// Event that can be hooked up to handle Response.Filter /// Transformation. Passed a string that you can modify and /// return back as a return value. The modified content /// will become the final output. /// </summary> public event Func<string, string> TransformString; protected virtual void OnCaptureStream(MemoryStream ms) { if (CaptureStream != null) CaptureStream(ms); } private void OnCaptureStringInternal(MemoryStream ms) { if (CaptureString != null) { string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); OnCaptureString(content); } } protected virtual void OnCaptureString(string output) { if (CaptureString != null) CaptureString(output); } protected virtual byte[] OnTransformWrite(byte[] buffer) { if (TransformWrite != null) return TransformWrite(buffer); return buffer; } private byte[] OnTransformWriteStringInternal(byte[] buffer) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = OnTransformWriteString(encoding.GetString(buffer)); return encoding.GetBytes(output); } private string OnTransformWriteString(string value) { if (TransformWriteString != null) return TransformWriteString(value); return value; } protected virtual MemoryStream OnTransformCompleteStream(MemoryStream ms) { if (TransformStream != null) return TransformStream(ms); return ms; } /// <summary> /// Allows transforming of strings /// /// Note this handler is internal and not meant to be overridden /// as the TransformString Event has to be hooked up in order /// for this handler to even fire to avoid the overhead of string /// conversion on every pass through. /// </summary> /// <param name="responseText"></param> /// <returns></returns> private string OnTransformCompleteString(string responseText) { if (TransformString != null) TransformString(responseText); return responseText; } /// <summary> /// Wrapper method form OnTransformString that handles /// stream to string and vice versa conversions /// </summary> /// <param name="ms"></param> /// <returns></returns> internal MemoryStream OnTransformCompleteStringInternal(MemoryStream ms) { if (TransformString == null) return ms; //string content = ms.GetAsString(); string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); content = TransformString(content); byte[] buffer = HttpContext.Current.Response.ContentEncoding.GetBytes(content); ms = new MemoryStream(); ms.Write(buffer, 0, buffer.Length); //ms.WriteString(content); return ms; } /// <summary> /// /// </summary> public override bool CanRead { get { return true; } } public override bool CanSeek { get { return true; } } /// <summary> /// /// </summary> public override bool CanWrite { get { return true; } } /// <summary> /// /// </summary> public override long Length { get { return 0; } } /// <summary> /// /// </summary> public override long Position { get { return _position; } set { _position = value; } } /// <summary> /// /// </summary> /// <param name="offset"></param> /// <param name="direction"></param> /// <returns></returns> public override long Seek(long offset, System.IO.SeekOrigin direction) { return _stream.Seek(offset, direction); } /// <summary> /// /// </summary> /// <param name="length"></param> public override void SetLength(long length) { _stream.SetLength(length); } /// <summary> /// /// </summary> public override void Close() { _stream.Close(); } /// <summary> /// Override flush by writing out the cached stream data /// </summary> public override void Flush() { if (IsCaptured && _cacheStream.Length > 0) { // Check for transform implementations _cacheStream = OnTransformCompleteStream(_cacheStream); _cacheStream = OnTransformCompleteStringInternal(_cacheStream); OnCaptureStream(_cacheStream); OnCaptureStringInternal(_cacheStream); // write the stream back out if output was delayed if (IsOutputDelayed) _stream.Write(_cacheStream.ToArray(), 0, (int)_cacheStream.Length); // Clear the cache once we've written it out _cacheStream.SetLength(0); } // default flush behavior _stream.Flush(); } /// <summary> /// /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> /// <returns></returns> public override int Read(byte[] buffer, int offset, int count) { return _stream.Read(buffer, offset, count); } /// <summary> /// Overriden to capture output written by ASP.NET and captured /// into a cached stream that is written out later when Flush() /// is called. /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> public override void Write(byte[] buffer, int offset, int count) { if ( IsCaptured ) { // copy to holding buffer only - we'll write out later _cacheStream.Write(buffer, 0, count); _cachePointer += count; } // just transform this buffer if (TransformWrite != null) buffer = OnTransformWrite(buffer); if (TransformWriteString != null) buffer = OnTransformWriteStringInternal(buffer); if (!IsOutputDelayed) _stream.Write(buffer, offset, buffer.Length); } } The key features are the events and corresponding OnXXX methods that handle the event hookups, and the Write() and Flush() methods of the stream implementation. All the rest of the members tend to be plain jane passthrough stream implementation code without much consequence. I do love the way Action<t> and Func<T> make it so easy to create the event signatures for the various events – sweet. A few Things to consider Performance Response.Filter is not great for performance in general as it adds another layer of indirection to the ASP.NET output pipeline, and this implementation in particular adds a memory hit as it basically duplicates the response output into the cached memory stream which is necessary since you may have to look at the entire response. If you have large pages in particular this can cause potentially serious memory pressure in your server application. So be careful of wholesale adoption of this (or other) Response.Filters. Make sure to do some performance testing to ensure it’s not killing your app’s performance. Response.Filter works everywhere A few questions came up in comments and discussion as to capturing ALL output hitting the site and – yes you can definitely do that by assigning a Response.Filter inside of a module. If you do this however you’ll want to be very careful and decide which content you actually want to capture especially in IIS 7 which passes ALL content – including static images/CSS etc. through the ASP.NET pipeline. So it is important to filter only on what you’re looking for – like the page extension or maybe more effectively the Response.ContentType. Response.Filter Chaining Originally I thought that filter chaining doesn’t work at all due to a bug in the stream implementation code. But it’s quite possible to assign multiple filters to the Response.Filter property. So the following actually works to both compress the output and apply the transformed content: WebUtils.GZipEncodePage(); ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; However the following does not work resulting in invalid content encoding errors: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; WebUtils.GZipEncodePage(); In other words multiple Response filters can work together but it depends entirely on the implementation whether they can be chained or in which order they can be chained. In this case running the GZip/Deflate stream filters apparently relies on the original content length of the output and chokes when the content is modified. But if attaching the compression first it works fine as unintuitive as that may seem. Resources Download example code Capture Output from ASP.NET Pages © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• IIS 7.5 , Tomcat 7 - Isapi redirector - Fail Over - sticky sessions

  - by Jose Matias

  I have two instances of Tomcat 7.0.8 running in the same machine (Tomcat7A and Tomcat7B) and IIS 7.5 acting as front-end load-balancer with isapi-redirector 1.2.31, running on Windows 2008 R2. When i disconnect the instance wich is handling a request i can see a new instance being assigned with the same sessionid but then the user is redirected to the login page. server.xml configuration file <Engine name="Catalina" defaultHost="localhost" jvmRoute="Tomcat7A"> <Realm className="org.apache.catalina.realm.LockOutRealm"> <Realm className="org.apache.catalina.realm.UserDatabaseRealm" resourceName="UserDatabase"/> </Realm> <Host name="localhost" appBase="webapps" unpackWARs="true" autoDeploy="true"> <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster" channelSendOptions="8"> <Manager className="org.apache.catalina.ha.session.DeltaManager" expireSessionsOnShutdown="false" notifyListenersOnReplication="true"/> <Channel className="org.apache.catalina.tribes.group.GroupChannel"> <Membership className="org.apache.catalina.tribes.membership.McastService" address="228.0.0.8" bind="7.3.1.22" port="45564" frequency="500" dropTime="3000"/> <Receiver className="org.apache.catalina.tribes.transport.nio.NioReceiver" address="auto" port="4200" autoBind="100" selectorTimeout="5000" maxThreads="6"/> <Sender className="org.apache.catalina.tribes.transport.ReplicationTransmitter"> <Transport className="org.apache.catalina.tribes.transport.nio.PooledParallelSender"/> </Sender> <Interceptor className="org.apache.catalina.tribes.group.interceptors.TcpFailureDetector"/> <Interceptor className="org.apache.catalina.tribes.group.interceptors.MessageDispatch15Interceptor"/> </Channel> <Valve className="org.apache.catalina.ha.tcp.ReplicationValve" filter=".*\.gif;.*\.js;.*\.jpg;.*\.htm;.*\.html;.*\.txt"/> <Valve className="org.apache.catalina.ha.session.JvmRouteBinderValve"/> <ClusterListener className="org.apache.catalina.ha.session.JvmRouteSessionIDBinderListener"/> <ClusterListener className="org.apache.catalina.ha.session.ClusterSessionListener"/> </Cluster> <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs" prefix="localhost_access_log." suffix=".txt" pattern="%h %l %u %t &quot;%r&quot; %s %b" resolveHosts="false"/> </Host> </Engine> worker_mount_file=C:\tomcat\iis\conf\uriworkermap_prod.properties worker.list = balancer,status worker.Tomcat7B.host = 7.3.1.22 worker.Tomcat7B.type = ajp13 worker.Tomcat7B.port = 8010 worker.Tomcat7B.lbfactor = 10 worker.Tomcat7A.host = 7.3.1.22 worker.Tomcat7A.type = ajp13 worker.Tomcat7A.port = 8009 worker.Tomcat7A.lbfactor = 10 worker.balancer.type = lb worker.balancer.sticky_session = 1 worker.balancer.balance_workers = Tomcat7B, Tomcat7A worker.status.type = status isapi_redirect log [debug] wc_get_worker_for_name::jk_worker.c (116): found a worker balancer [debug] HttpExtensionProc::jk_isapi_plugin.c (2188): got a worker for name balancer [debug] service::jk_lb_worker.c (1118): service sticky_session=1 id='89569C584CC4F58740D649C4BE655D36.Tomcat7B' [debug] get_most_suitable_worker::jk_lb_worker.c (946): searching worker for partial sessionid 89569C584CC4F58740D649C4BE655D36.Tomcat7B [debug] get_most_suitable_worker::jk_lb_worker.c (954): searching worker for session route Tomcat7B [debug] get_most_suitable_worker::jk_lb_worker.c (968): found worker Tomcat7B (Tomcat7B) for route Tomcat7B and partial sessionid 89569C584CC4F58740D649C4BE655D36.Tomcat7B [debug] service::jk_lb_worker.c (1161): service worker=Tomcat7B route=Tomcat7B [debug] ajp_get_endpoint::jk_ajp_common.c (3096): acquired connection pool slot=0 after 0 retries [debug] ajp_marshal_into_msgb::jk_ajp_common.c (605): ajp marshaling done [debug] ajp_service::jk_ajp_common.c (2379): processing Tomcat7B with 2 retries [debug] jk_shutdown_socket::jk_connect.c (726): About to shutdown socket 820 [7.3.1.22:24482 -> 7.3.1.22:8010] [debug] jk_shutdown_socket::jk_connect.c (797): shutting down the read side of socket 820 [7.3.1.22:24482 -> 7.3.1.22:8010] [debug] jk_shutdown_socket::jk_connect.c (808): Shutdown socket 820 [7.3.1.22:24482 -> 7.3.1.22:8010] and read 0 lingering bytes in 0 sec. [debug] ajp_send_request::jk_ajp_common.c (1496): (Tomcat7B) failed sending request, socket 820 is not connected any more (errno=-10000) [debug] ajp_next_connection::jk_ajp_common.c (823): (Tomcat7B) Will try pooled connection socket 896 from slot 1 [debug] jk_shutdown_socket::jk_connect.c (726): About to shutdown socket 896 [7.3.1.22:24488 -> 7.3.1.22:8010] [debug] jk_shutdown_socket::jk_connect.c (797): shutting down the read side of socket 896 [7.3.1.22:24488 -> 7.3.1.22:8010] [debug] jk_shutdown_socket::jk_connect.c (808): Shutdown socket 896 [7.3.1.22:24488 -> 7.3.1.22:8010] and read 0 lingering bytes in 0 sec. [debug] ajp_send_request::jk_ajp_common.c (1496): (Tomcat7B) failed sending request, socket 896 is not connected any more (errno=-10000) [info] ajp_send_request::jk_ajp_common.c (1567): (Tomcat7B) all endpoints are disconnected, detected by connect check (2), cping (0), send (0) [debug] jk_open_socket::jk_connect.c (484): socket TCP_NODELAY set to On [debug] jk_open_socket::jk_connect.c (608): trying to connect socket 896 to 7.3.1.22:8010 [info] jk_open_socket::jk_connect.c (626): connect to 7.3.1.22:8010 failed (errno=61) [info] ajp_connect_to_endpoint::jk_ajp_common.c (959): Failed opening socket to (7.3.1.22:8010) (errno=61) [error] ajp_send_request::jk_ajp_common.c (1578): (Tomcat7B) connecting to backend failed. Tomcat is probably not started or is listening on the wrong port (errno=61) [info] ajp_service::jk_ajp_common.c (2543): (Tomcat7B) sending request to tomcat failed (recoverable), because of error during request sending (attempt=1) [debug] ajp_service::jk_ajp_common.c (2400): retry 1, sleeping for 100 ms before retrying [debug] ajp_send_request::jk_ajp_common.c (1572): (Tomcat7B) all endpoints are disconnected. [debug] jk_open_socket::jk_connect.c (484): socket TCP_NODELAY set to On [debug] jk_open_socket::jk_connect.c (608): trying to connect socket 896 to 7.3.1.22:8010 [info] jk_open_socket::jk_connect.c (626): connect to 7.3.1.22:8010 failed (errno=61) [info] ajp_connect_to_endpoint::jk_ajp_common.c (959): Failed opening socket to (7.3.1.22:8010) (errno=61) [error] ajp_send_request::jk_ajp_common.c (1578): (Tomcat7B) connecting to backend failed. Tomcat is probably not started or is listening on the wrong port (errno=61) [info] ajp_service::jk_ajp_common.c (2543): (Tomcat7B) sending request to tomcat failed (recoverable), because of error during request sending (attempt=2) [error] ajp_service::jk_ajp_common.c (2562): (Tomcat7B) connecting to tomcat failed. [debug] ajp_reset_endpoint::jk_ajp_common.c (757): (Tomcat7B) resetting endpoint with socket -1 (socket shutdown) [debug] ajp_done::jk_ajp_common.c (3013): recycling connection pool slot=0 for worker Tomcat7B [debug] service::jk_lb_worker.c (1374): worker Tomcat7B escalating local error to global error [info] service::jk_lb_worker.c (1388): service failed, worker Tomcat7B is in error state [debug] service::jk_lb_worker.c (1399): recoverable error... will try to recover on other worker [debug] get_most_suitable_worker::jk_lb_worker.c (946): searching worker for partial sessionid 89569C584CC4F58740D649C4BE655D36.Tomcat7B [debug] get_most_suitable_worker::jk_lb_worker.c (954): searching worker for session route Tomcat7B [debug] get_most_suitable_worker::jk_lb_worker.c (1001): found best worker Tomcat7A (Tomcat7A) using method 'Request' [debug] service::jk_lb_worker.c (1161): service worker=Tomcat7A route=Tomcat7B [debug] ajp_get_endpoint::jk_ajp_common.c (3096): acquired connection pool slot=0 after 0 retries [debug] ajp_marshal_into_msgb::jk_ajp_common.c (605): ajp marshaling done [debug] ajp_service::jk_ajp_common.c (2379): processing Tomcat7A with 2 retries [debug] ajp_send_request::jk_ajp_common.c (1572): (Tomcat7A) all endpoints are disconnected. [debug] jk_open_socket::jk_connect.c (484): socket TCP_NODELAY set to On [debug] jk_open_socket::jk_connect.c (608): trying to connect socket 896 to 7.3.1.22:8009 [debug] jk_open_socket::jk_connect.c (634): socket 896 [7.3.1.22:24496 -> 7.3.1.22:8009] connected [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): sending to ajp13 pos=4 len=615 max=8192 [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0000 .4.c....HTTP/1.1 [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0010 .../Accounter/pr [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0020 intFrameSet.jhtm [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0030 l...::1...::1... [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0040 localhost..P.... [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0050 ...Keep-Alive... [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0060 ..0....rimage/jp [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0070 eg,.image/gif,.i [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0080 mage/pjpeg,.appl [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0090 ication/x-ms-app [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00a0 lication,.applic [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00b0 ation/xaml+xml,. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00c0 application/x-ms [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00d0 -xbap,.*/*...Acc [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00e0 ept-Encoding...g [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00f0 zip,.deflate...A [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0100 ccept-Language.. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0110 .nb-NO....]Usern [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0120 ame=NA_jose.mati [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0130 as_AT_addenergy. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0140 no;.JSESSIONID=8 [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0150 9569C584CC4F5874 [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0160 0D649C4BE655D36. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0170 Tomcat7B.....loc [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0180 alhost.....http: [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0190 //localhost/Acco [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01a0 unter/NemsAccoun [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01b0 ter.jhtml....uMo [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01c0 zilla/4.0.(compa [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01d0 tible;.MSIE.8.0; [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01e0 .Windows.NT.6.1; [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01f0 .WOW64;.Trident/ [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0200 4.0;.SLCC2;..NET [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0210 .CLR.2.0.50727;. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0220 .NET4.0C;..NET4. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0230 0E)............F [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0240 rameName=Reports [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0250 _CS_EUETS....Tom [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0260 cat7B........... [debug] ajp_send_request::jk_ajp_common.c (1632): (Tomcat7A) request body to send 0 - request body to resend 0 [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): received from ajp13 pos=0 len=238 max=8192 [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0000 .....Moved.Tempo [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0010 rarily......OJSE [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0020 SSIONID=6A2507A4 [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0030 626F698EC74A733C [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0040 DBA7D9FE.Tomcat7 [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0050 A;.Path=/Account [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0060 er;.HttpOnly...P [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0070 ragma...no-cache [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0080 ...Cache-Control [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0090 ...no-cache....& [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 00a0 http://localhost [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 00b0 /Accounter/login [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 00c0 .jhtml.....text/ [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 00d0 html;charset=ISO [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 00e0 -8859-1.....0... [debug] ajp_unmarshal_response::jk_ajp_common.c (660): status = 302 [debug] ajp_unmarshal_response::jk_ajp_common.c (667): Number of headers is = 6 [debug] ajp_unmarshal_response::jk_ajp_common.c (723): Header[0] [Set-Cookie] = [JSESSIONID=6A2507A4626F698EC74A733CDBA7D9FE.Tomcat7A; Path=/Accounter; HttpOnly] [debug] ajp_unmarshal_response::jk_ajp_common.c (723): Header[1] [Pragma] = [no-cache] [debug] ajp_unmarshal_response::jk_ajp_common.c (723): Header[2] [Cache-Control] = [no-cache] [debug] ajp_unmarshal_response::jk_ajp_common.c (723): Header[3] [Location] = [http://localhost/Accounter/login.jhtml] [debug] ajp_unmarshal_response::jk_ajp_common.c (723): Header[4] [Content-Type] = [text/html;charset=ISO-8859-1] [debug] ajp_unmarshal_response::jk_ajp_common.c (723): Header[5] [Content-Length] = [0] [debug] start_response::jk_isapi_plugin.c (963): Starting response for URI '/Accounter/printFrameSet.jhtml' (protocol HTTP/1.1) [debug] start_response::jk_isapi_plugin.c (1063): Not using Keep-Alive [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): received from ajp13 pos=0 len=2 max=8192 [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0000 ................ [debug] ajp_process_callback::jk_ajp_common.c (1943): AJP13 protocol: Reuse is OK [debug] ajp_reset_endpoint::jk_ajp_common.c (757): (Tomcat7A) resetting endpoint with socket 896 [debug] ajp_done::jk_ajp_common.c (3013): recycling connection pool slot=0 for worker Tomcat7A [debug] HttpExtensionProc::jk_isapi_plugin.c (2211): service() returned OK [debug] HttpFilterProc::jk_isapi_plugin.c (1851): Filter started [debug] map_uri_to_worker_ext::jk_uri_worker_map.c (1036): Attempting to map URI '/localhost/Accounter/login.jhtml' from 8 maps [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/servlet/*=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/ws/*=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/nems*.pdf=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/*.service=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/*.jhtml=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/*.json=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/jkmanager=status' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/servlet/*=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/ws/*=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/nems*.pdf=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/*.service=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (850): Attempting to map context URI '/Accounter/*.jhtml=balancer' source 'uriworkermap' [debug] find_match::jk_uri_worker_map.c (863): Found a wildchar match '/Accounter/*.jhtml=balancer' [debug] HttpFilterProc::jk_isapi_plugin.c (1938): check if [/Accounter/login.jhtml] points to the web-inf directory [debug] HttpFilterProc::jk_isapi_plugin.c (1954): [/Accounter/login.jhtml] is a servlet url - should redirect to balancer [debug] HttpFilterProc::jk_isapi_plugin.c (1994): fowarding escaped URI [/Accounter/login.jhtml] [debug] init_ws_service::jk_isapi_plugin.c (2982): Reading extension header HTTP_TOMCATWORKER0000000180000000: balancer [debug] init_ws_service::jk_isapi_plugin.c (2983): Reading extension header HTTP_TOMCATWORKERIDX0000000180000000: 5 [debug] init_ws_service::jk_isapi_plugin.c (2984): Reading extension header HTTP_TOMCATURI0000000180000000: /Accounter/login.jhtml [debug] init_ws_service::jk_isapi_plugin.c (2985): Reading extension header HTTP_TOMCATQUERY0000000180000000: (null) [debug] init_ws_service::jk_isapi_plugin.c (3040): Applying service extensions [debug] init_ws_service::jk_isapi_plugin.c (3298): Service protocol=HTTP/1.1 method=GET host=::1 addr=::1 name=localhost port=80 auth= user= uri=/Accounter/login.jhtml [debug] init_ws_service::jk_isapi_plugin.c (3310): Service request headers=9 attributes=0 chunked=no content-length=0 available=0 [debug] wc_get_worker_for_name::jk_worker.c (116): found a worker balancer [debug] HttpExtensionProc::jk_isapi_plugin.c (2188): got a worker for name balancer [debug] service::jk_lb_worker.c (1118): service sticky_session=1 id='6A2507A4626F698EC74A733CDBA7D9FE.Tomcat7A' [debug] get_most_suitable_worker::jk_lb_worker.c (946): searching worker for partial sessionid 6A2507A4626F698EC74A733CDBA7D9FE.Tomcat7A [debug] get_most_suitable_worker::jk_lb_worker.c (954): searching worker for session route Tomcat7A [debug] get_most_suitable_worker::jk_lb_worker.c (968): found worker Tomcat7A (Tomcat7A) for route Tomcat7A and partial sessionid 6A2507A4626F698EC74A733CDBA7D9FE.Tomcat7A [debug] service::jk_lb_worker.c (1161): service worker=Tomcat7A route=Tomcat7A [debug] ajp_get_endpoint::jk_ajp_common.c (3096): acquired connection pool slot=0 after 0 retries [debug] ajp_marshal_into_msgb::jk_ajp_common.c (605): ajp marshaling done [debug] ajp_service::jk_ajp_common.c (2379): processing Tomcat7A with 2 retries [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): sending to ajp13 pos=4 len=577 max=8192 [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0000 .4.=....HTTP/1.1 [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0010 .../Accounter/lo [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0020 gin.jhtml...::1. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0030 ..::1...localhos [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0040 t..P.......Keep- [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0050 Alive.....0....r [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0060 image/jpeg,.imag [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0070 e/gif,.image/pjp [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0080 eg,.application/ [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0090 x-ms-application [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00a0 ,.application/xa [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00b0 ml+xml,.applicat [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00c0 ion/x-ms-xbap,.* [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00d0 /*...Accept-Enco [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00e0 ding...gzip,.def [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 00f0 late...Accept-La [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0100 nguage...nb-NO.. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0110 ..]Username=NA_j [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0120 ose.matias_AT_ad [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0130 denergy.no;.JSES [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0140 SIONID=6A2507A46 [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0150 26F698EC74A733CD [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0160 BA7D9FE.Tomcat7A [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0170 .....localhost.. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0180 ...http://localh [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0190 ost/Accounter/Ne [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01a0 msAccounter.jhtm [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01b0 l....uMozilla/4. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01c0 0.(compatible;.M [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01d0 SIE.8.0;.Windows [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01f0 Trident/4.0;.SLC [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 01e0 .NT.6.1;.WOW64;. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0200 C2;..NET.CLR.2.0 [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0210 .50727;..NET4.0C [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0220 ;..NET4.0E)..... [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0230 .......Tomcat7A. [debug] ajp_connection_tcp_send_message::jk_ajp_common.c (1145): 0240 ................ [debug] ajp_send_request::jk_ajp_common.c (1621): (Tomcat7A) Statistics about invalid connections: connect check (0), cping (0), send (0) [debug] ajp_send_request::jk_ajp_common.c (1632): (Tomcat7A) request body to send 0 - request body to resend 0 [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): received from ajp13 pos=0 len=135 max=8192 [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0000 .....OK.....Prag [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0010 ma...no-cache... [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0020 Expires...Thu,.0 [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0030 1.Jan.1970.00:00 [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0040 :00.GMT...Cache- [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0050 Control...no-cac [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0060 he...Cache-Contr [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0070 ol...no-store... [debug] ajp_connection_tcp_get_message::jk_ajp_common.c (1329): 0080 ..2995..........

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• Red Gate Coder interviews: Alex Davies

  - by Michael Williamson

  Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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• Windows Azure: Import/Export Hard Drives, VM ACLs, Web Sockets, Remote Debugging, Continuous Delivery, New Relic, Billing Alerts and More

  - by ScottGu

  Two weeks ago we released a giant set of improvements to Windows Azure, as well as a significant update of the Windows Azure SDK. This morning we released another massive set of enhancements to Windows Azure.  Today’s new capabilities include: Storage: Import/Export Hard Disk Drives to your Storage Accounts HDInsight: General Availability of our Hadoop Service in the cloud Virtual Machines: New VM Gallery, ACL support for VIPs Web Sites: WebSocket and Remote Debugging Support Notification Hubs: Segmented customer push notification support with tag expressions TFS & GIT: Continuous Delivery Support for Web Sites + Cloud Services Developer Analytics: New Relic support for Web Sites + Mobile Services Service Bus: Support for partitioned queues and topics Billing: New Billing Alert Service that sends emails notifications when your bill hits a threshold you define All of these improvements are now available to use immediately (note that some features are still in preview).  Below are more details about them. Storage: Import/Export Hard Disk Drives to Windows Azure I am excited to announce the preview of our new Windows Azure Import/Export Service! The Windows Azure Import/Export Service enables you to move large amounts of on-premises data into and out of your Windows Azure Storage accounts. It does this by enabling you to securely ship hard disk drives directly to our Windows Azure data centers. Once we receive the drives we’ll automatically transfer the data to or from your Windows Azure Storage account.  This enables you to import or export massive amounts of data more quickly and cost effectively (and not be constrained by available network bandwidth). Encrypted Transport Our Import/Export service provides built-in support for BitLocker disk encryption – which enables you to securely encrypt data on the hard drives before you send it, and not have to worry about it being compromised even if the disk is lost/stolen in transit (since the content on the transported hard drives is completely encrypted and you are the only one who has the key to it).  The drive preparation tool we are shipping today makes setting up bitlocker encryption on these hard drives easy. How to Import/Export your first Hard Drive of Data You can read our Getting Started Guide to learn more about how to begin using the import/export service.  You can create import and export jobs via the Windows Azure Management Portal as well as programmatically using our Server Management APIs. It is really easy to create a new import or export job using the Windows Azure Management Portal.  Simply navigate to a Windows Azure storage account, and then click the new Import/Export tab now available within it (note: if you don’t have this tab make sure to sign-up for the Import/Export preview): Then click the “Create Import Job” or “Create Export Job” commands at the bottom of it.  This will launch a wizard that easily walks you through the steps required: For more comprehensive information about Import/Export, refer to Windows Azure Storage team blog.  You can also send questions and comments to the [email protected] email address. We think you’ll find this new service makes it much easier to move data into and out of Windows Azure, and it will dramatically cut down the network bandwidth required when working on large data migration projects.  We hope you like it. HDInsight: 100% Compatible Hadoop Service in the Cloud Last week we announced the general availability release of Windows Azure HDInsight. HDInsight is a 100% compatible Hadoop service that allows you to easily provision and manage Hadoop clusters for big data processing in Windows Azure.  This release is now live in production, backed by an enterprise SLA, supported 24x7 by Microsoft Support, and is ready to use for production scenarios. HDInsight allows you to use Apache Hadoop tools, such as Pig and Hive, to process large amounts of data in Windows Azure Blob Storage. Because data is stored in Windows Azure Blob Storage, you can choose to dynamically create Hadoop clusters only when you need them, and then shut them down when they are no longer required (since you pay only for the time the Hadoop cluster instances are running this provides a super cost effective way to use them).  You can create Hadoop clusters using either the Windows Azure Management Portal (see below) or using our PowerShell and Cross Platform Command line tools: The import/export hard drive support that came out today is a perfect companion service to use with HDInsight – the combination allows you to easily ingest, process and optionally export a limitless amount of data.  We’ve also integrated HDInsight with our Business Intelligence tools, so users can leverage familiar tools like Excel in order to analyze the output of jobs.  You can find out more about how to get started with HDInsight here. Virtual Machines: VM Gallery Enhancements Today’s update of Windows Azure brings with it a new Virtual Machine gallery that you can use to create new VMs in the cloud.  You can launch the gallery by doing New->Compute->Virtual Machine->From Gallery within the Windows Azure Management Portal: The new Virtual Machine Gallery includes some nice enhancements that make it even easier to use: Search: You can now easily search and filter images using the search box in the top-right of the dialog.  For example, simply type “SQL” and we’ll filter to show those images in the gallery that contain that substring. Category Tree-view: Each month we add more built-in VM images to the gallery.  You can continue to browse these using the “All” view within the VM Gallery – or now quickly filter them using the category tree-view on the left-hand side of the dialog.  For example, by selecting “Oracle” in the tree-view you can now quickly filter to see the official Oracle supplied images. MSDN and Supported checkboxes: With today’s update we are also introducing filters that makes it easy to filter out types of images that you may not be interested in. The first checkbox is MSDN: using this filter you can exclude any image that is not part of the Windows Azure benefits for MSDN subscribers (which have highly discounted pricing - you can learn more about the MSDN pricing here). The second checkbox is Supported: this filter will exclude any image that contains prerelease software, so you can feel confident that the software you choose to deploy is fully supported by Windows Azure and our partners. Sort options: We sort gallery images by what we think customers are most interested in, but sometimes you might want to sort using different views. So we’re providing some additional sort options, like “Newest,” to customize the image list for what suits you best. Pricing information: We now provide additional pricing information about images and options on how to cost effectively run them directly within the VM Gallery. The above improvements make it even easier to use the VM Gallery and quickly create launch and run Virtual Machines in the cloud. Virtual Machines: ACL Support for VIPs A few months ago we exposed the ability to configure Access Control Lists (ACLs) for Virtual Machines using Windows PowerShell cmdlets and our Service Management API. With today’s release, you can now configure VM ACLs using the Windows Azure Management Portal as well. You can now do this by clicking the new Manage ACL command in the Endpoints tab of a virtual machine instance: This will enable you to configure an ordered list of permit and deny rules to scope the traffic that can access your VM’s network endpoints. For example, if you were on a virtual network, you could limit RDP access to a Windows Azure virtual machine to only a few computers attached to your enterprise. Or if you weren’t on a virtual network you could alternatively limit traffic from public IPs that can access your workloads: Here is the default behaviors for ACLs in Windows Azure: By default (i.e. no rules specified), all traffic is permitted. When using only Permit rules, all other traffic is denied. When using only Deny rules, all other traffic is permitted. When there is a combination of Permit and Deny rules, all other traffic is denied. Lastly, remember that configuring endpoints does not automatically configure them within the VM if it also has firewall rules enabled at the OS level.  So if you create an endpoint using the Windows Azure Management Portal, Windows PowerShell, or REST API, be sure to also configure your guest VM firewall appropriately as well. Web Sites: Web Sockets Support With today’s release you can now use Web Sockets with Windows Azure Web Sites.  This feature enables you to easily integrate real-time communication scenarios within your web based applications, and is available at no extra charge (it even works with the free tier).  Higher level programming libraries like SignalR and socket.io are also now supported with it. You can enable Web Sockets support on a web site by navigating to the Configure tab of a Web Site, and by toggling Web Sockets support to “on”: Once Web Sockets is enabled you can start to integrate some really cool scenarios into your web applications.  Check out the new SignalR documentation hub on www.asp.net to learn more about some of the awesome scenarios you can do with it. Web Sites: Remote Debugging Support The Windows Azure SDK 2.2 we released two weeks ago introduced remote debugging support for Windows Azure Cloud Services. With today’s Windows Azure release we are extending this remote debugging support to also work with Windows Azure Web Sites. With live, remote debugging support inside of Visual Studio, you are able to have more visibility than ever before into how your code is operating live in Windows Azure. It is now super easy to attach the debugger and quickly see what is going on with your application in the cloud. Remote Debugging of a Windows Azure Web Site using VS 2013 Enabling the remote debugging of a Windows Azure Web Site using VS 2013 is really easy.  Start by opening up your web application’s project within Visual Studio. Then navigate to the “Server Explorer” tab within Visual Studio, and click on the deployed web-site you want to debug that is running within Windows Azure using the Windows Azure->Web Sites node in the Server Explorer.  Then right-click and choose the “Attach Debugger” option on it: When you do this Visual Studio will remotely attach the debugger to the Web Site running within Windows Azure.  The debugger will then stop the web site’s execution when it hits any break points that you have set within your web application’s project inside Visual Studio.  For example, below I set a breakpoint on the “ViewBag.Message” assignment statement within the HomeController of the standard ASP.NET MVC project template.  When I hit refresh on the “About” page of the web site within the browser, the breakpoint was triggered and I am now able to debug the app remotely using Visual Studio: Note above how we can debug variables (including autos/watchlist/etc), as well as use the Immediate and Command Windows. In the debug session above I used the Immediate Window to explore some of the request object state, as well as to dynamically change the ViewBag.Message property.  When we click the the “Continue” button (or press F5) the app will continue execution and the Web Site will render the content back to the browser.  This makes it super easy to debug web apps remotely. Tips for Better Debugging To get the best experience while debugging, we recommend publishing your site using the Debug configuration within Visual Studio’s Web Publish dialog. This will ensure that debug symbol information is uploaded to the Web Site which will enable a richer debug experience within Visual Studio.  You can find this option on the Web Publish dialog on the Settings tab: When you ultimately deploy/run the application in production we recommend using the “Release” configuration setting – the release configuration is memory optimized and will provide the best production performance.  To learn more about diagnosing and debugging Windows Azure Web Sites read our new Troubleshooting Windows Azure Web Sites in Visual Studio guide. Notification Hubs: Segmented Push Notification support with tag expressions In August we announced the General Availability of Windows Azure Notification Hubs - a powerful Mobile Push Notifications service that makes it easy to send high volume push notifications with low latency from any mobile app back-end.  Notification hubs can be used with any mobile app back-end (including ones built using our Mobile Services capability) and can also be used with back-ends that run in the cloud as well as on-premises. Beginning with the initial release, Notification Hubs allowed developers to send personalized push notifications to both individual users as well as groups of users by interest, by associating their devices with tags representing the logical target of the notification. For example, by registering all devices of customers interested in a favorite MLB team with a corresponding tag, it is possible to broadcast one message to millions of Boston Red Sox fans and another message to millions of St. Louis Cardinals fans with a single API call respectively. New support for using tag expressions to enable advanced customer segmentation With today’s release we are adding support for even more advanced customer targeting.  You can now identify customers that you want to send push notifications to by defining rich tag expressions. With tag expressions, you can now not only broadcast notifications to Boston Red Sox fans, but take that segmenting a step farther and reach more granular segments. This opens up a variety of scenarios, for example: Offers based on multiple preferences—e.g. send a game day vegetarian special to users tagged as both a Boston Red Sox fan AND a vegetarian Push content to multiple segments in a single message—e.g. rain delay information only to users who are tagged as either a Boston Red Sox fan OR a St. Louis Cardinal fan Avoid presenting subsets of a segment with irrelevant content—e.g. season ticket availability reminder to users who are tagged as a Boston Red Sox fan but NOT also a season ticket holder To illustrate with code, consider a restaurant chain app that sends an offer related to a Red Sox vs Cardinals game for users in Boston. Devices can be tagged by your app with location tags (e.g. “Loc:Boston”) and interest tags (e.g. “Follows:RedSox”, “Follows:Cardinals”), and then a notification can be sent by your back-end to “(Follows:RedSox || Follows:Cardinals) && Loc:Boston” in order to deliver an offer to all devices in Boston that follow either the RedSox or the Cardinals. This can be done directly in your server backend send logic using the code below: var notification = new WindowsNotification(messagePayload); hub.SendNotificationAsync(notification, "(Follows:RedSox || Follows:Cardinals) && Loc:Boston"); In your expressions you can use all Boolean operators: AND (&&), OR (||), and NOT (!).  Some other cool use cases for tag expressions that are now supported include: Social: To “all my group except me” - group:id && !user:id Events: Touchdown event is sent to everybody following either team or any of the players involved in the action: Followteam:A || Followteam:B || followplayer:1 || followplayer:2 … Hours: Send notifications at specific times. E.g. Tag devices with time zone and when it is 12pm in Seattle send to: GMT8 && follows:thaifood Versions and platforms: Send a reminder to people still using your first version for Android - version:1.0 && platform:Android For help on getting started with Notification Hubs, visit the Notification Hub documentation center.  Then download the latest NuGet package (or use the Notification Hubs REST APIs directly) to start sending push notifications using tag expressions.  They are really powerful and enable a bunch of great new scenarios. TFS & GIT: Continuous Delivery Support for Web Sites + Cloud Services With today’s Windows Azure release we are making it really easy to enable continuous delivery support with Windows Azure and Team Foundation Services.  Team Foundation Services is a cloud based offering from Microsoft that provides integrated source control (with both TFS and Git support), build server, test execution, collaboration tools, and agile planning support.  It makes it really easy to setup a team project (complete with automated builds and test runners) in the cloud, and it has really rich integration with Visual Studio. With today’s Windows Azure release it is now really easy to enable continuous delivery support with both TFS and Git based repositories hosted using Team Foundation Services.  This enables a workflow where when code is checked in, built successfully on an automated build server, and all tests pass on it – I can automatically have the app deployed on Windows Azure with zero manual intervention or work required. The below screen-shots demonstrate how to quickly setup a continuous delivery workflow to Windows Azure with a Git-based ASP.NET MVC project hosted using Team Foundation Services. Enabling Continuous Delivery to Windows Azure with Team Foundation Services The project I’m going to enable continuous delivery with is a simple ASP.NET MVC project whose source code I’m hosting using Team Foundation Services.  I did this by creating a “SimpleContinuousDeploymentTest” repository there using Git – and then used the new built-in Git tooling support within Visual Studio 2013 to push the source code to it.  Below is a screen-shot of the Git repository hosted within Team Foundation Services: I can access the repository within Visual Studio 2013 and easily make commits with it (as well as branch, merge and do other tasks).  Using VS 2013 I can also setup automated builds to take place in the cloud using Team Foundation Services every time someone checks in code to the repository: The cool thing about this is that I don’t have to buy or rent my own build server – Team Foundation Services automatically maintains its own build server farm and can automatically queue up a build for me (for free) every time someone checks in code using the above settings.  This build server (and automated testing) support now works with both TFS and Git based source control repositories. Connecting a Team Foundation Services project to Windows Azure Once I have a source repository hosted in Team Foundation Services with Automated Builds and Testing set up, I can then go even further and set it up so that it will be automatically deployed to Windows Azure when a source code commit is made to the repository (assuming the Build + Tests pass).  Enabling this is now really easy.  To set this up with a Windows Azure Web Site simply use the New->Compute->Web Site->Custom Create command inside the Windows Azure Management Portal.  This will create a dialog like below.  I gave the web site a name and then made sure the “Publish from source control” checkbox was selected: When we click next we’ll be prompted for the location of the source repository.  We’ll select “Team Foundation Services”: Once we do this we’ll be prompted for our Team Foundation Services account that our source repository is hosted under (in this case my TFS account is “scottguthrie”): When we click the “Authorize Now” button we’ll be prompted to give Windows Azure permissions to connect to the Team Foundation Services account.  Once we do this we’ll be prompted to pick the source repository we want to connect to.  Starting with today’s Windows Azure release you can now connect to both TFS and Git based source repositories.  This new support allows me to connect to the “SimpleContinuousDeploymentTest” respository we created earlier: Clicking the finish button will then create the Web Site with the continuous delivery hooks setup with Team Foundation Services.  Now every time someone pushes source control to the repository in Team Foundation Services, it will kick off an automated build, run all of the unit tests in the solution , and if they pass the app will be automatically deployed to our Web Site in Windows Azure.  You can monitor the history and status of these automated deployments using the Deployments tab within the Web Site: This enables a really slick continuous delivery workflow, and enables you to build and deploy apps in a really nice way. Developer Analytics: New Relic support for Web Sites + Mobile Services With today’s Windows Azure release we are making it really easy to enable Developer Analytics and Monitoring support with both Windows Azure Web Site and Windows Azure Mobile Services.  We are partnering with New Relic, who provide a great dev analytics and app performance monitoring offering, to enable this - and we have updated the Windows Azure Management Portal to make it really easy to configure. Enabling New Relic with a Windows Azure Web Site Enabling New Relic support with a Windows Azure Web Site is now really easy.  Simply navigate to the Configure tab of a Web Site and scroll down to the “developer analytics” section that is now within it: Clicking the “add-on” button will display some additional UI.  If you don’t already have a New Relic subscription, you can click the “view windows azure store” button to obtain a subscription (note: New Relic has a perpetually free tier so you can enable it even without paying anything): Clicking the “view windows azure store” button will launch the integrated Windows Azure Store experience we have within the Windows Azure Management Portal.  You can use this to browse from a variety of great add-on services – including New Relic: Select “New Relic” within the dialog above, then click the next button, and you’ll be able to choose which type of New Relic subscription you wish to purchase.  For this demo we’ll simply select the “Free Standard Version” – which does not cost anything and can be used forever:  Once we’ve signed-up for our New Relic subscription and added it to our Windows Azure account, we can go back to the Web Site’s configuration tab and choose to use the New Relic add-on with our Windows Azure Web Site.  We can do this by simply selecting it from the “add-on” dropdown (it is automatically populated within it once we have a New Relic subscription in our account): Clicking the “Save” button will then cause the Windows Azure Management Portal to automatically populate all of the needed New Relic configuration settings to our Web Site: Deploying the New Relic Agent as part of a Web Site The final step to enable developer analytics using New Relic is to add the New Relic runtime agent to our web app.  We can do this within Visual Studio by right-clicking on our web project and selecting the “Manage NuGet Packages” context menu: This will bring up the NuGet package manager.  You can search for “New Relic” within it to find the New Relic agent.  Note that there is both a 32-bit and 64-bit edition of it – make sure to install the version that matches how your Web Site is running within Windows Azure (note: you can configure your Web Site to run in either 32-bit or 64-bit mode using the Web Site’s “Configuration” tab within the Windows Azure Management Portal): Once we install the NuGet package we are all set to go.  We’ll simply re-publish the web site again to Windows Azure and New Relic will now automatically start monitoring the application Monitoring a Web Site using New Relic Now that the application has developer analytics support with New Relic enabled, we can launch the New Relic monitoring portal to start monitoring the health of it.  We can do this by clicking on the “Add Ons” tab in the left-hand side of the Windows Azure Management Portal.  Then select the New Relic add-on we signed-up for within it.  The Windows Azure Management Portal will provide some default information about the add-on when we do this.  Clicking the “Manage” button in the tray at the bottom will launch a new browser tab and single-sign us into the New Relic monitoring portal associated with our account: When we do this a new browser tab will launch with the New Relic admin tool loaded within it: We can now see insights into how our app is performing – without having to have written a single line of monitoring code.  The New Relic service provides a ton of great built-in monitoring features allowing us to quickly see: Performance times (including browser rendering speed) for the overall site and individual pages.  You can optionally set alert thresholds to trigger if the speed does not meet a threshold you specify. Information about where in the world your customers are hitting the site from (and how performance varies by region) Details on the latency performance of external services your web apps are using (for example: SQL, Storage, Twitter, etc) Error information including call stack details for exceptions that have occurred at runtime SQL Server profiling information – including which queries executed against your database and what their performance was And a whole bunch more… The cool thing about New Relic is that you don’t need to write monitoring code within your application to get all of the above reports (plus a lot more).  The New Relic agent automatically enables the CLR profiler within applications and automatically captures the information necessary to identify these.  This makes it super easy to get started and immediately have a rich developer analytics view for your solutions with very little effort. If you haven’t tried New Relic out yet with Windows Azure I recommend you do so – I think you’ll find it helps you build even better cloud applications.  Following the above steps will help you get started and deliver you a really good application monitoring solution in only minutes. Service Bus: Support for partitioned queues and topics With today’s release, we are enabling support within Service Bus for partitioned queues and topics. Enabling partitioning enables you to achieve a higher message throughput and better availability from your queues and topics. Higher message throughput is achieved by implementing multiple message brokers for each partitioned queue and topic.  The  multiple messaging stores will also provide higher availability. You can create a partitioned queue or topic by simply checking the Enable Partitioning option in the custom create wizard for a Queue or Topic: Read this article to learn more about partitioned queues and topics and how to take advantage of them today. Billing: New Billing Alert Service Today’s Windows Azure update enables a new Billing Alert Service Preview that enables you to get proactive email notifications when your Windows Azure bill goes above a certain monetary threshold that you configure.  This makes it easier to manage your bill and avoid potential surprises at the end of the month. With the Billing Alert Service Preview, you can now create email alerts to monitor and manage your monetary credits or your current bill total.  To set up an alert first sign-up for the free Billing Alert Service Preview.  Then visit the account management page, click on a subscription you have setup, and then navigate to the new Alerts tab that is available: The alerts tab allows you to setup email alerts that will be sent automatically once a certain threshold is hit.  For example, by clicking the “add alert” button above I can setup a rule to send myself email anytime my Windows Azure bill goes above $100 for the month: The Billing Alert Service will evolve to support additional aspects of your bill as well as support multiple forms of alerts such as SMS.  Try out the new Billing Alert Service Preview today and give us feedback. Summary Today’s Windows Azure release enables a ton of great new scenarios, and makes building applications hosted in the cloud even easier. If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using all of the above features today.  Then visit the Windows Azure Developer Center to learn more about how to build apps with it. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• value types in the vm

  - by john.rose

  value types in the vm p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} p.p2 {margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times} p.p3 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times} p.p4 {margin: 0.0px 0.0px 15.0px 0.0px; font: 14.0px Times} p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier} p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier; min-height: 17.0px} p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p8 {margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px; font: 14.0px Times; min-height: 18.0px} p.p9 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p10 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; color: #000000} li.li1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} li.li7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} span.s1 {font: 14.0px Courier} span.s2 {color: #000000} span.s3 {font: 14.0px Courier; color: #000000} ol.ol1 {list-style-type: decimal} Or, enduring values for a changing world. Introduction A value type is a data type which, generally speaking, is designed for being passed by value in and out of methods, and stored by value in data structures. The only value types which the Java language directly supports are the eight primitive types. Java indirectly and approximately supports value types, if they are implemented in terms of classes. For example, both Integer and String may be viewed as value types, especially if their usage is restricted to avoid operations appropriate to Object. In this note, we propose a definition of value types in terms of a design pattern for Java classes, accompanied by a set of usage restrictions. We also sketch the relation of such value types to tuple types (which are a JVM-level notion), and point out JVM optimizations that can apply to value types. This note is a thought experiment to extend the JVM’s performance model in support of value types. The demonstration has two phases.  Initially the extension can simply use design patterns, within the current bytecode architecture, and in today’s Java language. But if the performance model is to be realized in practice, it will probably require new JVM bytecode features, changes to the Java language, or both.  We will look at a few possibilities for these new features. An Axiom of Value In the context of the JVM, a value type is a data type equipped with construction, assignment, and equality operations, and a set of typed components, such that, whenever two variables of the value type produce equal corresponding values for their components, the values of the two variables cannot be distinguished by any JVM operation. Here are some corollaries: A value type is immutable, since otherwise a copy could be constructed and the original could be modified in one of its components, allowing the copies to be distinguished. Changing the component of a value type requires construction of a new value. The equals and hashCode operations are strictly component-wise. If a value type is represented by a JVM reference, that reference cannot be successfully synchronized on, and cannot be usefully compared for reference equality. A value type can be viewed in terms of what it doesn’t do. We can say that a value type omits all value-unsafe operations, which could violate the constraints on value types.  These operations, which are ordinarily allowed for Java object types, are pointer equality comparison (the acmp instruction), synchronization (the monitor instructions), all the wait and notify methods of class Object, and non-trivial finalize methods. The clone method is also value-unsafe, although for value types it could be treated as the identity function. Finally, and most importantly, any side effect on an object (however visible) also counts as an value-unsafe operation. A value type may have methods, but such methods must not change the components of the value. It is reasonable and useful to define methods like toString, equals, and hashCode on value types, and also methods which are specifically valuable to users of the value type. Representations of Value Value types have two natural representations in the JVM, unboxed and boxed. An unboxed value consists of the components, as simple variables. For example, the complex number x=(1+2i), in rectangular coordinate form, may be represented in unboxed form by the following pair of variables: /*Complex x = Complex.valueOf(1.0, 2.0):*/ double x_re = 1.0, x_im = 2.0; These variables might be locals, parameters, or fields. Their association as components of a single value is not defined to the JVM. Here is a sample computation which computes the norm of the difference between two complex numbers: double distance(/*Complex x:*/ double x_re, double x_im,         /*Complex y:*/ double y_re, double y_im) {     /*Complex z = x.minus(y):*/     double z_re = x_re - y_re, z_im = x_im - y_im;     /*return z.abs():*/     return Math.sqrt(z_re*z_re + z_im*z_im); } A boxed representation groups component values under a single object reference. The reference is to a ‘wrapper class’ that carries the component values in its fields. (A primitive type can naturally be equated with a trivial value type with just one component of that type. In that view, the wrapper class Integer can serve as a boxed representation of value type int.) The unboxed representation of complex numbers is practical for many uses, but it fails to cover several major use cases: return values, array elements, and generic APIs. The two components of a complex number cannot be directly returned from a Java function, since Java does not support multiple return values. The same story applies to array elements: Java has no ’array of structs’ feature. (Double-length arrays are a possible workaround for complex numbers, but not for value types with heterogeneous components.) By generic APIs I mean both those which use generic types, like Arrays.asList and those which have special case support for primitive types, like String.valueOf and PrintStream.println. Those APIs do not support unboxed values, and offer some problems to boxed values. Any ’real’ JVM type should have a story for returns, arrays, and API interoperability. The basic problem here is that value types fall between primitive types and object types. Value types are clearly more complex than primitive types, and object types are slightly too complicated. Objects are a little bit dangerous to use as value carriers, since object references can be compared for pointer equality, and can be synchronized on. Also, as many Java programmers have observed, there is often a performance cost to using wrapper objects, even on modern JVMs. Even so, wrapper classes are a good starting point for talking about value types. If there were a set of structural rules and restrictions which would prevent value-unsafe operations on value types, wrapper classes would provide a good notation for defining value types. This note attempts to define such rules and restrictions. Let’s Start Coding Now it is time to look at some real code. Here is a definition, written in Java, of a complex number value type. @ValueSafe public final class Complex implements java.io.Serializable {     // immutable component structure:     public final double re, im;     private Complex(double re, double im) {         this.re = re; this.im = im;     }     // interoperability methods:     public String toString() { return "Complex("+re+","+im+")"; }     public List<Double> asList() { return Arrays.asList(re, im); }     public boolean equals(Complex c) {         return re == c.re && im == c.im;     }     public boolean equals(@ValueSafe Object x) {         return x instanceof Complex && equals((Complex) x);     }     public int hashCode() {         return 31*Double.valueOf(re).hashCode()                 + Double.valueOf(im).hashCode();     }     // factory methods:     public static Complex valueOf(double re, double im) {         return new Complex(re, im);     }     public Complex changeRe(double re2) { return valueOf(re2, im); }     public Complex changeIm(double im2) { return valueOf(re, im2); }     public static Complex cast(@ValueSafe Object x) {         return x == null ? ZERO : (Complex) x;     }     // utility methods and constants:     public Complex plus(Complex c)  { return new Complex(re+c.re, im+c.im); }     public Complex minus(Complex c) { return new Complex(re-c.re, im-c.im); }     public double abs() { return Math.sqrt(re*re + im*im); }     public static final Complex PI = valueOf(Math.PI, 0.0);     public static final Complex ZERO = valueOf(0.0, 0.0); } This is not a minimal definition, because it includes some utility methods and other optional parts.  The essential elements are as follows: The class is marked as a value type with an annotation. The class is final, because it does not make sense to create subclasses of value types. The fields of the class are all non-private and final.  (I.e., the type is immutable and structurally transparent.) From the supertype Object, all public non-final methods are overridden. The constructor is private. Beyond these bare essentials, we can observe the following features in this example, which are likely to be typical of all value types: One or more factory methods are responsible for value creation, including a component-wise valueOf method. There are utility methods for complex arithmetic and instance creation, such as plus and changeIm. There are static utility constants, such as PI. The type is serializable, using the default mechanisms. There are methods for converting to and from dynamically typed references, such as asList and cast. The Rules In order to use value types properly, the programmer must avoid value-unsafe operations.  A helpful Java compiler should issue errors (or at least warnings) for code which provably applies value-unsafe operations, and should issue warnings for code which might be correct but does not provably avoid value-unsafe operations.  No such compilers exist today, but to simplify our account here, we will pretend that they do exist. A value-safe type is any class, interface, or type parameter marked with the @ValueSafe annotation, or any subtype of a value-safe type.  If a value-safe class is marked final, it is in fact a value type.  All other value-safe classes must be abstract.  The non-static fields of a value class must be non-public and final, and all its constructors must be private. Under the above rules, a standard interface could be helpful to define value types like Complex.  Here is an example: @ValueSafe public interface ValueType extends java.io.Serializable {     // All methods listed here must get redefined.     // Definitions must be value-safe, which means     // they may depend on component values only.     List<? extends Object> asList();     int hashCode();     boolean equals(@ValueSafe Object c);     String toString(); } //@ValueSafe inherited from supertype: public final class Complex implements ValueType { … The main advantage of such a conventional interface is that (unlike an annotation) it is reified in the runtime type system.  It could appear as an element type or parameter bound, for facilities which are designed to work on value types only.  More broadly, it might assist the JVM to perform dynamic enforcement of the rules for value types. Besides types, the annotation @ValueSafe can mark fields, parameters, local variables, and methods.  (This is redundant when the type is also value-safe, but may be useful when the type is Object or another supertype of a value type.)  Working forward from these annotations, an expression E is defined as value-safe if it satisfies one or more of the following: The type of E is a value-safe type. E names a field, parameter, or local variable whose declaration is marked @ValueSafe. E is a call to a method whose declaration is marked @ValueSafe. E is an assignment to a value-safe variable, field reference, or array reference. E is a cast to a value-safe type from a value-safe expression. E is a conditional expression E0 ? E1 : E2, and both E1 and E2 are value-safe. Assignments to value-safe expressions and initializations of value-safe names must take their values from value-safe expressions. A value-safe expression may not be the subject of a value-unsafe operation.  In particular, it cannot be synchronized on, nor can it be compared with the “==” operator, not even with a null or with another value-safe type. In a program where all of these rules are followed, no value-type value will be subject to a value-unsafe operation.  Thus, the prime axiom of value types will be satisfied, that no two value type will be distinguishable as long as their component values are equal. More Code To illustrate these rules, here are some usage examples for Complex: Complex pi = Complex.valueOf(Math.PI, 0); Complex zero = pi.changeRe(0);  //zero = pi; zero.re = 0; ValueType vtype = pi; @SuppressWarnings("value-unsafe")   Object obj = pi; @ValueSafe Object obj2 = pi; obj2 = new Object();  // ok List<Complex> clist = new ArrayList<Complex>(); clist.add(pi);  // (ok assuming List.add param is @ValueSafe) List<ValueType> vlist = new ArrayList<ValueType>(); vlist.add(pi);  // (ok) List<Object> olist = new ArrayList<Object>(); olist.add(pi);  // warning: "value-unsafe" boolean z = pi.equals(zero); boolean z1 = (pi == zero);  // error: reference comparison on value type boolean z2 = (pi == null);  // error: reference comparison on value type boolean z3 = (pi == obj2);  // error: reference comparison on value type synchronized (pi) { }  // error: synch of value, unpredictable result synchronized (obj2) { }  // unpredictable result Complex qq = pi; qq = null;  // possible NPE; warning: “null-unsafe" qq = (Complex) obj;  // warning: “null-unsafe" qq = Complex.cast(obj);  // OK @SuppressWarnings("null-unsafe")   Complex empty = null;  // possible NPE qq = empty;  // possible NPE (null pollution) The Payoffs It follows from this that either the JVM or the java compiler can replace boxed value-type values with unboxed ones, without affecting normal computations.  Fields and variables of value types can be split into their unboxed components.  Non-static methods on value types can be transformed into static methods which take the components as value parameters. Some common questions arise around this point in any discussion of value types. Why burden the programmer with all these extra rules?  Why not detect programs automagically and perform unboxing transparently?  The answer is that it is easy to break the rules accidently unless they are agreed to by the programmer and enforced.  Automatic unboxing optimizations are tantalizing but (so far) unreachable ideal.  In the current state of the art, it is possible exhibit benchmarks in which automatic unboxing provides the desired effects, but it is not possible to provide a JVM with a performance model that assures the programmer when unboxing will occur.  This is why I’m writing this note, to enlist help from, and provide assurances to, the programmer.  Basically, I’m shooting for a good set of user-supplied “pragmas” to frame the desired optimization. Again, the important thing is that the unboxing must be done reliably, or else programmers will have no reason to work with the extra complexity of the value-safety rules.  There must be a reasonably stable performance model, wherein using a value type has approximately the same performance characteristics as writing the unboxed components as separate Java variables. There are some rough corners to the present scheme.  Since Java fields and array elements are initialized to null, value-type computations which incorporate uninitialized variables can produce null pointer exceptions.  One workaround for this is to require such variables to be null-tested, and the result replaced with a suitable all-zero value of the value type.  That is what the “cast” method does above. Generically typed APIs like List<T> will continue to manipulate boxed values always, at least until we figure out how to do reification of generic type instances.  Use of such APIs will elicit warnings until their type parameters (and/or relevant members) are annotated or typed as value-safe.  Retrofitting List<T> is likely to expose flaws in the present scheme, which we will need to engineer around.  Here are a couple of first approaches: public interface java.util.List<@ValueSafe T> extends Collection<T> { … public interface java.util.List<T extends Object|ValueType> extends Collection<T> { … (The second approach would require disjunctive types, in which value-safety is “contagious” from the constituent types.) With more transformations, the return value types of methods can also be unboxed.  This may require significant bytecode-level transformations, and would work best in the presence of a bytecode representation for multiple value groups, which I have proposed elsewhere under the title “Tuples in the VM”. But for starters, the JVM can apply this transformation under the covers, to internally compiled methods.  This would give a way to express multiple return values and structured return values, which is a significant pain-point for Java programmers, especially those who work with low-level structure types favored by modern vector and graphics processors.  The lack of multiple return values has a strong distorting effect on many Java APIs. Even if the JVM fails to unbox a value, there is still potential benefit to the value type.  Clustered computing systems something have copy operations (serialization or something similar) which apply implicitly to command operands.  When copying JVM objects, it is extremely helpful to know when an object’s identity is important or not.  If an object reference is a copied operand, the system may have to create a proxy handle which points back to the original object, so that side effects are visible.  Proxies must be managed carefully, and this can be expensive.  On the other hand, value types are exactly those types which a JVM can “copy and forget” with no downside. Array types are crucial to bulk data interfaces.  (As data sizes and rates increase, bulk data becomes more important than scalar data, so arrays are definitely accompanying us into the future of computing.)  Value types are very helpful for adding structure to bulk data, so a successful value type mechanism will make it easier for us to express richer forms of bulk data. Unboxing arrays (i.e., arrays containing unboxed values) will provide better cache and memory density, and more direct data movement within clustered or heterogeneous computing systems.  They require the deepest transformations, relative to today’s JVM.  There is an impedance mismatch between value-type arrays and Java’s covariant array typing, so compromises will need to be struck with existing Java semantics.  It is probably worth the effort, since arrays of unboxed value types are inherently more memory-efficient than standard Java arrays, which rely on dependent pointer chains. It may be sufficient to extend the “value-safe” concept to array declarations, and allow low-level transformations to change value-safe array declarations from the standard boxed form into an unboxed tuple-based form.  Such value-safe arrays would not be convertible to Object[] arrays.  Certain connection points, such as Arrays.copyOf and System.arraycopy might need additional input/output combinations, to allow smooth conversion between arrays with boxed and unboxed elements. Alternatively, the correct solution may have to wait until we have enough reification of generic types, and enough operator overloading, to enable an overhaul of Java arrays. Implicit Method Definitions The example of class Complex above may be unattractively complex.  I believe most or all of the elements of the example class are required by the logic of value types. If this is true, a programmer who writes a value type will have to write lots of error-prone boilerplate code.  On the other hand, I think nearly all of the code (except for the domain-specific parts like plus and minus) can be implicitly generated. Java has a rule for implicitly defining a class’s constructor, if no it defines no constructors explicitly.  Likewise, there are rules for providing default access modifiers for interface members.  Because of the highly regular structure of value types, it might be reasonable to perform similar implicit transformations on value types.  Here’s an example of a “highly implicit” definition of a complex number type: public class Complex implements ValueType {  // implicitly final     public double re, im;  // implicitly public final     //implicit methods are defined elementwise from te fields:     //  toString, asList, equals(2), hashCode, valueOf, cast     //optionally, explicit methods (plus, abs, etc.) would go here } In other words, with the right defaults, a simple value type definition can be a one-liner.  The observant reader will have noticed the similarities (and suitable differences) between the explicit methods above and the corresponding methods for List<T>. Another way to abbreviate such a class would be to make an annotation the primary trigger of the functionality, and to add the interface(s) implicitly: public @ValueType class Complex { … // implicitly final, implements ValueType (But to me it seems better to communicate the “magic” via an interface, even if it is rooted in an annotation.) Implicitly Defined Value Types So far we have been working with nominal value types, which is to say that the sequence of typed components is associated with a name and additional methods that convey the intention of the programmer.  A simple ordered pair of floating point numbers can be variously interpreted as (to name a few possibilities) a rectangular or polar complex number or Cartesian point.  The name and the methods convey the intended meaning. But what if we need a truly simple ordered pair of floating point numbers, without any further conceptual baggage?  Perhaps we are writing a method (like “divideAndRemainder”) which naturally returns a pair of numbers instead of a single number.  Wrapping the pair of numbers in a nominal type (like “QuotientAndRemainder”) makes as little sense as wrapping a single return value in a nominal type (like “Quotient”).  What we need here are structural value types commonly known as tuples. For the present discussion, let us assign a conventional, JVM-friendly name to tuples, roughly as follows: public class java.lang.tuple.$DD extends java.lang.tuple.Tuple {      double $1, $2; } Here the component names are fixed and all the required methods are defined implicitly.  The supertype is an abstract class which has suitable shared declarations.  The name itself mentions a JVM-style method parameter descriptor, which may be “cracked” to determine the number and types of the component fields. The odd thing about such a tuple type (and structural types in general) is it must be instantiated lazily, in response to linkage requests from one or more classes that need it.  The JVM and/or its class loaders must be prepared to spin a tuple type on demand, given a simple name reference, $xyz, where the xyz is cracked into a series of component types.  (Specifics of naming and name mangling need some tasteful engineering.) Tuples also seem to demand, even more than nominal types, some support from the language.  (This is probably because notations for non-nominal types work best as combinations of punctuation and type names, rather than named constructors like Function3 or Tuple2.)  At a minimum, languages with tuples usually (I think) have some sort of simple bracket notation for creating tuples, and a corresponding pattern-matching syntax (or “destructuring bind”) for taking tuples apart, at least when they are parameter lists.  Designing such a syntax is no simple thing, because it ought to play well with nominal value types, and also with pre-existing Java features, such as method parameter lists, implicit conversions, generic types, and reflection.  That is a task for another day. Other Use Cases Besides complex numbers and simple tuples there are many use cases for value types.  Many tuple-like types have natural value-type representations. These include rational numbers, point locations and pixel colors, and various kinds of dates and addresses. Other types have a variable-length ‘tail’ of internal values. The most common example of this is String, which is (mathematically) a sequence of UTF-16 character values. Similarly, bit vectors, multiple-precision numbers, and polynomials are composed of sequences of values. Such types include, in their representation, a reference to a variable-sized data structure (often an array) which (somehow) represents the sequence of values. The value type may also include ’header’ information. Variable-sized values often have a length distribution which favors short lengths. In that case, the design of the value type can make the first few values in the sequence be direct ’header’ fields of the value type. In the common case where the header is enough to represent the whole value, the tail can be a shared null value, or even just a null reference. Note that the tail need not be an immutable object, as long as the header type encapsulates it well enough. This is the case with String, where the tail is a mutable (but never mutated) character array. Field types and their order must be a globally visible part of the API.  The structure of the value type must be transparent enough to have a globally consistent unboxed representation, so that all callers and callees agree about the type and order of components  that appear as parameters, return types, and array elements.  This is a trade-off between efficiency and encapsulation, which is forced on us when we remove an indirection enjoyed by boxed representations.  A JVM-only transformation would not care about such visibility, but a bytecode transformation would need to take care that (say) the components of complex numbers would not get swapped after a redefinition of Complex and a partial recompile.  Perhaps constant pool references to value types need to declare the field order as assumed by each API user. This brings up the delicate status of private fields in a value type.  It must always be possible to load, store, and copy value types as coordinated groups, and the JVM performs those movements by moving individual scalar values between locals and stack.  If a component field is not public, what is to prevent hostile code from plucking it out of the tuple using a rogue aload or astore instruction?  Nothing but the verifier, so we may need to give it more smarts, so that it treats value types as inseparable groups of stack slots or locals (something like long or double). My initial thought was to make the fields always public, which would make the security problem moot.  But public is not always the right answer; consider the case of String, where the underlying mutable character array must be encapsulated to prevent security holes.  I believe we can win back both sides of the tradeoff, by training the verifier never to split up the components in an unboxed value.  Just as the verifier encapsulates the two halves of a 64-bit primitive, it can encapsulate the the header and body of an unboxed String, so that no code other than that of class String itself can take apart the values. Similar to String, we could build an efficient multi-precision decimal type along these lines: public final class DecimalValue extends ValueType {     protected final long header;     protected private final BigInteger digits;     public DecimalValue valueOf(int value, int scale) {         assert(scale >= 0);         return new DecimalValue(((long)value << 32) + scale, null);     }     public DecimalValue valueOf(long value, int scale) {         if (value == (int) value)             return valueOf((int)value, scale);         return new DecimalValue(-scale, new BigInteger(value));     } } Values of this type would be passed between methods as two machine words. Small values (those with a significand which fits into 32 bits) would be represented without any heap data at all, unless the DecimalValue itself were boxed. (Note the tension between encapsulation and unboxing in this case.  It would be better if the header and digits fields were private, but depending on where the unboxing information must “leak”, it is probably safer to make a public revelation of the internal structure.) Note that, although an array of Complex can be faked with a double-length array of double, there is no easy way to fake an array of unboxed DecimalValues.  (Either an array of boxed values or a transposed pair of homogeneous arrays would be reasonable fallbacks, in a current JVM.)  Getting the full benefit of unboxing and arrays will require some new JVM magic. Although the JVM emphasizes portability, system dependent code will benefit from using machine-level types larger than 64 bits.  For example, the back end of a linear algebra package might benefit from value types like Float4 which map to stock vector types.  This is probably only worthwhile if the unboxing arrays can be packed with such values. More Daydreams A more finely-divided design for dynamic enforcement of value safety could feature separate marker interfaces for each invariant.  An empty marker interface Unsynchronizable could cause suitable exceptions for monitor instructions on objects in marked classes.  More radically, a Interchangeable marker interface could cause JVM primitives that are sensitive to object identity to raise exceptions; the strangest result would be that the acmp instruction would have to be specified as raising an exception. @ValueSafe public interface ValueType extends java.io.Serializable,         Unsynchronizable, Interchangeable { … public class Complex implements ValueType {     // inherits Serializable, Unsynchronizable, Interchangeable, @ValueSafe     … It seems possible that Integer and the other wrapper types could be retro-fitted as value-safe types.  This is a major change, since wrapper objects would be unsynchronizable and their references interchangeable.  It is likely that code which violates value-safety for wrapper types exists but is uncommon.  It is less plausible to retro-fit String, since the prominent operation String.intern is often used with value-unsafe code. We should also reconsider the distinction between boxed and unboxed values in code.  The design presented above obscures that distinction.  As another thought experiment, we could imagine making a first class distinction in the type system between boxed and unboxed representations.  Since only primitive types are named with a lower-case initial letter, we could define that the capitalized version of a value type name always refers to the boxed representation, while the initial lower-case variant always refers to boxed.  For example: complex pi = complex.valueOf(Math.PI, 0); Complex boxPi = pi;  // convert to boxed myList.add(boxPi); complex z = myList.get(0);  // unbox Such a convention could perhaps absorb the current difference between int and Integer, double and Double. It might also allow the programmer to express a helpful distinction among array types. As said above, array types are crucial to bulk data interfaces, but are limited in the JVM.  Extending arrays beyond the present limitations is worth thinking about; for example, the Maxine JVM implementation has a hybrid object/array type.  Something like this which can also accommodate value type components seems worthwhile.  On the other hand, does it make sense for value types to contain short arrays?  And why should random-access arrays be the end of our design process, when bulk data is often sequentially accessed, and it might make sense to have heterogeneous streams of data as the natural “jumbo” data structure.  These considerations must wait for another day and another note. More Work It seems to me that a good sequence for introducing such value types would be as follows: Add the value-safety restrictions to an experimental version of javac. Code some sample applications with value types, including Complex and DecimalValue. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. A staggered roll-out like this would decouple language changes from bytecode changes, which is always a convenient thing. A similar investigation should be applied (concurrently) to array types.  In this case, it seems to me that the starting point is in the JVM: Add an experimental unboxing array data structure to a production JVM, perhaps along the lines of Maxine hybrids.  No bytecode or language support is required at first; everything can be done with encapsulated unsafe operations and/or method handles. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. That’s enough musing me for now.  Back to work!

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• Java Cloud Service Integration to REST Service

  - by Jani Rautiainen

  Service (JCS) provides a platform to develop and deploy business applications in the cloud. In Fusion Applications Cloud deployments customers do not have the option to deploy custom applications developed with JDeveloper to ensure the integrity and supportability of the hosted application service. Instead the custom applications can be deployed to the JCS and integrated to the Fusion Application Cloud instance. This series of articles will go through the features of JCS, provide end-to-end examples on how to develop and deploy applications on JCS and how to integrate them with the Fusion Applications instance. In this article a custom application integrating with REST service will be implemented. We will use REST services provided by Taleo as an example; however the same approach will work with any REST service. In this example the data from the REST service is used to populate a dynamic table. Pre-requisites Access to Cloud instance In order to deploy the application access to a JCS instance is needed, a free trial JCS instance can be obtained from Oracle Cloud site. To register you will need a credit card even if the credit card will not be charged. To register simply click "Try it" and choose the "Java" option. The confirmation email will contain the connection details. See this video for example of the registration.Once the request is processed you will be assigned 2 service instances; Java and Database. Applications deployed to the JCS must use Oracle Database Cloud Service as their underlying database. So when JCS instance is created a database instance is associated with it using a JDBC data source.The cloud services can be monitored and managed through the web UI. For details refer to Getting Started with Oracle Cloud. JDeveloper JDeveloper contains Cloud specific features related to e.g. connection and deployment. To use these features download the JDeveloper from JDeveloper download site by clicking the "Download JDeveloper 11.1.1.7.1 for ADF deployment on Oracle Cloud" link, this version of JDeveloper will have the JCS integration features that will be used in this article. For versions that do not include the Cloud integration features the Oracle Java Cloud Service SDK or the JCS Java Console can be used for deployment. For details on installing and configuring the JDeveloper refer to the installation guideFor details on SDK refer to Using the Command-Line Interface to Monitor Oracle Java Cloud Service and Using the Command-Line Interface to Manage Oracle Java Cloud Service. Access to a local database The database associated with the JCS instance cannot be connected to with JDBC.  Since creating ADFbc business component requires a JDBC connection we will need access to a local database. 3rd party libraries This example will use some 3rd party libraries for implementing the REST service call and processing the input / output content. Other libraries may also be used, however these are tested to work. Jersey 1.x Jersey library will be used as a client to make the call to the REST service. JCS documentation for supported specifications states: Java API for RESTful Web Services (JAX-RS) 1.1 So Jersey 1.x will be used. Download the single-JAR Jersey bundle; in this example Jersey 1.18 JAR bundle is used. Json-simple Jjson-simple library will be used to process the json objects. Download the  JAR file; in this example json-simple-1.1.1.jar is used. Accessing data in Taleo Before implementing the application it is beneficial to familiarize oneself with the data in Taleo. Easiest way to do this is by using a RESTClient on your browser. Once added to the browser you can access the UI: The client can be used to call the REST services to test the URLs and data before adding them into the application. First derive the base URL for the service this can be done with: Method: GET URL: https://tbe.taleo.net/MANAGER/dispatcher/api/v1/serviceUrl/<company name> The response will contain the base URL to be used for the service calls for the company. Next obtain authentication token with: Method: POST URL: https://ch.tbe.taleo.net/CH07/ats/api/v1/login?orgCode=<company>&userName=<user name>&password=<password> The response includes an authentication token that can be used for few hours to authenticate with the service: {   "response": {     "authToken": "webapi26419680747505890557"   },   "status": {     "detail": {},     "success": true   } } To authenticate the service calls navigate to "Headers -> Custom Header": And add a new request header with: Name: Cookie Value: authToken=webapi26419680747505890557 Once authentication token is defined the tool can be used to invoke REST services; for example: Method: GET URL: https://ch.tbe.taleo.net/CH07/ats/api/v1/object/candidate/search.xml?status=16 This data will be used on the application to be created. For details on the Taleo REST services refer to the Taleo Business Edition REST API Guide. Create Application First Fusion Web Application is created and configured. Start JDeveloper and click "New Application": Application Name: JcsRestDemo Application Package Prefix: oracle.apps.jcs.test Application Template: Fusion Web Application (ADF) Configure Local Cloud Connection Follow the steps documented in the "Java Cloud Service ADF Web Application" article to configure a local database connection needed to create the ADFbc objects. Configure Libraries Add the 3rd party libraries into the class path. Create the following directory and copy the jar files into it: <JDEV_USER_HOME>/JcsRestDemo/lib  Select the "Model" project, navigate "Application -> Project Properties -> Libraries and Classpath -> Add JAR / Directory" and add the 2 3rd party libraries: Accessing Data from Taleo To access data from Taleo using the REST service the 3rd party libraries will be used. 2 Java classes are implemented, one representing the Candidate object and another for accessing the Taleo repository Candidate Candidate object is a POJO object used to represent the candidate data obtained from the Taleo repository. The data obtained will be used to populate the ADFbc object used to display the data on the UI. The candidate object contains simply the variables we obtain using the REST services and the getters / setters for them: Navigate "New -> General -> Java -> Java Class", enter "Candidate" as the name and create it in the package "oracle.apps.jcs.test.model".  Copy / paste the following as the content: import oracle.jbo.domain.Number; public class Candidate { private Number candId; private String firstName; private String lastName; public Candidate() { super(); } public Candidate(Number candId, String firstName, String lastName) { super(); this.candId = candId; this.firstName = firstName; this.lastName = lastName; } public void setCandId(Number candId) { this.candId = candId; } public Number getCandId() { return candId; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getFirstName() { return firstName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getLastName() { return lastName; } } Taleo Repository Taleo repository class will interact with the Taleo REST services. The logic will query data from Taleo and populate Candidate objects with the data. The Candidate object will then be used to populate the ADFbc object used to display data on the UI. Navigate "New -> General -> Java -> Java Class", enter "TaleoRepository" as the name and create it in the package "oracle.apps.jcs.test.model".  Copy / paste the following as the content (for details of the implementation refer to the documentation in the code): import com.sun.jersey.api.client.Client; import com.sun.jersey.api.client.ClientResponse; import com.sun.jersey.api.client.WebResource; import com.sun.jersey.core.util.MultivaluedMapImpl; import java.io.StringReader; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import java.util.Map; import javax.ws.rs.core.MediaType; import javax.ws.rs.core.MultivaluedMap; import oracle.jbo.domain.Number; import org.json.simple.JSONArray; import org.json.simple.JSONObject; import org.json.simple.parser.JSONParser; /** * This class interacts with the Taleo REST services */ public class TaleoRepository { /** * Connection information needed to access the Taleo services */ String _company = null; String _userName = null; String _password = null; /** * Jersey client used to access the REST services */ Client _client = null; /** * Parser for processing the JSON objects used as * input / output for the services */ JSONParser _parser = null; /** * The base url for constructing the REST URLs. This is obtained * from Taleo with a service call */ String _baseUrl = null; /** * Authentication token obtained from Taleo using a service call. * The token can be used to authenticate on subsequent * service calls. The token will expire in 4 hours */ String _authToken = null; /** * Static url that can be used to obtain the url used to construct * service calls for a given company */ private static String _taleoUrl = "https://tbe.taleo.net/MANAGER/dispatcher/api/v1/serviceUrl/"; /** * Default constructor for the repository * Authentication details are passed as parameters and used to generate * authentication token. Note that each service call will * generate its own token. This is done to avoid dealing with the expiry * of the token. Also only 20 tokens are allowed per user simultaneously. * So instead for each call there is login / logout. * * @param company the company for which the service calls are made * @param userName the user name to authenticate with * @param password the password to authenticate with. */ public TaleoRepository(String company, String userName, String password) { super(); _company = company; _userName = userName; _password = password; _client = Client.create(); _parser = new JSONParser(); _baseUrl = getBaseUrl(); } /** * This obtains the base url for a company to be used * to construct the urls for service calls * @return base url for the service calls */ private String getBaseUrl() { String result = null; if (null != _baseUrl) { result = _baseUrl; } else { try { String company = _company; WebResource resource = _client.resource(_taleoUrl + company); ClientResponse response = resource.type(MediaType.APPLICATION_FORM_URLENCODED_TYPE).get(ClientResponse.class); String entity = response.getEntity(String.class); JSONObject jsonObject = (JSONObject)_parser.parse(new StringReader(entity)); JSONObject jsonResponse = (JSONObject)jsonObject.get("response"); result = (String)jsonResponse.get("URL"); } catch (Exception ex) { ex.printStackTrace(); } } return result; } /** * Generates authentication token, that can be used to authenticate on * subsequent service calls. Note that each service call will * generate its own token. This is done to avoid dealing with the expiry * of the token. Also only 20 tokens are allowed per user simultaneously. * So instead for each call there is login / logout. * @return authentication token that can be used to authenticate on * subsequent service calls */ private String login() { String result = null; try { MultivaluedMap<String, String> formData = new MultivaluedMapImpl(); formData.add("orgCode", _company); formData.add("userName", _userName); formData.add("password", _password); WebResource resource = _client.resource(_baseUrl + "login"); ClientResponse response = resource.type(MediaType.APPLICATION_FORM_URLENCODED_TYPE).post(ClientResponse.class, formData); String entity = response.getEntity(String.class); JSONObject jsonObject = (JSONObject)_parser.parse(new StringReader(entity)); JSONObject jsonResponse = (JSONObject)jsonObject.get("response"); result = (String)jsonResponse.get("authToken"); } catch (Exception ex) { throw new RuntimeException("Unable to login ", ex); } if (null == result) throw new RuntimeException("Unable to login "); return result; } /** * Releases a authentication token. Each call to login must be followed * by call to logout after the processing is done. This is required as * the tokens are limited to 20 per user and if not released the tokens * will only expire after 4 hours. * @param authToken */ private void logout(String authToken) { WebResource resource = _client.resource(_baseUrl + "logout"); resource.header("cookie", "authToken=" + authToken).post(ClientResponse.class); } /** * This method is used to obtain a list of candidates using a REST * service call. At this example the query is hard coded to query * based on status. The url constructed to access the service is: * <_baseUrl>/object/candidate/search.xml?status=16 * @return List of candidates obtained with the service call */ public List<Candidate> getCandidates() { List<Candidate> result = new ArrayList<Candidate>(); try { // First login, note that in finally block we must have logout _authToken = "authToken=" + login(); /** * Construct the URL, the resulting url will be: * <_baseUrl>/object/candidate/search.xml?status=16 */ MultivaluedMap<String, String> formData = new MultivaluedMapImpl(); formData.add("status", "16"); JSONArray searchResults = (JSONArray)getTaleoResource("object/candidate/search", "searchResults", formData); /** * Process the results, the resulting JSON object is something like * this (simplified for readability): * * { * "response": * { * "searchResults": * [ * { * "candidate": * { * "candId": 211, * "firstName": "Mary", * "lastName": "Stochi", * logic here will find the candidate object(s), obtain the desired * data from them, construct a Candidate object based on the data * and add it to the results. */ for (Object object : searchResults) { JSONObject temp = (JSONObject)object; JSONObject candidate = (JSONObject)findObject(temp, "candidate"); Long candIdTemp = (Long)candidate.get("candId"); Number candId = (null == candIdTemp ? null : new Number(candIdTemp)); String firstName = (String)candidate.get("firstName"); String lastName = (String)candidate.get("lastName"); result.add(new Candidate(candId, firstName, lastName)); } } catch (Exception ex) { ex.printStackTrace(); } finally { if (null != _authToken) logout(_authToken); } return result; } /** * Convenience method to construct url for the service call, invoke the * service and obtain a resource from the response * @param path the path for the service to be invoked. This is combined * with the base url to construct a url for the service * @param resource the key for the object in the response that will be * obtained * @param parameters any parameters used for the service call. The call * is slightly different depending whether parameters exist or not. * @return the resource from the response for the service call */ private Object getTaleoResource(String path, String resource, MultivaluedMap<String, String> parameters) { Object result = null; try { WebResource webResource = _client.resource(_baseUrl + path); ClientResponse response = null; if (null == parameters) response = webResource.header("cookie", _authToken).get(ClientResponse.class); else response = webResource.queryParams(parameters).header("cookie", _authToken).get(ClientResponse.class); String entity = response.getEntity(String.class); JSONObject jsonObject = (JSONObject)_parser.parse(new StringReader(entity)); result = findObject(jsonObject, resource); } catch (Exception ex) { ex.printStackTrace(); } return result; } /** * Convenience method to recursively find a object with an key * traversing down from a given root object. This will traverse a * JSONObject / JSONArray recursively to find a matching key, if found * the object with the key is returned. * @param root root object which contains the key searched for * @param key the key for the object to search for * @return the object matching the key */ private Object findObject(Object root, String key) { Object result = null; if (root instanceof JSONObject) { JSONObject rootJSON = (JSONObject)root; if (rootJSON.containsKey(key)) { result = rootJSON.get(key); } else { Iterator children = rootJSON.entrySet().iterator(); while (children.hasNext()) { Map.Entry entry = (Map.Entry)children.next(); Object child = entry.getValue(); if (child instanceof JSONObject || child instanceof JSONArray) { result = findObject(child, key); if (null != result) break; } } } } else if (root instanceof JSONArray) { JSONArray rootJSON = (JSONArray)root; for (Object child : rootJSON) { if (child instanceof JSONObject || child instanceof JSONArray) { result = findObject(child, key); if (null != result) break; } } } return result; } }   Creating Business Objects While JCS application can be created without a local database, the local database is required when using ADFbc objects even if database objects are not referred. For this example we will create a "Transient" view object that will be programmatically populated based the data obtained from Taleo REST services. Creating ADFbc objects Choose the "Model" project and navigate "New -> Business Tier : ADF Business Components : View Object". On the "Initialize Business Components Project" choose the local database connection created in previous step. On Step 1 enter "JcsRestDemoVO" on the "Name" and choose "Rows populated programmatically, not based on query": On step 2 create the following attributes: CandId Type: Number Updatable: Always Key Attribute: checked Name Type: String Updatable: Always On steps 3 and 4 accept defaults and click "Next".  On step 5 check the "Application Module" checkbox and enter "JcsRestDemoAM" as the name: Click "Finish" to generate the objects. Populating the VO To display the data on the UI the "transient VO" is populated programmatically based on the data obtained from the Taleo REST services. Open the "JcsRestDemoVOImpl.java". Copy / paste the following as the content (for details of the implementation refer to the documentation in the code): import java.sql.ResultSet; import java.util.List; import java.util.ListIterator; import oracle.jbo.server.ViewObjectImpl; import oracle.jbo.server.ViewRowImpl; import oracle.jbo.server.ViewRowSetImpl; // --------------------------------------------------------------------- // --- File generated by Oracle ADF Business Components Design Time. // --- Tue Feb 18 09:40:25 PST 2014 // --- Custom code may be added to this class. // --- Warning: Do not modify method signatures of generated methods. // --------------------------------------------------------------------- public class JcsRestDemoVOImpl extends ViewObjectImpl { /** * This is the default constructor (do not remove). */ public JcsRestDemoVOImpl() { } @Override public void executeQuery() { /** * For some reason we need to reset everything, otherwise * 2nd entry to the UI screen may fail with * "java.util.NoSuchElementException" in createRowFromResultSet * call to "candidates.next()". I am not sure why this is happening * as the Iterator is new and "hasNext" is true at the point * of the execution. My theory is that since the iterator object is * exactly the same the VO cache somehow reuses the iterator including * the pointer that has already exhausted the iterable elements on the * previous run. Working around the issue * here by cleaning out everything on the VO every time before query * is executed on the VO. */ getViewDef().setQuery(null); getViewDef().setSelectClause(null); setQuery(null); this.reset(); this.clearCache(); super.executeQuery(); } /** * executeQueryForCollection - overridden for custom java data source support. */ protected void executeQueryForCollection(Object qc, Object[] params, int noUserParams) { /** * Integrate with the Taleo REST services using TaleoRepository class. * A list of candidates matching a hard coded query is obtained. */ TaleoRepository repository = new TaleoRepository(<company>, <username>, <password>); List<Candidate> candidates = repository.getCandidates(); /** * Store iterator for the candidates as user data on the collection. * This will be used in createRowFromResultSet to create rows based on * the custom iterator. */ ListIterator<Candidate> candidatescIterator = candidates.listIterator(); setUserDataForCollection(qc, candidatescIterator); super.executeQueryForCollection(qc, params, noUserParams); } /** * hasNextForCollection - overridden for custom java data source support. */ protected boolean hasNextForCollection(Object qc) { boolean result = false; /** * Determines whether there are candidates for which to create a row */ ListIterator<Candidate> candidates = (ListIterator<Candidate>)getUserDataForCollection(qc); result = candidates.hasNext(); /** * If all candidates to be created indicate that processing is done */ if (!result) { setFetchCompleteForCollection(qc, true); } return result; } /** * createRowFromResultSet - overridden for custom java data source support. */ protected ViewRowImpl createRowFromResultSet(Object qc, ResultSet resultSet) { /** * Obtain the next candidate from the collection and create a row * for it. */ ListIterator<Candidate> candidates = (ListIterator<Candidate>)getUserDataForCollection(qc); ViewRowImpl row = createNewRowForCollection(qc); try { Candidate candidate = candidates.next(); row.setAttribute("CandId", candidate.getCandId()); row.setAttribute("Name", candidate.getFirstName() + " " + candidate.getLastName()); } catch (Exception e) { e.printStackTrace(); } return row; } /** * getQueryHitCount - overridden for custom java data source support. */ public long getQueryHitCount(ViewRowSetImpl viewRowSet) { /** * For this example this is not implemented rather we always return 0. */ return 0; } } Creating UI Choose the "ViewController" project and navigate "New -> Web Tier : JSF : JSF Page". On the "Create JSF Page" enter "JcsRestDemo" as name and ensure that the "Create as XML document (*.jspx)" is checked.  Open "JcsRestDemo.jspx" and navigate to "Data Controls -> JcsRestDemoAMDataControl -> JcsRestDemoVO1" and drag & drop the VO to the "<af:form> " as a "ADF Read-only Table": Accept the defaults in "Edit Table Columns". To execute the query navigate to to "Data Controls -> JcsRestDemoAMDataControl -> JcsRestDemoVO1 -> Operations -> Execute" and drag & drop the operation to the "<af:form> " as a "Button": Deploying to JCS Follow the same steps as documented in previous article"Java Cloud Service ADF Web Application". Once deployed the application can be accessed with URL: https://java-[identity domain].java.[data center].oraclecloudapps.com/JcsRestDemo-ViewController-context-root/faces/JcsRestDemo.jspx The UI displays a list of candidates obtained from the Taleo REST Services: Summary In this article we learned how to integrate with REST services using Jersey library in JCS. In future articles various other integration techniques will be covered.

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• Squid + Dans Guardian (simple configuration)

  - by The Digital Ninja

  I just built a new proxy server and compiled the latest versions of squid and dansguardian. We use basic authentication to select what users are allowed outside of our network. It seems squid is working just fine and accepts my username and password and lets me out. But if i connect to dans guardian, it prompts for username and password and then displays a message saying my username is not allowed to access the internet. Its pulling my username for the error message so i know it knows who i am. The part i get confused on is i thought that part was handled all by squid, and squid is working flawlessly. Can someone please double check my config files and tell me if i'm missing something or there is some new option i must set to get this to work. dansguardian.conf # Web Access Denied Reporting (does not affect logging) # # -1 = log, but do not block - Stealth mode # 0 = just say 'Access Denied' # 1 = report why but not what denied phrase # 2 = report fully # 3 = use HTML template file (accessdeniedaddress ignored) - recommended # reportinglevel = 3 # Language dir where languages are stored for internationalisation. # The HTML template within this dir is only used when reportinglevel # is set to 3. When used, DansGuardian will display the HTML file instead of # using the perl cgi script. This option is faster, cleaner # and easier to customise the access denied page. # The language file is used no matter what setting however. # languagedir = '/etc/dansguardian/languages' # language to use from languagedir. language = 'ukenglish' # Logging Settings # # 0 = none 1 = just denied 2 = all text based 3 = all requests loglevel = 3 # Log Exception Hits # Log if an exception (user, ip, URL, phrase) is matched and so # the page gets let through. Can be useful for diagnosing # why a site gets through the filter. on | off logexceptionhits = on # Log File Format # 1 = DansGuardian format 2 = CSV-style format # 3 = Squid Log File Format 4 = Tab delimited logfileformat = 1 # Log file location # # Defines the log directory and filename. #loglocation = '/var/log/dansguardian/access.log' # Network Settings # # the IP that DansGuardian listens on. If left blank DansGuardian will # listen on all IPs. That would include all NICs, loopback, modem, etc. # Normally you would have your firewall protecting this, but if you want # you can limit it to only 1 IP. Yes only one. filterip = # the port that DansGuardian listens to. filterport = 8080 # the ip of the proxy (default is the loopback - i.e. this server) proxyip = 127.0.0.1 # the port DansGuardian connects to proxy on proxyport = 3128 # accessdeniedaddress is the address of your web server to which the cgi # dansguardian reporting script was copied # Do NOT change from the default if you are not using the cgi. # accessdeniedaddress = 'http://YOURSERVER.YOURDOMAIN/cgi-bin/dansguardian.pl' # Non standard delimiter (only used with accessdeniedaddress) # Default is enabled but to go back to the original standard mode dissable it. nonstandarddelimiter = on # Banned image replacement # Images that are banned due to domain/url/etc reasons including those # in the adverts blacklists can be replaced by an image. This will, # for example, hide images from advert sites and remove broken image # icons from banned domains. # 0 = off # 1 = on (default) usecustombannedimage = 1 custombannedimagefile = '/etc/dansguardian/transparent1x1.gif' # Filter groups options # filtergroups sets the number of filter groups. A filter group is a set of content # filtering options you can apply to a group of users. The value must be 1 or more. # DansGuardian will automatically look for dansguardianfN.conf where N is the filter # group. To assign users to groups use the filtergroupslist option. All users default # to filter group 1. You must have some sort of authentication to be able to map users # to a group. The more filter groups the more copies of the lists will be in RAM so # use as few as possible. filtergroups = 1 filtergroupslist = '/etc/dansguardian/filtergroupslist' # Authentication files location bannediplist = '/etc/dansguardian/bannediplist' exceptioniplist = '/etc/dansguardian/exceptioniplist' banneduserlist = '/etc/dansguardian/banneduserlist' exceptionuserlist = '/etc/dansguardian/exceptionuserlist' # Show weighted phrases found # If enabled then the phrases found that made up the total which excedes # the naughtyness limit will be logged and, if the reporting level is # high enough, reported. on | off showweightedfound = on # Weighted phrase mode # There are 3 possible modes of operation: # 0 = off = do not use the weighted phrase feature. # 1 = on, normal = normal weighted phrase operation. # 2 = on, singular = each weighted phrase found only counts once on a page. # weightedphrasemode = 2 # Positive result caching for text URLs # Caches good pages so they don't need to be scanned again # 0 = off (recommended for ISPs with users with disimilar browsing) # 1000 = recommended for most users # 5000 = suggested max upper limit urlcachenumber = # # Age before they are stale and should be ignored in seconds # 0 = never # 900 = recommended = 15 mins urlcacheage = # Smart and Raw phrase content filtering options # Smart is where the multiple spaces and HTML are removed before phrase filtering # Raw is where the raw HTML including meta tags are phrase filtered # CPU usage can be effectively halved by using setting 0 or 1 # 0 = raw only # 1 = smart only # 2 = both (default) phrasefiltermode = 2 # Lower casing options # When a document is scanned the uppercase letters are converted to lower case # in order to compare them with the phrases. However this can break Big5 and # other 16-bit texts. If needed preserve the case. As of version 2.7.0 accented # characters are supported. # 0 = force lower case (default) # 1 = do not change case preservecase = 0 # Hex decoding options # When a document is scanned it can optionally convert %XX to chars. # If you find documents are getting past the phrase filtering due to encoding # then enable. However this can break Big5 and other 16-bit texts. # 0 = disabled (default) # 1 = enabled hexdecodecontent = 0 # Force Quick Search rather than DFA search algorithm # The current DFA implementation is not totally 16-bit character compatible # but is used by default as it handles large phrase lists much faster. # If you wish to use a large number of 16-bit character phrases then # enable this option. # 0 = off (default) # 1 = on (Big5 compatible) forcequicksearch = 0 # Reverse lookups for banned site and URLs. # If set to on, DansGuardian will look up the forward DNS for an IP URL # address and search for both in the banned site and URL lists. This would # prevent a user from simply entering the IP for a banned address. # It will reduce searching speed somewhat so unless you have a local caching # DNS server, leave it off and use the Blanket IP Block option in the # bannedsitelist file instead. reverseaddresslookups = off # Reverse lookups for banned and exception IP lists. # If set to on, DansGuardian will look up the forward DNS for the IP # of the connecting computer. This means you can put in hostnames in # the exceptioniplist and bannediplist. # It will reduce searching speed somewhat so unless you have a local DNS server, # leave it off. reverseclientiplookups = off # Build bannedsitelist and bannedurllist cache files. # This will compare the date stamp of the list file with the date stamp of # the cache file and will recreate as needed. # If a bsl or bul .processed file exists, then that will be used instead. # It will increase process start speed by 300%. On slow computers this will # be significant. Fast computers do not need this option. on | off createlistcachefiles = on # POST protection (web upload and forms) # does not block forms without any file upload, i.e. this is just for # blocking or limiting uploads # measured in kibibytes after MIME encoding and header bumph # use 0 for a complete block # use higher (e.g. 512 = 512Kbytes) for limiting # use -1 for no blocking #maxuploadsize = 512 #maxuploadsize = 0 maxuploadsize = -1 # Max content filter page size # Sometimes web servers label binary files as text which can be very # large which causes a huge drain on memory and cpu resources. # To counter this, you can limit the size of the document to be # filtered and get it to just pass it straight through. # This setting also applies to content regular expression modification. # The size is in Kibibytes - eg 2048 = 2Mb # use 0 for no limit maxcontentfiltersize = # Username identification methods (used in logging) # You can have as many methods as you want and not just one. The first one # will be used then if no username is found, the next will be used. # * proxyauth is for when basic proxy authentication is used (no good for # transparent proxying). # * ntlm is for when the proxy supports the MS NTLM authentication # protocol. (Only works with IE5.5 sp1 and later). **NOT IMPLEMENTED** # * ident is for when the others don't work. It will contact the computer # that the connection came from and try to connect to an identd server # and query it for the user owner of the connection. usernameidmethodproxyauth = on usernameidmethodntlm = off # **NOT IMPLEMENTED** usernameidmethodident = off # Preemptive banning - this means that if you have proxy auth enabled and a user accesses # a site banned by URL for example they will be denied straight away without a request # for their user and pass. This has the effect of requiring the user to visit a clean # site first before it knows who they are and thus maybe an admin user. # This is how DansGuardian has always worked but in some situations it is less than # ideal. So you can optionally disable it. Default is on. # As a side effect disabling this makes AD image replacement work better as the mime # type is know. preemptivebanning = on # Misc settings # if on it adds an X-Forwarded-For: <clientip> to the HTTP request # header. This may help solve some problem sites that need to know the # source ip. on | off forwardedfor = on # if on it uses the X-Forwarded-For: <clientip> to determine the client # IP. This is for when you have squid between the clients and DansGuardian. # Warning - headers are easily spoofed. on | off usexforwardedfor = off # if on it logs some debug info regarding fork()ing and accept()ing which # can usually be ignored. These are logged by syslog. It is safe to leave # it on or off logconnectionhandlingerrors = on # Fork pool options # sets the maximum number of processes to sporn to handle the incomming # connections. Max value usually 250 depending on OS. # On large sites you might want to try 180. maxchildren = 180 # sets the minimum number of processes to sporn to handle the incomming connections. # On large sites you might want to try 32. minchildren = 32 # sets the minimum number of processes to be kept ready to handle connections. # On large sites you might want to try 8. minsparechildren = 8 # sets the minimum number of processes to sporn when it runs out # On large sites you might want to try 10. preforkchildren = 10 # sets the maximum number of processes to have doing nothing. # When this many are spare it will cull some of them. # On large sites you might want to try 64. maxsparechildren = 64 # sets the maximum age of a child process before it croaks it. # This is the number of connections they handle before exiting. # On large sites you might want to try 10000. maxagechildren = 5000 # Process options # (Change these only if you really know what you are doing). # These options allow you to run multiple instances of DansGuardian on a single machine. # Remember to edit the log file path above also if that is your intention. # IPC filename # # Defines IPC server directory and filename used to communicate with the log process. ipcfilename = '/tmp/.dguardianipc' # URL list IPC filename # # Defines URL list IPC server directory and filename used to communicate with the URL # cache process. urlipcfilename = '/tmp/.dguardianurlipc' # PID filename # # Defines process id directory and filename. #pidfilename = '/var/run/dansguardian.pid' # Disable daemoning # If enabled the process will not fork into the background. # It is not usually advantageous to do this. # on|off ( defaults to off ) nodaemon = off # Disable logging process # on|off ( defaults to off ) nologger = off # Daemon runas user and group # This is the user that DansGuardian runs as. Normally the user/group nobody. # Uncomment to use. Defaults to the user set at compile time. # daemonuser = 'nobody' # daemongroup = 'nobody' # Soft restart # When on this disables the forced killing off all processes in the process group. # This is not to be confused with the -g run time option - they are not related. # on|off ( defaults to off ) softrestart = off maxcontentramcachescansize = 2000 maxcontentfilecachescansize = 20000 downloadmanager = '/etc/dansguardian/downloadmanagers/default.conf' authplugin = '/etc/dansguardian/authplugins/proxy-basic.conf' Squid.conf http_port 3128 hierarchy_stoplist cgi-bin ? acl QUERY urlpath_regex cgi-bin \? cache deny QUERY acl apache rep_header Server ^Apache #broken_vary_encoding allow apache access_log /squid/var/logs/access.log squid hosts_file /etc/hosts auth_param basic program /squid/libexec/ncsa_auth /squid/etc/userbasic.auth auth_param basic children 5 auth_param basic realm proxy auth_param basic credentialsttl 2 hours auth_param basic casesensitive off refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern . 0 20% 4320 acl NoAuthNec src <HIDDEN FOR SECURITY> acl BrkRm src <HIDDEN FOR SECURITY> acl Dials src <HIDDEN FOR SECURITY> acl Comps src <HIDDEN FOR SECURITY> acl whsws dstdom_regex -i .opensuse.org .novell.com .suse.com mirror.mcs.an1.gov mirrors.kernerl.org www.suse.de suse.mirrors.tds.net mirrros.usc.edu ftp.ale.org suse.cs.utah.edu mirrors.usc.edu mirror.usc.an1.gov linux.nssl.noaa.gov noaa.gov .kernel.org ftp.ale.org ftp.gwdg.de .medibuntu.org mirrors.xmission.com .canonical.com .ubuntu. acl opensites dstdom_regex -i .mbsbooks.com .bowker.com .usps.com .usps.gov .ups.com .fedex.com go.microsoft.com .microsoft.com .apple.com toolbar.msn.com .contacts.msn.com update.services.openoffice.org fms2.pointroll.speedera.net services.wmdrm.windowsmedia.com windowsupdate.com .adobe.com .symantec.com .vitalbook.com vxn1.datawire.net vxn.datawire.net download.lavasoft.de .download.lavasoft.com .lavasoft.com updates.ls-servers.com .canadapost. .myyellow.com minirick symantecliveupdate.com wm.overdrive.com www.overdrive.com productactivation.one.microsoft.com www.update.microsoft.com testdrive.whoson.com www.columbia.k12.mo.us banners.wunderground.com .kofax.com .gotomeeting.com tools.google.com .dl.google.com .cache.googlevideo.com .gpdl.google.com .clients.google.com cache.pack.google.com kh.google.com maps.google.com auth.keyhole.com .contacts.msn.com .hrblock.com .taxcut.com .merchantadvantage.com .jtv.com .malwarebytes.org www.google-analytics.com dcs.support.xerox.com .dhl.com .webtrendslive.com javadl-esd.sun.com javadl-alt.sun.com .excelsior.edu .dhlglobalmail.com .nessus.org .foxitsoftware.com foxit.vo.llnwd.net installshield.com .mindjet.com .mediascouter.com media.us.elsevierhealth.com .xplana.com .govtrack.us sa.tulsacc.edu .omniture.com fpdownload.macromedia.com webservices.amazon.com acl password proxy_auth REQUIRED acl all src all acl manager proto cache_object acl localhost src 127.0.0.1/255.255.255.255 acl to_localhost dst 127.0.0.0/8 acl SSL_ports port 443 563 631 2001 2005 8731 9001 9080 10000 acl Safe_ports port 80 # 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  Read the article

• How John Got 15x Improvement Without Really Trying

  - by rchrd

  The following article was published on a Sun Microsystems website a number of years ago by John Feo. It is still useful and worth preserving. So I'm republishing it here.  How I Got 15x Improvement Without Really Trying John Feo, Sun Microsystems Taking ten "personal" program codes used in scientific and engineering research, the author was able to get from 2 to 15 times performance improvement easily by applying some simple general optimization techniques. Introduction Scientific research based on computer simulation depends on the simulation for advancement. The research can advance only as fast as the computational codes can execute. The codes' efficiency determines both the rate and quality of results. In the same amount of time, a faster program can generate more results and can carry out a more detailed simulation of physical phenomena than a slower program. Highly optimized programs help science advance quickly and insure that monies supporting scientific research are used as effectively as possible. Scientific computer codes divide into three broad categories: ISV, community, and personal. ISV codes are large, mature production codes developed and sold commercially. The codes improve slowly over time both in methods and capabilities, and they are well tuned for most vendor platforms. Since the codes are mature and complex, there are few opportunities to improve their performance solely through code optimization. Improvements of 10% to 15% are typical. Examples of ISV codes are DYNA3D, Gaussian, and Nastran. Community codes are non-commercial production codes used by a particular research field. Generally, they are developed and distributed by a single academic or research institution with assistance from the community. Most users just run the codes, but some develop new methods and extensions that feed back into the general release. The codes are available on most vendor platforms. Since these codes are younger than ISV codes, there are more opportunities to optimize the source code. Improvements of 50% are not unusual. Examples of community codes are AMBER, CHARM, BLAST, and FASTA. Personal codes are those written by single users or small research groups for their own use. These codes are not distributed, but may be passed from professor-to-student or student-to-student over several years. They form the primordial ocean of applications from which community and ISV codes emerge. Government research grants pay for the development of most personal codes. This paper reports on the nature and performance of this class of codes. Over the last year, I have looked at over two dozen personal codes from more than a dozen research institutions. The codes cover a variety of scientific fields, including astronomy, atmospheric sciences, bioinformatics, biology, chemistry, geology, and physics. The sources range from a few hundred lines to more than ten thousand lines, and are written in Fortran, Fortran 90, C, and C++. For the most part, the codes are modular, documented, and written in a clear, straightforward manner. They do not use complex language features, advanced data structures, programming tricks, or libraries. I had little trouble understanding what the codes did or how data structures were used. Most came with a makefile. Surprisingly, only one of the applications is parallel. All developers have access to parallel machines, so availability is not an issue. Several tried to parallelize their applications, but stopped after encountering difficulties. Lack of education and a perception that parallelism is difficult prevented most from trying. I parallelized several of the codes using OpenMP, and did not judge any of the codes as difficult to parallelize. Even more surprising than the lack of parallelism is the inefficiency of the codes. I was able to get large improvements in performance in a matter of a few days applying simple optimization techniques. Table 1 lists ten representative codes [names and affiliation are omitted to preserve anonymity]. Improvements on one processor range from 2x to 15.5x with a simple average of 4.75x. I did not use sophisticated performance tools or drill deep into the program's execution character as one would do when tuning ISV or community codes. Using only a profiler and source line timers, I identified inefficient sections of code and improved their performance by inspection. The changes were at a high level. I am sure there is another factor of 2 or 3 in each code, and more if the codes are parallelized. The study’s results show that personal scientific codes are running many times slower than they should and that the problem is pervasive. Computational scientists are not sloppy programmers; however, few are trained in the art of computer programming or code optimization. I found that most have a working knowledge of some programming language and standard software engineering practices; but they do not know, or think about, how to make their programs run faster. They simply do not know the standard techniques used to make codes run faster. In fact, they do not even perceive that such techniques exist. The case studies described in this paper show that applying simple, well known techniques can significantly increase the performance of personal codes. It is important that the scientific community and the Government agencies that support scientific research find ways to better educate academic scientific programmers. The inefficiency of their codes is so bad that it is retarding both the quality and progress of scientific research. # cacheperformance redundantoperations loopstructures performanceimprovement 1 x x 15.5 2 x 2.8 3 x x 2.5 4 x 2.1 5 x x 2.0 6 x 5.0 7 x 5.8 8 x 6.3 9 2.2 10 x x 3.3 Table 1 — Area of improvement and performance gains of 10 codes The remainder of the paper is organized as follows: sections 2, 3, and 4 discuss the three most common sources of inefficiencies in the codes studied. These are cache performance, redundant operations, and loop structures. Each section includes several examples. The last section summaries the work and suggests a possible solution to the issues raised. Optimizing cache performance Commodity microprocessor systems use caches to increase memory bandwidth and reduce memory latencies. Typical latencies from processor to L1, L2, local, and remote memory are 3, 10, 50, and 200 cycles, respectively. Moreover, bandwidth falls off dramatically as memory distances increase. Programs that do not use cache effectively run many times slower than programs that do. When optimizing for cache, the biggest performance gains are achieved by accessing data in cache order and reusing data to amortize the overhead of cache misses. Secondary considerations are prefetching, associativity, and replacement; however, the understanding and analysis required to optimize for the latter are probably beyond the capabilities of the non-expert. Much can be gained simply by accessing data in the correct order and maximizing data reuse. 6 out of the 10 codes studied here benefited from such high level optimizations. Array Accesses The most important cache optimization is the most basic: accessing Fortran array elements in column order and C array elements in row order. Four of the ten codes—1, 2, 4, and 10—got it wrong. Compilers will restructure nested loops to optimize cache performance, but may not do so if the loop structure is too complex, or the loop body includes conditionals, complex addressing, or function calls. In code 1, the compiler failed to invert a key loop because of complex addressing do I = 0, 1010, delta_x IM = I - delta_x IP = I + delta_x do J = 5, 995, delta_x JM = J - delta_x JP = J + delta_x T1 = CA1(IP, J) + CA1(I, JP) T2 = CA1(IM, J) + CA1(I, JM) S1 = T1 + T2 - 4 * CA1(I, J) CA(I, J) = CA1(I, J) + D * S1 end do end do In code 2, the culprit is conditionals do I = 1, N do J = 1, N If (IFLAG(I,J) .EQ. 0) then T1 = Value(I, J-1) T2 = Value(I-1, J) T3 = Value(I, J) T4 = Value(I+1, J) T5 = Value(I, J+1) Value(I,J) = 0.25 * (T1 + T2 + T5 + T4) Delta = ABS(T3 - Value(I,J)) If (Delta .GT. MaxDelta) MaxDelta = Delta endif enddo enddo I fixed both programs by inverting the loops by hand. Code 10 has three-dimensional arrays and triply nested loops. The structure of the most computationally intensive loops is too complex to invert automatically or by hand. The only practical solution is to transpose the arrays so that the dimension accessed by the innermost loop is in cache order. The arrays can be transposed at construction or prior to entering a computationally intensive section of code. The former requires all array references to be modified, while the latter is cost effective only if the cost of the transpose is amortized over many accesses. I used the second approach to optimize code 10. Code 5 has four-dimensional arrays and loops are nested four deep. For all of the reasons cited above the compiler is not able to restructure three key loops. Assume C arrays and let the four dimensions of the arrays be i, j, k, and l. In the original code, the index structure of the three loops is L1: for i L2: for i L3: for i for l for l for j for k for j for k for j for k for l So only L3 accesses array elements in cache order. L1 is a very complex loop—much too complex to invert. I brought the loop into cache alignment by transposing the second and fourth dimensions of the arrays. Since the code uses a macro to compute all array indexes, I effected the transpose at construction and changed the macro appropriately. The dimensions of the new arrays are now: i, l, k, and j. L3 is a simple loop and easily inverted. L2 has a loop-carried scalar dependence in k. By promoting the scalar name that carries the dependence to an array, I was able to invert the third and fourth subloops aligning the loop with cache. Code 5 is by far the most difficult of the four codes to optimize for array accesses; but the knowledge required to fix the problems is no more than that required for the other codes. I would judge this code at the limits of, but not beyond, the capabilities of appropriately trained computational scientists. Array Strides When a cache miss occurs, a line (64 bytes) rather than just one word is loaded into the cache. If data is accessed stride 1, than the cost of the miss is amortized over 8 words. Any stride other than one reduces the cost savings. Two of the ten codes studied suffered from non-unit strides. The codes represent two important classes of "strided" codes. Code 1 employs a multi-grid algorithm to reduce time to convergence. The grids are every tenth, fifth, second, and unit element. Since time to convergence is inversely proportional to the distance between elements, coarse grids converge quickly providing good starting values for finer grids. The better starting values further reduce the time to convergence. The downside is that grids of every nth element, n > 1, introduce non-unit strides into the computation. In the original code, much of the savings of the multi-grid algorithm were lost due to this problem. I eliminated the problem by compressing (copying) coarse grids into continuous memory, and rewriting the computation as a function of the compressed grid. On convergence, I copied the final values of the compressed grid back to the original grid. The savings gained from unit stride access of the compressed grid more than paid for the cost of copying. Using compressed grids, the loop from code 1 included in the previous section becomes do j = 1, GZ do i = 1, GZ T1 = CA(i+0, j-1) + CA(i-1, j+0) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) S1 = T1 + T4 - 4 * CA1(i+0, j+0) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 enddo enddo where CA and CA1 are compressed arrays of size GZ. Code 7 traverses a list of objects selecting objects for later processing. The labels of the selected objects are stored in an array. The selection step has unit stride, but the processing steps have irregular stride. A fix is to save the parameters of the selected objects in temporary arrays as they are selected, and pass the temporary arrays to the processing functions. The fix is practical if the same parameters are used in selection as in processing, or if processing comprises a series of distinct steps which use overlapping subsets of the parameters. Both conditions are true for code 7, so I achieved significant improvement by copying parameters to temporary arrays during selection. Data reuse In the previous sections, we optimized for spatial locality. It is also important to optimize for temporal locality. Once read, a datum should be used as much as possible before it is forced from cache. Loop fusion and loop unrolling are two techniques that increase temporal locality. Unfortunately, both techniques increase register pressure—as loop bodies become larger, the number of registers required to hold temporary values grows. Once register spilling occurs, any gains evaporate quickly. For multiprocessors with small register sets or small caches, the sweet spot can be very small. In the ten codes presented here, I found no opportunities for loop fusion and only two opportunities for loop unrolling (codes 1 and 3). In code 1, unrolling the outer and inner loop one iteration increases the number of result values computed by the loop body from 1 to 4, do J = 1, GZ-2, 2 do I = 1, GZ-2, 2 T1 = CA1(i+0, j-1) + CA1(i-1, j+0) T2 = CA1(i+1, j-1) + CA1(i+0, j+0) T3 = CA1(i+0, j+0) + CA1(i-1, j+1) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) T5 = CA1(i+2, j+0) + CA1(i+1, j+1) T6 = CA1(i+1, j+1) + CA1(i+0, j+2) T7 = CA1(i+2, j+1) + CA1(i+1, j+2) S1 = T1 + T4 - 4 * CA1(i+0, j+0) S2 = T2 + T5 - 4 * CA1(i+1, j+0) S3 = T3 + T6 - 4 * CA1(i+0, j+1) S4 = T4 + T7 - 4 * CA1(i+1, j+1) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 CA(i+1, j+0) = CA1(i+1, j+0) + DD * S2 CA(i+0, j+1) = CA1(i+0, j+1) + DD * S3 CA(i+1, j+1) = CA1(i+1, j+1) + DD * S4 enddo enddo The loop body executes 12 reads, whereas as the rolled loop shown in the previous section executes 20 reads to compute the same four values. In code 3, two loops are unrolled 8 times and one loop is unrolled 4 times. Here is the before for (k = 0; k < NK[u]; k++) { sum = 0.0; for (y = 0; y < NY; y++) { sum += W[y][u][k] * delta[y]; } backprop[i++]=sum; } and after code for (k = 0; k < KK - 8; k+=8) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (y = 0; y < NY; y++) { sum0 += W[y][0][k+0] * delta[y]; sum1 += W[y][0][k+1] * delta[y]; sum2 += W[y][0][k+2] * delta[y]; sum3 += W[y][0][k+3] * delta[y]; sum4 += W[y][0][k+4] * delta[y]; sum5 += W[y][0][k+5] * delta[y]; sum6 += W[y][0][k+6] * delta[y]; sum7 += W[y][0][k+7] * delta[y]; } backprop[k+0] = sum0; backprop[k+1] = sum1; backprop[k+2] = sum2; backprop[k+3] = sum3; backprop[k+4] = sum4; backprop[k+5] = sum5; backprop[k+6] = sum6; backprop[k+7] = sum7; } for one of the loops unrolled 8 times. Optimizing for temporal locality is the most difficult optimization considered in this paper. The concepts are not difficult, but the sweet spot is small. Identifying where the program can benefit from loop unrolling or loop fusion is not trivial. Moreover, it takes some effort to get it right. Still, educating scientific programmers about temporal locality and teaching them how to optimize for it will pay dividends. Reducing instruction count Execution time is a function of instruction count. Reduce the count and you usually reduce the time. The best solution is to use a more efficient algorithm; that is, an algorithm whose order of complexity is smaller, that converges quicker, or is more accurate. Optimizing source code without changing the algorithm yields smaller, but still significant, gains. This paper considers only the latter because the intent is to study how much better codes can run if written by programmers schooled in basic code optimization techniques. The ten codes studied benefited from three types of "instruction reducing" optimizations. The two most prevalent were hoisting invariant memory and data operations out of inner loops. The third was eliminating unnecessary data copying. The nature of these inefficiencies is language dependent. Memory operations The semantics of C make it difficult for the compiler to determine all the invariant memory operations in a loop. The problem is particularly acute for loops in functions since the compiler may not know the values of the function's parameters at every call site when compiling the function. Most compilers support pragmas to help resolve ambiguities; however, these pragmas are not comprehensive and there is no standard syntax. To guarantee that invariant memory operations are not executed repetitively, the user has little choice but to hoist the operations by hand. The problem is not as severe in Fortran programs because in the absence of equivalence statements, it is a violation of the language's semantics for two names to share memory. Codes 3 and 5 are C programs. In both cases, the compiler did not hoist all invariant memory operations from inner loops. Consider the following loop from code 3 for (y = 0; y < NY; y++) { i = 0; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += delta[y] * I1[i++]; } } } Since dW[y][u] can point to the same memory space as delta for one or more values of y and u, assignment to dW[y][u][k] may change the value of delta[y]. In reality, dW and delta do not overlap in memory, so I rewrote the loop as for (y = 0; y < NY; y++) { i = 0; Dy = delta[y]; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += Dy * I1[i++]; } } } Failure to hoist invariant memory operations may be due to complex address calculations. If the compiler can not determine that the address calculation is invariant, then it can hoist neither the calculation nor the associated memory operations. As noted above, code 5 uses a macro to address four-dimensional arrays #define MAT4D(a,q,i,j,k) (double *)((a)->data + (q)*(a)->strides[0] + (i)*(a)->strides[3] + (j)*(a)->strides[2] + (k)*(a)->strides[1]) The macro is too complex for the compiler to understand and so, it does not identify any subexpressions as loop invariant. The simplest way to eliminate the address calculation from the innermost loop (over i) is to define a0 = MAT4D(a,q,0,j,k) before the loop and then replace all instances of *MAT4D(a,q,i,j,k) in the loop with a0[i] A similar problem appears in code 6, a Fortran program. The key loop in this program is do n1 = 1, nh nx1 = (n1 - 1) / nz + 1 nz1 = n1 - nz * (nx1 - 1) do n2 = 1, nh nx2 = (n2 - 1) / nz + 1 nz2 = n2 - nz * (nx2 - 1) ndx = nx2 - nx1 ndy = nz2 - nz1 gxx = grn(1,ndx,ndy) gyy = grn(2,ndx,ndy) gxy = grn(3,ndx,ndy) balance(n1,1) = balance(n1,1) + (force(n2,1) * gxx + force(n2,2) * gxy) * h1 balance(n1,2) = balance(n1,2) + (force(n2,1) * gxy + force(n2,2) * gyy)*h1 end do end do The programmer has written this loop well—there are no loop invariant operations with respect to n1 and n2. However, the loop resides within an iterative loop over time and the index calculations are independent with respect to time. Trading space for time, I precomputed the index values prior to the entering the time loop and stored the values in two arrays. I then replaced the index calculations with reads of the arrays. Data operations Ways to reduce data operations can appear in many forms. Implementing a more efficient algorithm produces the biggest gains. The closest I came to an algorithm change was in code 4. This code computes the inner product of K-vectors A(i) and B(j), 0 = i < N, 0 = j < M, for most values of i and j. Since the program computes most of the NM possible inner products, it is more efficient to compute all the inner products in one triply-nested loop rather than one at a time when needed. The savings accrue from reading A(i) once for all B(j) vectors and from loop unrolling. for (i = 0; i < N; i+=8) { for (j = 0; j < M; j++) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (k = 0; k < K; k++) { sum0 += A[i+0][k] * B[j][k]; sum1 += A[i+1][k] * B[j][k]; sum2 += A[i+2][k] * B[j][k]; sum3 += A[i+3][k] * B[j][k]; sum4 += A[i+4][k] * B[j][k]; sum5 += A[i+5][k] * B[j][k]; sum6 += A[i+6][k] * B[j][k]; sum7 += A[i+7][k] * B[j][k]; } C[i+0][j] = sum0; C[i+1][j] = sum1; C[i+2][j] = sum2; C[i+3][j] = sum3; C[i+4][j] = sum4; C[i+5][j] = sum5; C[i+6][j] = sum6; C[i+7][j] = sum7; }} This change requires knowledge of a typical run; i.e., that most inner products are computed. The reasons for the change, however, derive from basic optimization concepts. It is the type of change easily made at development time by a knowledgeable programmer. In code 5, we have the data version of the index optimization in code 6. Here a very expensive computation is a function of the loop indices and so cannot be hoisted out of the loop; however, the computation is invariant with respect to an outer iterative loop over time. We can compute its value for each iteration of the computation loop prior to entering the time loop and save the values in an array. The increase in memory required to store the values is small in comparison to the large savings in time. The main loop in Code 8 is doubly nested. The inner loop includes a series of guarded computations; some are a function of the inner loop index but not the outer loop index while others are a function of the outer loop index but not the inner loop index for (j = 0; j < N; j++) { for (i = 0; i < M; i++) { r = i * hrmax; R = A[j]; temp = (PRM[3] == 0.0) ? 1.0 : pow(r, PRM[3]); high = temp * kcoeff * B[j] * PRM[2] * PRM[4]; low = high * PRM[6] * PRM[6] / (1.0 + pow(PRM[4] * PRM[6], 2.0)); kap = (R > PRM[6]) ? high * R * R / (1.0 + pow(PRM[4]*r, 2.0) : low * pow(R/PRM[6], PRM[5]); < rest of loop omitted > }} Note that the value of temp is invariant to j. Thus, we can hoist the computation for temp out of the loop and save its values in an array. for (i = 0; i < M; i++) { r = i * hrmax; TEMP[i] = pow(r, PRM[3]); } [N.B. – the case for PRM[3] = 0 is omitted and will be reintroduced later.] We now hoist out of the inner loop the computations invariant to i. Since the conditional guarding the value of kap is invariant to i, it behooves us to hoist the computation out of the inner loop, thereby executing the guard once rather than M times. The final version of the code is for (j = 0; j < N; j++) { R = rig[j] / 1000.; tmp1 = kcoeff * par[2] * beta[j] * par[4]; tmp2 = 1.0 + (par[4] * par[4] * par[6] * par[6]); tmp3 = 1.0 + (par[4] * par[4] * R * R); tmp4 = par[6] * par[6] / tmp2; tmp5 = R * R / tmp3; tmp6 = pow(R / par[6], par[5]); if ((par[3] == 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp5; } else if ((par[3] == 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp4 * tmp6; } else if ((par[3] != 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp5; } else if ((par[3] != 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp4 * tmp6; } for (i = 0; i < M; i++) { kap = KAP[i]; r = i * hrmax; < rest of loop omitted > } } Maybe not the prettiest piece of code, but certainly much more efficient than the original loop, Copy operations Several programs unnecessarily copy data from one data structure to another. This problem occurs in both Fortran and C programs, although it manifests itself differently in the two languages. Code 1 declares two arrays—one for old values and one for new values. At the end of each iteration, the array of new values is copied to the array of old values to reset the data structures for the next iteration. This problem occurs in Fortran programs not included in this study and in both Fortran 77 and Fortran 90 code. Introducing pointers to the arrays and swapping pointer values is an obvious way to eliminate the copying; but pointers is not a feature that many Fortran programmers know well or are comfortable using. An easy solution not involving pointers is to extend the dimension of the value array by 1 and use the last dimension to differentiate between arrays at different times. For example, if the data space is N x N, declare the array (N, N, 2). Then store the problem’s initial values in (_, _, 2) and define the scalar names new = 2 and old = 1. At the start of each iteration, swap old and new to reset the arrays. The old–new copy problem did not appear in any C program. In programs that had new and old values, the code swapped pointers to reset data structures. Where unnecessary coping did occur is in structure assignment and parameter passing. Structures in C are handled much like scalars. Assignment causes the data space of the right-hand name to be copied to the data space of the left-hand name. Similarly, when a structure is passed to a function, the data space of the actual parameter is copied to the data space of the formal parameter. If the structure is large and the assignment or function call is in an inner loop, then copying costs can grow quite large. While none of the ten programs considered here manifested this problem, it did occur in programs not included in the study. A simple fix is always to refer to structures via pointers. Optimizing loop structures Since scientific programs spend almost all their time in loops, efficient loops are the key to good performance. Conditionals, function calls, little instruction level parallelism, and large numbers of temporary values make it difficult for the compiler to generate tightly packed, highly efficient code. Conditionals and function calls introduce jumps that disrupt code flow. Users should eliminate or isolate conditionls to their own loops as much as possible. Often logical expressions can be substituted for if-then-else statements. For example, code 2 includes the following snippet MaxDelta = 0.0 do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) if (Delta > MaxDelta) MaxDelta = Delta enddo enddo if (MaxDelta .gt. 0.001) goto 200 Since the only use of MaxDelta is to control the jump to 200 and all that matters is whether or not it is greater than 0.001, I made MaxDelta a boolean and rewrote the snippet as MaxDelta = .false. do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) MaxDelta = MaxDelta .or. (Delta .gt. 0.001) enddo enddo if (MaxDelta) goto 200 thereby, eliminating the conditional expression from the inner loop. A microprocessor can execute many instructions per instruction cycle. Typically, it can execute one or more memory, floating point, integer, and jump operations. To be executed simultaneously, the operations must be independent. Thick loops tend to have more instruction level parallelism than thin loops. Moreover, they reduce memory traffice by maximizing data reuse. Loop unrolling and loop fusion are two techniques to increase the size of loop bodies. Several of the codes studied benefitted from loop unrolling, but none benefitted from loop fusion. This observation is not too surpising since it is the general tendency of programmers to write thick loops. As loops become thicker, the number of temporary values grows, increasing register pressure. If registers spill, then memory traffic increases and code flow is disrupted. A thick loop with many temporary values may execute slower than an equivalent series of thin loops. The biggest gain will be achieved if the thick loop can be split into a series of independent loops eliminating the need to write and read temporary arrays. I found such an occasion in code 10 where I split the loop do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do into two disjoint loops do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) end do end do do i = 1, n do j = 1, m C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do Conclusions Over the course of the last year, I have had the opportunity to work with over two dozen academic scientific programmers at leading research universities. Their research interests span a broad range of scientific fields. Except for two programs that relied almost exclusively on library routines (matrix multiply and fast Fourier transform), I was able to improve significantly the single processor performance of all codes. Improvements range from 2x to 15.5x with a simple average of 4.75x. Changes to the source code were at a very high level. I did not use sophisticated techniques or programming tools to discover inefficiencies or effect the changes. Only one code was parallel despite the availability of parallel systems to all developers. Clearly, we have a problem—personal scientific research codes are highly inefficient and not running parallel. The developers are unaware of simple optimization techniques to make programs run faster. They lack education in the art of code optimization and parallel programming. I do not believe we can fix the problem by publishing additional books or training manuals. To date, the developers in questions have not studied the books or manual available, and are unlikely to do so in the future. Short courses are a possible solution, but I believe they are too concentrated to be much use. The general concepts can be taught in a three or four day course, but that is not enough time for students to practice what they learn and acquire the experience to apply and extend the concepts to their codes. Practice is the key to becoming proficient at optimization. I recommend that graduate students be required to take a semester length course in optimization and parallel programming. We would never give someone access to state-of-the-art scientific equipment costing hundreds of thousands of dollars without first requiring them to demonstrate that they know how to use the equipment. Yet the criterion for time on state-of-the-art supercomputers is at most an interesting project. Requestors are never asked to demonstrate that they know how to use the system, or can use the system effectively. A semester course would teach them the required skills. Government agencies that fund academic scientific research pay for most of the computer systems supporting scientific research as well as the development of most personal scientific codes. These agencies should require graduate schools to offer a course in optimization and parallel programming as a requirement for funding. About the Author John Feo received his Ph.D. in Computer Science from The University of Texas at Austin in 1986. After graduate school, Dr. Feo worked at Lawrence Livermore National Laboratory where he was the Group Leader of the Computer Research Group and principal investigator of the Sisal Language Project. In 1997, Dr. Feo joined Tera Computer Company where he was project manager for the MTA, and oversaw the programming and evaluation of the MTA at the San Diego Supercomputer Center. In 2000, Dr. Feo joined Sun Microsystems as an HPC application specialist. He works with university research groups to optimize and parallelize scientific codes. Dr. Feo has published over two dozen research articles in the areas of parallel parallel programming, parallel programming languages, and application performance.

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• How to reduce RAM consumption when my server is idle

  - by Julien Genestoux

  We use Slicehost, with 512MB instances. We run Ubuntu 9.10 on them. I installed a few packages, and I'm now trying to optimize RAM consumption before running anything on there. A simple ps gives me the list of running processes : # ps faux USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 2 0.0 0.0 0 0 ? S< Jan04 0:00 [kthreadd] root 3 0.0 0.0 0 0 ? S< Jan04 0:15 \_ [migration/0] root 4 0.0 0.0 0 0 ? S< Jan04 0:01 \_ [ksoftirqd/0] root 5 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [watchdog/0] root 6 0.0 0.0 0 0 ? S< Jan04 0:04 \_ [events/0] root 7 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [cpuset] root 8 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [khelper] root 9 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [async/mgr] root 10 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xenwatch] root 11 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xenbus] root 13 0.0 0.0 0 0 ? S< Jan04 0:02 \_ [migration/1] root 14 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [ksoftirqd/1] root 15 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [watchdog/1] root 16 0.0 0.0 0 0 ? S< Jan04 0:07 \_ [events/1] root 17 0.0 0.0 0 0 ? S< Jan04 0:02 \_ [migration/2] root 18 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [ksoftirqd/2] root 19 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [watchdog/2] root 20 0.0 0.0 0 0 ? R< Jan04 0:07 \_ [events/2] root 21 0.0 0.0 0 0 ? S< Jan04 0:04 \_ [migration/3] root 22 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [ksoftirqd/3] root 23 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [watchdog/3] root 24 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [events/3] root 25 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kintegrityd/0] root 26 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kintegrityd/1] root 27 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kintegrityd/2] root 28 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kintegrityd/3] root 29 0.0 0.0 0 0 ? S< Jan04 0:01 \_ [kblockd/0] root 30 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kblockd/1] root 31 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kblockd/2] root 32 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kblockd/3] root 33 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kseriod] root 34 0.0 0.0 0 0 ? S Jan04 0:00 \_ [khungtaskd] root 35 0.0 0.0 0 0 ? S Jan04 0:05 \_ [pdflush] root 36 0.0 0.0 0 0 ? S Jan04 0:06 \_ [pdflush] root 37 0.0 0.0 0 0 ? S< Jan04 1:02 \_ [kswapd0] root 38 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [aio/0] root 39 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [aio/1] root 40 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [aio/2] root 41 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [aio/3] root 42 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [jfsIO] root 43 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [jfsCommit] root 44 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [jfsCommit] root 45 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [jfsCommit] root 46 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [jfsCommit] root 47 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [jfsSync] root 48 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfs_mru_cache] root 49 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfslogd/0] root 50 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfslogd/1] root 51 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfslogd/2] root 52 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfslogd/3] root 53 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfsdatad/0] root 54 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfsdatad/1] root 55 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfsdatad/2] root 56 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfsdatad/3] root 57 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfsconvertd/0] root 58 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfsconvertd/1] root 59 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfsconvertd/2] root 60 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [xfsconvertd/3] root 61 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [glock_workqueue] root 62 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [glock_workqueue] root 63 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [glock_workqueue] root 64 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [glock_workqueue] root 65 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [delete_workqueu] root 66 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [delete_workqueu] root 67 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [delete_workqueu] root 68 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [delete_workqueu] root 69 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kslowd] root 70 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kslowd] root 71 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [crypto/0] root 72 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [crypto/1] root 73 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [crypto/2] root 74 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [crypto/3] root 77 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [net_accel/0] root 78 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [net_accel/1] root 79 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [net_accel/2] root 80 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [net_accel/3] root 81 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [sfc_netfront/0] root 82 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [sfc_netfront/1] root 83 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [sfc_netfront/2] root 84 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [sfc_netfront/3] root 310 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [kstriped] root 315 0.0 0.0 0 0 ? S< Jan04 0:00 \_ [ksnapd] root 1452 0.0 0.0 0 0 ? S< Jan04 4:31 \_ [kjournald] root 1 0.0 0.1 19292 948 ? Ss Jan04 0:15 /sbin/init root 1545 0.0 0.1 13164 1064 ? S Jan04 0:00 upstart-udev-bridge --daemon root 1547 0.0 0.1 17196 996 ? S<s Jan04 0:00 udevd --daemon root 1728 0.0 0.2 20284 1468 ? S< Jan04 0:00 \_ udevd --daemon root 1729 0.0 0.1 17192 792 ? S< Jan04 0:00 \_ udevd --daemon root 1881 0.0 0.0 8192 152 ? Ss Jan04 0:00 dd bs=1 if=/proc/kmsg of=/var/run/rsyslog/kmsg syslog 1884 0.0 0.2 185252 1200 ? Sl Jan04 1:00 rsyslogd -c4 103 1894 0.0 0.1 23328 700 ? Ss Jan04 1:08 dbus-daemon --system --fork root 2046 0.0 0.0 136 32 ? Ss Jan04 4:05 runsvdir -P /etc/service log: gems/custom_require.rb:31:in `require'??from /mnt/app/superfeedr-firehoser/current/script/component:52?/opt/ruby-enterprise/lib/ruby/si root 2055 0.0 0.0 112 32 ? Ss Jan04 0:00 \_ runsv chef-client root 2060 0.0 0.0 132 40 ? S Jan04 0:02 | \_ svlogd -tt ./main root 2056 0.0 0.0 112 28 ? Ss Jan04 0:20 \_ runsv superfeedr-firehoser_2 root 2059 0.0 0.0 132 40 ? S Jan04 0:29 | \_ svlogd /var/log/superfeedr-firehoser_2 root 2057 0.0 0.0 112 28 ? Ss Jan04 0:20 \_ runsv superfeedr-firehoser_1 root 2062 0.0 0.0 132 44 ? S Jan04 0:26 \_ svlogd /var/log/superfeedr-firehoser_1 root 2058 0.0 0.0 18708 316 ? Ss Jan04 0:01 cron root 2095 0.0 0.1 49072 764 ? Ss Jan04 0:06 /usr/sbin/sshd root 9832 0.0 0.5 78916 3500 ? Ss 00:37 0:00 \_ sshd: root@pts/0 root 9846 0.0 0.3 17900 2036 pts/0 Ss 00:37 0:00 \_ -bash root 10132 0.0 0.1 15020 1064 pts/0 R+ 09:51 0:00 \_ ps faux root 2180 0.0 0.0 5988 140 tty1 Ss+ Jan04 0:00 /sbin/getty -8 38400 tty1 root 27610 0.0 1.4 47060 8436 ? S Apr04 2:21 python /usr/sbin/denyhosts --daemon --purge --config=/etc/denyhosts.conf --config=/etc/denyhosts.conf root 22640 0.0 0.7 119244 4164 ? Ssl Apr05 0:05 /usr/sbin/console-kit-daemon root 10113 0.0 0.0 3904 316 ? Ss 09:46 0:00 /usr/sbin/collectdmon -P /var/run/collectdmon.pid -- -C /etc/collectd/collectd.conf root 10114 0.0 0.2 201084 1464 ? Sl 09:46 0:00 \_ collectd -C /etc/collectd/collectd.conf -f As you can see there is nothing serious here. If I sum up the RSS line on all this, I get the following : # ps -aeo rss | awk '{sum+=$1} END {print sum}' 30096 Which makes sense. However, I have a pretty big surprise when I do a free: # free total used free shared buffers cached Mem: 591180 343684 247496 0 25432 161256 -/+ buffers/cache: 156996 434184 Swap: 1048568 0 1048568 As you can see 60% of the available memory is already consumed... which leaves me with only 40% to run my own applications if I want to avoid swapping. Quite disapointing! 2 questions arise : Where is all this memory? How to take some of it back for my own apps?

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• OpenVPN - Windows 8 to Windows 2008 Server, not connecting

  - by niico

  I have followed this tutorial about setting up an OpenVPN Server on Windows Server - and a client on Windows (in this case Windows 8). The server appears to be running fine - but it is not connecting with this error: Mon Jul 22 19:09:04 2013 Warning: cannot open --log file: C:\Program Files\OpenVPN\log\my-laptop.log: Access is denied. (errno=5) Mon Jul 22 19:09:04 2013 OpenVPN 2.3.2 x86_64-w64-mingw32 [SSL (OpenSSL)] [LZO] [PKCS11] [eurephia] [IPv6] built on Jun 3 2013 Mon Jul 22 19:09:04 2013 MANAGEMENT: TCP Socket listening on [AF_INET]127.0.0.1:25340 Mon Jul 22 19:09:04 2013 Need hold release from management interface, waiting... Mon Jul 22 19:09:05 2013 MANAGEMENT: Client connected from [AF_INET]127.0.0.1:25340 Mon Jul 22 19:09:05 2013 MANAGEMENT: CMD 'state on' Mon Jul 22 19:09:05 2013 MANAGEMENT: CMD 'log all on' Mon Jul 22 19:09:05 2013 MANAGEMENT: CMD 'hold off' Mon Jul 22 19:09:05 2013 MANAGEMENT: CMD 'hold release' Mon Jul 22 19:09:05 2013 Socket Buffers: R=[65536->65536] S=[65536->65536] Mon Jul 22 19:09:05 2013 UDPv4 link local: [undef] Mon Jul 22 19:09:05 2013 UDPv4 link remote: [AF_INET]66.666.66.666:9999 Mon Jul 22 19:09:05 2013 MANAGEMENT: >STATE:1374494945,WAIT,,, Mon Jul 22 19:10:05 2013 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity) Mon Jul 22 19:10:05 2013 TLS Error: TLS handshake failed Mon Jul 22 19:10:05 2013 SIGUSR1[soft,tls-error] received, process restarting Mon Jul 22 19:10:05 2013 MANAGEMENT: >STATE:1374495005,RECONNECTING,tls-error,, Mon Jul 22 19:10:05 2013 Restart pause, 2 second(s) Note I have changed the IP and port no (it uses a non-standard port for security reasons). That port is open on the hardware firewall. The server logs are showing a connection attempt from my client: TLS: Initial packet from [AF_INET]118.68.xx.xx:65011, sid=081af4ed xxxxxxxx Mon Jul 22 14:19:15 2013 118.68.xx.xx:65011 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity) How can I problem solve this & find the problem? Thx Update - Client config file: ############################################## # Sample client-side OpenVPN 2.0 config file # # for connecting to multi-client server. # # # # This configuration can be used by multiple # # clients, however each client should have # # its own cert and key files. # # # # On Windows, you might want to rename this # # file so it has a .ovpn extension # ############################################## # Specify that we are a client and that we # will be pulling certain config file directives # from the server. client # Use the same setting as you are using on # the server. # On most systems, the VPN will not function # unless you partially or fully disable # the firewall for the TUN/TAP interface. ;dev tap dev tun # Windows needs the TAP-Win32 adapter name # from the Network Connections panel # if you have more than one. On XP SP2, # you may need to disable the firewall # for the TAP adapter. ;dev-node MyTap # Are we connecting to a TCP or # UDP server? Use the same setting as # on the server. ;proto tcp proto udp # The hostname/IP and port of the server. # You can have multiple remote entries # to load balance between the servers. remote 00.00.00.00 1194 ;remote 00.00.00.00 9999 ;remote my-server-2 1194 # Choose a random host from the remote # list for load-balancing. Otherwise # try hosts in the order specified. ;remote-random # Keep trying indefinitely to resolve the # host name of the OpenVPN server. Very useful # on machines which are not permanently connected # to the internet such as laptops. resolv-retry infinite # Most clients don't need to bind to # a specific local port number. nobind # Downgrade privileges after initialization (non-Windows only) ;user nobody ;group nobody # Try to preserve some state across restarts. persist-key persist-tun # If you are connecting through an # HTTP proxy to reach the actual OpenVPN # server, put the proxy server/IP and # port number here. See the man page # if your proxy server requires # authentication. ;http-proxy-retry # retry on connection failures ;http-proxy [proxy server] [proxy port #] # Wireless networks often produce a lot # of duplicate packets. Set this flag # to silence duplicate packet warnings. ;mute-replay-warnings # SSL/TLS parms. # See the server config file for more # description. It's best to use # a separate .crt/.key file pair # for each client. A single ca # file can be used for all clients. ca "C:\\Program Files\\OpenVPN\\config\\ca.crt" cert "C:\\Program Files\\OpenVPN\\config\\my-laptop.crt" key "C:\\Program Files\\OpenVPN\\config\\my-laptop.key" # Verify server certificate by checking # that the certicate has the nsCertType # field set to "server". This is an # important precaution to protect against # a potential attack discussed here: # http://openvpn.net/howto.html#mitm # # To use this feature, you will need to generate # your server certificates with the nsCertType # field set to "server". The build-key-server # script in the easy-rsa folder will do this. ns-cert-type server # If a tls-auth key is used on the server # then every client must also have the key. ;tls-auth ta.key 1 # Select a cryptographic cipher. # If the cipher option is used on the server # then you must also specify it here. ;cipher x # Enable compression on the VPN link. # Don't enable this unless it is also # enabled in the server config file. comp-lzo # Set log file verbosity. verb 3 # Silence repeating messages ;mute 20 Server config file: ################################################# # Sample OpenVPN 2.0 config file for # # multi-client server. # # # # This file is for the server side # # of a many-clients <-> one-server # # OpenVPN configuration. # # # # OpenVPN also supports # # single-machine <-> single-machine # # configurations (See the Examples page # # on the web site for more info). # # # # This config should work on Windows # # or Linux/BSD systems. Remember on # # Windows to quote pathnames and use # # double backslashes, e.g.: # # "C:\\Program Files\\OpenVPN\\config\\foo.key" # # # # Comments are preceded with '#' or ';' # ################################################# # Which local IP address should OpenVPN # listen on? (optional) ;local 00.00.00.00 # Which TCP/UDP port should OpenVPN listen on? # If you want to run multiple OpenVPN instances # on the same machine, use a different port # number for each one. You will need to # open up this port on your firewall. std 1194 port 1194 # TCP or UDP server? ;proto tcp proto udp # "dev tun" will create a routed IP tunnel, # "dev tap" will create an ethernet tunnel. # Use "dev tap0" if you are ethernet bridging # and have precreated a tap0 virtual interface # and bridged it with your ethernet interface. # If you want to control access policies # over the VPN, you must create firewall # rules for the the TUN/TAP interface. # On non-Windows systems, you can give # an explicit unit number, such as tun0. # On Windows, use "dev-node" for this. # On most systems, the VPN will not function # unless you partially or fully disable # the firewall for the TUN/TAP interface. ;dev tap dev tun # Windows needs the TAP-Win32 adapter name # from the Network Connections panel if you # have more than one. On XP SP2 or higher, # you may need to selectively disable the # Windows firewall for the TAP adapter. # Non-Windows systems usually don't need this. ;dev-node MyTap # SSL/TLS root certificate (ca), certificate # (cert), and private key (key). Each client # and the server must have their own cert and # key file. The server and all clients will # use the same ca file. # # See the "easy-rsa" directory for a series # of scripts for generating RSA certificates # and private keys. Remember to use # a unique Common Name for the server # and each of the client certificates. # # Any X509 key management system can be used. # OpenVPN can also use a PKCS #12 formatted key file # (see "pkcs12" directive in man page). ca "C:\\Program Files\\OpenVPN\\config\\ca.crt" cert "C:\\Program Files\\OpenVPN\\config\\server.crt" key "C:\\Program Files\\OpenVPN\\config\\server.key" # Diffie hellman parameters. # Generate your own with: # openssl dhparam -out dh1024.pem 1024 # Substitute 2048 for 1024 if you are using # 2048 bit keys. dh "C:\\Program Files\\OpenVPN\\config\\dh2048.pem" # Configure server mode and supply a VPN subnet # for OpenVPN to draw client addresses from. # The server will take 10.8.0.1 for itself, # the rest will be made available to clients. # Each client will be able to reach the server # on 10.8.0.1. Comment this line out if you are # ethernet bridging. See the man page for more info. server 10.8.0.0 255.255.255.0 # Maintain a record of client <-> virtual IP address # associations in this file. If OpenVPN goes down or # is restarted, reconnecting clients can be assigned # the same virtual IP address from the pool that was # previously assigned. ifconfig-pool-persist ipp.txt # Configure server mode for ethernet bridging. # You must first use your OS's bridging capability # to bridge the TAP interface with the ethernet # NIC interface. Then you must manually set the # IP/netmask on the bridge interface, here we # assume 10.8.0.4/255.255.255.0. Finally we # must set aside an IP range in this subnet # (start=10.8.0.50 end=10.8.0.100) to allocate # to connecting clients. Leave this line commented # out unless you are ethernet bridging. ;server-bridge 10.8.0.4 255.255.255.0 10.8.0.50 10.8.0.100 # Configure server mode for ethernet bridging # using a DHCP-proxy, where clients talk # to the OpenVPN server-side DHCP server # to receive their IP address allocation # and DNS server addresses. You must first use # your OS's bridging capability to bridge the TAP # interface with the ethernet NIC interface. # Note: this mode only works on clients (such as # Windows), where the client-side TAP adapter is # bound to a DHCP client. ;server-bridge # Push routes to the client to allow it # to reach other private subnets behind # the server. Remember that these # private subnets will also need # to know to route the OpenVPN client # address pool (10.8.0.0/255.255.255.0) # back to the OpenVPN server. ;push "route 192.168.10.0 255.255.255.0" ;push "route 192.168.20.0 255.255.255.0" # To assign specific IP addresses to specific # clients or if a connecting client has a private # subnet behind it that should also have VPN access, # use the subdirectory "ccd" for client-specific # configuration files (see man page for more info). # EXAMPLE: Suppose the client # having the certificate common name "Thelonious" # also has a small subnet behind his connecting # machine, such as 192.168.40.128/255.255.255.248. # First, uncomment out these lines: ;client-config-dir ccd ;route 192.168.40.128 255.255.255.248 # Then create a file ccd/Thelonious with this line: # iroute 192.168.40.128 255.255.255.248 # This will allow Thelonious' private subnet to # access the VPN. This example will only work # if you are routing, not bridging, i.e. you are # using "dev tun" and "server" directives. # EXAMPLE: Suppose you want to give # Thelonious a fixed VPN IP address of 10.9.0.1. # First uncomment out these lines: ;client-config-dir ccd ;route 10.9.0.0 255.255.255.252 # Then add this line to ccd/Thelonious: # ifconfig-push 10.9.0.1 10.9.0.2 # Suppose that you want to enable different # firewall access policies for different groups # of clients. There are two methods: # (1) Run multiple OpenVPN daemons, one for each # group, and firewall the TUN/TAP interface # for each group/daemon appropriately. # (2) (Advanced) Create a script to dynamically # modify the firewall in response to access # from different clients. See man # page for more info on learn-address script. ;learn-address ./script # If enabled, this directive will configure # all clients to redirect their default # network gateway through the VPN, causing # all IP traffic such as web browsing and # and DNS lookups to go through the VPN # (The OpenVPN server machine may need to NAT # or bridge the TUN/TAP interface to the internet # in order for this to work properly). ;push "redirect-gateway def1 bypass-dhcp" # Certain Windows-specific network settings # can be pushed to clients, such as DNS # or WINS server addresses. CAVEAT: # http://openvpn.net/faq.html#dhcpcaveats # The addresses below refer to the public # DNS servers provided by opendns.com. ;push "dhcp-option DNS 208.67.222.222" ;push "dhcp-option DNS 208.67.220.220" # Uncomment this directive to allow differenta # clients to be able to "see" each other. # By default, clients will only see the server. # To force clients to only see the server, you # will also need to appropriately firewall the # server's TUN/TAP interface. ;client-to-client # Uncomment this directive if multiple clients # might connect with the same certificate/key # files or common names. This is recommended # only for testing purposes. For production use, # each client should have its own certificate/key # pair. # # IF YOU HAVE NOT GENERATED INDIVIDUAL # CERTIFICATE/KEY PAIRS FOR EACH CLIENT, # EACH HAVING ITS OWN UNIQUE "COMMON NAME", # UNCOMMENT THIS LINE OUT. ;duplicate-cn # The keepalive directive causes ping-like # messages to be sent back and forth over # the link so that each side knows when # the other side has gone down. # Ping every 10 seconds, assume that remote # peer is down if no ping received during # a 120 second time period. keepalive 10 120 # For extra security beyond that provided # by SSL/TLS, create an "HMAC firewall" # to help block DoS attacks and UDP port flooding. # # Generate with: # openvpn --genkey --secret ta.key # # The server and each client must have # a copy of this key. # The second parameter should be '0' # on the server and '1' on the clients. ;tls-auth ta.key 0 # This file is secret # Select a cryptographic cipher. # This config item must be copied to # the client config file as well. ;cipher BF-CBC # Blowfish (default) ;cipher AES-128-CBC # AES ;cipher DES-EDE3-CBC # Triple-DES # Enable compression on the VPN link. # If you enable it here, you must also # enable it in the client config file. comp-lzo # The maximum number of concurrently connected # clients we want to allow. ;max-clients 100 # It's a good idea to reduce the OpenVPN # daemon's privileges after initialization. # # You can uncomment this out on # non-Windows systems. ;user nobody ;group nobody # The persist options will try to avoid # accessing certain resources on restart # that may no longer be accessible because # of the privilege downgrade. persist-key persist-tun # Output a short status file showing # current connections, truncated # and rewritten every minute. status openvpn-status.log # By default, log messages will go to the syslog (or # on Windows, if running as a service, they will go to # the "\Program Files\OpenVPN\log" directory). # Use log or log-append to override this default. # "log" will truncate the log file on OpenVPN startup, # while "log-append" will append to it. Use one # or the other (but not both). ;log openvpn.log ;log-append openvpn.log # Set the appropriate level of log # file verbosity. # # 0 is silent, except for fatal errors # 4 is reasonable for general usage # 5 and 6 can help to debug connection problems # 9 is extremely verbose verb 3 # Silence repeating messages. At most 20 # sequential messages of the same message # category will be output to the log. ;mute 20 I have changed IP's for security

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• Diving into OpenStack Network Architecture - Part 2 - Basic Use Cases

  - by Ronen Kofman

    rkofman Normal rkofman 4 138 2014-06-05T03:38:00Z 2014-06-05T05:04:00Z 3 2735 15596 Oracle Corporation 129 36 18295 12.00 Clean Clean false false false false EN-US X-NONE HE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi; mso-bidi-language:AR-SA;} In the previous post we reviewed several network components including Open vSwitch, Network Namespaces, Linux Bridges and veth pairs. In this post we will take three simple use cases and see how those basic components come together to create a complete SDN solution in OpenStack. With those three use cases we will review almost the entire network setup and see how all the pieces work together. The use cases we will use are: 1.       Create network – what happens when we create network and how can we create multiple isolated networks 2.       Launch a VM – once we have networks we can launch VMs and connect them to networks. 3.       DHCP request from a VM – OpenStack can automatically assign IP addresses to VMs. This is done through local DHCP service controlled by OpenStack Neutron. We will see how this service runs and how does a DHCP request and response look like. In this post we will show connectivity, we will see how packets get from point A to point B. We first focus on how a configured deployment looks like and only later we will discuss how and when the configuration is created. Personally I found it very valuable to see the actual interfaces and how they connect to each other through examples and hands on experiments. After the end game is clear and we know how the connectivity works, in a later post, we will take a step back and explain how Neutron configures the components to be able to provide such connectivity.  We are going to get pretty technical shortly and I recommend trying these examples on your own deployment or using the Oracle OpenStack Tech Preview. Understanding these three use cases thoroughly and how to look at them will be very helpful when trying to debug a deployment in case something does not work. Use case #1: Create Network Create network is a simple operation it can be performed from the GUI or command line. When we create a network in OpenStack the network is only available to the tenant who created it or it could be defined as “shared” and then it can be used by all tenants. A network can have multiple subnets but for this demonstration purpose and for simplicity we will assume that each network has exactly one subnet. Creating a network from the command line will look like this: # neutron net-create net1 Created a new network: +---------------------------+--------------------------------------+ | Field                     | Value                                | +---------------------------+--------------------------------------+ | admin_state_up            | True                                 | | id                        | 5f833617-6179-4797-b7c0-7d420d84040c | | name                      | net1                                 | | provider:network_type     | vlan                                 | | provider:physical_network | default                              | | provider:segmentation_id  | 1000                                 | | shared                    | False                                | | status                    | ACTIVE                               | | subnets                   |                                      | | tenant_id                 | 9796e5145ee546508939cd49ad59d51f     | +---------------------------+--------------------------------------+ Creating a subnet for this network will look like this: # neutron subnet-create net1 10.10.10.0/24 Created a new subnet: +------------------+------------------------------------------------+ | Field            | Value                                          | +------------------+------------------------------------------------+ | allocation_pools | {"start": "10.10.10.2", "end": "10.10.10.254"} | | cidr             | 10.10.10.0/24                                  | | dns_nameservers  |                                                | | enable_dhcp      | True                                           | | gateway_ip       | 10.10.10.1                                     | | host_routes      |                                                | | id               | 2d7a0a58-0674-439a-ad23-d6471aaae9bc           | | ip_version       | 4                                              | | name             |                                                | | network_id       | 5f833617-6179-4797-b7c0-7d420d84040c           | | tenant_id        | 9796e5145ee546508939cd49ad59d51f               | +------------------+------------------------------------------------+ We now have a network and a subnet, on the network topology view this looks like this: Now let’s dive in and see what happened under the hood. Looking at the control node we will discover that a new namespace was created: # ip netns list qdhcp-5f833617-6179-4797-b7c0-7d420d84040c   The name of the namespace is qdhcp-<network id> (see above), let’s look into the namespace and see what’s in it: # ip netns exec qdhcp-5f833617-6179-4797-b7c0-7d420d84040c ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00     inet 127.0.0.1/8 scope host lo     inet6 ::1/128 scope host        valid_lft forever preferred_lft forever 12: tap26c9b807-7c: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN     link/ether fa:16:3e:1d:5c:81 brd ff:ff:ff:ff:ff:ff     inet 10.10.10.3/24 brd 10.10.10.255 scope global tap26c9b807-7c     inet6 fe80::f816:3eff:fe1d:5c81/64 scope link        valid_lft forever preferred_lft forever   We see two interfaces in the namespace, one is the loopback and the other one is an interface called “tap26c9b807-7c”. This interface has the IP address of 10.10.10.3 and it will also serve dhcp requests in a way we will see later. Let’s trace the connectivity of the “tap26c9b807-7c” interface from the namespace.  First stop is OVS, we see that the interface connects to bridge  “br-int” on OVS: # ovs-vsctl show 8a069c7c-ea05-4375-93e2-b9fc9e4b3ca1     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2"                 type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"     Bridge br-ex         Port br-ex             Interface br-ex                 type: internal     Bridge br-int         Port "int-br-eth2"             Interface "int-br-eth2"         Port "tap26c9b807-7c"             tag: 1             Interface "tap26c9b807-7c"                 type: internal         Port br-int             Interface br-int                 type: internal     ovs_version: "1.11.0"   In the picture above we have a veth pair which has two ends called “int-br-eth2” and "phy-br-eth2", this veth pair is used to connect two bridge in OVS "br-eth2" and "br-int". In the previous post we explained how to check the veth connectivity using the ethtool command. It shows that the two are indeed a pair: # ethtool -S int-br-eth2 NIC statistics:      peer_ifindex: 10 . .   #ip link . . 10: phy-br-eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 . . Note that “phy-br-eth2” is connected to a bridge called "br-eth2" and one of this bridge's interfaces is the physical link eth2. This means that the network which we have just created has created a namespace which is connected to the physical interface eth2. eth2 is the “VM network” the physical interface where all the virtual machines connect to where all the VMs are connected. About network isolation: OpenStack supports creation of multiple isolated networks and can use several mechanisms to isolate the networks from one another. The isolation mechanism can be VLANs, VxLANs or GRE tunnels, this is configured as part of the initial setup in our deployment we use VLANs. When using VLAN tagging as an isolation mechanism a VLAN tag is allocated by Neutron from a pre-defined VLAN tags pool and assigned to the newly created network. By provisioning VLAN tags to the networks Neutron allows creation of multiple isolated networks on the same physical link.  The big difference between this and other platforms is that the user does not have to deal with allocating and managing VLANs to networks. The VLAN allocation and provisioning is handled by Neutron which keeps track of the VLAN tags, and responsible for allocating and reclaiming VLAN tags. In the example above net1 has the VLAN tag 1000, this means that whenever a VM is created and connected to this network the packets from that VM will have to be tagged with VLAN tag 1000 to go on this particular network. This is true for namespace as well, if we would like to connect a namespace to a particular network we have to make sure that the packets to and from the namespace are correctly tagged when they reach the VM network. In the example above we see that the namespace interface “tap26c9b807-7c” has vlan tag 1 assigned to it, if we examine OVS we see that it has flows which modify VLAN tag 1 to VLAN tag 1000 when a packet goes to the VM network on eth2 and vice versa. We can see this using the dump-flows command on OVS for packets going to the VM network we see the modification done on br-eth2: #  ovs-ofctl dump-flows br-eth2 NXST_FLOW reply (xid=0x4):  cookie=0x0, duration=18669.401s, table=0, n_packets=857, n_bytes=163350, idle_age=25, priority=4,in_port=2,dl_vlan=1 actions=mod_vlan_vid:1000,NORMAL  cookie=0x0, duration=165108.226s, table=0, n_packets=14, n_bytes=1000, idle_age=5343, hard_age=65534, priority=2,in_port=2 actions=drop  cookie=0x0, duration=165109.813s, table=0, n_packets=1671, n_bytes=213304, idle_age=25, hard_age=65534, priority=1 actions=NORMAL   For packets coming from the interface to the namespace we see the following modification: #  ovs-ofctl dump-flows br-int NXST_FLOW reply (xid=0x4):  cookie=0x0, duration=18690.876s, table=0, n_packets=1610, n_bytes=210752, idle_age=1, priority=3,in_port=1,dl_vlan=1000 actions=mod_vlan_vid:1,NORMAL  cookie=0x0, duration=165130.01s, table=0, n_packets=75, n_bytes=3686, idle_age=4212, hard_age=65534, priority=2,in_port=1 actions=drop  cookie=0x0, duration=165131.96s, table=0, n_packets=863, n_bytes=160727, idle_age=1, hard_age=65534, priority=1 actions=NORMAL   To summarize we can see that when a user creates a network Neutron creates a namespace and this namespace is connected through OVS to the “VM network”. OVS also takes care of tagging the packets from the namespace to the VM network with the correct VLAN tag and knows to modify the VLAN for packets coming from VM network to the namespace. Now let’s see what happens when a VM is launched and how it is connected to the “VM network”. Use case #2: Launch a VM Launching a VM can be done from Horizon or from the command line this is how we do it from Horizon: Attach the network: And Launch Once the virtual machine is up and running we can see the associated IP using the nova list command : # nova list +--------------------------------------+--------------+--------+------------+-------------+-----------------+ | ID                                   | Name         | Status | Task State | Power State | Networks        | +--------------------------------------+--------------+--------+------------+-------------+-----------------+ | 3707ac87-4f5d-4349-b7ed-3a673f55e5e1 | Oracle Linux | ACTIVE | None       | Running     | net1=10.10.10.2 | +--------------------------------------+--------------+--------+------------+-------------+-----------------+ The nova list command shows us that the VM is running and that the IP 10.10.10.2 is assigned to this VM. Let’s trace the connectivity from the VM to VM network on eth2 starting with the VM definition file. The configuration files of the VM including the virtual disk(s), in case of ephemeral storage, are stored on the compute node at/var/lib/nova/instances/<instance-id>/. Looking into the VM definition file ,libvirt.xml,  we see that the VM is connected to an interface called “tap53903a95-82” which is connected to a Linux bridge called “qbr53903a95-82”: <interface type="bridge">       <mac address="fa:16:3e:fe:c7:87"/>       <source bridge="qbr53903a95-82"/>       <target dev="tap53903a95-82"/>     </interface>   Looking at the bridge using the brctl show command we see this: # brctl show bridge name     bridge id               STP enabled     interfaces qbr53903a95-82          8000.7e7f3282b836       no              qvb53903a95-82                                                         tap53903a95-82    The bridge has two interfaces, one connected to the VM (“tap53903a95-82 “) and another one ( “qvb53903a95-82”) connected to “br-int” bridge on OVS: # ovs-vsctl show 83c42f80-77e9-46c8-8560-7697d76de51c     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2"                 type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"     Bridge br-int         Port br-int             Interface br-int                 type: internal         Port "int-br-eth2"             Interface "int-br-eth2"         Port "qvo53903a95-82"             tag: 3             Interface "qvo53903a95-82"     ovs_version: "1.11.0"   As we showed earlier “br-int” is connected to “br-eth2” on OVS using the veth pair int-br-eth2,phy-br-eth2 and br-eth2 is connected to the physical interface eth2. The whole flow end to end looks like this: VM è tap53903a95-82 (virtual interface)è qbr53903a95-82 (Linux bridge) è qvb53903a95-82 (interface connected from Linux bridge to OVS bridge br-int) è int-br-eth2 (veth one end) è phy-br-eth2 (veth the other end) è eth2 physical interface. The purpose of the Linux Bridge connecting to the VM is to allow security group enforcement with iptables. Security groups are enforced at the edge point which are the interface of the VM, since iptables nnot be applied to OVS bridges we use Linux bridge to apply them. In the future we hope to see this Linux Bridge going away rules.  VLAN tags: As we discussed in the first use case net1 is using VLAN tag 1000, looking at OVS above we see that qvo41f1ebcf-7c is tagged with VLAN tag 3. The modification from VLAN tag 3 to 1000 as we go to the physical network is done by OVS  as part of the packet flow of br-eth2 in the same way we showed before. To summarize, when a VM is launched it is connected to the VM network through a chain of elements as described here. During the packet from VM to the network and back the VLAN tag is modified. Use case #3: Serving a DHCP request coming from the virtual machine In the previous use cases we have shown that both the namespace called dhcp-<some id> and the VM end up connecting to the physical interface eth2  on their respective nodes, both will tag their packets with VLAN tag 1000.We saw that the namespace has an interface with IP of 10.10.10.3. Since the VM and the namespace are connected to each other and have interfaces on the same subnet they can ping each other, in this picture we see a ping from the VM which was assigned 10.10.10.2 to the namespace: The fact that they are connected and can ping each other can become very handy when something doesn’t work right and we need to isolate the problem. In such case knowing that we should be able to ping from the VM to the namespace and back can be used to trace the disconnect using tcpdump or other monitoring tools. To serve DHCP requests coming from VMs on the network Neutron uses a Linux tool called “dnsmasq”,this is a lightweight DNS and DHCP service you can read more about it here. If we look at the dnsmasq on the control node with the ps command we see this: dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces --interface=tap26c9b807-7c --except-interface=lo --pid-file=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/pid --dhcp-hostsfile=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/host --dhcp-optsfile=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/opts --leasefile-ro --dhcp-range=tag0,10.10.10.0,static,120s --dhcp-lease-max=256 --conf-file= --domain=openstacklocal The service connects to the tap interface in the namespace (“--interface=tap26c9b807-7c”), If we look at the hosts file we see this: # cat  /var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/host fa:16:3e:fe:c7:87,host-10-10-10-2.openstacklocal,10.10.10.2   If you look at the console output above you can see the MAC address fa:16:3e:fe:c7:87 which is the VM MAC. This MAC address is mapped to IP 10.10.10.2 and so when a DHCP request comes with this MAC dnsmasq will return the 10.10.10.2.If we look into the namespace at the time we initiate a DHCP request from the VM (this can be done by simply restarting the network service in the VM) we see the following: # ip netns exec qdhcp-5f833617-6179-4797-b7c0-7d420d84040c tcpdump -n 19:27:12.191280 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:fe:c7:87, length 310 19:27:12.191666 IP 10.10.10.3.bootps > 10.10.10.2.bootpc: BOOTP/DHCP, Reply, length 325   To summarize, the DHCP service is handled by dnsmasq which is configured by Neutron to listen to the interface in the DHCP namespace. Neutron also configures dnsmasq with the combination of MAC and IP so when a DHCP request comes along it will receive the assigned IP. Summary In this post we relied on the components described in the previous post and saw how network connectivity is achieved using three simple use cases. These use cases gave a good view of the entire network stack and helped understand how an end to end connection is being made between a VM on a compute node and the DHCP namespace on the control node. One conclusion we can draw from what we saw here is that if we launch a VM and it is able to perform a DHCP request and receive a correct IP then there is reason to believe that the network is working as expected. We saw that a packet has to travel through a long list of components before reaching its destination and if it has done so successfully this means that many components are functioning properly. In the next post we will look at some more sophisticated services Neutron supports and see how they work. We will see that while there are some more components involved for the most part the concepts are the same. @RonenKofman

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