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• Configuring OpenLDAP and SSL

  - by Stormshadow

  I am having trouble trying to connect to a secure OpenLDAP server which I have set up. On running my LDAP client code java -Djavax.net.debug=ssl LDAPConnector I get the following exception trace (java version 1.6.0_17) trigger seeding of SecureRandom done seeding SecureRandom %% No cached client session *** ClientHello, TLSv1 RandomCookie: GMT: 1256110124 bytes = { 224, 19, 193, 148, 45, 205, 108, 37, 101, 247, 112, 24, 157, 39, 111, 177, 43, 53, 206, 224, 68, 165, 55, 185, 54, 203, 43, 91 } Session ID: {} Cipher Suites: [SSL_RSA_WITH_RC4_128_MD5, SSL_RSA_WITH_RC4_128_SHA, TLS_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_DSS_WITH_AES_128_CBC_SHA, SSL_RSA_W ITH_3DES_EDE_CBC_SHA, SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA, SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA, SSL_RSA_WITH_DES_CBC_SHA, SSL_DHE_RSA_WITH_DES_CBC_SHA, SSL_DHE_DSS_WITH_DES_CBC_SH A, SSL_RSA_EXPORT_WITH_RC4_40_MD5, SSL_RSA_EXPORT_WITH_DES40_CBC_SHA, SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA, SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA] Compression Methods: { 0 } *** Thread-0, WRITE: TLSv1 Handshake, length = 73 Thread-0, WRITE: SSLv2 client hello message, length = 98 Thread-0, received EOFException: error Thread-0, handling exception: javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake Thread-0, SEND TLSv1 ALERT: fatal, description = handshake_failure Thread-0, WRITE: TLSv1 Alert, length = 2 Thread-0, called closeSocket() main, handling exception: javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake javax.naming.CommunicationException: simple bind failed: ldap.natraj.com:636 [Root exception is javax.net.ssl.SSLHandshakeException: Remote host closed connection during hands hake] at com.sun.jndi.ldap.LdapClient.authenticate(Unknown Source) at com.sun.jndi.ldap.LdapCtx.connect(Unknown Source) at com.sun.jndi.ldap.LdapCtx.<init>(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getUsingURL(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getUsingURLs(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxInstance(Unknown Source) at com.sun.jndi.ldap.LdapCtxFactory.getInitialContext(Unknown Source) at javax.naming.spi.NamingManager.getInitialContext(Unknown Source) at javax.naming.InitialContext.getDefaultInitCtx(Unknown Source) at javax.naming.InitialContext.init(Unknown Source) at javax.naming.InitialContext.<init>(Unknown Source) at javax.naming.directory.InitialDirContext.<init>(Unknown Source) at LDAPConnector.CallSecureLDAPServer(LDAPConnector.java:43) at LDAPConnector.main(LDAPConnector.java:237) Caused by: javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(Unknown Source) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readDataRecord(Unknown Source) at com.sun.net.ssl.internal.ssl.AppInputStream.read(Unknown Source) at java.io.BufferedInputStream.fill(Unknown Source) at java.io.BufferedInputStream.read1(Unknown Source) at java.io.BufferedInputStream.read(Unknown Source) at com.sun.jndi.ldap.Connection.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.io.EOFException: SSL peer shut down incorrectly at com.sun.net.ssl.internal.ssl.InputRecord.read(Unknown Source) ... 9 more I am able to connect to the same secure LDAP server however if I use another version of java (1.6.0_14) I have created and installed the server certificates in the cacerts of both the JRE's as mentioned in this guide -- OpenLDAP with SSL When I run ldapsearch -x on the server I get # extended LDIF # # LDAPv3 # base <dc=localdomain> (default) with scope subtree # filter: (objectclass=*) # requesting: ALL # # localdomain dn: dc=localdomain objectClass: top objectClass: dcObject objectClass: organization o: localdomain dc: localdomain # admin, localdomain dn: cn=admin,dc=localdomain objectClass: simpleSecurityObject objectClass: organizationalRole cn: admin description: LDAP administrator # search result search: 2 result: 0 Success # numResponses: 3 # numEntries: 2 On running openssl s_client -connect ldap.natraj.com:636 -showcerts , I obtain the self signed certificate. My slapd.conf file is as follows ####################################################################### # Global Directives: # Features to permit #allow bind_v2 # Schema and objectClass definitions include /etc/ldap/schema/core.schema include /etc/ldap/schema/cosine.schema include /etc/ldap/schema/nis.schema include /etc/ldap/schema/inetorgperson.schema # Where the pid file is put. The init.d script # will not stop the server if you change this. pidfile /var/run/slapd/slapd.pid # List of arguments that were passed to the server argsfile /var/run/slapd/slapd.args # Read slapd.conf(5) for possible values loglevel none # Where the dynamically loaded modules are stored modulepath /usr/lib/ldap moduleload back_hdb # The maximum number of entries that is returned for a search operation sizelimit 500 # The tool-threads parameter sets the actual amount of cpu's that is used # for indexing. tool-threads 1 ####################################################################### # Specific Backend Directives for hdb: # Backend specific directives apply to this backend until another # 'backend' directive occurs backend hdb ####################################################################### # Specific Backend Directives for 'other': # Backend specific directives apply to this backend until another # 'backend' directive occurs #backend <other> ####################################################################### # Specific Directives for database #1, of type hdb: # Database specific directives apply to this databasse until another # 'database' directive occurs database hdb # The base of your directory in database #1 suffix "dc=localdomain" # rootdn directive for specifying a superuser on the database. This is needed # for syncrepl. rootdn "cn=admin,dc=localdomain" # Where the database file are physically stored for database #1 directory "/var/lib/ldap" # The dbconfig settings are used to generate a DB_CONFIG file the first # time slapd starts. They do NOT override existing an existing DB_CONFIG # file. You should therefore change these settings in DB_CONFIG directly # or remove DB_CONFIG and restart slapd for changes to take effect. # For the Debian package we use 2MB as default but be sure to update this # value if you have plenty of RAM dbconfig set_cachesize 0 2097152 0 # Sven Hartge reported that he had to set this value incredibly high # to get slapd running at all. See http://bugs.debian.org/303057 for more # information. # Number of objects that can be locked at the same time. dbconfig set_lk_max_objects 1500 # Number of locks (both requested and granted) dbconfig set_lk_max_locks 1500 # Number of lockers dbconfig set_lk_max_lockers 1500 # Indexing options for database #1 index objectClass eq # Save the time that the entry gets modified, for database #1 lastmod on # Checkpoint the BerkeleyDB database periodically in case of system # failure and to speed slapd shutdown. checkpoint 512 30 # Where to store the replica logs for database #1 # replogfile /var/lib/ldap/replog # The userPassword by default can be changed # by the entry owning it if they are authenticated. # Others should not be able to see it, except the # admin entry below # These access lines apply to database #1 only access to attrs=userPassword,shadowLastChange by dn="cn=admin,dc=localdomain" write by anonymous auth by self write by * none # Ensure read access to the base for things like # supportedSASLMechanisms. Without this you may # have problems with SASL not knowing what # mechanisms are available and the like. # Note that this is covered by the 'access to *' # ACL below too but if you change that as people # are wont to do you'll still need this if you # want SASL (and possible other things) to work # happily. access to dn.base="" by * read # The admin dn has full write access, everyone else # can read everything. access to * by dn="cn=admin,dc=localdomain" write by * read # For Netscape Roaming support, each user gets a roaming # profile for which they have write access to #access to dn=".*,ou=Roaming,o=morsnet" # by dn="cn=admin,dc=localdomain" write # by dnattr=owner write ####################################################################### # Specific Directives for database #2, of type 'other' (can be hdb too): # Database specific directives apply to this databasse until another # 'database' directive occurs #database <other> # The base of your directory for database #2 #suffix "dc=debian,dc=org" ####################################################################### # SSL: # Uncomment the following lines to enable SSL and use the default # snakeoil certificates. #TLSCertificateFile /etc/ssl/certs/ssl-cert-snakeoil.pem #TLSCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key TLSCipherSuite TLS_RSA_AES_256_CBC_SHA TLSCACertificateFile /etc/ldap/ssl/server.pem TLSCertificateFile /etc/ldap/ssl/server.pem TLSCertificateKeyFile /etc/ldap/ssl/server.pem My ldap.conf file is # # LDAP Defaults # # See ldap.conf(5) for details # This file should be world readable but not world writable. HOST ldap.natraj.com PORT 636 BASE dc=localdomain URI ldaps://ldap.natraj.com TLS_CACERT /etc/ldap/ssl/server.pem TLS_REQCERT allow #SIZELIMIT 12 #TIMELIMIT 15 #DEREF never Why is it that I can connect to the same server using one version of JRE while I cannot with another ?

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• How to use sudo with WinSCP and ProFTPd?

  - by Gaia

  I need to run the SFTP fileserver binary as root, but direct root login is not allowed. In WinSCP, if I use "default" on SFTP server protocol option everything works as expected. Following the instructions to sudo in WinSCP, I tried using "sudo /usr/sbin/proftpd" (works on the command line without any prompts) but it brings up "Cannot initialize SFTP protocol. Is the host running a SFTP server?" How to use sudo with WinSCP and ProFTPd? WinSCP 4.3.7 GUI Protocol: SFTP-3 CentOS 6.2 Webmin/Virtualmin (Current Version) PS: only cert based login is allowed . 2012-06-17 11:05:56.998 -------------------------------------------------------------------------- . 2012-06-17 11:05:56.998 WinSCP Version 4.3.7 (Build 1679) (OS 6.1.7601 Service Pack 1) . 2012-06-17 11:05:56.998 Configuration: HKEY_CURRENT_USER\Software\Martin Prikryl\WinSCP 2\ . 2012-06-17 11:05:56.999 Login time: Sunday, June 17, 2012 11:05:56 AM . 2012-06-17 11:05:56.999 -------------------------------------------------------------------------- . 2012-06-17 11:05:56.999 Session name: KVM1 (Modified stored session) . 2012-06-17 11:05:57.047 Host name: mykvm.com (Port: 22) . 2012-06-17 11:05:57.048 User name: adminuser (Password: No, Key file: Yes) . 2012-06-17 11:05:57.048 Tunnel: No . 2012-06-17 11:05:57.048 Transfer Protocol: SFTP (SCP) . 2012-06-17 11:05:57.048 Ping type: -, Ping interval: 30 sec; Timeout: 15 sec . 2012-06-17 11:05:57.048 Proxy: none . 2012-06-17 11:05:57.048 SSH protocol version: 2; Compression: Yes . 2012-06-17 11:05:57.048 Bypass authentication: No . 2012-06-17 11:05:57.048 Try agent: Yes; Agent forwarding: No; TIS/CryptoCard: No; KI: Yes; GSSAPI: No . 2012-06-17 11:05:57.048 Ciphers: aes,blowfish,3des,WARN,arcfour,des; Ssh2DES: No . 2012-06-17 11:05:57.048 SSH Bugs: -,-,-,-,-,-,-,-,- . 2012-06-17 11:05:57.048 SFTP Bugs: -,- . 2012-06-17 11:05:57.048 Return code variable: Autodetect; Lookup user groups: Yes . 2012-06-17 11:05:57.048 Shell: default . 2012-06-17 11:05:57.048 EOL: 0, UTF: 2 . 2012-06-17 11:05:57.048 Clear aliases: Yes, Unset nat.vars: Yes, Resolve symlinks: Yes . 2012-06-17 11:05:57.048 LS: ls -la, Ign LS warn: Yes, Scp1 Comp: No . 2012-06-17 11:05:57.048 Local directory: default, Remote directory: home, Update: No, Cache: Yes . 2012-06-17 11:05:57.048 Cache directory changes: Yes, Permanent: Yes . 2012-06-17 11:05:57.048 DST mode: 1 . 2012-06-17 11:05:57.048 -------------------------------------------------------------------------- . 2012-06-17 11:05:57.113 Looking up host "mykvm.com" . 2012-06-17 11:05:57.132 Connecting to xxx.xxx.128.59 port 22 . 2012-06-17 11:05:57.499 Server version: SSH-2.0-OpenSSH_5.3 . 2012-06-17 11:05:57.499 Using SSH protocol version 2 . 2012-06-17 11:05:57.499 We claim version: SSH-2.0-WinSCP_release_4.3.7 . 2012-06-17 11:05:57.679 Server supports delayed compression; will try this later . 2012-06-17 11:05:57.679 Doing Diffie-Hellman group exchange . 2012-06-17 11:05:58.077 Doing Diffie-Hellman key exchange with hash SHA-1 . 2012-06-17 11:05:58.498 Host key fingerprint is: . 2012-06-17 11:05:58.498 ssh-rsa 2048 bd:e4:34:b1:d4:69:d6:4e:e4:26:04:8b:b7:b3:de:c3 . 2012-06-17 11:05:58.498 Initialised AES-256 SDCTR client->server encryption . 2012-06-17 11:05:58.498 Initialised HMAC-SHA1 client->server MAC algorithm . 2012-06-17 11:05:58.498 Initialised AES-256 SDCTR server->client encryption . 2012-06-17 11:05:58.498 Initialised HMAC-SHA1 server->client MAC algorithm . 2012-06-17 11:05:58.922 Reading private key file "D:\id_rsa.ppk" ! 2012-06-17 11:05:58.924 Using username "adminuser". . 2012-06-17 11:05:59.550 Offered public key . 2012-06-17 11:05:59.743 Offer of public key accepted ! 2012-06-17 11:05:59.743 Authenticating with public key "masterkey for admin" . 2012-06-17 11:05:59.764 Prompt (3, SSH key passphrase, , Passphrase for key "masterkey for admin": ) . 2012-06-17 11:06:02.938 Sent public key signature . 2012-06-17 11:06:03.352 Access granted . 2012-06-17 11:06:03.352 Initiating key re-exchange (enabling delayed compression) . 2012-06-17 11:06:03.765 Doing Diffie-Hellman group exchange . 2012-06-17 11:06:03.955 Doing Diffie-Hellman key exchange with hash SHA-1 . 2012-06-17 11:06:04.410 Initialised AES-256 SDCTR client->server encryption . 2012-06-17 11:06:04.410 Initialised HMAC-SHA1 client->server MAC algorithm . 2012-06-17 11:06:04.410 Initialised zlib (RFC1950) compression . 2012-06-17 11:06:04.410 Initialised AES-256 SDCTR server->client encryption . 2012-06-17 11:06:04.410 Initialised HMAC-SHA1 server->client MAC algorithm . 2012-06-17 11:06:04.410 Initialised zlib (RFC1950) decompression . 2012-06-17 11:06:04.839 Opened channel for session . 2012-06-17 11:06:05.247 Started a shell/command . 2012-06-17 11:06:05.253 -------------------------------------------------------------------------- . 2012-06-17 11:06:05.253 Using SFTP protocol. . 2012-06-17 11:06:05.253 Doing startup conversation with host. > 2012-06-17 11:06:05.259 Type: SSH_FXP_INIT, Size: 5, Number: -1 . 2012-06-17 11:06:05.354 Server sent command exit status 0 . 2012-06-17 11:06:05.354 Disconnected: All channels closed * 2012-06-17 11:06:05.380 (ESshFatal) Connection has been unexpectedly closed. Server sent command exit status 0. * 2012-06-17 11:06:05.380 Cannot initialize SFTP protocol. Is the host running a SFTP server?

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• Moving the swapfiles to a dedicated partition in Snow Leopard

  - by e.James

  I have been able to move Apple's virtual memory swapfiles to a dedicated partition on my hard drive up until now. The technique I have been using is described in a thread on forums.macosxhints.com. However, with the developer preview of Snow Leopard, this method no longer works. Does anyone know how it could be done with the new OS? Update: I have marked dblu's answer as accepted even though it didn't quite work because he gave excellent, detailed instructions and because his suggestion to use plutil ultimately pointed me in the right direction. The complete, working solution is posted here in the question because I don't have enough reputation to edit the accepted answer. Complete solution: 1. Open Terminal and make a backup copy of Apple's default dynamic_pager.plist: $ cd /System/Library/LaunchDaemons $ sudo cp com.apple.dynamic_pager.plist{,_bak} 2. Convert the plist from binary to plain XML: $ sudo plutil -convert xml1 com.apple.dynamic_pager.plist 3. Open the converted plist with your text editor of choice. (I use pico, see dblu's answer for an example using vim): $ sudo pico -w com.apple.dynamic_pager.plist It should look as follows: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs$ <plist version="1.0"> <dict> <key>EnableTransactions</key> <true/> <key>HopefullyExitsLast</key> <true/> <key>Label</key> <string>com.apple.dynamic_pager</string> <key>OnDemand</key> <false/> <key>ProgramArguments</key> <array> <string>/sbin/dynamic_pager</string> <string>-F</string> <string>/private/var/vm/swapfile</string> </array> </dict> </plist> 4. Change the ProgramArguments array (lines 13 through 18) so that it launches an intermediate shell script instead of launching dynamic_pager directly. See note #1 for details on why this is necessary. <key>ProgramArguments</key> <array> <string>/sbin/dynamic_pager_init</string> </array> 5. Save the plist, and return to the terminal prompt. Using pico, the commands would be: <ctrl+o> to save the file <enter> to accept the same filename (com.apple.dynamic_pager.plist) <ctrl+x> to exit 6. Convert the modified plist back to binary: $ sudo plutil -convert binary1 com.apple.dynamic_pager.plist 7. Create the intermediate shell script: $ cd /sbin $ sudo pico -w dynamic_pager_init The script should look as follows (my partition is called 'Swap', and I chose to put the swapfiles in a hidden directory on that partition, called '.vm' be sure that the directory you specify actually exists): Update: This version of the script makes use of wait4path as suggested by ZILjr: #!/bin/bash #launch Apple's dynamic_pager only when the swap volume is mounted echo "Waiting for Swap volume to mount"; wait4path /Volumes/Swap; echo "Launching dynamic pager on volume Swap"; /sbin/dynamic_pager -F /Volumes/Swap/.vm/swapfile; 8. Save and close dynamic_pager_init (same commands as step 5) 9. Modify permissions and ownership for dynamic_pager_init: $ sudo chmod a+x-w /sbin/dynamic_pager_init $ sudo chown root:wheel /sbin/dynamic_pager_init 10. Verify the permissions on dynamic_pager_init: $ ls -l dynamic_pager_init -r-xr-xr-x 1 root wheel 6 18 Sep 15:11 dynamic_pager_init 11. Restart your Mac. If you run into trouble, switch to verbose startup mode by holding down Command-v immediately after the startup chime. This will let you see all of the startup messages that appear during startup. If you run into even worse trouble (i.e. you never see the login screen), hold down Command-s instead. This will boot the computer in single-user mode (no graphical UI, just a command prompt) and allow you to restore the backup copy of com.apple.dynamic_pager.plist that you made in step 1. 12. Once the computer boots, fire up Terminal and verify that the swap files have actually been moved: $ cd /Volumes/Swap/.vm $ ls -l You should see something like this: -rw------- 1 someUser staff 67108864 18 Sep 12:02 swapfile0 13. Delete the old swapfiles: $ cd /private/var/vm $ sudo rm swapfile* 14. Profit! Note 1 Simply modifying the arguments to dynamic_pager in the plist does not always work, and when it fails, it does so in a spectacularly silent way. The problem stems from the fact that dynamic_pager is launched very early in the startup process. If your swap partition has not yet been mounted when dynamic_pager is first loaded (in my experience, this happens 99% of the time), then the system will fake its way through. It will create a symbolic link in your /Volumes directory which has the same name as your swap partition, but points back to the default swapfile location (/private/var/vm). Then, when your actual swap partition mounts, it will be given the name Swap 1 (or YourDriveName 1). You can see the problem by opening up Terminal and listing the contents of your /Volumes directory: $ cd /Volumes $ ls -l You will see something like this: drwxrwxrwx 11 yourUser staff 442 16 Sep 12:13 Swap -> private/var/vm drwxrwxrwx 14 yourUser staff 5 16 Sep 12:13 Swap 1 lrwxr-xr-x 1 root admin 1 17 Sep 12:01 System -> / Note that this failure can be very hard to spot. If you were to check for the swapfiles as I show in step 12, you would still see them! The symbolic link would make it seem as though your swapfiles had been moved, even though they were actually being stored in the default location. Note 2 I was originally unable to get this to work in Snow Leopard because com.apple.dynamic_pager.plist was stored in binary format. I made a copy of the original file and opened it with Apple's Property List Editor (available with Xcode) in order to make changes, but this process added some extended attributes to the plist file which caused the system to ignore it and just use the defaults. As dblu pointed out, using plutil to convert the file to plain XML works like a charm. Note 3 You can check the Console application to see any messages that dynamic_pager_init echos to the screen. If you see the following lines repeated over and over again, there is a problem with the setup. I ran into these messages because I forgot to create the '.vm' directory that I specified in dynamic_pager_init. com.apple.launchd[1] (com.apple.dynamic_pager[176]) Exited with exit code: 1 com.apple.launchd[1] (com.apple.dynamic_pager) Throttling respawn: Will start in 10 seconds When everything is working properly, you may see the above message a couple of times, but you should also see the following message, and then no more of the "Throttling respawn" messages afterwards. com.apple.dynamic_pager[???] Launching dynamic pager on volume Swap This means that the script did have to wait for the partition to load, but in the end it was successful.

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• Why is Varnish not caching?

  - by Justin

  I am troubleshooting the setup of Varnish 3.x on my Ubuntu server. I'm running Drupal 7 on two sites set up on the box, via named-based vhosts. Before trying to get Varnish to play nice with Drupal I'm trying to just get Varnish to a PNG from cache. Here are the headers I get from a curl -I request of the PNG file: HTTP/1.1 200 OK Server: Apache/2.2.22 (Ubuntu) Last-Modified: Sun, 07 Oct 2012 21:18:59 GMT ETag: "a57c2-3850-4cb7ea73db6c0" Accept-Ranges: bytes Content-Length: 14416 Cache-Control: max-age=1209600 Expires: Thu, 25 Oct 2012 22:55:14 GMT Content-Type: image/png Accept-Ranges: bytes Date: Thu, 11 Oct 2012 22:55:14 GMT X-Varnish: 1766703058 Age: 0 Via: 1.1 varnish Connection: keep-alive X-Varnish-Cache: MISS Here is the Varnish VCL file I'm using (It's a default VCL configuration designed for Drupal): # Default backend definition. Set this to point to your content # server. # backend default { .host = "127.0.0.1"; .port = "8080"; } # Respond to incoming requests. sub vcl_recv { # Use anonymous, cached pages if all backends are down. if (!req.backend.healthy) { unset req.http.Cookie; } # Allow the backend to serve up stale content if it is responding slowly. set req.grace = 6h; # Pipe these paths directly to Apache for streaming. #if (req.url ~ "^/admin/content/backup_migrate/export") { # return (pipe); #} # Do not cache these paths. if (req.url ~ "^/status\.php$" || req.url ~ "^/update\.php$" || req.url ~ "^/admin$" || req.url ~ "^/admin/.*$" || req.url ~ "^/flag/.*$" || req.url ~ "^.*/ajax/.*$" || req.url ~ "^.*/ahah/.*$") { return (pass); } # Do not allow outside access to cron.php or install.php. #if (req.url ~ "^/(cron|install)\.php$" && !client.ip ~ internal) { # Have Varnish throw the error directly. # error 404 "Page not found."; # Use a custom error page that you've defined in Drupal at the path "404". # set req.url = "/404"; #} # Always cache the following file types for all users. This list of extensions # appears twice, once here and again in vcl_fetch so make sure you edit both # and keep them equal. if (req.url ~ "(?i)\.(pdf|asc|dat|txt|doc|xls|ppt|tgz|csv|png|gif|jpeg|jpg|ico|swf|css|js)(\?.*)?$") { unset req.http.Cookie; } # Remove all cookies that Drupal doesn't need to know about. We explicitly # list the ones that Drupal does need, the SESS and NO_CACHE. If, after # running this code we find that either of these two cookies remains, we # will pass as the page cannot be cached. if (req.http.Cookie) { # 1. Append a semi-colon to the front of the cookie string. # 2. Remove all spaces that appear after semi-colons. # 3. Match the cookies we want to keep, adding the space we removed # previously back. (\1) is first matching group in the regsuball. # 4. Remove all other cookies, identifying them by the fact that they have # no space after the preceding semi-colon. # 5. Remove all spaces and semi-colons from the beginning and end of the # cookie string. set req.http.Cookie = ";" + req.http.Cookie; set req.http.Cookie = regsuball(req.http.Cookie, "; +", ";"); set req.http.Cookie = regsuball(req.http.Cookie, ";(SESS[a-z0-9]+|SSESS[a-z0-9]+|NO_CACHE)=", "; \1="); set req.http.Cookie = regsuball(req.http.Cookie, ";[^ ][^;]*", ""); set req.http.Cookie = regsuball(req.http.Cookie, "^[; ]+|[; ]+$", ""); if (req.http.Cookie == "") { # If there are no remaining cookies, remove the cookie header. If there # aren't any cookie headers, Varnish's default behavior will be to cache # the page. unset req.http.Cookie; } else { # If there is any cookies left (a session or NO_CACHE cookie), do not # cache the page. Pass it on to Apache directly. return (pass); } } } # Set a header to track a cache HIT/MISS. sub vcl_deliver { if (obj.hits > 0) { set resp.http.X-Varnish-Cache = "HIT"; } else { set resp.http.X-Varnish-Cache = "MISS"; } } # Code determining what to do when serving items from the Apache servers. # beresp == Back-end response from the web server. sub vcl_fetch { # We need this to cache 404s, 301s, 500s. Otherwise, depending on backend but # definitely in Drupal's case these responses are not cacheable by default. if (beresp.status == 404 || beresp.status == 301 || beresp.status == 500) { set beresp.ttl = 10m; } # Don't allow static files to set cookies. # (?i) denotes case insensitive in PCRE (perl compatible regular expressions). # This list of extensions appears twice, once here and again in vcl_recv so # make sure you edit both and keep them equal. if (req.url ~ "(?i)\.(pdf|asc|dat|txt|doc|xls|ppt|tgz|csv|png|gif|jpeg|jpg|ico|swf|css|js)(\?.*)?$") { unset beresp.http.set-cookie; } # Allow items to be stale if needed. set beresp.grace = 6h; } # In the event of an error, show friendlier messages. sub vcl_error { # Redirect to some other URL in the case of a homepage failure. #if (req.url ~ "^/?$") { # set obj.status = 302; # set obj.http.Location = "http://backup.example.com/"; #} # Otherwise redirect to the homepage, which will likely be in the cache. set obj.http.Content-Type = "text/html; charset=utf-8"; synthetic {" <html> <head> <title>Page Unavailable</title> <style> body { background: #303030; text-align: center; color: white; } #page { border: 1px solid #CCC; width: 500px; margin: 100px auto 0; padding: 30px; background: #323232; } a, a:link, a:visited { color: #CCC; } .error { color: #222; } </style> </head> <body onload="setTimeout(function() { window.location = '/' }, 5000)"> <div id="page"> <h1 class="title">Page Unavailable</h1> <p>The page you requested is temporarily unavailable.</p> <p>We're redirecting you to the <a href="/">homepage</a> in 5 seconds.</p> <div class="error">(Error "} + obj.status + " " + obj.response + {")</div> </div> </body> </html> "}; return (deliver); } I'm getting a MISS and age 0 every time. If I'm understanding correctly, this means the file isn't being returned from Varnish's cache. Is there a problem with my Varnish config?

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• Nagios plugin script not working as expected

  - by Linker3000

  I have modified an off-the-shelf Nagios plugin perl script to (in theory) return a one or zero according to the existence, or not, of a file on a remote linux server. The script runs a remote ssh session and logs in as the nagios user. The remote linux servers have private keys setup for that user, and on the bash command line the script works as expected, but when run as a plugin it always returns '1' (true) even if the file does not exist. Some help with the logic or a comment on why things are not working as expected within Nagios would be appreciated. I'd prefer to use this ssh login method rather than having to install nrpe on all the linux servers. To run from a command line (assuming remote server has a user called nagios with a valid private key): ./check_reboot_required -e ssh -H remote-servers-ip-addr -p 'filename-to-check' -v Ta. #! /usr/bin/perl -w # # # License Information: # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. # ############################################################################ use POSIX; use strict; use Getopt::Long; use lib "/usr/lib/nagios/plugins" ; use vars qw($host $opt_V $opt_h $opt_v $verbose $PROGNAME $pattern $opt_p $mmin $opt_e $opt_t $opt_H $status $state $msg $msg_q $MAILQ $SHELL $device $used $avail $percent $fs $blocks $CMD $RMTOS); use utils qw(%ERRORS &print_revision &support &usage ); sub print_help (); sub print_usage (); sub process_arguments (); $ENV{'PATH'}=''; $ENV{'BASH_ENV'}=''; $ENV{'ENV'}=''; $PROGNAME = "check_reboot_required"; Getopt::Long::Configure('bundling'); $status = process_arguments(); if ($status){ print "ERROR: processing arguments\n"; exit $ERRORS{'UNKNOWN'}; } $SIG{'ALRM'} = sub { print ("ERROR: timed out waiting for $CMD on $host\n"); exit $ERRORS{'WARNING'}; }; $host = $opt_H; $pattern = $opt_p; print "Pattern >" . $pattern . "< " if $verbose; alarm($opt_t); #$CMD = "/usr/bin/find " . $pattern . " -type f 2>/dev/null| /usr/bin/wc -l"; $CMD = "[ -f " . $pattern . " ] && echo 1 || echo 0"; alarm($opt_t); ## get cmd output from remote system if (! open (OUTPUT, "$SHELL $host $CMD|" ) ) { print "ERROR: could not open $CMD on $host\n"; exit $ERRORS{'UNKNOWN'}; } my $perfdata = ""; my $state = "3"; my $msg = "Indeterminate result"; # only first line is relevant in this iteration. while (<OUTPUT>) { my $result = chomp($_); $msg = $result; print "Shell returned >" . $result . "< length is " . length($result) . " " if $verbose; if ( $result == 1 ) { $msg = "Reboot required (NB: Result still not accurate)" . $result ; $state = $ERRORS{'WARNING'}; last; } elsif ( $result == 0 ) { $msg = "No reboot required (NB: Result still not accurate) " . $result ; $state = $ERRORS{'OK'}; last; } else { $msg = "Output received, but it was neither a 1 nor a 0" ; last; } } close (OUTPUT); print "$msg | $perfdata\n"; exit $state; ##################################### #### subs sub process_arguments(){ GetOptions ("V" => \$opt_V, "version" => \$opt_V, "v" => \$opt_v, "verbose" => \$opt_v, "h" => \$opt_h, "help" => \$opt_h, "e=s" => \$opt_e, "shell=s" => \$opt_e, "p=s" => \$opt_p, "pattern=s" => \$opt_p, "t=i" => \$opt_t, "timeout=i" => \$opt_t, "H=s" => \$opt_H, "hostname=s" => \$opt_H ); if ($opt_V) { print_revision($PROGNAME,'$Revision: 1.0 $ '); exit $ERRORS{'OK'}; } if ($opt_h) { print_help(); exit $ERRORS{'OK'}; } if (defined $opt_v ){ $verbose = $opt_v; } if (defined $opt_e ){ if ( $opt_e eq "ssh" ) { if (-x "/usr/local/bin/ssh") { $SHELL = "/usr/local/bin/ssh"; } elsif ( -x "/usr/bin/ssh" ) { $SHELL = "/usr/bin/ssh"; } else { print_usage(); exit $ERRORS{'UNKNOWN'}; } } elsif ( $opt_e eq "rsh" ) { $SHELL = "/usr/bin/rsh"; } else { print_usage(); exit $ERRORS{'UNKNOWN'}; } } else { print_usage(); exit $ERRORS{'UNKNOWN'}; } unless (defined $opt_t) { $opt_t = $utils::TIMEOUT ; # default timeout } unless (defined $opt_H) { print_usage(); exit $ERRORS{'UNKNOWN'}; } return $ERRORS{'OK'}; } sub print_usage () { print "Usage: $PROGNAME -e <shell> -H <hostname> -p <directory/file pattern> [-t <timeout>] [-v verbose]\n"; } sub print_help () { print_revision($PROGNAME,'$Revision: 0.1 $'); print "\n"; print_usage(); print "\n"; print " Checks for the presence of a 'reboot-required' file on a remote host via SSH or RSH\n"; print "-e (--shell) = ssh or rsh (required)\n"; print "-H (--hostname) = remote server name (required)"; print "-p (--pattern) = File pattern for find command (default = /var/run/reboot-required)\n"; print "-t (--timeout) = Plugin timeout in seconds (default = $utils::TIMEOUT)\n"; print "-h (--help)\n"; print "-V (--version)\n"; print "-v (--verbose) = debugging output\n"; print "\n\n"; support(); }

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• Microsoft and jQuery

  - by Rick Strahl

  The jQuery JavaScript library has been steadily getting more popular and with recent developments from Microsoft, jQuery is also getting ever more exposure on the ASP.NET platform including now directly from Microsoft. jQuery is a light weight, open source DOM manipulation library for JavaScript that has changed how many developers think about JavaScript. You can download it and find more information on jQuery on www.jquery.com. For me jQuery has had a huge impact on how I develop Web applications and was probably the main reason I went from dreading to do JavaScript development to actually looking forward to implementing client side JavaScript functionality. It has also had a profound impact on my JavaScript skill level for me by seeing how the library accomplishes things (and often reviewing the terse but excellent source code). jQuery made an uncomfortable development platform (JavaScript + DOM) a joy to work on. Although jQuery is by no means the only JavaScript library out there, its ease of use, small size, huge community of plug-ins and pure usefulness has made it easily the most popular JavaScript library available today. As a long time jQuery user, I’ve been excited to see the developments from Microsoft that are bringing jQuery to more ASP.NET developers and providing more integration with jQuery for ASP.NET’s core features rather than relying on the ASP.NET AJAX library. Microsoft and jQuery – making Friends jQuery is an open source project but in the last couple of years Microsoft has really thrown its weight behind supporting this open source library as a supported component on the Microsoft platform. When I say supported I literally mean supported: Microsoft now offers actual tech support for jQuery as part of their Product Support Services (PSS) as jQuery integration has become part of several of the ASP.NET toolkits and ships in several of the default Web project templates in Visual Studio 2010. The ASP.NET MVC 3 framework (still in Beta) also uses jQuery for a variety of client side support features including client side validation and we can look forward toward more integration of client side functionality via jQuery in both MVC and WebForms in the future. In other words jQuery is becoming an optional but included component of the ASP.NET platform. PSS support means that support staff will answer jQuery related support questions as part of any support incidents related to ASP.NET which provides some piece of mind to some corporate development shops that require end to end support from Microsoft. In addition to including jQuery and supporting it, Microsoft has also been getting involved in providing development resources for extending jQuery’s functionality via plug-ins. Microsoft’s last version of the Microsoft Ajax Library – which is the successor to the native ASP.NET AJAX Library – included some really cool functionality for client templates, databinding and localization. As it turns out Microsoft has rebuilt most of that functionality using jQuery as the base API and provided jQuery plug-ins of these components. Very recently these three plug-ins were submitted and have been approved for inclusion in the official jQuery plug-in repository and been taken over by the jQuery team for further improvements and maintenance. Even more surprising: The jQuery-templates component has actually been approved for inclusion in the next major update of the jQuery core in jQuery V1.5, which means it will become a native feature that doesn’t require additional script files to be loaded. Imagine this – an open source contribution from Microsoft that has been accepted into a major open source project for a core feature improvement. Microsoft has come a long way indeed! What the Microsoft Involvement with jQuery means to you For Microsoft jQuery support is a strategic decision that affects their direction in client side development, but nothing stopped you from using jQuery in your applications prior to Microsoft’s official backing and in fact a large chunk of developers did so readily prior to Microsoft’s announcement. Official support from Microsoft brings a few benefits to developers however. jQuery support in Visual Studio 2010 means built-in support for jQuery IntelliSense, automatically added jQuery scripts in many projects types and a common base for client side functionality that actually uses what most developers are already using. If you have already been using jQuery and were worried about straying from the Microsoft line and their internal Microsoft Ajax Library – worry no more. With official support and the change in direction towards jQuery Microsoft is now following along what most in the ASP.NET community had already been doing by using jQuery, which is likely the reason for Microsoft’s shift in direction in the first place. ASP.NET AJAX and the Microsoft AJAX Library weren’t bad technology – there was tons of useful functionality buried in these libraries. However, these libraries never got off the ground, mainly because early incarnations were squarely aimed at control/component developers rather than application developers. For all the functionality that these controls provided for control developers they lacked in useful and easily usable application developer functionality that was easily accessible in day to day client side development. The result was that even though Microsoft shipped support for these tools in the box (in .NET 3.5 and 4.0), other than for the internal support in ASP.NET for things like the UpdatePanel and the ASP.NET AJAX Control Toolkit as well as some third party vendors, the Microsoft client libraries were largely ignored by the developer community opening the door for other client side solutions. Microsoft seems to be acknowledging developer choice in this case: Many more developers were going down the jQuery path rather than using the Microsoft built libraries and there seems to be little sense in continuing development of a technology that largely goes unused by the majority of developers. Kudos for Microsoft for recognizing this and gracefully changing directions. Note that even though there will be no further development in the Microsoft client libraries they will continue to be supported so if you’re using them in your applications there’s no reason to start running for the exit in a panic and start re-writing everything with jQuery. Although that might be a reasonable choice in some cases, jQuery and the Microsoft libraries work well side by side so that you can leave existing solutions untouched even as you enhance them with jQuery. The Microsoft jQuery Plug-ins – Solid Core Features One of the most interesting developments in Microsoft’s embracing of jQuery is that Microsoft has started contributing to jQuery via standard mechanism set for jQuery developers: By submitting plug-ins. Microsoft took some of the nicest new features of the unpublished Microsoft Ajax Client Library and re-wrote these components for jQuery and then submitted them as plug-ins to the jQuery plug-in repository. Accepted plug-ins get taken over by the jQuery team and that’s exactly what happened with the three plug-ins submitted by Microsoft with the templating plug-in even getting slated to be published as part of the jQuery core in the next major release (1.5). The following plug-ins are provided by Microsoft: jQuery Templates – a client side template rendering engine jQuery Data Link – a client side databinder that can synchronize changes without code jQuery Globalization – provides formatting and conversion features for dates and numbers The first two are ports of functionality that was slated for the Microsoft Ajax Library while functionality for the globalization library provides functionality that was already found in the original ASP.NET AJAX library. To me all three plug-ins address a pressing need in client side applications and provide functionality I’ve previously used in other incarnations, but with more complete implementations. Let’s take a close look at these plug-ins. jQuery Templates http://api.jquery.com/category/plugins/templates/ Client side templating is a key component for building rich JavaScript applications in the browser. Templating on the client lets you avoid from manually creating markup by creating DOM nodes and injecting them individually into the document via code. Rather you can create markup templates – similar to the way you create classic ASP server markup – and merge data into these templates to render HTML which you can then inject into the document or replace existing content with. Output from templates are rendered as a jQuery matched set and can then be easily inserted into the document as needed. Templating is key to minimize client side code and reduce repeated code for rendering logic. Instead a single template can be used in many places for updating and adding content to existing pages. Further if you build pure AJAX interfaces that rely entirely on client rendering of the initial page content, templates allow you to a use a single markup template to handle all rendering of each specific HTML section/element. I’ve used a number of different client rendering template engines with jQuery in the past including jTemplates (a PHP style templating engine) and a modified version of John Resig’s MicroTemplating engine which I built into my own set of libraries because it’s such a commonly used feature in my client side applications. jQuery templates adds a much richer templating model that allows for sub-templates and access to the data items. Like John Resig’s original Micro Template engine, the core basics of the templating engine create JavaScript code which means that templates can include JavaScript code. To give you a basic idea of how templates work imagine I have an application that downloads a set of stock quotes based on a symbol list then displays them in the document. To do this you can create an ‘item’ template that describes how each of the quotes is renderd as a template inside of the document: <script id="stockTemplate" type="text/x-jquery-tmpl"> <div id="divStockQuote" class="errordisplay" style="width: 500px;"> <div class="label">Company:</div><div><b>${Company}(${Symbol})</b></div> <div class="label">Last Price:</div><div>${LastPrice}</div> <div class="label">Net Change:</div><div> {{if NetChange > 0}} <b style="color:green" >${NetChange}</b> {{else}} <b style="color:red" >${NetChange}</b> {{/if}} </div> <div class="label">Last Update:</div><div>${LastQuoteTimeString}</div> </div> </script> The ‘template’ is little more than HTML with some markup expressions inside of it that define the template language. Notice the embedded ${} expressions which reference data from the quote objects returned from an AJAX call on the server. You can embed any JavaScript or value expression in these template expressions. There are also a number of structural commands like {{if}} and {{each}} that provide for rudimentary logic inside of your templates as well as commands ({{tmpl}} and {{wrap}}) for nesting templates. You can find more about the full set of markup expressions available in the documentation. To load up this data you can use code like the following: <script type="text/javascript"> //var Proxy = new ServiceProxy("../PageMethods/PageMethodsService.asmx/"); $(document).ready(function () { $("#btnGetQuotes").click(GetQuotes); }); function GetQuotes() { var symbols = $("#txtSymbols").val().split(","); $.ajax({ url: "../PageMethods/PageMethodsService.asmx/GetStockQuotes", data: JSON.stringify({ symbols: symbols }), // parameter map type: "POST", // data has to be POSTed contentType: "application/json", timeout: 10000, dataType: "json", success: function (result) { var quotes = result.d; var jEl = $("#stockTemplate").tmpl(quotes); $("#quoteDisplay").empty().append(jEl); }, error: function (xhr, status) { alert(status + "\r\n" + xhr.responseText); } }); }; </script> In this case an ASMX AJAX service is called to retrieve the stock quotes. The service returns an array of quote objects. The result is returned as an object with the .d property (in Microsoft service style) that returns the actual array of quotes. The template is applied with: var jEl = $("#stockTemplate").tmpl(quotes); which selects the template script tag and uses the .tmpl() function to apply the data to it. The result is a jQuery matched set of elements that can then be appended to the quote display element in the page. The template is merged against an array in this example. When the result is an array the template is automatically applied to each each array item. If you pass a single data item – like say a stock quote – the template works exactly the same way but is applied only once. Templates also have access to a $data item which provides the current data item and information about the tempalte that is currently executing. This makes it possible to keep context within the context of the template itself and also to pass context from a parent template to a child template which is very powerful. Templates can be evaluated by using the template selector and calling the .tmpl() function on the jQuery matched set as shown above or you can use the static $.tmpl() function to provide a template as a string. This allows you to dynamically create templates in code or – more likely – to load templates from the server via AJAX calls. In short there are options The above shows off some of the basics, but there’s much for functionality available in the template engine. Check the documentation link for more information and links to additional examples. The plug-in download also comes with a number of examples that demonstrate functionality. jQuery templates will become a native component in jQuery Core 1.5, so it’s definitely worthwhile checking out the engine today and get familiar with this interface. As much as I’m stoked about templating becoming part of the jQuery core because it’s such an integral part of many applications, there are also a couple shortcomings in the current incarnation: Lack of Error Handling Currently if you embed an expression that is invalid it’s simply not rendered. There’s no error rendered into the template nor do the various  template functions throw errors which leaves finding of bugs as a runtime exercise. I would like some mechanism – optional if possible – to be able to get error info of what is failing in a template when it’s rendered. No String Output Templates are always rendered into a jQuery matched set and there’s no way that I can see to directly render to a string. String output can be useful for debugging as well as opening up templating for creating non-HTML string output. Limited JavaScript Access Unlike John Resig’s original MicroTemplating Engine which was entirely based on JavaScript code generation these templates are limited to a few structured commands that can ‘execute’. There’s no code execution inside of script code which means you’re limited to calling expressions available in global objects or the data item passed in. This may or may not be a big deal depending on the complexity of your template logic. Error handling has been discussed quite a bit and it’s likely there will be some solution to that particualar issue by the time jQuery templates ship. The others are relatively minor issues but something to think about anyway. jQuery Data Link http://api.jquery.com/category/plugins/data-link/ jQuery Data Link provides the ability to do two-way data binding between input controls and an underlying object’s properties. The typical scenario is linking a textbox to a property of an object and have the object updated when the text in the textbox is changed and have the textbox change when the value in the object or the entire object changes. The plug-in also supports converter functions that can be applied to provide the conversion logic from string to some other value typically necessary for mapping things like textbox string input to say a number property and potentially applying additional formatting and calculations. In theory this sounds great, however in reality this plug-in has some serious usability issues. Using the plug-in you can do things like the following to bind data: person = { firstName: "rick", lastName: "strahl"}; $(document).ready( function() { // provide for two-way linking of inputs $("form").link(person); // bind to non-input elements explicitly $("#objFirst").link(person, { firstName: { name: "objFirst", convertBack: function (value, source, target) { $(target).text(value); } } }); $("#objLast").link(person, { lastName: { name: "objLast", convertBack: function (value, source, target) { $(target).text(value); } } }); }); This code hooks up two-way linking between a couple of textboxes on the page and the person object. The first line in the .ready() handler provides mapping of object to form field with the same field names as properties on the object. Note that .link() does NOT bind items into the textboxes when you call .link() – changes are mapped only when values change and you move out of the field. Strike one. The two following commands allow manual binding of values to specific DOM elements which is effectively a one-way bind. You specify the object and a then an explicit mapping where name is an ID in the document. The converter is required to explicitly assign the value to the element. Strike two. You can also detect changes to the underlying object and cause updates to the input elements bound. Unfortunately the syntax to do this is not very natural as you have to rely on the jQuery data object. To update an object’s properties and get change notification looks like this: function updateFirstName() { $(person).data("firstName", person.firstName + " (code updated)"); } This works fine in causing any linked fields to be updated. In the bindings above both the firstName input field and objFirst DOM element gets updated. But the syntax requires you to use a jQuery .data() call for each property change to ensure that the changes are tracked properly. Really? Sure you’re binding through multiple layers of abstraction now but how is that better than just manually assigning values? The code savings (if any) are going to be minimal. As much as I would like to have a WPF/Silverlight/Observable-like binding mechanism in client script, this plug-in doesn’t help much towards that goal in its current incarnation. While you can bind values, the ‘binder’ is too limited to be really useful. If initial values can’t be assigned from the mappings you’re going to end up duplicating work loading the data using some other mechanism. There’s no easy way to re-bind data with a different object altogether since updates trigger only through the .data members. Finally, any non-input elements have to be bound via code that’s fairly verbose and frankly may be more voluminous than what you might write by hand for manual binding and unbinding. Two way binding can be very useful but it has to be easy and most importantly natural. If it’s more work to hook up a binding than writing a couple of lines to do binding/unbinding this sort of thing helps very little in most scenarios. In talking to some of the developers the feature set for Data Link is not complete and they are still soliciting input for features and functionality. If you have ideas on how you want this feature to be more useful get involved and post your recommendations. As it stands, it looks to me like this component needs a lot of love to become useful. For this component to really provide value, bindings need to be able to be refreshed easily and work at the object level, not just the property level. It seems to me we would be much better served by a model binder object that can perform these binding/unbinding tasks in bulk rather than a tool where each link has to be mapped first. I also find the choice of creating a jQuery plug-in questionable – it seems a standalone object – albeit one that relies on the jQuery library – would provide a more intuitive interface than the current forcing of options onto a plug-in style interface. Out of the three Microsoft created components this is by far the least useful and least polished implementation at this point. jQuery Globalization http://github.com/jquery/jquery-global Globalization in JavaScript applications often gets short shrift and part of the reason for this is that natively in JavaScript there’s little support for formatting and parsing of numbers and dates. There are a number of JavaScript libraries out there that provide some support for globalization, but most are limited to a particular portion of globalization. As .NET developers we’re fairly spoiled by the richness of APIs provided in the framework and when dealing with client development one really notices the lack of these features. While you may not necessarily need to localize your application the globalization plug-in also helps with some basic tasks for non-localized applications: Dealing with formatting and parsing of dates and time values. Dates in particular are problematic in JavaScript as there are no formatters whatsoever except the .toString() method which outputs a verbose and next to useless long string. With the globalization plug-in you get a good chunk of the formatting and parsing functionality that the .NET framework provides on the server. You can write code like the following for example to format numbers and dates: var date = new Date(); var output = $.format(date, "MMM. dd, yy") + "\r\n" + $.format(date, "d") + "\r\n" + // 10/25/2010 $.format(1222.32213, "N2") + "\r\n" + $.format(1222.33, "c") + "\r\n"; alert(output); This becomes even more useful if you combine it with templates which can also include any JavaScript expressions. Assuming the globalization plug-in is loaded you can create template expressions that use the $.format function. Here’s the template I used earlier for the stock quote again with a couple of formats applied: <script id="stockTemplate" type="text/x-jquery-tmpl"> <div id="divStockQuote" class="errordisplay" style="width: 500px;"> <div class="label">Company:</div><div><b>${Company}(${Symbol})</b></div> <div class="label">Last Price:</div> <div>${$.format(LastPrice,"N2")}</div> <div class="label">Net Change:</div><div> {{if NetChange > 0}} <b style="color:green" >${NetChange}</b> {{else}} <b style="color:red" >${NetChange}</b> {{/if}} </div> <div class="label">Last Update:</div> <div>${$.format(LastQuoteTime,"MMM dd, yyyy")}</div> </div> </script> There are also parsing methods that can parse dates and numbers from strings into numbers easily: alert($.parseDate("25.10.2010")); alert($.parseInt("12.222")); // de-DE uses . for thousands separators As you can see culture specific options are taken into account when parsing. The globalization plugin provides rich support for a variety of locales: Get a list of all available cultures Query cultures for culture items (like currency symbol, separators etc.) Localized string names for all calendar related items (days of week, months) Generated off of .NET’s supported locales In short you get much of the same functionality that you already might be using in .NET on the server side. The plugin includes a huge number of locales and an Globalization.all.min.js file that contains the text defaults for each of these locales as well as small locale specific script files that define each of the locale specific settings. It’s highly recommended that you NOT use the huge globalization file that includes all locales, but rather add script references to only those languages you explicitly care about. Overall this plug-in is a welcome helper. Even if you use it with a single locale (like en-US) and do no other localization, you’ll gain solid support for number and date formatting which is a vital feature of many applications. Changes for Microsoft It’s good to see Microsoft coming out of its shell and away from the ‘not-built-here’ mentality that has been so pervasive in the past. It’s especially good to see it applied to jQuery – a technology that has stood in drastic contrast to Microsoft’s own internal efforts in terms of design, usage model and… popularity. It’s great to see that Microsoft is paying attention to what customers prefer to use and supporting the customer sentiment – even if it meant drastically changing course of policy and moving into a more open and sharing environment in the process. The additional jQuery support that has been introduced in the last two years certainly has made lives easier for many developers on the ASP.NET platform. It’s also nice to see Microsoft submitting proposals through the standard jQuery process of plug-ins and getting accepted for various very useful projects. Certainly the jQuery Templates plug-in is going to be very useful to many especially since it will be baked into the jQuery core in jQuery 1.5. I hope we see more of this type of involvement from Microsoft in the future. Kudos!© Rick Strahl, West Wind Technologies, 2005-2010Posted in jQuery  ASP.NET  

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• Tools and Utilities for the .NET Developer

  - by mbcrump

  Tweet this list! Add a link to my site to your bookmarks to quickly find this page again! Add me to twitter! This is a list of the tools/utilities that I use to do my job/hobby. I wanted this page to load fast and contain information that only you care about. If I have missed a tool that you like, feel free to contact me and I will add it to the list. Also, this list took a lot of time to complete. Please do not steal my work, if you like the page then please link back to my site. I will keep the links/information updated as new tools/utilities are created.  Windows/.NET Development – This is a list of tools that any Windows/.NET developer should have in his bag. I have used at some point in my career everything listed on this page and below is the tools worth keeping. Name Description License AnkhSVN Subversion support for Visual Studio. It also works with VS2010. Free Aurora XAML Designer One of the best XAML creation tools available. Has a ton of built in templates that you can copy/paste into VS2010. COST/Trial BeyondCompare Beyond Compare 3 is the ideal tool for comparing files and folders on your Windows or Linux system. Visualize changes in your code and carefully reconcile them. COST/Trial BuildIT Automated Task Tool Its main purpose is to automate tasks, whether it is the final packaging of a product, an automated daily build, maybe sending out a mailing list, even backing-up files. Free C Sharper for VB Convert VB to C#. COST CLRProfiler Analyze and improve the behavior of your .NET app. Free CodeRush Direct competitor to ReSharper, contains similar feature. This is one of those decide for yourself. COST/Trial Disk2VHD Disk2vhd is a utility that creates VHD (Virtual Hard Disk - Microsoft's Virtual Machine disk format) versions of physical disks for use in Microsoft Virtual PC or Microsoft Hyper-V virtual machines (VMs). Free Eazfuscator.NET Is a free obfuscator for .NET. The main purpose is to protect intellectual property of software. Free EQATEC Profiler Make your .NET app run faster. No source code changes are needed. Just point the profiler to your app, run the modified code, and get a visual report. COST Expression Studio 3/4 Comes with Web, Blend, Sketch Flow and more. You can create websites, produce beautiful XAML and more. COST/Trial Expresso The award-winning Expresso editor is equally suitable as a teaching tool for the beginning user of regular expressions or as a full-featured development environment for the experienced programmer or web designer with an extensive knowledge of regular expressions. Free Fiddler Fiddler is a web debugging proxy which logs all HTTP(s) traffic between your computer and the internet. Free Firebug Powerful Web development tool. If you build websites, you will need this. Free FxCop FxCop is an application that analyzes managed code assemblies (code that targets the .NET Framework common language runtime) and reports information about the assemblies, such as possible design, localization, performance, and security improvements. Free GAC Browser and Remover Easy way to remove multiple assemblies from the GAC. Assemblies registered by programs like Install Shield can also be removed. Free GAC Util The Global Assembly Cache tool allows you to view and manipulate the contents of the global assembly cache and download cache. Free HelpScribble Help Scribble is a full-featured, easy-to-use help authoring tool for creating help files from start to finish. You can create Win Help (.hlp) files, HTML Help (.chm) files, a printed manual and online documentation (on a web site) all from the same Help Scribble project. COST/Trial IETester IETester is a free Web Browser that allows you to have the rendering and JavaScript engines of IE9 preview, IE8, IE7 IE 6 and IE5.5 on Windows 7, Vista and XP, as well as the installed IE in the same process. Free iTextSharp iText# (iTextSharp) is a port of the iText open source java library for PDF generation written entirely in C# for the .NET platform. Use the iText mailing list to get support. Free Kaxaml Kaxaml is a lightweight XAML editor that gives you a "split view" so you can see both your XAML and your rendered content. Free LINQPad LinqPad lets you interactively query databases in a LINQ. Free Linquer Many programmers are familiar with SQL and will need a help in the transition to LINQ. Sometimes there are complicated queries to be written and Linqer can help by converting SQL scripts to LINQ. COST/Trial LiquidXML Liquid XML Studio 2010 is an advanced XML developers toolkit and IDE, containing all the tools needed for designing and developing XML schema and applications. COST/Trial Log4Net log4net is a tool to help the programmer output log statements to a variety of output targets. log4net is a port of the excellent log4j framework to the .NET runtime. We have kept the framework similar in spirit to the original log4j while taking advantage of new features in the .NET runtime. For more information on log4net see the features document. Free Microsoft Web Platform Installer The Microsoft Web Platform Installer 2.0 (Web PI) is a free tool that makes getting the latest components of the Microsoft Web Platform, including Internet Information Services (IIS), SQL Server Express, .NET Framework and Visual Web Developer easy. Free Mono Development Don't have Visual Studio - no problem! This is an open Source C# and .NET development environment for Linux, Windows, and Mac OS X Free Net Mass Downloader While it’s great that Microsoft has released the .NET Reference Source Code, you can only get it one file at a time while you’re debugging. If you’d like to batch download it for reading or to populate the cache, you’d have to write a program that instantiated and called each method in the Framework Class Library. Fortunately, .NET Mass Downloader comes to the rescue! Free nMap Nmap ("Network Mapper") is a free and open source (license) utility for network exploration or security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Free NoScript (Firefox add-in) The NoScript Firefox extension provides extra protection for Firefox, Flock, Seamonkey and other Mozilla-based browsers: this free, open source add-on allows JavaScript, Java and Flash and other plug-ins to be executed only by trusted web sites of your choice (e.g. your online bank), and provides the most powerful Anti-XSS protection available in a browser. Free NotePad 2 Notepad2, a fast and light-weight Notepad-like text editor with syntax highlighting. This program can be run out of the box without installation, and does not touch your system's registry. Free PageSpy PageSpy is a small add-on for Internet Explorer that allows you to select any element within a webpage, select an option in the context menu, and view detailed information about both the coding behind the page and the element you selected. Free Phrase Express PhraseExpress manages your frequently used text snippets in customizable categories for quick access. Free PowerGui PowerGui is a free community for PowerGUI, a graphical user interface and script editor for Microsoft Windows PowerShell! Free Powershell Comes with Win7, but you can automate tasks by using the .NET Framework. Great for network admins. Free Process Explorer Ever wondered which program has a particular file or directory open? Now you can find out. Process Explorer shows you information about which handles and DLLs processes have opened or loaded. Also, included in the SysInterals Suite. Free Process Monitor Process Monitor is an advanced monitoring tool for Windows that shows real-time file system, Registry and process/thread activity. Free Reflector Explore and analyze compiled .NET assemblies, viewing them in C#, Visual Basic, and IL. This is an Essential for any .NET developer. Free Regular Expression Library Stuck on a Regular Expression but you think someone has already figured it out? Chances are they have. Free Regulator Regulator makes Regular Expressions easy. This is a must have for a .NET Developer. Free RenameMaestro RenameMaestro is probably the easiest batch file renamer you'll find to instantly rename multiple files COST ReSharper The one program that I cannot live without. Supports VS2010 and offers simple refactoring, code analysis/assistance/cleanup/templates. One of the few applications that is worth the $$$. COST/Trial ScrewTurn Wiki ScrewTurn Wiki allows you to create, manage and share wikis. A wiki is a collaboratively-edited, information-centered website: the most famous is Wikipedia. Free SharpDevelop What is #develop? SharpDevelop is a free IDE for C# and VB.NET projects on Microsoft's .NET platform. Free Show Me The Template Show Me The Template is a tool for exploring the templates, be their data, control or items panel, that comes with the controls built into WPF for all 6 themes. Free SnippetCompiler Compiles code snippets without opening Visual Studio. It does not support .NET 4. Free SQL Prompt SQL Prompt is a plug-in that increases how fast you can work with SQL. It provides code-completion for SQL server, reformatting, db schema information and snippets. Awesome! COST/Trial SQLinForm SQLinForm is an automatic SQL code formatter for all major databases  including ORACLE, SQL Server, DB2, UDB, Sybase, Informix, PostgreSQL, Teradata, MySQL, MS Access etc. with over 70 formatting options. COST/OnlineFree SSMS Tools SSMS Tools Pack is an add-in for Microsoft SQL Server Management Studio (SSMS) including SSMS Express. Free Storm STORM is a free and open source tool for testing web services. Free Telerik Code Convertor Convert code from VB to C Sharp and Vice Versa. Free TurtoiseSVN TortoiseSVN is a really easy to use Revision control / version control / source control software for Windows.Since it's not an integration for a specific IDE you can use it with whatever development tools you like. Free UltraEdit UltraEdit is the ideal text, HTML and hex editor, and an advanced PHP, Perl, Java and JavaScript editor for programmers. UltraEdit is also an XML editor including a tree-style XML parser. An industry-award winner, UltraEdit supports disk-based 64-bit file handling (standard) on 32-bit Windows platforms (Windows 2000 and later). COST/Trial Virtual Windows XP Comes with some W7 version and allows you to run WinXP along side W7. Free VirtualBox Virtualization by Sun Microsystems. You can virtualize Windows, Linux and more. Free Visual Log Parser SQL queries against a variety of log files and other system data sources. Free WinMerge WinMerge is an Open Source differencing and merging tool for Windows. WinMerge can compare both folders and files, presenting differences in a visual text format that is easy to understand and handle. Free Wireshark Wireshark is one of the best network protocol analyzer's for Unix and windows. This has been used several times to get me out of a bind. Free XML Notepad 07 Old, but still one of my favorite XML viewers. Free Productivity Tools – This is the list of tools that I use to save time or quickly navigate around Windows. Name Description License AutoHotKey Automate almost anything by sending keystrokes and mouse clicks. You can write a mouse or keyboard macro by hand or use the macro recorder. Free CLCL CLCL is clipboard caching utility. Free Ditto Ditto is an extension to the standard windows clipboard. It saves each item placed on the clipboard allowing you access to any of those items at a later time. Ditto allows you to save any type of information that can be put on the clipboard, text, images, html, custom formats, ..... Free Evernote Remember everything from notes to photos. It will synch between computers/devices. Free InfoRapid Inforapid is a search tool that will display all you search results in a html like browser. If you click on a word in that browser, it will start another search to the word you clicked on. Handy if you want to trackback something to it's true origin. The word you looked for will be highlighted in red. Clicking on the red word will open the containing file in a text based viewer. Clicking on any word in the opened document will start another search on that word. Free KatMouse The prime purpose of the KatMouse utility is to enhance the functionality of mice with a scroll wheel, offering 'universal' scrolling: moving the mouse wheel will scroll the window directly beneath the mouse cursor (not the one with the keyboard focus, which is default on Windows OSes). This is a major increase in the usefulness of the mouse wheel. Free ScreenR Instant Screencast with nothing to download. Works with Mac or PC and free. Free Start++ Start++ is an enhancement for the Start Menu in Windows Vista. It also extends the Run box and the command-line with customizable commands.  For example, typing "w Windows Vista" will take you to the Windows Vista page on Wikipedia! Free Synergy Synergy lets you easily share a single mouse and keyboard between multiple computers with different operating systems, each with its own display, without special hardware. It's intended for users with multiple computers on their desk since each system uses its own monitor(s). Free Texter Texter lets you define text substitution hot strings that, when triggered, will replace hotstring with a larger piece of text. By entering your most commonly-typed snippets of text into Texter, you can save countless keystrokes in the course of the day. Free Total Commander File handling, FTP, Archive handling and much more. Even works with Win3.11. COST/Trial Available Wizmouse WizMouse is a mouse enhancement utility that makes your mouse wheel work on the window currently under the mouse pointer, instead of the currently focused window. This means you no longer have to click on a window before being able to scroll it with the mouse wheel. This is a far more comfortable and practical way to make use of the mouse wheel. Free Xmarks Bookmark sync and search between computers. Free General Utilities – This is a list for power user users or anyone that wants more out of Windows. I usually install a majority of these whenever I get a new system. Name Description License µTorrent µTorrent is a lightweight and efficient BitTorrent client for Windows or Mac with many features. I use this for downloading LEGAL media. Free Audacity Audacity® is free, open source software for recording and editing sounds. It is available for Mac OS X, Microsoft Windows, GNU/Linux, and other operating systems. Learn more about Audacity... Also check our Wiki and Forum for more information. Free AVast Free FREE Antivirus. Free CD Burner XP Pro CDBurnerXP is a free application to burn CDs and DVDs, including Blu-Ray and HD-DVDs. It also includes the feature to burn and create ISOs, as well as a multilanguage interface. Free CDEX You can extract digital audio CDs into mp3/wav. Free Combofix Combofix is a freeware (a legitimate spyware remover created by sUBs), Combofix was designed to scan a computer for known malware, spyware (SurfSideKick, QooLogic, and Look2Me as well as any other combination of the mentioned spyware applications) and remove them. Free Cpu-Z Provides information about some of the main devices of your system. Free Cropper Cropper is a screen capture utility written in C#. It makes it fast and easy to grab parts of your screen. Use it to easily crop out sections of vector graphic files such as Fireworks without having to flatten the files or open in a new editor. Use it to easily capture parts of a web site, including text and images. It's also great for writing documentation that needs images of your application or web site. Free DropBox Drag and Drop files to sync between computers. Free DVD-Fab Converts/Copies DVDs/Blu-Ray to different formats. (like mp4, mkv, avi) COST/Trial Available FastStone Capture FastStone Capture is a powerful, lightweight, yet full-featured screen capture tool that allows you to easily capture and annotate anything on the screen including windows, objects, menus, full screen, rectangular/freehand regions and even scrolling windows/web pages. Free ffdshow FFDShow is a DirectShow decoding filter for decompressing DivX, XviD, H.264, FLV1, WMV, MPEG-1 and MPEG-2, MPEG-4 movies. Free Filezilla FileZilla Client is a fast and reliable cross-platform FTP, FTPS and SFTP client with lots of useful features and an intuitive graphical user interface. You can also download a server version. Free FireFox Web Browser, do you really need an explanation? Free FireGestures A customizable mouse gestures extension which enables you to execute various commands and user scripts with five types of gestures. Free FoxIt Reader Light weight PDF viewer. You should install this with the advanced setting or it will install a toolbar and setup some shortcuts. Free gSynchIt Synch Gmail and Outlook. Even supports Outlook 2010 32/64 bit COST/Trial Available Hulu Desktop At home or in a hotel, this has replaced my cable/satellite subscription. Free ImgBurn ImgBurn is a lightweight CD / DVD / HD DVD / Blu-ray burning application that everyone should have in their toolkit! Free Infrarecorder InfraRecorder is a free CD/DVD burning solution for Microsoft Windows. It offers a wide range of powerful features; all through an easy to use application interface and Windows Explorer integration. Free KeePass KeePass is a free open source password manager, which helps you to manage your passwords in a secure way. Free LastPass Another password management, synchronize between browsers, automatic form filling and more. Free Live Essentials One download and lots of programs including Mail, Live Writer, Movie Maker and more! Free Monitores MonitorES is a small windows utility that helps you to turnoff monitor display when you lock down your machine.Also when you lock your machine, it will pause all your running media programs & set your IM status message to "Away" / Custom message(via options) and restore it back to normal when you back. Free mRemote mRemote is a full-featured, multi-tab remote connections manager. Free Open Office OpenOffice.org 3 is the leading open-source office software suite for word processing, spreadsheets, presentations, graphics, databases and more. It is available in many languages and works on all common computers. It stores all your data in an international open standard format and can also read and write files from other common office software packages. It can be downloaded and used completely free of charge for any purpose. Free Paint.NET Simple, intuitive, and innovative user interface for editing photos. Free Picasa Picasa is free photo editing software from Google that makes your pictures look great. Free Pidgin Pidgin is an easy to use and free chat client used by millions. Connect to AIM, MSN, Yahoo, and more chat networks all at once. Free PING PING is a live Linux ISO, based on the excellent Linux From Scratch (LFS) documentation. It can be burnt on a CD and booted, or integrated into a PXE / RIS environment. Free Putty PuTTY is an SSH and telnet client, developed originally by Simon Tatham for the Windows platform. Free Revo Uninstaller Revo Uninstaller Pro helps you to uninstall software and remove unwanted programs installed on your computer easily! Even if you have problems uninstalling and cannot uninstall them from "Windows Add or Remove Programs" control panel applet.Revo Uninstaller is a much faster and more powerful alternative to "Windows Add or Remove Programs" applet! It has very powerful features to uninstall and remove programs. Free Security Essentials Microsoft Security Essentials is a new, free consumer anti-malware solution for your computer. Free SetupVirtualCloneDrive Virtual CloneDrive works and behaves just like a physical CD/DVD drive, however it exists only virtually. Point to the .ISO file and it appears in Windows Explorer as a Drive. Free Shark 007 Codec Pack Play just about any file format with this download. Also includes my W7 Media Playlist Generator. Free Snagit 9 Screen Capture on steroids. Add arrows, captions, etc to any screenshot. COST/Trial Available SysinternalsSuite Go ahead and download the entire sys internals suite. I have mentioned multiple programs in this suite already. Free TeraCopy TeraCopy is a compact program designed to copy and move files at the maximum possible speed, providing the user with a lot of features. Free for Home TrueCrypt Free open-source disk encryption software for Windows 7/Vista/XP, Mac OS X, and Linux Free TweetDeck Fully featured Twitter client. Free UltraVNC UltraVNC is a powerful, easy to use and free software that can display the screen of another computer (via internet or network) on your own screen. The program allows you to use your mouse and keyboard to control the other PC remotely. It means that you can work on a remote computer, as if you were sitting in front of it, right from your current location. Free Unlocker Unlocks locked files. Pretty simple right? Free VLC Media Player VLC media player is a highly portable multimedia player and multimedia framework capable of reading most audio and video formats Free Windows 7 Media Playlist This program is special to my heart because I wrote it. It has been mentioned on podcast and various websites. It allows you to quickly create wvx video playlist for Windows Media Center. Free WinRAR WinRAR is a powerful archive manager. It can backup your data and reduce the size of email attachments, decompress RAR, ZIP and other files downloaded from Internet and create new archives in RAR and ZIP file format. COST/Trial Available Blogging – I use the following for my blog. Name Description License Insert Code for Windows Live Writer Insert Code for Windows Live Writer will format a snippet of text in a number of programming languages such as C#, HTML, MSH, JavaScript, Visual Basic and TSQL. Free LiveWriter Included in Live Essentials, but the ultimate in Windows Blogging Free PasteAsVSCode Plug-in for Windows Live Writer that pastes clipboard content as Visual Studio code. Preserves syntax highlighting, indentation and background color. Converts RTF, outputted by Visual Studio, into HTML. Free Desktop Management – The list below represent the best in Windows Desktop Management. Name Description License 7 Stacks Allows users to have "stacks" of icons in their taskbar. Free Executor Executor is a multi purpose launcher and a more advanced and customizable version of windows run. Free Fences Fences is a program that helps you organize your desktop and can hide your icons when they are not in use. Free RocketDock Rocket Dock is a smoothly animated, alpha blended application launcher. It provides a nice clean interface to drop shortcuts on for easy access and organization. With each item completely customizable there is no end to what you can add and launch from the dock. Free WindowsTab Tabbing is an essential feature of modern web browsers. Window Tabs brings the productivity of tabbed window management to all of your desktop applications. Free

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• ASP.NET Web API Exception Handling

  - by Fredrik N

  When I talk about exceptions in my product team I often talk about two kind of exceptions, business and critical exceptions. Business exceptions are exceptions thrown based on “business rules”, for example if you aren’t allowed to do a purchase. Business exceptions in most case aren’t important to log into a log file, they can directly be shown to the user. An example of a business exception could be "DeniedToPurchaseException”, or some validation exceptions such as “FirstNameIsMissingException” etc. Critical Exceptions are all other kind of exceptions such as the SQL server is down etc. Those kind of exception message need to be logged and should not reach the user, because they can contain information that can be harmful if it reach out to wrong kind of users. I often distinguish business exceptions from critical exceptions by creating a base class called BusinessException, then in my error handling code I catch on the type BusinessException and all other exceptions will be handled as critical exceptions. This blog post will be about different ways to handle exceptions and how Business and Critical Exceptions could be handled. Web API and Exceptions the basics When an exception is thrown in a ApiController a response message will be returned with a status code set to 500 and a response formatted by the formatters based on the “Accept” or “Content-Type” HTTP header, for example JSON or XML. Here is an example:   public IEnumerable<string> Get() { throw new ApplicationException("Error!!!!!"); return new string[] { "value1", "value2" }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The response message will be: HTTP/1.1 500 Internal Server Error Content-Length: 860 Content-Type: application/json; charset=utf-8 { "ExceptionType":"System.ApplicationException","Message":"Error!!!!!","StackTrace":" at ..."} .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The stack trace will be returned to the client, this is because of making it easier to debug. Be careful so you don’t leak out some sensitive information to the client. So as long as you are developing your API, this is not harmful. In a production environment it can be better to log exceptions and return a user friendly exception instead of the original exception. There is a specific exception shipped with ASP.NET Web API that will not use the formatters based on the “Accept” or “Content-Type” HTTP header, it is the exception is the HttpResponseException class. Here is an example where the HttpReponseExcetpion is used: // GET api/values [ExceptionHandling] public IEnumerable<string> Get() { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.InternalServerError)); return new string[] { "value1", "value2" }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The response will not contain any content, only header information and the status code based on the HttpStatusCode passed as an argument to the HttpResponseMessage. Because the HttpResponsException takes a HttpResponseMessage as an argument, we can give the response a content: public IEnumerable<string> Get() { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent("My Error Message"), ReasonPhrase = "Critical Exception" }); return new string[] { "value1", "value2" }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The code above will have the following response:   HTTP/1.1 500 Critical Exception Content-Length: 5 Content-Type: text/plain; charset=utf-8 My Error Message .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The Content property of the HttpResponseMessage doesn’t need to be just plain text, it can also be other formats, for example JSON, XML etc. By using the HttpResponseException we can for example catch an exception and throw a user friendly exception instead: public IEnumerable<string> Get() { try { DoSomething(); return new string[] { "value1", "value2" }; } catch (Exception e) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent("An error occurred, please try again or contact the administrator."), ReasonPhrase = "Critical Exception" }); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Adding a try catch to every ApiController methods will only end in duplication of code, by using a custom ExceptionFilterAttribute or our own custom ApiController base class we can reduce code duplicationof code and also have a more general exception handler for our ApiControllers . By creating a custom ApiController’s and override the ExecuteAsync method, we can add a try catch around the base.ExecuteAsync method, but I prefer to skip the creation of a own custom ApiController, better to use a solution that require few files to be modified. The ExceptionFilterAttribute has a OnException method that we can override and add our exception handling. Here is an example: using System; using System.Diagnostics; using System.Net; using System.Net.Http; using System.Web.Http; using System.Web.Http.Filters; public class ExceptionHandlingAttribute : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { if (context.Exception is BusinessException) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent(context.Exception.Message), ReasonPhrase = "Exception" }); } //Log Critical errors Debug.WriteLine(context.Exception); throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent("An error occurred, please try again or contact the administrator."), ReasonPhrase = "Critical Exception" }); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Note: Something to have in mind is that the ExceptionFilterAttribute will be ignored if the ApiController action method throws a HttpResponseException. The code above will always make sure a HttpResponseExceptions will be returned, it will also make sure the critical exceptions will show a more user friendly message. The OnException method can also be used to log exceptions. By using a ExceptionFilterAttribute the Get() method in the previous example can now look like this: public IEnumerable<string> Get() { DoSomething(); return new string[] { "value1", "value2" }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To use the an ExceptionFilterAttribute, we can for example add the ExceptionFilterAttribute to our ApiControllers methods or to the ApiController class definition, or register it globally for all ApiControllers. You can read more about is here. Note: If something goes wrong in the ExceptionFilterAttribute and an exception is thrown that is not of type HttpResponseException, a formatted exception will be thrown with stack trace etc to the client. How about using a custom IHttpActionInvoker? We can create our own IHTTPActionInvoker and add Exception handling to the invoker. The IHttpActionInvoker will be used to invoke the ApiController’s ExecuteAsync method. Here is an example where the default IHttpActionInvoker, ApiControllerActionInvoker, is used to add exception handling: public class MyApiControllerActionInvoker : ApiControllerActionInvoker { public override Task<HttpResponseMessage> InvokeActionAsync(HttpActionContext actionContext, System.Threading.CancellationToken cancellationToken) { var result = base.InvokeActionAsync(actionContext, cancellationToken); if (result.Exception != null && result.Exception.GetBaseException() != null) { var baseException = result.Exception.GetBaseException(); if (baseException is BusinessException) { return Task.Run<HttpResponseMessage>(() => new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent(baseException.Message), ReasonPhrase = "Error" }); } else { //Log critical error Debug.WriteLine(baseException); return Task.Run<HttpResponseMessage>(() => new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent(baseException.Message), ReasonPhrase = "Critical Error" }); } } return result; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You can register the IHttpActionInvoker with your own IoC to resolve the MyApiContollerActionInvoker, or add it in the Global.asax: GlobalConfiguration.Configuration.Services.Remove(typeof(IHttpActionInvoker), GlobalConfiguration.Configuration.Services.GetActionInvoker()); GlobalConfiguration.Configuration.Services.Add(typeof(IHttpActionInvoker), new MyApiControllerActionInvoker()); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   How about using a Message Handler for Exception Handling? By creating a custom Message Handler, we can handle error after the ApiController and the ExceptionFilterAttribute is invoked and in that way create a global exception handler, BUT, the only thing we can take a look at is the HttpResponseMessage, we can’t add a try catch around the Message Handler’s SendAsync method. The last Message Handler that will be used in the Wep API pipe-line is the HttpControllerDispatcher and this Message Handler is added to the HttpServer in an early stage. The HttpControllerDispatcher will use the IHttpActionInvoker to invoke the ApiController method. The HttpControllerDipatcher has a try catch that will turn ALL exceptions into a HttpResponseMessage, so that is the reason why a try catch around the SendAsync in a custom Message Handler want help us. If we create our own Host for the Wep API we could create our own custom HttpControllerDispatcher and add or exception handler to that class, but that would be little tricky but is possible. We can in a Message Handler take a look at the HttpResponseMessage’s IsSuccessStatusCode property to see if the request has failed and if we throw the HttpResponseException in our ApiControllers, we could use the HttpResponseException and give it a Reason Phrase and use that to identify business exceptions or critical exceptions. I wouldn’t add an exception handler into a Message Handler, instead I should use the ExceptionFilterAttribute and register it globally for all ApiControllers. BUT, now to another interesting issue. What will happen if we have a Message Handler that throws an exception?  Those exceptions will not be catch and handled by the ExceptionFilterAttribute. I found a  bug in my previews blog post about “Log message Request and Response in ASP.NET WebAPI” in the MessageHandler I use to log incoming and outgoing messages. Here is the code from my blog before I fixed the bug:   public abstract class MessageHandler : DelegatingHandler { protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) { var corrId = string.Format("{0}{1}", DateTime.Now.Ticks, Thread.CurrentThread.ManagedThreadId); var requestInfo = string.Format("{0} {1}", request.Method, request.RequestUri); var requestMessage = await request.Content.ReadAsByteArrayAsync(); await IncommingMessageAsync(corrId, requestInfo, requestMessage); var response = await base.SendAsync(request, cancellationToken); var responseMessage = await response.Content.ReadAsByteArrayAsync(); await OutgoingMessageAsync(corrId, requestInfo, responseMessage); return response; } protected abstract Task IncommingMessageAsync(string correlationId, string requestInfo, byte[] message); protected abstract Task OutgoingMessageAsync(string correlationId, string requestInfo, byte[] message); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   If a ApiController throws a HttpResponseException, the Content property of the HttpResponseMessage from the SendAsync will be NULL. So a null reference exception is thrown within the MessageHandler. The yellow screen of death will be returned to the client, and the content is HTML and the Http status code is 500. The bug in the MessageHandler was solved by adding a check against the HttpResponseMessage’s IsSuccessStatusCode property: public abstract class MessageHandler : DelegatingHandler { protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) { var corrId = string.Format("{0}{1}", DateTime.Now.Ticks, Thread.CurrentThread.ManagedThreadId); var requestInfo = string.Format("{0} {1}", request.Method, request.RequestUri); var requestMessage = await request.Content.ReadAsByteArrayAsync(); await IncommingMessageAsync(corrId, requestInfo, requestMessage); var response = await base.SendAsync(request, cancellationToken); byte[] responseMessage; if (response.IsSuccessStatusCode) responseMessage = await response.Content.ReadAsByteArrayAsync(); else responseMessage = Encoding.UTF8.GetBytes(response.ReasonPhrase); await OutgoingMessageAsync(corrId, requestInfo, responseMessage); return response; } protected abstract Task IncommingMessageAsync(string correlationId, string requestInfo, byte[] message); protected abstract Task OutgoingMessageAsync(string correlationId, string requestInfo, byte[] message); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If we don’t handle the exceptions that can occur in a custom Message Handler, we can have a hard time to find the problem causing the exception. The savior in this case is the Global.asax’s Application_Error: protected void Application_Error() { var exception = Server.GetLastError(); Debug.WriteLine(exception); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } I would recommend you to add the Application_Error to the Global.asax and log all exceptions to make sure all kind of exception is handled. Summary There are different ways we could add Exception Handling to the Wep API, we can use a custom ApiController, ExceptionFilterAttribute, IHttpActionInvoker or Message Handler. The ExceptionFilterAttribute would be a good place to add a global exception handling, require very few modification, just register it globally for all ApiControllers, even the IHttpActionInvoker can be used to minimize the modifications of files. Adding the Application_Error to the global.asax is a good way to catch all unhandled exception that can occur, for example exception thrown in a Message Handler.   If you want to know when I have posted a blog post, you can follow me on twitter @fredrikn

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• Camera for 2.5D Game

  - by me--

  I'm hoping someone can explain this to me like I'm 5, because I've been struggling with this for hours and simply cannot understand what I'm doing wrong. I've written a Camera class for my 2.5D game. The intention is to support world and screen spaces like this: The camera is the black thing on the right. The +Z axis is upwards in that image, with -Z heading downwards. As you can see, both world space and screen space have (0, 0) at their top-left. I started writing some unit tests to prove that my camera was working as expected, and that's where things started getting...strange. My tests plot coordinates in world, view, and screen spaces. Eventually I will use image comparison to assert that they are correct, but for now my test just displays the result. The render logic uses Camera.ViewMatrix to transform world space to view space, and Camera.WorldPointToScreen to transform world space to screen space. Here is an example test: [Fact] public void foo() { var camera = new Camera(new Viewport(0, 0, 250, 100)); DrawingVisual worldRender; DrawingVisual viewRender; DrawingVisual screenRender; this.Render(camera, out worldRender, out viewRender, out screenRender, new Vector3(30, 0, 0), new Vector3(30, 40, 0)); this.ShowRenders(camera, worldRender, viewRender, screenRender); } And here's what pops up when I run this test: World space looks OK, although I suspect the z axis is going into the screen instead of towards the viewer. View space has me completely baffled. I was expecting the camera to be sitting above (0, 0) and looking towards the center of the scene. Instead, the z axis seems to be the wrong way around, and the camera is positioned in the opposite corner to what I expect! I suspect screen space will be another thing altogether, but can anyone explain what I'm doing wrong in my Camera class? UPDATE I made some progress in terms of getting things to look visually as I expect, but only through intuition: not an actual understanding of what I'm doing. Any enlightenment would be greatly appreciated. I realized that my view space was flipped both vertically and horizontally compared to what I expected, so I changed my view matrix to scale accordingly: this.viewMatrix = Matrix.CreateLookAt(this.location, this.target, this.up) * Matrix.CreateScale(this.zoom, this.zoom, 1) * Matrix.CreateScale(-1, -1, 1); I could combine the two CreateScale calls, but have left them separate for clarity. Again, I have no idea why this is necessary, but it fixed my view space: But now my screen space needs to be flipped vertically, so I modified my projection matrix accordingly: this.projectionMatrix = Matrix.CreatePerspectiveFieldOfView(0.7853982f, viewport.AspectRatio, 1, 2) * Matrix.CreateScale(1, -1, 1); And this results in what I was expecting from my first attempt: I have also just tried using Camera to render sprites via a SpriteBatch to make sure everything works there too, and it does. But the question remains: why do I need to do all this flipping of axes to get the space coordinates the way I expect? UPDATE 2 I've since improved my rendering logic in my test suite so that it supports geometries and so that lines get lighter the further away they are from the camera. I wanted to do this to avoid optical illusions and to further prove to myself that I'm looking at what I think I am. Here is an example: In this case, I have 3 geometries: a cube, a sphere, and a polyline on the top face of the cube. Notice how the darkening and lightening of the lines correctly identifies those portions of the geometries closer to the camera. If I remove the negative scaling I had to put in, I see: So you can see I'm still in the same boat - I still need those vertical and horizontal flips in my matrices to get things to appear correctly. In the interests of giving people a repro to play with, here is the complete code needed to generate the above. If you want to run via the test harness, just install the xunit package: Camera.cs: using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Graphics; using System.Diagnostics; public sealed class Camera { private readonly Viewport viewport; private readonly Matrix projectionMatrix; private Matrix? viewMatrix; private Vector3 location; private Vector3 target; private Vector3 up; private float zoom; public Camera(Viewport viewport) { this.viewport = viewport; // for an explanation of the negative scaling, see: http://gamedev.stackexchange.com/questions/63409/ this.projectionMatrix = Matrix.CreatePerspectiveFieldOfView(0.7853982f, viewport.AspectRatio, 1, 2) * Matrix.CreateScale(1, -1, 1); // defaults this.location = new Vector3(this.viewport.Width / 2, this.viewport.Height, 100); this.target = new Vector3(this.viewport.Width / 2, this.viewport.Height / 2, 0); this.up = new Vector3(0, 0, 1); this.zoom = 1; } public Viewport Viewport { get { return this.viewport; } } public Vector3 Location { get { return this.location; } set { this.location = value; this.viewMatrix = null; } } public Vector3 Target { get { return this.target; } set { this.target = value; this.viewMatrix = null; } } public Vector3 Up { get { return this.up; } set { this.up = value; this.viewMatrix = null; } } public float Zoom { get { return this.zoom; } set { this.zoom = value; this.viewMatrix = null; } } public Matrix ProjectionMatrix { get { return this.projectionMatrix; } } public Matrix ViewMatrix { get { if (this.viewMatrix == null) { // for an explanation of the negative scaling, see: http://gamedev.stackexchange.com/questions/63409/ this.viewMatrix = Matrix.CreateLookAt(this.location, this.target, this.up) * Matrix.CreateScale(this.zoom) * Matrix.CreateScale(-1, -1, 1); } return this.viewMatrix.Value; } } public Vector2 WorldPointToScreen(Vector3 point) { var result = viewport.Project(point, this.ProjectionMatrix, this.ViewMatrix, Matrix.Identity); return new Vector2(result.X, result.Y); } public void WorldPointsToScreen(Vector3[] points, Vector2[] destination) { Debug.Assert(points != null); Debug.Assert(destination != null); Debug.Assert(points.Length == destination.Length); for (var i = 0; i < points.Length; ++i) { destination[i] = this.WorldPointToScreen(points[i]); } } } CameraFixture.cs: using Microsoft.Xna.Framework.Graphics; using System; using System.Collections.Generic; using System.Linq; using System.Windows; using System.Windows.Controls; using System.Windows.Media; using Xunit; using XNA = Microsoft.Xna.Framework; public sealed class CameraFixture { [Fact] public void foo() { var camera = new Camera(new Viewport(0, 0, 250, 100)); DrawingVisual worldRender; DrawingVisual viewRender; DrawingVisual screenRender; this.Render( camera, out worldRender, out viewRender, out screenRender, new Sphere(30, 15) { WorldMatrix = XNA.Matrix.CreateTranslation(155, 50, 0) }, new Cube(30) { WorldMatrix = XNA.Matrix.CreateTranslation(75, 60, 15) }, new PolyLine(new XNA.Vector3(0, 0, 0), new XNA.Vector3(10, 10, 0), new XNA.Vector3(20, 0, 0), new XNA.Vector3(0, 0, 0)) { WorldMatrix = XNA.Matrix.CreateTranslation(65, 55, 30) }); this.ShowRenders(worldRender, viewRender, screenRender); } #region Supporting Fields private static readonly Pen xAxisPen = new Pen(Brushes.Red, 2); private static readonly Pen yAxisPen = new Pen(Brushes.Green, 2); private static readonly Pen zAxisPen = new Pen(Brushes.Blue, 2); private static readonly Pen viewportPen = new Pen(Brushes.Gray, 1); private static readonly Pen nonScreenSpacePen = new Pen(Brushes.Black, 0.5); private static readonly Color geometryBaseColor = Colors.Black; #endregion #region Supporting Methods private void Render(Camera camera, out DrawingVisual worldRender, out DrawingVisual viewRender, out DrawingVisual screenRender, params Geometry[] geometries) { var worldDrawingVisual = new DrawingVisual(); var viewDrawingVisual = new DrawingVisual(); var screenDrawingVisual = new DrawingVisual(); const int axisLength = 15; using (var worldDrawingContext = worldDrawingVisual.RenderOpen()) using (var viewDrawingContext = viewDrawingVisual.RenderOpen()) using (var screenDrawingContext = screenDrawingVisual.RenderOpen()) { // draw lines around the camera's viewport var viewportBounds = camera.Viewport.Bounds; var viewportLines = new Tuple<int, int, int, int>[] { Tuple.Create(viewportBounds.Left, viewportBounds.Bottom, viewportBounds.Left, viewportBounds.Top), Tuple.Create(viewportBounds.Left, viewportBounds.Top, viewportBounds.Right, viewportBounds.Top), Tuple.Create(viewportBounds.Right, viewportBounds.Top, viewportBounds.Right, viewportBounds.Bottom), Tuple.Create(viewportBounds.Right, viewportBounds.Bottom, viewportBounds.Left, viewportBounds.Bottom) }; foreach (var viewportLine in viewportLines) { var viewStart = XNA.Vector3.Transform(new XNA.Vector3(viewportLine.Item1, viewportLine.Item2, 0), camera.ViewMatrix); var viewEnd = XNA.Vector3.Transform(new XNA.Vector3(viewportLine.Item3, viewportLine.Item4, 0), camera.ViewMatrix); var screenStart = camera.WorldPointToScreen(new XNA.Vector3(viewportLine.Item1, viewportLine.Item2, 0)); var screenEnd = camera.WorldPointToScreen(new XNA.Vector3(viewportLine.Item3, viewportLine.Item4, 0)); worldDrawingContext.DrawLine(viewportPen, new Point(viewportLine.Item1, viewportLine.Item2), new Point(viewportLine.Item3, viewportLine.Item4)); viewDrawingContext.DrawLine(viewportPen, new Point(viewStart.X, viewStart.Y), new Point(viewEnd.X, viewEnd.Y)); screenDrawingContext.DrawLine(viewportPen, new Point(screenStart.X, screenStart.Y), new Point(screenEnd.X, screenEnd.Y)); } // draw axes var axisLines = new Tuple<int, int, int, int, int, int, Pen>[] { Tuple.Create(0, 0, 0, axisLength, 0, 0, xAxisPen), Tuple.Create(0, 0, 0, 0, axisLength, 0, yAxisPen), Tuple.Create(0, 0, 0, 0, 0, axisLength, zAxisPen) }; foreach (var axisLine in axisLines) { var viewStart = XNA.Vector3.Transform(new XNA.Vector3(axisLine.Item1, axisLine.Item2, axisLine.Item3), camera.ViewMatrix); var viewEnd = XNA.Vector3.Transform(new XNA.Vector3(axisLine.Item4, axisLine.Item5, axisLine.Item6), camera.ViewMatrix); var screenStart = camera.WorldPointToScreen(new XNA.Vector3(axisLine.Item1, axisLine.Item2, axisLine.Item3)); var screenEnd = camera.WorldPointToScreen(new XNA.Vector3(axisLine.Item4, axisLine.Item5, axisLine.Item6)); worldDrawingContext.DrawLine(axisLine.Item7, new Point(axisLine.Item1, axisLine.Item2), new Point(axisLine.Item4, axisLine.Item5)); viewDrawingContext.DrawLine(axisLine.Item7, new Point(viewStart.X, viewStart.Y), new Point(viewEnd.X, viewEnd.Y)); screenDrawingContext.DrawLine(axisLine.Item7, new Point(screenStart.X, screenStart.Y), new Point(screenEnd.X, screenEnd.Y)); } // for all points in all geometries to be rendered, find the closest and furthest away from the camera so we can lighten lines that are further away var distancesToAllGeometrySections = from geometry in geometries let geometryViewMatrix = geometry.WorldMatrix * camera.ViewMatrix from section in geometry.Sections from point in new XNA.Vector3[] { section.Item1, section.Item2 } let viewPoint = XNA.Vector3.Transform(point, geometryViewMatrix) select viewPoint.Length(); var furthestDistance = distancesToAllGeometrySections.Max(); var closestDistance = distancesToAllGeometrySections.Min(); var deltaDistance = Math.Max(0.000001f, furthestDistance - closestDistance); // draw each geometry for (var i = 0; i < geometries.Length; ++i) { var geometry = geometries[i]; // there's probably a more correct name for this, but basically this gets the geometry relative to the camera so we can check how far away each point is from the camera var geometryViewMatrix = geometry.WorldMatrix * camera.ViewMatrix; // we order roughly by those sections furthest from the camera to those closest, so that the closer ones "overwrite" the ones further away var orderedSections = from section in geometry.Sections let startPointRelativeToCamera = XNA.Vector3.Transform(section.Item1, geometryViewMatrix) let endPointRelativeToCamera = XNA.Vector3.Transform(section.Item2, geometryViewMatrix) let startPointDistance = startPointRelativeToCamera.Length() let endPointDistance = endPointRelativeToCamera.Length() orderby (startPointDistance + endPointDistance) descending select new { Section = section, DistanceToStart = startPointDistance, DistanceToEnd = endPointDistance }; foreach (var orderedSection in orderedSections) { var start = XNA.Vector3.Transform(orderedSection.Section.Item1, geometry.WorldMatrix); var end = XNA.Vector3.Transform(orderedSection.Section.Item2, geometry.WorldMatrix); var viewStart = XNA.Vector3.Transform(start, camera.ViewMatrix); var viewEnd = XNA.Vector3.Transform(end, camera.ViewMatrix); worldDrawingContext.DrawLine(nonScreenSpacePen, new Point(start.X, start.Y), new Point(end.X, end.Y)); viewDrawingContext.DrawLine(nonScreenSpacePen, new Point(viewStart.X, viewStart.Y), new Point(viewEnd.X, viewEnd.Y)); // screen rendering is more complicated purely because I wanted geometry to fade the further away it is from the camera // otherwise, it's very hard to tell whether the rendering is actually correct or not var startDistanceRatio = (orderedSection.DistanceToStart - closestDistance) / deltaDistance; var endDistanceRatio = (orderedSection.DistanceToEnd - closestDistance) / deltaDistance; // lerp towards white based on distance from camera, but only to a maximum of 90% var startColor = Lerp(geometryBaseColor, Colors.White, startDistanceRatio * 0.9f); var endColor = Lerp(geometryBaseColor, Colors.White, endDistanceRatio * 0.9f); var screenStart = camera.WorldPointToScreen(start); var screenEnd = camera.WorldPointToScreen(end); var brush = new LinearGradientBrush { StartPoint = new Point(screenStart.X, screenStart.Y), EndPoint = new Point(screenEnd.X, screenEnd.Y), MappingMode = BrushMappingMode.Absolute }; brush.GradientStops.Add(new GradientStop(startColor, 0)); brush.GradientStops.Add(new GradientStop(endColor, 1)); var pen = new Pen(brush, 1); brush.Freeze(); pen.Freeze(); screenDrawingContext.DrawLine(pen, new Point(screenStart.X, screenStart.Y), new Point(screenEnd.X, screenEnd.Y)); } } } worldRender = worldDrawingVisual; viewRender = viewDrawingVisual; screenRender = screenDrawingVisual; } private static float Lerp(float start, float end, float amount) { var difference = end - start; var adjusted = difference * amount; return start + adjusted; } private static Color Lerp(Color color, Color to, float amount) { var sr = color.R; var sg = color.G; var sb = color.B; var er = to.R; var eg = to.G; var eb = to.B; var r = (byte)Lerp(sr, er, amount); var g = (byte)Lerp(sg, eg, amount); var b = (byte)Lerp(sb, eb, amount); return Color.FromArgb(255, r, g, b); } private void ShowRenders(DrawingVisual worldRender, DrawingVisual viewRender, DrawingVisual screenRender) { var itemsControl = new ItemsControl(); itemsControl.Items.Add(new HeaderedContentControl { Header = "World", Content = new DrawingVisualHost(worldRender)}); itemsControl.Items.Add(new HeaderedContentControl { Header = "View", Content = new DrawingVisualHost(viewRender) }); itemsControl.Items.Add(new HeaderedContentControl { Header = "Screen", Content = new DrawingVisualHost(screenRender) }); var window = new Window { Title = "Renders", Content = itemsControl, ShowInTaskbar = true, SizeToContent = SizeToContent.WidthAndHeight }; window.ShowDialog(); } #endregion #region Supporting Types // stupidly simple 3D geometry class, consisting of a series of sections that will be connected by lines private abstract class Geometry { public abstract IEnumerable<Tuple<XNA.Vector3, XNA.Vector3>> Sections { get; } public XNA.Matrix WorldMatrix { get; set; } } private sealed class Line : Geometry { private readonly XNA.Vector3 magnitude; public Line(XNA.Vector3 magnitude) { this.magnitude = magnitude; } public override IEnumerable<Tuple<XNA.Vector3, XNA.Vector3>> Sections { get { yield return Tuple.Create(XNA.Vector3.Zero, this.magnitude); } } } private sealed class PolyLine : Geometry { private readonly XNA.Vector3[] points; public PolyLine(params XNA.Vector3[] points) { this.points = points; } public override IEnumerable<Tuple<XNA.Vector3, XNA.Vector3>> Sections { get { if (this.points.Length < 2) { yield break; } var end = this.points[0]; for (var i = 1; i < this.points.Length; ++i) { var start = end; end = this.points[i]; yield return Tuple.Create(start, end); } } } } private sealed class Cube : Geometry { private readonly float size; public Cube(float size) { this.size = size; } public override IEnumerable<Tuple<XNA.Vector3, XNA.Vector3>> Sections { get { var halfSize = this.size / 2; var frontBottomLeft = new XNA.Vector3(-halfSize, halfSize, -halfSize); var frontBottomRight = new XNA.Vector3(halfSize, halfSize, -halfSize); var frontTopLeft = new XNA.Vector3(-halfSize, halfSize, halfSize); var frontTopRight = new XNA.Vector3(halfSize, halfSize, halfSize); var backBottomLeft = new XNA.Vector3(-halfSize, -halfSize, -halfSize); var backBottomRight = new XNA.Vector3(halfSize, -halfSize, -halfSize); var backTopLeft = new XNA.Vector3(-halfSize, -halfSize, halfSize); var backTopRight = new XNA.Vector3(halfSize, -halfSize, halfSize); // front face yield return Tuple.Create(frontBottomLeft, frontBottomRight); yield return Tuple.Create(frontBottomLeft, frontTopLeft); yield return Tuple.Create(frontTopLeft, frontTopRight); yield return Tuple.Create(frontTopRight, frontBottomRight); // left face yield return Tuple.Create(frontTopLeft, backTopLeft); yield return Tuple.Create(backTopLeft, backBottomLeft); yield return Tuple.Create(backBottomLeft, frontBottomLeft); // right face yield return Tuple.Create(frontTopRight, backTopRight); yield return Tuple.Create(backTopRight, backBottomRight); yield return Tuple.Create(backBottomRight, frontBottomRight); // back face yield return Tuple.Create(backBottomLeft, backBottomRight); yield return Tuple.Create(backTopLeft, backTopRight); } } } private sealed class Sphere : Geometry { private readonly float radius; private readonly int subsections; public Sphere(float radius, int subsections) { this.radius = radius; this.subsections = subsections; } public override IEnumerable<Tuple<XNA.Vector3, XNA.Vector3>> Sections { get { var latitudeLines = this.subsections; var longitudeLines = this.subsections; // see http://stackoverflow.com/a/4082020/5380 var results = from latitudeLine in Enumerable.Range(0, latitudeLines) from longitudeLine in Enumerable.Range(0, longitudeLines) let latitudeRatio = latitudeLine / (float)latitudeLines let longitudeRatio = longitudeLine / (float)longitudeLines let nextLatitudeRatio = (latitudeLine + 1) / (float)latitudeLines let nextLongitudeRatio = (longitudeLine + 1) / (float)longitudeLines let z1 = Math.Cos(Math.PI * latitudeRatio) let z2 = Math.Cos(Math.PI * nextLatitudeRatio) let x1 = Math.Sin(Math.PI * latitudeRatio) * Math.Cos(Math.PI * 2 * longitudeRatio) let y1 = Math.Sin(Math.PI * latitudeRatio) * Math.Sin(Math.PI * 2 * longitudeRatio) let x2 = Math.Sin(Math.PI * nextLatitudeRatio) * Math.Cos(Math.PI * 2 * longitudeRatio) let y2 = Math.Sin(Math.PI * nextLatitudeRatio) * Math.Sin(Math.PI * 2 * longitudeRatio) let x3 = Math.Sin(Math.PI * latitudeRatio) * Math.Cos(Math.PI * 2 * nextLongitudeRatio) let y3 = Math.Sin(Math.PI * latitudeRatio) * Math.Sin(Math.PI * 2 * nextLongitudeRatio) let start = new XNA.Vector3((float)x1 * radius, (float)y1 * radius, (float)z1 * radius) let firstEnd = new XNA.Vector3((float)x2 * radius, (float)y2 * radius, (float)z2 * radius) let secondEnd = new XNA.Vector3((float)x3 * radius, (float)y3 * radius, (float)z1 * radius) select new { First = Tuple.Create(start, firstEnd), Second = Tuple.Create(start, secondEnd) }; foreach (var result in results) { yield return result.First; yield return result.Second; } } } } #endregion }

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• Creating Custom Ajax Control Toolkit Controls

  - by Stephen Walther

  The goal of this blog entry is to explain how you can extend the Ajax Control Toolkit with custom Ajax Control Toolkit controls. I describe how you can create the two halves of an Ajax Control Toolkit control: the server-side control extender and the client-side control behavior. Finally, I explain how you can use the new Ajax Control Toolkit control in a Web Forms page. At the end of this blog entry, there is a link to download a Visual Studio 2010 solution which contains the code for two Ajax Control Toolkit controls: SampleExtender and PopupHelpExtender. The SampleExtender contains the minimum skeleton for creating a new Ajax Control Toolkit control. You can use the SampleExtender as a starting point for your custom Ajax Control Toolkit controls. The PopupHelpExtender control is a super simple custom Ajax Control Toolkit control. This control extender displays a help message when you start typing into a TextBox control. The animated GIF below demonstrates what happens when you click into a TextBox which has been extended with the PopupHelp extender. Here’s a sample of a Web Forms page which uses the control: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowPopupHelp.aspx.cs" Inherits="MyACTControls.Web.Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html > <head runat="server"> <title>Show Popup Help</title> </head> <body> <form id="form1" runat="server"> <div> <act:ToolkitScriptManager ID="tsm" runat="server" /> <%-- Social Security Number --%> <asp:Label ID="lblSSN" Text="SSN:" AssociatedControlID="txtSSN" runat="server" /> <asp:TextBox ID="txtSSN" runat="server" /> <act:PopupHelpExtender id="ph1" TargetControlID="txtSSN" HelpText="Please enter your social security number." runat="server" /> <%-- Social Security Number --%> <asp:Label ID="lblPhone" Text="Phone Number:" AssociatedControlID="txtPhone" runat="server" /> <asp:TextBox ID="txtPhone" runat="server" /> <act:PopupHelpExtender id="ph2" TargetControlID="txtPhone" HelpText="Please enter your phone number." runat="server" /> </div> </form> </body> </html> In the page above, the PopupHelp extender is used to extend the functionality of the two TextBox controls. When focus is given to a TextBox control, the popup help message is displayed. An Ajax Control Toolkit control extender consists of two parts: a server-side control extender and a client-side behavior. For example, the PopupHelp extender consists of a server-side PopupHelpExtender control (PopupHelpExtender.cs) and a client-side PopupHelp behavior JavaScript script (PopupHelpBehavior.js). Over the course of this blog entry, I describe how you can create both the server-side extender and the client-side behavior. Writing the Server-Side Code Creating a Control Extender You create a control extender by creating a class that inherits from the abstract ExtenderControlBase class. For example, the PopupHelpExtender control is declared like this: public class PopupHelpExtender: ExtenderControlBase { } The ExtenderControlBase class is part of the Ajax Control Toolkit. This base class contains all of the common server properties and methods of every Ajax Control Toolkit extender control. The ExtenderControlBase class inherits from the ExtenderControl class. The ExtenderControl class is a standard class in the ASP.NET framework located in the System.Web.UI namespace. This class is responsible for generating a client-side behavior. The class generates a call to the Microsoft Ajax Library $create() method which looks like this: <script type="text/javascript"> $create(MyACTControls.PopupHelpBehavior, {"HelpText":"Please enter your social security number.","id":"ph1"}, null, null, $get("txtSSN")); }); </script> The JavaScript $create() method is part of the Microsoft Ajax Library. The reference for this method can be found here: http://msdn.microsoft.com/en-us/library/bb397487.aspx This method accepts the following parameters: type – The type of client behavior to create. The $create() method above creates a client PopupHelpBehavior. Properties – Enables you to pass initial values for the properties of the client behavior. For example, the initial value of the HelpText property. This is how server property values are passed to the client. Events – Enables you to pass client-side event handlers to the client behavior. References – Enables you to pass references to other client components. Element – The DOM element associated with the client behavior. This will be the DOM element associated with the control being extended such as the txtSSN TextBox. The $create() method is generated for you automatically. You just need to focus on writing the server-side control extender class. Specifying the Target Control All Ajax Control Toolkit extenders inherit a TargetControlID property from the ExtenderControlBase class. This property, the TargetControlID property, points at the control that the extender control extends. For example, the Ajax Control Toolkit TextBoxWatermark control extends a TextBox, the ConfirmButton control extends a Button, and the Calendar control extends a TextBox. You must indicate the type of control which your extender is extending. You indicate the type of control by adding a [TargetControlType] attribute to your control. For example, the PopupHelp extender is declared like this: [TargetControlType(typeof(TextBox))] public class PopupHelpExtender: ExtenderControlBase { } The PopupHelp extender can be used to extend a TextBox control. If you try to use the PopupHelp extender with another type of control then an exception is thrown. If you want to create an extender control which can be used with any type of ASP.NET control (Button, DataView, TextBox or whatever) then use the following attribute: [TargetControlType(typeof(Control))] Decorating Properties with Attributes If you decorate a server-side property with the [ExtenderControlProperty] attribute then the value of the property gets passed to the control’s client-side behavior. The value of the property gets passed to the client through the $create() method discussed above. The PopupHelp control contains the following HelpText property: [ExtenderControlProperty] [RequiredProperty] public string HelpText { get { return GetPropertyValue("HelpText", "Help Text"); } set { SetPropertyValue("HelpText", value); } } The HelpText property determines the help text which pops up when you start typing into a TextBox control. Because the HelpText property is decorated with the [ExtenderControlProperty] attribute, any value assigned to this property on the server is passed to the client automatically. For example, if you declare the PopupHelp extender in a Web Form page like this: <asp:TextBox ID="txtSSN" runat="server" /> <act:PopupHelpExtender id="ph1" TargetControlID="txtSSN" HelpText="Please enter your social security number." runat="server" />   Then the PopupHelpExtender renders the call to the the following Microsoft Ajax Library $create() method: $create(MyACTControls.PopupHelpBehavior, {"HelpText":"Please enter your social security number.","id":"ph1"}, null, null, $get("txtSSN")); You can see this call to the JavaScript $create() method by selecting View Source in your browser. This call to the $create() method calls a method named set_HelpText() automatically and passes the value “Please enter your social security number”. There are several attributes which you can use to decorate server-side properties including: ExtenderControlProperty – When a property is marked with this attribute, the value of the property is passed to the client automatically. ExtenderControlEvent – When a property is marked with this attribute, the property represents a client event handler. Required – When a value is not assigned to this property on the server, an error is displayed. DefaultValue – The default value of the property passed to the client. ClientPropertyName – The name of the corresponding property in the JavaScript behavior. For example, the server-side property is named ID (uppercase) and the client-side property is named id (lower-case). IDReferenceProperty – Applied to properties which refer to the IDs of other controls. URLProperty – Calls ResolveClientURL() to convert from a server-side URL to a URL which can be used on the client. ElementReference – Returns a reference to a DOM element by performing a client $get(). The WebResource, ClientResource, and the RequiredScript Attributes The PopupHelp extender uses three embedded resources named PopupHelpBehavior.js, PopupHelpBehavior.debug.js, and PopupHelpBehavior.css. The first two files are JavaScript files and the final file is a Cascading Style sheet file. These files are compiled as embedded resources. You don’t need to mark them as embedded resources in your Visual Studio solution because they get added to the assembly when the assembly is compiled by a build task. You can see that these files get embedded into the MyACTControls assembly by using Red Gate’s .NET Reflector tool: In order to use these files with the PopupHelp extender, you need to work with both the WebResource and the ClientScriptResource attributes. The PopupHelp extender includes the following three WebResource attributes. [assembly: WebResource("PopupHelp.PopupHelpBehavior.js", "text/javascript")] [assembly: WebResource("PopupHelp.PopupHelpBehavior.debug.js", "text/javascript")] [assembly: WebResource("PopupHelp.PopupHelpBehavior.css", "text/css", PerformSubstitution = true)] These WebResource attributes expose the embedded resource from the assembly so that they can be accessed by using the ScriptResource.axd or WebResource.axd handlers. The first parameter passed to the WebResource attribute is the name of the embedded resource and the second parameter is the content type of the embedded resource. The PopupHelp extender also includes the following ClientScriptResource and ClientCssResource attributes: [ClientScriptResource("MyACTControls.PopupHelpBehavior", "PopupHelp.PopupHelpBehavior.js")] [ClientCssResource("PopupHelp.PopupHelpBehavior.css")] Including these attributes causes the PopupHelp extender to request these resources when you add the PopupHelp extender to a page. If you open View Source in a browser which uses the PopupHelp extender then you will see the following link for the Cascading Style Sheet file: <link href="/WebResource.axd?d=0uONMsWXUuEDG-pbJHAC1kuKiIMteQFkYLmZdkgv7X54TObqYoqVzU4mxvaa4zpn5H9ch0RDwRYKwtO8zM5mKgO6C4WbrbkWWidKR07LD1d4n4i_uNB1mHEvXdZu2Ae5mDdVNDV53znnBojzCzwvSw2&amp;t=634417392021676003" type="text/css" rel="stylesheet" /> You also will see the following script include for the JavaScript file: <script src="/ScriptResource.axd?d=pIS7xcGaqvNLFBvExMBQSp_0xR3mpDfS0QVmmyu1aqDUjF06TrW1jVDyXNDMtBHxpRggLYDvgFTWOsrszflZEDqAcQCg-hDXjun7ON0Ol7EXPQIdOe1GLMceIDv3OeX658-tTq2LGdwXhC1-dE7_6g2&amp;t=ffffffff88a33b59" type="text/javascript"></script> The JavaScrpt file returned by this request to ScriptResource.axd contains the combined scripts for any and all Ajax Control Toolkit controls in a page. By default, the Ajax Control Toolkit combines all of the JavaScript files required by a page into a single JavaScript file. Combining files in this way really speeds up how quickly all of the JavaScript files get delivered from the web server to the browser. So, by default, there will be only one ScriptResource.axd include for all of the JavaScript files required by a page. If you want to disable Script Combining, and create separate links, then disable Script Combining like this: <act:ToolkitScriptManager ID="tsm" runat="server" CombineScripts="false" /> There is one more important attribute used by Ajax Control Toolkit extenders. The PopupHelp behavior uses the following two RequirdScript attributes to load the JavaScript files which are required by the PopupHelp behavior: [RequiredScript(typeof(CommonToolkitScripts), 0)] [RequiredScript(typeof(PopupExtender), 1)] The first parameter of the RequiredScript attribute represents either the string name of a JavaScript file or the type of an Ajax Control Toolkit control. The second parameter represents the order in which the JavaScript files are loaded (This second parameter is needed because .NET attributes are intrinsically unordered). In this case, the RequiredScript attribute will load the JavaScript files associated with the CommonToolkitScripts type and the JavaScript files associated with the PopupExtender in that order. The PopupHelp behavior depends on these JavaScript files. Writing the Client-Side Code The PopupHelp extender uses a client-side behavior written with the Microsoft Ajax Library. Here is the complete code for the client-side behavior: (function () { // The unique name of the script registered with the // client script loader var scriptName = "PopupHelpBehavior"; function execute() { Type.registerNamespace('MyACTControls'); MyACTControls.PopupHelpBehavior = function (element) { /// <summary> /// A behavior which displays popup help for a textbox /// </summmary> /// <param name="element" type="Sys.UI.DomElement">The element to attach to</param> MyACTControls.PopupHelpBehavior.initializeBase(this, [element]); this._textbox = Sys.Extended.UI.TextBoxWrapper.get_Wrapper(element); this._cssClass = "ajax__popupHelp"; this._popupBehavior = null; this._popupPosition = Sys.Extended.UI.PositioningMode.BottomLeft; this._popupDiv = null; this._helpText = "Help Text"; this._element$delegates = { focus: Function.createDelegate(this, this._element_onfocus), blur: Function.createDelegate(this, this._element_onblur) }; } MyACTControls.PopupHelpBehavior.prototype = { initialize: function () { MyACTControls.PopupHelpBehavior.callBaseMethod(this, 'initialize'); // Add event handlers for focus and blur var element = this.get_element(); $addHandlers(element, this._element$delegates); }, _ensurePopup: function () { if (!this._popupDiv) { var element = this.get_element(); var id = this.get_id(); this._popupDiv = $common.createElementFromTemplate({ nodeName: "div", properties: { id: id + "_popupDiv" }, cssClasses: ["ajax__popupHelp"] }, element.parentNode); this._popupBehavior = new $create(Sys.Extended.UI.PopupBehavior, { parentElement: element }, {}, {}, this._popupDiv); this._popupBehavior.set_positioningMode(this._popupPosition); } }, get_HelpText: function () { return this._helpText; }, set_HelpText: function (value) { if (this._HelpText != value) { this._helpText = value; this._ensurePopup(); this._popupDiv.innerHTML = value; this.raisePropertyChanged("Text") } }, _element_onfocus: function (e) { this.show(); }, _element_onblur: function (e) { this.hide(); }, show: function () { this._popupBehavior.show(); }, hide: function () { if (this._popupBehavior) { this._popupBehavior.hide(); } }, dispose: function() { var element = this.get_element(); $clearHandlers(element); if (this._popupBehavior) { this._popupBehavior.dispose(); this._popupBehavior = null; } } }; MyACTControls.PopupHelpBehavior.registerClass('MyACTControls.PopupHelpBehavior', Sys.Extended.UI.BehaviorBase); Sys.registerComponent(MyACTControls.PopupHelpBehavior, { name: "popupHelp" }); } // execute if (window.Sys && Sys.loader) { Sys.loader.registerScript(scriptName, ["ExtendedBase", "ExtendedCommon"], execute); } else { execute(); } })();   In the following sections, we’ll discuss how this client-side behavior works. Wrapping the Behavior for the Script Loader The behavior is wrapped with the following script: (function () { // The unique name of the script registered with the // client script loader var scriptName = "PopupHelpBehavior"; function execute() { // Behavior Content } // execute if (window.Sys && Sys.loader) { Sys.loader.registerScript(scriptName, ["ExtendedBase", "ExtendedCommon"], execute); } else { execute(); } })(); This code is required by the Microsoft Ajax Library Script Loader. You need this code if you plan to use a behavior directly from client-side code and you want to use the Script Loader. If you plan to only use your code in the context of the Ajax Control Toolkit then you can leave out this code. Registering a JavaScript Namespace The PopupHelp behavior is declared within a namespace named MyACTControls. In the code above, this namespace is created with the following registerNamespace() method: Type.registerNamespace('MyACTControls'); JavaScript does not have any built-in way of creating namespaces to prevent naming conflicts. The Microsoft Ajax Library extends JavaScript with support for namespaces. You can learn more about the registerNamespace() method here: http://msdn.microsoft.com/en-us/library/bb397723.aspx Creating the Behavior The actual Popup behavior is created with the following code. MyACTControls.PopupHelpBehavior = function (element) { /// <summary> /// A behavior which displays popup help for a textbox /// </summmary> /// <param name="element" type="Sys.UI.DomElement">The element to attach to</param> MyACTControls.PopupHelpBehavior.initializeBase(this, [element]); this._textbox = Sys.Extended.UI.TextBoxWrapper.get_Wrapper(element); this._cssClass = "ajax__popupHelp"; this._popupBehavior = null; this._popupPosition = Sys.Extended.UI.PositioningMode.BottomLeft; this._popupDiv = null; this._helpText = "Help Text"; this._element$delegates = { focus: Function.createDelegate(this, this._element_onfocus), blur: Function.createDelegate(this, this._element_onblur) }; } MyACTControls.PopupHelpBehavior.prototype = { initialize: function () { MyACTControls.PopupHelpBehavior.callBaseMethod(this, 'initialize'); // Add event handlers for focus and blur var element = this.get_element(); $addHandlers(element, this._element$delegates); }, _ensurePopup: function () { if (!this._popupDiv) { var element = this.get_element(); var id = this.get_id(); this._popupDiv = $common.createElementFromTemplate({ nodeName: "div", properties: { id: id + "_popupDiv" }, cssClasses: ["ajax__popupHelp"] }, element.parentNode); this._popupBehavior = new $create(Sys.Extended.UI.PopupBehavior, { parentElement: element }, {}, {}, this._popupDiv); this._popupBehavior.set_positioningMode(this._popupPosition); } }, get_HelpText: function () { return this._helpText; }, set_HelpText: function (value) { if (this._HelpText != value) { this._helpText = value; this._ensurePopup(); this._popupDiv.innerHTML = value; this.raisePropertyChanged("Text") } }, _element_onfocus: function (e) { this.show(); }, _element_onblur: function (e) { this.hide(); }, show: function () { this._popupBehavior.show(); }, hide: function () { if (this._popupBehavior) { this._popupBehavior.hide(); } }, dispose: function() { var element = this.get_element(); $clearHandlers(element); if (this._popupBehavior) { this._popupBehavior.dispose(); this._popupBehavior = null; } } }; The code above has two parts. The first part of the code is used to define the constructor function for the PopupHelp behavior. This is a factory method which returns an instance of a PopupHelp behavior: MyACTControls.PopupHelpBehavior = function (element) { } The second part of the code modified the prototype for the PopupHelp behavior: MyACTControls.PopupHelpBehavior.prototype = { } Any code which is particular to a single instance of the PopupHelp behavior should be placed in the constructor function. For example, the default value of the _helpText field is assigned in the constructor function: this._helpText = "Help Text"; Any code which is shared among all instances of the PopupHelp behavior should be added to the PopupHelp behavior’s prototype. For example, the public HelpText property is added to the prototype: get_HelpText: function () { return this._helpText; }, set_HelpText: function (value) { if (this._HelpText != value) { this._helpText = value; this._ensurePopup(); this._popupDiv.innerHTML = value; this.raisePropertyChanged("Text") } }, Registering a JavaScript Class After you create the PopupHelp behavior, you must register the behavior as a class by using the Microsoft Ajax registerClass() method like this: MyACTControls.PopupHelpBehavior.registerClass('MyACTControls.PopupHelpBehavior', Sys.Extended.UI.BehaviorBase); This call to registerClass() registers PopupHelp behavior as a class which derives from the base Sys.Extended.UI.BehaviorBase class. Like the ExtenderControlBase class on the server side, the BehaviorBase class on the client side contains method used by every behavior. The documentation for the BehaviorBase class can be found here: http://msdn.microsoft.com/en-us/library/bb311020.aspx The most important methods and properties of the BehaviorBase class are the following: dispose() – Use this method to clean up all resources used by your behavior. In the case of the PopupHelp behavior, the dispose() method is used to remote the event handlers created by the behavior and disposed the Popup behavior. get_element() -- Use this property to get the DOM element associated with the behavior. In other words, the DOM element which the behavior extends. get_id() – Use this property to the ID of the current behavior. initialize() – Use this method to initialize the behavior. This method is called after all of the properties are set by the $create() method. Creating Debug and Release Scripts You might have noticed that the PopupHelp behavior uses two scripts named PopupHelpBehavior.js and PopupHelpBehavior.debug.js. However, you never create these two scripts. Instead, you only create a single script named PopupHelpBehavior.pre.js. The pre in PopupHelpBehavior.pre.js stands for preprocessor. When you build the Ajax Control Toolkit (or the sample Visual Studio Solution at the end of this blog entry), a build task named JSBuild generates the PopupHelpBehavior.js release script and PopupHelpBehavior.debug.js debug script automatically. The JSBuild preprocessor supports the following directives: #IF #ELSE #ENDIF #INCLUDE #LOCALIZE #DEFINE #UNDEFINE The preprocessor directives are used to mark code which should only appear in the debug version of the script. The directives are used extensively in the Microsoft Ajax Library. For example, the Microsoft Ajax Library Array.contains() method is created like this: $type.contains = function Array$contains(array, item) { //#if DEBUG var e = Function._validateParams(arguments, [ {name: "array", type: Array, elementMayBeNull: true}, {name: "item", mayBeNull: true} ]); if (e) throw e; //#endif return (indexOf(array, item) >= 0); } Notice that you add each of the preprocessor directives inside a JavaScript comment. The comment prevents Visual Studio from getting confused with its Intellisense. The release version, but not the debug version, of the PopupHelpBehavior script is also minified automatically by the Microsoft Ajax Minifier. The minifier is invoked by a build step in the project file. Conclusion The goal of this blog entry was to explain how you can create custom AJAX Control Toolkit controls. In the first part of this blog entry, you learned how to create the server-side portion of an Ajax Control Toolkit control. You learned how to derive a new control from the ExtenderControlBase class and decorate its properties with the necessary attributes. Next, in the second part of this blog entry, you learned how to create the client-side portion of an Ajax Control Toolkit control by creating a client-side behavior with JavaScript. You learned how to use the methods of the Microsoft Ajax Library to extend your client behavior from the BehaviorBase class. Download the Custom ACT Starter Solution

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• A Taxonomy of Numerical Methods v1

  - by JoshReuben

  Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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• An Introduction to Meteor

  - by Stephen.Walther

  The goal of this blog post is to give you a brief introduction to Meteor which is a framework for building Single Page Apps. In this blog entry, I provide a walkthrough of building a simple Movie database app. What is special about Meteor? Meteor has two jaw-dropping features: Live HTML – If you make any changes to the HTML, CSS, JavaScript, or data on the server then every client shows the changes automatically without a browser refresh. For example, if you change the background color of a page to yellow then every open browser will show the new yellow background color without a refresh. Or, if you add a new movie to a collection of movies, then every open browser will display the new movie automatically. With Live HTML, users no longer need a refresh button. Changes to an application happen everywhere automatically without any effort. The Meteor framework handles all of the messy details of keeping all of the clients in sync with the server for you. Latency Compensation – When you modify data on the client, these modifications appear as if they happened on the server without any delay. For example, if you create a new movie then the movie appears instantly. However, that is all an illusion. In the background, Meteor updates the database with the new movie. If, for whatever reason, the movie cannot be added to the database then Meteor removes the movie from the client automatically. Latency compensation is extremely important for creating a responsive web application. You want the user to be able to make instant modifications in the browser and the framework to handle the details of updating the database without slowing down the user. Installing Meteor Meteor is licensed under the open-source MIT license and you can start building production apps with the framework right now. Be warned that Meteor is still in the “early preview” stage. It has not reached a 1.0 release. According to the Meteor FAQ, Meteor will reach version 1.0 in “More than a month, less than a year.” Don’t be scared away by that. You should be aware that, unlike most open source projects, Meteor has financial backing. The Meteor project received an $11.2 million round of financing from Andreessen Horowitz. So, it would be a good bet that this project will reach the 1.0 mark. And, if it doesn’t, the framework as it exists right now is still very powerful. Meteor runs on top of Node.js. You write Meteor apps by writing JavaScript which runs both on the client and on the server. You can build Meteor apps on Windows, Mac, or Linux (Although the support for Windows is still officially unofficial). If you want to install Meteor on Windows then download the MSI from the following URL: http://win.meteor.com/ If you want to install Meteor on Mac/Linux then run the following CURL command from your terminal: curl https://install.meteor.com | /bin/sh Meteor will install all of its dependencies automatically including Node.js. However, I recommend that you install Node.js before installing Meteor by installing Node.js from the following address: http://nodejs.org/ If you let Meteor install Node.js then Meteor won’t install NPM which is the standard package manager for Node.js. If you install Node.js and then you install Meteor then you get NPM automatically. Creating a New Meteor App To get a sense of how Meteor works, I am going to walk through the steps required to create a simple Movie database app. Our app will display a list of movies and contain a form for creating a new movie. The first thing that we need to do is create our new Meteor app. Open a command prompt/terminal window and execute the following command: Meteor create MovieApp After you execute this command, you should see something like the following: Follow the instructions: execute cd MovieApp to change to your MovieApp directory, and run the meteor command. Executing the meteor command starts Meteor on port 3000. Open up your favorite web browser and navigate to http://localhost:3000 and you should see the default Meteor Hello World page: Open up your favorite development environment to see what the Meteor app looks like. Open the MovieApp folder which we just created. Here’s what the MovieApp looks like in Visual Studio 2012: Notice that our MovieApp contains three files named MovieApp.css, MovieApp.html, and MovieApp.js. In other words, it contains a Cascading Style Sheet file, an HTML file, and a JavaScript file. Just for fun, let’s see how the Live HTML feature works. Open up multiple browsers and point each browser at http://localhost:3000. Now, open the MovieApp.html page and modify the text “Hello World!” to “Hello Cruel World!” and save the change. The text in all of the browsers should update automatically without a browser refresh. Pretty amazing, right? Controlling Where JavaScript Executes You write a Meteor app using JavaScript. Some of the JavaScript executes on the client (the browser) and some of the JavaScript executes on the server and some of the JavaScript executes in both places. For a super simple app, you can use the Meteor.isServer and Meteor.isClient properties to control where your JavaScript code executes. For example, the following JavaScript contains a section of code which executes on the server and a section of code which executes in the browser: if (Meteor.isClient) { console.log("Hello Browser!"); } if (Meteor.isServer) { console.log("Hello Server!"); } console.log("Hello Browser and Server!"); When you run the app, the message “Hello Browser!” is written to the browser JavaScript console. The message “Hello Server!” is written to the command/terminal window where you ran Meteor. Finally, the message “Hello Browser and Server!” is execute on both the browser and server and the message appears in both places. For simple apps, using Meteor.isClient and Meteor.isServer to control where JavaScript executes is fine. For more complex apps, you should create separate folders for your server and client code. Here are the folders which you can use in a Meteor app: · client – This folder contains any JavaScript which executes only on the client. · server – This folder contains any JavaScript which executes only on the server. · common – This folder contains any JavaScript code which executes on both the client and server. · lib – This folder contains any JavaScript files which you want to execute before any other JavaScript files. · public – This folder contains static application assets such as images. For the Movie App, we need the client, server, and common folders. Delete the existing MovieApp.js, MovieApp.html, and MovieApp.css files. We will create new files in the right locations later in this walkthrough. Combining HTML, CSS, and JavaScript Files Meteor combines all of your JavaScript files, and all of your Cascading Style Sheet files, and all of your HTML files automatically. If you want to create one humongous JavaScript file which contains all of the code for your app then that is your business. However, if you want to build a more maintainable application, then you should break your JavaScript files into many separate JavaScript files and let Meteor combine them for you. Meteor also combines all of your HTML files into a single file. HTML files are allowed to have the following top-level elements: <head> — All <head> files are combined into a single <head> and served with the initial page load. <body> — All <body> files are combined into a single <body> and served with the initial page load. <template> — All <template> files are compiled into JavaScript templates. Because you are creating a single page app, a Meteor app typically will contain a single HTML file for the <head> and <body> content. However, a Meteor app typically will contain several template files. In other words, all of the interesting stuff happens within the <template> files. Displaying a List of Movies Let me start building the Movie App by displaying a list of movies. In order to display a list of movies, we need to create the following four files: · client\movies.html – Contains the HTML for the <head> and <body> of the page for the Movie app. · client\moviesTemplate.html – Contains the HTML template for displaying the list of movies. · client\movies.js – Contains the JavaScript for supplying data to the moviesTemplate. · server\movies.js – Contains the JavaScript for seeding the database with movies. After you create these files, your folder structure should looks like this: Here’s what the client\movies.html file looks like: <head> <title>My Movie App</title> </head> <body> <h1>Movies</h1> {{> moviesTemplate }} </body>   Notice that it contains <head> and <body> top-level elements. The <body> element includes the moviesTemplate with the syntax {{> moviesTemplate }}. The moviesTemplate is defined in the client/moviesTemplate.html file: <template name="moviesTemplate"> <ul> {{#each movies}} <li> {{title}} </li> {{/each}} </ul> </template> By default, Meteor uses the Handlebars templating library. In the moviesTemplate above, Handlebars is used to loop through each of the movies using {{#each}}…{{/each}} and display the title for each movie using {{title}}. The client\movies.js JavaScript file is used to bind the moviesTemplate to the Movies collection on the client. Here’s what this JavaScript file looks like: // Declare client Movies collection Movies = new Meteor.Collection("movies"); // Bind moviesTemplate to Movies collection Template.moviesTemplate.movies = function () { return Movies.find(); }; The Movies collection is a client-side proxy for the server-side Movies database collection. Whenever you want to interact with the collection of Movies stored in the database, you use the Movies collection instead of communicating back to the server. The moviesTemplate is bound to the Movies collection by assigning a function to the Template.moviesTemplate.movies property. The function simply returns all of the movies from the Movies collection. The final file which we need is the server-side server\movies.js file: // Declare server Movies collection Movies = new Meteor.Collection("movies"); // Seed the movie database with a few movies Meteor.startup(function () { if (Movies.find().count() == 0) { Movies.insert({ title: "Star Wars", director: "Lucas" }); Movies.insert({ title: "Memento", director: "Nolan" }); Movies.insert({ title: "King Kong", director: "Jackson" }); } }); The server\movies.js file does two things. First, it declares the server-side Meteor Movies collection. When you declare a server-side Meteor collection, a collection is created in the MongoDB database associated with your Meteor app automatically (Meteor uses MongoDB as its database automatically). Second, the server\movies.js file seeds the Movies collection (MongoDB collection) with three movies. Seeding the database gives us some movies to look at when we open the Movies app in a browser. Creating New Movies Let me modify the Movies Database App so that we can add new movies to the database of movies. First, I need to create a new template file – named client\movieForm.html – which contains an HTML form for creating a new movie: <template name="movieForm"> <fieldset> <legend>Add New Movie</legend> <form> <div> <label> Title: <input id="title" /> </label> </div> <div> <label> Director: <input id="director" /> </label> </div> <div> <input type="submit" value="Add Movie" /> </div> </form> </fieldset> </template> In order for the new form to show up, I need to modify the client\movies.html file to include the movieForm.html template. Notice that I added {{> movieForm }} to the client\movies.html file: <head> <title>My Movie App</title> </head> <body> <h1>Movies</h1> {{> moviesTemplate }} {{> movieForm }} </body> After I make these modifications, our Movie app will display the form: The next step is to handle the submit event for the movie form. Below, I’ve modified the client\movies.js file so that it contains a handler for the submit event raised when you submit the form contained in the movieForm.html template: // Declare client Movies collection Movies = new Meteor.Collection("movies"); // Bind moviesTemplate to Movies collection Template.moviesTemplate.movies = function () { return Movies.find(); }; // Handle movieForm events Template.movieForm.events = { 'submit': function (e, tmpl) { // Don't postback e.preventDefault(); // create the new movie var newMovie = { title: tmpl.find("#title").value, director: tmpl.find("#director").value }; // add the movie to the db Movies.insert(newMovie); } }; The Template.movieForm.events property contains an event map which maps event names to handlers. In this case, I am mapping the form submit event to an anonymous function which handles the event. In the event handler, I am first preventing a postback by calling e.preventDefault(). This is a single page app, no postbacks are allowed! Next, I am grabbing the new movie from the HTML form. I’m taking advantage of the template find() method to retrieve the form field values. Finally, I am calling Movies.insert() to insert the new movie into the Movies collection. Here, I am explicitly inserting the new movie into the client-side Movies collection. Meteor inserts the new movie into the server-side Movies collection behind the scenes. When Meteor inserts the movie into the server-side collection, the new movie is added to the MongoDB database associated with the Movies app automatically. If server-side insertion fails for whatever reasons – for example, your internet connection is lost – then Meteor will remove the movie from the client-side Movies collection automatically. In other words, Meteor takes care of keeping the client Movies collection and the server Movies collection in sync. If you open multiple browsers, and add movies, then you should notice that all of the movies appear on all of the open browser automatically. You don’t need to refresh individual browsers to update the client-side Movies collection. Meteor keeps everything synchronized between the browsers and server for you. Removing the Insecure Module To make it easier to develop and debug a new Meteor app, by default, you can modify the database directly from the client. For example, you can delete all of the data in the database by opening up your browser console window and executing multiple Movies.remove() commands. Obviously, enabling anyone to modify your database from the browser is not a good idea in a production application. Before you make a Meteor app public, you should first run the meteor remove insecure command from a command/terminal window: Running meteor remove insecure removes the insecure package from the Movie app. Unfortunately, it also breaks our Movie app. We’ll get an “Access denied” error in our browser console whenever we try to insert a new movie. No worries. I’ll fix this issue in the next section. Creating Meteor Methods By taking advantage of Meteor Methods, you can create methods which can be invoked on both the client and the server. By taking advantage of Meteor Methods you can: 1. Perform form validation on both the client and the server. For example, even if an evil hacker bypasses your client code, you can still prevent the hacker from submitting an invalid value for a form field by enforcing validation on the server. 2. Simulate database operations on the client but actually perform the operations on the server. Let me show you how we can modify our Movie app so it uses Meteor Methods to insert a new movie. First, we need to create a new file named common\methods.js which contains the definition of our Meteor Methods: Meteor.methods({ addMovie: function (newMovie) { // Perform form validation if (newMovie.title == "") { throw new Meteor.Error(413, "Missing title!"); } if (newMovie.director == "") { throw new Meteor.Error(413, "Missing director!"); } // Insert movie (simulate on client, do it on server) return Movies.insert(newMovie); } }); The addMovie() method is called from both the client and the server. This method does two things. First, it performs some basic validation. If you don’t enter a title or you don’t enter a director then an error is thrown. Second, the addMovie() method inserts the new movie into the Movies collection. When called on the client, inserting the new movie into the Movies collection just updates the collection. When called on the server, inserting the new movie into the Movies collection causes the database (MongoDB) to be updated with the new movie. You must add the common\methods.js file to the common folder so it will get executed on both the client and the server. Our folder structure now looks like this: We actually call the addMovie() method within our client code in the client\movies.js file. Here’s what the updated file looks like: // Declare client Movies collection Movies = new Meteor.Collection("movies"); // Bind moviesTemplate to Movies collection Template.moviesTemplate.movies = function () { return Movies.find(); }; // Handle movieForm events Template.movieForm.events = { 'submit': function (e, tmpl) { // Don't postback e.preventDefault(); // create the new movie var newMovie = { title: tmpl.find("#title").value, director: tmpl.find("#director").value }; // add the movie to the db Meteor.call( "addMovie", newMovie, function (err, result) { if (err) { alert("Could not add movie " + err.reason); } } ); } }; The addMovie() method is called – on both the client and the server – by calling the Meteor.call() method. This method accepts the following parameters: · The string name of the method to call. · The data to pass to the method (You can actually pass multiple params for the data if you like). · A callback function to invoke after the method completes. In the JavaScript code above, the addMovie() method is called with the new movie retrieved from the HTML form. The callback checks for an error. If there is an error then the error reason is displayed in an alert (please don’t use alerts for validation errors in a production app because they are ugly!). Summary The goal of this blog post was to provide you with a brief walk through of a simple Meteor app. I showed you how you can create a simple Movie Database app which enables you to display a list of movies and create new movies. I also explained why it is important to remove the Meteor insecure package from a production app. I showed you how to use Meteor Methods to insert data into the database instead of doing it directly from the client. I’m very impressed with the Meteor framework. The support for Live HTML and Latency Compensation are required features for many real world Single Page Apps but implementing these features by hand is not easy. Meteor makes it easy.

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• Toorcon 15 (2013)

  - by danx

  The Toorcon gang (senior staff): h1kari (founder), nfiltr8, and Geo Introduction to Toorcon 15 (2013) A Tale of One Software Bypass of MS Windows 8 Secure Boot Breaching SSL, One Byte at a Time Running at 99%: Surviving an Application DoS Security Response in the Age of Mass Customized Attacks x86 Rewriting: Defeating RoP and other Shinanighans Clowntown Express: interesting bugs and running a bug bounty program Active Fingerprinting of Encrypted VPNs Making Attacks Go Backwards Mask Your Checksums—The Gorry Details Adventures with weird machines thirty years after "Reflections on Trusting Trust" Introduction to Toorcon 15 (2013) Toorcon 15 is the 15th annual security conference held in San Diego. I've attended about a third of them and blogged about previous conferences I attended here starting in 2003. As always, I've only summarized the talks I attended and interested me enough to write about them. Be aware that I may have misrepresented the speaker's remarks and that they are not my remarks or opinion, or those of my employer, so don't quote me or them. Those seeking further details may contact the speakers directly or use The Google. For some talks, I have a URL for further information. A Tale of One Software Bypass of MS Windows 8 Secure Boot Andrew Furtak and Oleksandr Bazhaniuk Yuri Bulygin, Oleksandr ("Alex") Bazhaniuk, and (not present) Andrew Furtak Yuri and Alex talked about UEFI and Bootkits and bypassing MS Windows 8 Secure Boot, with vendor recommendations. They previously gave this talk at the BlackHat 2013 conference. MS Windows 8 Secure Boot Overview UEFI (Unified Extensible Firmware Interface) is interface between hardware and OS. UEFI is processor and architecture independent. Malware can replace bootloader (bootx64.efi, bootmgfw.efi). Once replaced can modify kernel. Trivial to replace bootloader. Today many legacy bootkits—UEFI replaces them most of them. MS Windows 8 Secure Boot verifies everything you load, either through signatures or hashes. UEFI firmware relies on secure update (with signed update). You would think Secure Boot would rely on ROM (such as used for phones0, but you can't do that for PCs—PCs use writable memory with signatures DXE core verifies the UEFI boat loader(s) OS Loader (winload.efi, winresume.efi) verifies the OS kernel A chain of trust is established with a root key (Platform Key, PK), which is a cert belonging to the platform vendor. Key Exchange Keys (KEKs) verify an "authorized" database (db), and "forbidden" database (dbx). X.509 certs with SHA-1/SHA-256 hashes. Keys are stored in non-volatile (NV) flash-based NVRAM. Boot Services (BS) allow adding/deleting keys (can't be accessed once OS starts—which uses Run-Time (RT)). Root cert uses RSA-2048 public keys and PKCS#7 format signatures. SecureBoot — enable disable image signature checks SetupMode — update keys, self-signed keys, and secure boot variables CustomMode — allows updating keys Secure Boot policy settings are: always execute, never execute, allow execute on security violation, defer execute on security violation, deny execute on security violation, query user on security violation Attacking MS Windows 8 Secure Boot Secure Boot does NOT protect from physical access. Can disable from console. Each BIOS vendor implements Secure Boot differently. There are several platform and BIOS vendors. It becomes a "zoo" of implementations—which can be taken advantage of. Secure Boot is secure only when all vendors implement it correctly. Allow only UEFI firmware signed updates protect UEFI firmware from direct modification in flash memory protect FW update components program SPI controller securely protect secure boot policy settings in nvram protect runtime api disable compatibility support module which allows unsigned legacy Can corrupt the Platform Key (PK) EFI root certificate variable in SPI flash. If PK is not found, FW enters setup mode wich secure boot turned off. Can also exploit TPM in a similar manner. One is not supposed to be able to directly modify the PK in SPI flash from the OS though. But they found a bug that they can exploit from User Mode (undisclosed) and demoed the exploit. It loaded and ran their own bootkit. The exploit requires a reboot. Multiple vendors are vulnerable. They will disclose this exploit to vendors in the future. Recommendations: allow only signed updates protect UEFI fw in ROM protect EFI variable store in ROM Breaching SSL, One Byte at a Time Yoel Gluck and Angelo Prado Angelo Prado and Yoel Gluck, Salesforce.com CRIME is software that performs a "compression oracle attack." This is possible because the SSL protocol doesn't hide length, and because SSL compresses the header. CRIME requests with every possible character and measures the ciphertext length. Look for the plaintext which compresses the most and looks for the cookie one byte-at-a-time. SSL Compression uses LZ77 to reduce redundancy. Huffman coding replaces common byte sequences with shorter codes. US CERT thinks the SSL compression problem is fixed, but it isn't. They convinced CERT that it wasn't fixed and they issued a CVE. BREACH, breachattrack.com BREACH exploits the SSL response body (Accept-Encoding response, Content-Encoding). It takes advantage of the fact that the response is not compressed. BREACH uses gzip and needs fairly "stable" pages that are static for ~30 seconds. It needs attacker-supplied content (say from a web form or added to a URL parameter). BREACH listens to a session's requests and responses, then inserts extra requests and responses. Eventually, BREACH guesses a session's secret key. Can use compression to guess contents one byte at-a-time. For example, "Supersecret SupersecreX" (a wrong guess) compresses 10 bytes, and "Supersecret Supersecret" (a correct guess) compresses 11 bytes, so it can find each character by guessing every character. To start the guess, BREACH needs at least three known initial characters in the response sequence. Compression length then "leaks" information. Some roadblocks include no winners (all guesses wrong) or too many winners (multiple possibilities that compress the same). The solutions include: lookahead (guess 2 or 3 characters at-a-time instead of 1 character). Expensive rollback to last known conflict check compression ratio can brute-force first 3 "bootstrap" characters, if needed (expensive) block ciphers hide exact plain text length. Solution is to align response in advance to block size Mitigations length: use variable padding secrets: dynamic CSRF tokens per request secret: change over time separate secret to input-less servlets Future work eiter understand DEFLATE/GZIP HTTPS extensions Running at 99%: Surviving an Application DoS Ryan Huber Ryan Huber, Risk I/O Ryan first discussed various ways to do a denial of service (DoS) attack against web services. One usual method is to find a slow web page and do several wgets. Or download large files. Apache is not well suited at handling a large number of connections, but one can put something in front of it Can use Apache alternatives, such as nginx How to identify malicious hosts short, sudden web requests user-agent is obvious (curl, python) same url requested repeatedly no web page referer (not normal) hidden links. hide a link and see if a bot gets it restricted access if not your geo IP (unless the website is global) missing common headers in request regular timing first seen IP at beginning of attack count requests per hosts (usually a very large number) Use of captcha can mitigate attacks, but you'll lose a lot of genuine users. Bouncer, goo.gl/c2vyEc and www.github.com/rawdigits/Bouncer Bouncer is software written by Ryan in netflow. Bouncer has a small, unobtrusive footprint and detects DoS attempts. It closes blacklisted sockets immediately (not nice about it, no proper close connection). Aggregator collects requests and controls your web proxies. Need NTP on the front end web servers for clean data for use by bouncer. Bouncer is also useful for a popularity storm ("Slashdotting") and scraper storms. Future features: gzip collection data, documentation, consumer library, multitask, logging destroyed connections. Takeaways: DoS mitigation is easier with a complete picture Bouncer designed to make it easier to detect and defend DoS—not a complete cure Security Response in the Age of Mass Customized Attacks Peleus Uhley and Karthik Raman Peleus Uhley and Karthik Raman, Adobe ASSET, blogs.adobe.com/asset/ Peleus and Karthik talked about response to mass-customized exploits. Attackers behave much like a business. "Mass customization" refers to concept discussed in the book Future Perfect by Stan Davis of Harvard Business School. Mass customization is differentiating a product for an individual customer, but at a mass production price. For example, the same individual with a debit card receives basically the same customized ATM experience around the world. Or designing your own PC from commodity parts. Exploit kits are another example of mass customization. The kits support multiple browsers and plugins, allows new modules. Exploit kits are cheap and customizable. Organized gangs use exploit kits. A group at Berkeley looked at 77,000 malicious websites (Grier et al., "Manufacturing Compromise: The Emergence of Exploit-as-a-Service", 2012). They found 10,000 distinct binaries among them, but derived from only a dozen or so exploit kits. Characteristics of Mass Malware: potent, resilient, relatively low cost Technical characteristics: multiple OS, multipe payloads, multiple scenarios, multiple languages, obfuscation Response time for 0-day exploits has gone down from ~40 days 5 years ago to about ~10 days now. So the drive with malware is towards mass customized exploits, to avoid detection There's plenty of evicence that exploit development has Project Manager bureaucracy. They infer from the malware edicts to: support all versions of reader support all versions of windows support all versions of flash support all browsers write large complex, difficult to main code (8750 lines of JavaScript for example Exploits have "loose coupling" of multipe versions of software (adobe), OS, and browser. This allows specific attacks against specific versions of multiple pieces of software. Also allows exploits of more obscure software/OS/browsers and obscure versions. Gave examples of exploits that exploited 2, 3, 6, or 14 separate bugs. However, these complete exploits are more likely to be buggy or fragile in themselves and easier to defeat. Future research includes normalizing malware and Javascript. Conclusion: The coming trend is that mass-malware with mass zero-day attacks will result in mass customization of attacks. x86 Rewriting: Defeating RoP and other Shinanighans Richard Wartell Richard Wartell The attack vector we are addressing here is: First some malware causes a buffer overflow. The malware has no program access, but input access and buffer overflow code onto stack Later the stack became non-executable. The workaround malware used was to write a bogus return address to the stack jumping to malware Later came ASLR (Address Space Layout Randomization) to randomize memory layout and make addresses non-deterministic. The workaround malware used was to jump t existing code segments in the program that can be used in bad ways "RoP" is Return-oriented Programming attacks. RoP attacks use your own code and write return address on stack to (existing) expoitable code found in program ("gadgets"). Pinkie Pie was paid $60K last year for a RoP attack. One solution is using anti-RoP compilers that compile source code with NO return instructions. ASLR does not randomize address space, just "gadgets". IPR/ILR ("Instruction Location Randomization") randomizes each instruction with a virtual machine. Richard's goal was to randomize a binary with no source code access. He created "STIR" (Self-Transofrming Instruction Relocation). STIR disassembles binary and operates on "basic blocks" of code. The STIR disassembler is conservative in what to disassemble. Each basic block is moved to a random location in memory. Next, STIR writes new code sections with copies of "basic blocks" of code in randomized locations. The old code is copied and rewritten with jumps to new code. the original code sections in the file is marked non-executible. STIR has better entropy than ASLR in location of code. Makes brute force attacks much harder. STIR runs on MS Windows (PEM) and Linux (ELF). It eliminated 99.96% or more "gadgets" (i.e., moved the address). Overhead usually 5-10% on MS Windows, about 1.5-4% on Linux (but some code actually runs faster!). The unique thing about STIR is it requires no source access and the modified binary fully works! Current work is to rewrite code to enforce security policies. For example, don't create a *.{exe,msi,bat} file. Or don't connect to the network after reading from the disk. Clowntown Express: interesting bugs and running a bug bounty program Collin Greene Collin Greene, Facebook Collin talked about Facebook's bug bounty program. Background at FB: FB has good security frameworks, such as security teams, external audits, and cc'ing on diffs. But there's lots of "deep, dark, forgotten" parts of legacy FB code. Collin gave several examples of bountied bugs. Some bounty submissions were on software purchased from a third-party (but bounty claimers don't know and don't care). We use security questions, as does everyone else, but they are basically insecure (often easily discoverable). Collin didn't expect many bugs from the bounty program, but they ended getting 20+ good bugs in first 24 hours and good submissions continue to come in. Bug bounties bring people in with different perspectives, and are paid only for success. Bug bounty is a better use of a fixed amount of time and money versus just code review or static code analysis. The Bounty program started July 2011 and paid out $1.5 million to date. 14% of the submissions have been high priority problems that needed to be fixed immediately. The best bugs come from a small % of submitters (as with everything else)—the top paid submitters are paid 6 figures a year. Spammers like to backstab competitors. The youngest sumitter was 13. Some submitters have been hired. Bug bounties also allows to see bugs that were missed by tools or reviews, allowing improvement in the process. Bug bounties might not work for traditional software companies where the product has release cycle or is not on Internet. Active Fingerprinting of Encrypted VPNs Anna Shubina Anna Shubina, Dartmouth Institute for Security, Technology, and Society (I missed the start of her talk because another track went overtime. But I have the DVD of the talk, so I'll expand later) IPsec leaves fingerprints. Using netcat, one can easily visually distinguish various crypto chaining modes just from packet timing on a chart (example, DES-CBC versus AES-CBC) One can tell a lot about VPNs just from ping roundtrips (such as what router is used) Delayed packets are not informative about a network, especially if far away from the network More needed to explore about how TCP works in real life with respect to timing Making Attacks Go Backwards Fuzzynop FuzzyNop, Mandiant This talk is not about threat attribution (finding who), product solutions, politics, or sales pitches. But who are making these malware threats? It's not a single person or group—they have diverse skill levels. There's a lot of fat-fingered fumblers out there. Always look for low-hanging fruit first: "hiding" malware in the temp, recycle, or root directories creation of unnamed scheduled tasks obvious names of files and syscalls ("ClearEventLog") uncleared event logs. Clearing event log in itself, and time of clearing, is a red flag and good first clue to look for on a suspect system Reverse engineering is hard. Disassembler use takes practice and skill. A popular tool is IDA Pro, but it takes multiple interactive iterations to get a clean disassembly. Key loggers are used a lot in targeted attacks. They are typically custom code or built in a backdoor. A big tip-off is that non-printable characters need to be printed out (such as "[Ctrl]" "[RightShift]") or time stamp printf strings. Look for these in files. Presence is not proof they are used. Absence is not proof they are not used. Java exploits. Can parse jar file with idxparser.py and decomile Java file. Java typially used to target tech companies. Backdoors are the main persistence mechanism (provided externally) for malware. Also malware typically needs command and control. Application of Artificial Intelligence in Ad-Hoc Static Code Analysis John Ashaman John Ashaman, Security Innovation Initially John tried to analyze open source files with open source static analysis tools, but these showed thousands of false positives. Also tried using grep, but tis fails to find anything even mildly complex. So next John decided to write his own tool. His approach was to first generate a call graph then analyze the graph. However, the problem is that making a call graph is really hard. For example, one problem is "evil" coding techniques, such as passing function pointer. First the tool generated an Abstract Syntax Tree (AST) with the nodes created from method declarations and edges created from method use. Then the tool generated a control flow graph with the goal to find a path through the AST (a maze) from source to sink. The algorithm is to look at adjacent nodes to see if any are "scary" (a vulnerability), using heuristics for search order. The tool, called "Scat" (Static Code Analysis Tool), currently looks for C# vulnerabilities and some simple PHP. Later, he plans to add more PHP, then JSP and Java. For more information see his posts in Security Innovation blog and NRefactory on GitHub. Mask Your Checksums—The Gorry Details Eric (XlogicX) Davisson Eric (XlogicX) Davisson Sometimes in emailing or posting TCP/IP packets to analyze problems, you may want to mask the IP address. But to do this correctly, you need to mask the checksum too, or you'll leak information about the IP. Problem reports found in stackoverflow.com, sans.org, and pastebin.org are usually not masked, but a few companies do care. If only the IP is masked, the IP may be guessed from checksum (that is, it leaks data). Other parts of packet may leak more data about the IP. TCP and IP checksums both refer to the same data, so can get more bits of information out of using both checksums than just using one checksum. Also, one can usually determine the OS from the TTL field and ports in a packet header. If we get hundreds of possible results (16x each masked nibble that is unknown), one can do other things to narrow the results, such as look at packet contents for domain or geo information. With hundreds of results, can import as CSV format into a spreadsheet. Can corelate with geo data and see where each possibility is located. Eric then demoed a real email report with a masked IP packet attached. Was able to find the exact IP address, given the geo and university of the sender. Point is if you're going to mask a packet, do it right. Eric wouldn't usually bother, but do it correctly if at all, to not create a false impression of security. Adventures with weird machines thirty years after "Reflections on Trusting Trust" Sergey Bratus Sergey Bratus, Dartmouth College (and Julian Bangert and Rebecca Shapiro, not present) "Reflections on Trusting Trust" refers to Ken Thompson's classic 1984 paper. "You can't trust code that you did not totally create yourself." There's invisible links in the chain-of-trust, such as "well-installed microcode bugs" or in the compiler, and other planted bugs. Thompson showed how a compiler can introduce and propagate bugs in unmodified source. But suppose if there's no bugs and you trust the author, can you trust the code? Hell No! There's too many factors—it's Babylonian in nature. Why not? Well, Input is not well-defined/recognized (code's assumptions about "checked" input will be violated (bug/vunerabiliy). For example, HTML is recursive, but Regex checking is not recursive. Input well-formed but so complex there's no telling what it does For example, ELF file parsing is complex and has multiple ways of parsing. Input is seen differently by different pieces of program or toolchain Any Input is a program input executes on input handlers (drives state changes & transitions) only a well-defined execution model can be trusted (regex/DFA, PDA, CFG) Input handler either is a "recognizer" for the inputs as a well-defined language (see langsec.org) or it's a "virtual machine" for inputs to drive into pwn-age ELF ABI (UNIX/Linux executible file format) case study. Problems can arise from these steps (without planting bugs): compiler linker loader ld.so/rtld relocator DWARF (debugger info) exceptions The problem is you can't really automatically analyze code (it's the "halting problem" and undecidable). Only solution is to freeze code and sign it. But you can't freeze everything! Can't freeze ASLR or loading—must have tables and metadata. Any sufficiently complex input data is the same as VM byte code Example, ELF relocation entries + dynamic symbols == a Turing Complete Machine (TM). @bxsays created a Turing machine in Linux from relocation data (not code) in an ELF file. For more information, see Rebecca "bx" Shapiro's presentation from last year's Toorcon, "Programming Weird Machines with ELF Metadata" @bxsays did same thing with Mach-O bytecode Or a DWARF exception handling data .eh_frame + glibc == Turning Machine X86 MMU (IDT, GDT, TSS): used address translation to create a Turning Machine. Page handler reads and writes (on page fault) memory. Uses a page table, which can be used as Turning Machine byte code. Example on Github using this TM that will fly a glider across the screen Next Sergey talked about "Parser Differentials". That having one input format, but two parsers, will create confusion and opportunity for exploitation. For example, CSRs are parsed during creation by cert requestor and again by another parser at the CA. Another example is ELF—several parsers in OS tool chain, which are all different. Can have two different Program Headers (PHDRs) because ld.so parses multiple PHDRs. The second PHDR can completely transform the executable. This is described in paper in the first issue of International Journal of PoC. Conclusions trusting computers not only about bugs! Bugs are part of a problem, but no by far all of it complex data formats means bugs no "chain of trust" in Babylon! (that is, with parser differentials) we need to squeeze complexity out of data until data stops being "code equivalent" Further information See and langsec.org. USENIX WOOT 2013 (Workshop on Offensive Technologies) for "weird machines" papers and videos.

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• C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

  - by James Michael Hare

  Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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• Automatic Standby Recreation for Data Guard

  - by pablo.boixeda(at)oracle.com

  Hi,Unfortunately sometimes a Standby Instance needs to be recreated. This can happen for many reasons such as lost archive logs, standby data files, failover, among others.This is why we wanted to have one script to recreate standby instances in an easy way.This script recreates the standby considering some prereqs:-Database Version should be at least 11gR1-Dummy instance started on the standby node (Seeking to improve this so it won't be needed)-Broker configuration hasn't been removed-In our case we have two TNSNAMES files, one for the Standby creation (using SID) and the other one for production using service names (including broker service name)-Some environment variables set up by the environment db script (like ORACLE_HOME, PATH...)-The directory tree should not have been modified in the stanby hostWe are currently using it on our 11gR2 Data Guard tests.Any improvements will be welcome! Normal 0 21 false false false ES X-NONE X-NONE MicrosoftInternetExplorer4 /* 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:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; 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-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} #!/bin/ksh ###    NOMBRE / VERSION ###       recrea_dg.sh   v.1.00 ### ###    DESCRIPCION ###       reacreacion de la Standby ### ###    DEVUELVE ###       0 Creacion de STANDBY correcta ###       1 Fallo ### ###    NOTAS ###       Este shell script NO DEBE MODIFICARSE. ###       Todas las variables y constantes necesarias se toman del entorno. ### ###    MODIFICADO POR:    FECHA:        COMENTARIOS: ###    ---------------    ----------    ------------------------------------- ###      Oracle           15/02/2011    Creacion. ### ### ### Cargar entorno ### V_ADMIN_DIR=`dirname $0` . ${V_ADMIN_DIR}/entorno_bd.sh 1>>/dev/null if [ $? -ne 0 ] then   echo "Error Loading the environment."   exit 1 fi V_RET=0 V_DATE=`/bin/date` V_DATE_F=`/bin/date +%Y%m%d_%H%M%S` V_LOGFILE=${V_TRAZAS}/recrea_dg_${V_DATE_F}.log exec 4>&1 tee ${V_FICH_LOG} >&4 |& exec 1>&p 2>&1 ### ### Variables para Recrear el Data Guard ### V_DB_BR=`echo ${V_DB_NAME}|tr '[:lower:]' '[:upper:]'` if [ "${ORACLE_SID}" = "${V_DB_NAME}01" ] then         V_LOCAL_BR=${V_DB_BR}'01'         V_REMOTE_BR=${V_DB_BR}'02' else         V_LOCAL_BR=${V_DB_BR}'02'         V_REMOTE_BR=${V_DB_BR}'01' fi echo " Getting local instance ROLE ${ORACLE_SID} ..." sqlplus -s /nolog 1>>/dev/null 2>&1 <<-! whenever sqlerror exit 1 connect / as sysdba variable salida number declare   v_database_role v\$database.database_role%type; begin   select database_role into v_database_role from v\$database;   :salida := case v_database_role        when 'PRIMARY' then 2        when 'PHYSICAL STANDBY' then 3        else 4      end; end; / exit :salida ! case $? in 1) echo " ERROR: Cannot get instance ROLE ." | tee -a ${V_LOGFILE}   2>&1    V_RET=1 ;; 2) echo " Local Instance with PRIMARY role." | tee -a ${V_LOGFILE}   2>&1    V_DB_ROLE_LCL=PRIMARY ;; 3) echo " Local Instance with PHYSICAL STANDBY role." | tee -a ${V_LOGFILE}   2>&1    V_DB_ROLE_LCL=STANDBY ;; *) echo " ERROR: UNKNOWN ROLE." | tee -a ${V_LOGFILE}   2>&1    V_RET=1 ;; esac if [ "${V_DB_ROLE_LCL}" = "PRIMARY" ] then         echo "####################################################################" | tee -a ${V_LOGFILE}   2>&1         echo "${V_DATE} - Reacreating  STANDBY Instance." | tee -a ${V_LOGFILE}   2>&1         echo "" | tee -a ${V_LOGFILE}   2>&1         echo "DATAFILES, CONTROL FILES, REDO LOGS and ARCHIVE LOGS in standby instance ${V_REMOTE_BR} will be removed" | tee -a ${V_LOGFILE}   2>&1         echo "" | tee -a ${V_LOGFILE}   2>&1         V_PRIMARY=${V_LOCAL_BR}         V_STANDBY=${V_REMOTE_BR} fi if [ "${V_DB_ROLE_LCL}" = "STANDBY" ] then         echo "####################################################################" | tee -a ${V_LOGFILE}   2>&1         echo "${V_DATE} - Reacreating  STANDBY Instance." | tee -a ${V_LOGFILE}   2>&1         echo "" | tee -a ${V_LOGFILE}   2>&1         echo "DATAFILES, CONTROL FILES, REDO LOGS and ARCHIVE LOGS in standby instance ${V_LOCAL_BR} will be removed" | tee -a ${V_LOGFILE}   2>&1         echo "" | tee -a ${V_LOGFILE}   2>&1         V_PRIMARY=${V_REMOTE_BR}         V_STANDBY=${V_LOCAL_BR} fi # Cargamos las variables de los hosts # Cargamos las variables de los hosts PRY_HOST=`sqlplus  /nolog << EOF | grep KEEP | sed 's/KEEP//;s/[   ]//g' connect sys/${V_DB_PWD}@${V_PRIMARY} as sysdba select 'KEEP',host_name from v\\$instance; EOF` SBY_HOST=`sqlplus  /nolog << EOF | grep KEEP | sed 's/KEEP//;s/[   ]//g' connect sys/${V_DB_PWD}@${V_STANDBY} as sysdba select 'KEEP',host_name from v\\$instance; EOF` echo "el HOST primary es: ${PRY_HOST}" | tee -a ${V_LOGFILE}   2>&1 echo "el HOST standby es: ${SBY_HOST}" | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 ## ## Paramos la instancia STANDBY ## V_DATE=`/bin/date` echo "${V_DATE} - Shutting down Standby instance" | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1 ## ## Paramos la instancia STANDBY ## SBY_STATUS=`sqlplus  /nolog << EOF | grep KEEP | sed 's/KEEP//;s/[   ]//g' connect sys/${V_DB_PWD}@${V_STANDBY} as sysdba select 'KEEP',status from v\\$instance; EOF` if [ ${SBY_STATUS} = 'STARTED' ] || [ ${SBY_STATUS} = 'MOUNTED' ] || [ ${SBY_STATUS} = 'OPEN' ] then         echo "${V_DATE} - Standby instance shutdown in progress..." | tee -a ${V_LOGFILE}   2>&1         echo "" | tee -a ${V_LOGFILE}   2>&1         echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1         sqlplus -s /nolog 1>>/dev/null 2>&1 <<-!         whenever sqlerror exit 1         connect sys/${V_DB_PWD}@${V_STANDBY} as sysdba         shutdown abort         ! fi V_DATE=`/bin/date` echo "" echo "${V_DATE} - Standby instance stopped" | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1 ## ## Eliminamos los ficheros de la base de datos ## V_SBY_SID=`echo ${V_STANDBY}|tr '[:upper:]' '[:lower:]'` V_PRY_SID=`echo ${V_PRIMARY}|tr '[:upper:]' '[:lower:]'` ssh ${SBY_HOST} rm /opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/data/*.dbf ssh ${SBY_HOST} rm /opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/arch/*.arc ssh ${SBY_HOST} rm /opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/ctl/*.ctl ssh ${SBY_HOST} rm /opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/redo/*.ctl ssh ${SBY_HOST} rm /opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/redo/*.rdo ## ## Startup nomount stby instance ## V_DATE=`/bin/date` echo "" | tee -a ${V_LOGFILE}   2>&1 echo "${V_DATE} - Starting  DUMMY Standby Instance " | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1 ssh ${SBY_HOST} touch /home/oracle/init_dg.ora ssh ${SBY_HOST} 'echo "DB_NAME='${V_DB_NAME}'">>/home/oracle/init_dg.ora' ssh ${SBY_HOST} touch /home/oracle/start_dummy.sh ssh ${SBY_HOST} 'echo "ORACLE_HOME=/opt/oracle/db/db'${V_DB_NAME}'/soft/db11.2.0.2 ">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "export ORACLE_HOME">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "PATH=\$ORACLE_HOME/bin:\$PATH">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "export PATH">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "ORACLE_SID='${V_SBY_SID}'">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "export ORACLE_SID">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "sqlplus -s /nolog <<-!" >>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "      whenever sqlerror exit 1 ">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "      connect / as sysdba ">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "      startup nomount pfile='\''/home/oracle/init_dg.ora'\''">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'echo "! ">>/home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'chmod 744 /home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'sh /home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'rm /home/oracle/start_dummy.sh' ssh ${SBY_HOST} 'rm /home/oracle/init_dg.ora' ## ## TNSNAMES change, specific for RMAN duplicate ## V_DATE=`/bin/date` echo "" | tee -a ${V_LOGFILE}   2>&1 echo "${V_DATE} - Setting up TNSNAMES in PRIMARY host " | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1 ssh ${PRY_HOST} 'cp /opt/oracle/db/db'${V_DB_NAME}'/soft/db11.2.0.2/network/admin/tnsnames.ora.inst  /opt/oracle/db/db'${V_DB_NAME}'/soft/db11.2.0.2/network/admin/tnsnames.ora' V_DATE=`/bin/date` echo "" | tee -a ${V_LOGFILE}   2>&1 echo "${V_DATE} - Starting STANDBY creation with RMAN.. " | tee -a ${V_LOGFILE}   2>&1 echo "" | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************" | tee -a ${V_LOGFILE}   2>&1 rman<<-! >>${V_LOGFILE} connect target sys/${V_DB_PWD}@${V_PRIMARY} connect auxiliary sys/${V_DB_PWD}@${V_STANDBY} run { allocate channel prmy1 type disk; allocate channel prmy2 type disk; allocate channel prmy3 type disk; allocate channel prmy4 type disk; allocate auxiliary channel stby type disk; duplicate target database for standby from active database dorecover spfile parameter_value_convert '${V_PRY_SID}','${V_SBY_SID}' set control_files='/opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/ctl/control01.ctl','/opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/redo/control02.ctl' set db_file_name_convert='/opt/oracle/db/db${V_DB_NAME}/${V_PRY_SID}/','/opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/' set log_file_name_convert='/opt/oracle/db/db${V_DB_NAME}/${V_PRY_SID}/','/opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/' set 'db_unique_name'='${V_SBY_SID}' set log_archive_config='DG_CONFIG=(${V_PRIMARY},${V_STANDBY})' set fal_client='${V_STANDBY}' set fal_server='${V_PRIMARY}' set log_archive_dest_1='LOCATION=/opt/oracle/db/db${V_DB_NAME}/${V_SBY_SID}/arch DB_UNIQUE_NAME=${V_SBY_SID} MANDATORY VALID_FOR=(ALL_LOGFILES,ALL_ROLES)' set log_archive_dest_2='SERVICE="${V_PRIMARY}"','SYNC AFFIRM DB_UNIQUE_NAME=${V_PRY_SID} DELAY=0 MAX_FAILURE=0 REOPEN=300 REGISTER VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE)' nofilenamecheck ; } ! V_DATE=`/bin/date` if [ $? -ne 0 ] then         echo ""         echo "${V_DATE} - Error creating STANDBY instance"         echo ""         echo "********************************************************************************" else         echo ""         echo "${V_DATE} - STANDBY instance created SUCCESSFULLY "         echo ""         echo "********************************************************************************" fi sqlplus -s /nolog 1>>/dev/null 2>&1 <<-!         whenever sqlerror exit 1         connect sys/${V_DB_PWD}@${V_STANDBY} as sysdba         alter system set local_listener='(ADDRESS=(PROTOCOL=TCP)(HOST=${SBY_HOST})(PORT=1544))' scope=both;         alter system set service_names='${V_DB_NAME}.eu.roca.net,${V_SBY_SID}.eu.roca.net,${V_SBY_SID}_DGMGRL.eu.roca.net' scope=both;         alter database recover managed standby database using current logfile disconnect from session;         alter system set dg_broker_start=true scope=both; ! ## ## TNSNAMES change, back to Production Mode ## V_DATE=`/bin/date` echo " " | tee -a ${V_LOGFILE}   2>&1 echo "${V_DATE} - Restoring TNSNAMES in PRIMARY "  | tee -a ${V_LOGFILE}   2>&1 echo ""  | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************"  | tee -a ${V_LOGFILE}   2>&1 ssh ${PRY_HOST} 'cp /opt/oracle/db/db'${V_DB_NAME}'/soft/db11.2.0.2/network/admin/tnsnames.ora.prod  /opt/oracle/db/db'${V_DB_NAME}'/soft/db11.2.0.2/network/admin/tnsnames.ora' echo ""  | tee -a ${V_LOGFILE}   2>&1 echo "${V_DATE} -  Waiting for media recovery before check the DATA GUARD Broker"  | tee -a ${V_LOGFILE}   2>&1 echo ""  | tee -a ${V_LOGFILE}   2>&1 echo "********************************************************************************"  | tee -a ${V_LOGFILE}   2>&1 sleep 200 dgmgrl <<-! | grep SUCCESS 1>/dev/null 2>&1     connect ${V_DB_USR}/${V_DB_PWD}@${V_STANDBY}     show configuration verbose; ! if [ $? -ne 0 ] ; then         echo "       ERROR: El status del Broker no es SUCCESS" | tee -a ${V_LOGFILE}   2>&1 ;         V_RET=1 else          echo "      DATA GUARD OK " | tee -a ${V_LOGFILE}   2>&1 ; Normal 0 21 false false false ES X-NONE X-NONE MicrosoftInternetExplorer4 /* 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:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; 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-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}         V_RET=0 fi Hope it helps.

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• C#/.NET Little Wonders: The ConcurrentDictionary

  - by James Michael Hare

  Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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• CodePlex Daily Summary for Saturday, October 29, 2011

  CodePlex Daily Summary for Saturday, October 29, 2011Popular Releasespatterns & practices: Enterprise Library Contrib: Enterprise Library Contrib - 5.0 (Oct 2011): This release of Enterprise Library Contrib is based on the Microsoft patterns & practices Enterprise Library 5.0 core and contains the following: Common extensionsTypeConfigurationElement<T> - A Polymorphic Configuration Element without having to be part of a PolymorphicConfigurationElementCollection. AnonymousConfigurationElement - A Configuration element that can be uniquely identified without having to define its name explicitly. Data Access Application Block extensionsMySql Provider - ...Network Monitor Open Source Parsers: Network Monitor Parsers 3.4.2748: The Network Monitor Parsers packages contain parsers for more than 400 network protocols, including RFC based public protocols and protocols for Microsoft products defined in the Microsoft Open Specifications for Windows and SQL Server. NetworkMonitor_Parsers.msi is the base parser package which defines parsers for commonly used public protocols and protocols for Microsoft Windows. In this release, NetowrkMonitor_Parsers.msi continues to improve quality and fix bugs. It has included the fo...Duckworth Lewis Professional Edition Calculator: DLcalc 3.0: DLcalc 3.0 can perform Duckworth/Lewis Professional Edition calculations 100% accurately. It also produces over-by-over and ball-by-ball PAR score tables.Folder Bookmarks: Folder Bookmarks 2.2.0.1: In this version: Custom Icons - now you can change the icons of the bookmarks. By default, whenever an image is added, the icon is automatically changed to a thumbnail of the picture. This can be turned off in the settings (Options... > Settings) Ability to remove items from the 'Recent' category Bugfixes - 'Choose' button in 'Edit Bookmark' now works Another bug fix: another problem in the 'Edit Bookmark' windowMedia Companion: MC 3.420b Weekly: Ensure .NET 4.0 Full Framework is installed. (Available from http://www.microsoft.com/download/en/details.aspx?id=17718) Ensure the NFO ID fix is applied when transitioning from versions prior to 3.416b. (Details here) Movies Fixed: Fanart and poster scraping issues TV Shows (Re)Added: Rebuild single show Fixed: Issue when shows are moved from original location Ability to handle " for actor nicknames Crash when episode name contains "<" (does not scrape yet) Clears fanart when switch...patterns & practices - Unity: Unity 3.0 for .NET4.5 Preview: The Unity 3.0.1026.0 Preview enables Unity to work on .NET 4.5 with both the WinRT and desktop profiles. The major changes include: Unity projects updated to target .NET 4.5. Dynamic build plans modified to use compiled lambda expressions instead of Reflection.Emit Converting reflection to use the new TypeInfo for reflection. Projects updated to work with the Microsoft Visual Studio 2011 Preview Notes/Known Issues: The Microsoft.Practices.Unity.UnityServiceLocator class cannot be use...Managed Extensibility Framework: MEF 2 Preview 4: Detailed information on this release is available on the BCL team blog.Image Converter: Image Converter 0.3: New Features: - English and German support Technical Improvements: - Microsoft All Rules using Code Analysis Planned Features for future release: 1. Unit testing 2. Command line interface 3. Automatic UpdatesAcDown????? - Anime&Comic Downloader: AcDown????? v3.6: ?? ● AcDown??????????、??????，??????????????????????，???????Acfun、Bilibili、???、???、???、Tucao.cc、SF???、?????80????，???????????、?????????。 ● AcDown???????????????????????????，???，???????????????????。 ● AcDown???????C#??，????.NET Framework 2.0??。?????"Acfun?????"。 ????32??64? Windows XP/Vista/7 ????????????? ??：????????Windows XP???,?????????.NET Framework 2.0???(x86)?.NET Framework 2.0???(x64)，?????"?????????"??? ??????????????，??????????： ??"AcDown?????"????????? ?? v3.6?? ??“????”...DotNetNuke® Events: 05.02.01: This release fixes any know bugs from any previous version. Events 05.02.01 will work for any DNN version 5.5.0 and up. Full details on the changes can be found at http://dnnevents.codeplex.com/workitem/list/basic Please review and rate this release... (stars are welcome)BUG FIXESAdded validation around category cookie RSS feed was missing an explicit close of the file when writing. Fixed. Added extra security into detail view .ICS Files did not include correct line folding. Fixed Cha...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.33: Add JSParser.ParseExpression method to parse JavaScript expressions rather than source-elements. Add -strict switch (CodeSettings.StrictMode) to force input code to ECMA5 Strict-mode (extra error-checking, "use strict" at top). Fixed bug when MinifyCode setting was set to false but RemoveUnneededCode was left it's default value of true.Path Copy Copy: 8.0: New version that mostly adds lots of requested features: 11340 11339 11338 11337 This version also features a more elaborate Settings UI that has several tabs. I tried to add some notes to better explain the use and purpose of the various options. The Path Copy Copy documentation is also on the way, both to explain how to develop custom plugins and to explain how to pre-configure options if you're a network admin. Stay tuned.MVC Controls Toolkit: Mvc Controls Toolkit 1.5.0: Added: The new Client Blocks feaure of Views A new "move" js method for the TreeViews The NewHtmlCreated js event to the DataGrid Improved the ChoiceList structure that now allows also the selection list of a dropdown to be chosen with a lambda expression Improved the AcceptViewHintAttribute controller filter. Now a client can specify not only the name of a View or Partial View it prefers, but also to receive just the rough data in Json format. Fixed: Issue with partial thrust Cl...Free SharePoint Master Pages: Buried Alive (Halloween) Theme: Release Notes *Created for Halloween, you will find theme file, custom css file and images. *Created by Al Roome @AlstarRoome Features: Custom styling for web part Custom background *Screenshot https://s3.amazonaws.com/kkhipple/post/sharepoint-showcase-halloween.pngDevForce Application Framework: DevForce AF 2.0.3 RTW: PrerequisitesWPF 4.0 Silverlight 4.0 DevForce 2010 6.1.3.1 Download ContentsDebug and Release Assemblies API Documentation Source code License.txt Requirements.txt Release HighlightsNew: EventAggregator event forwarding New: EntityManagerInterceptor<T> to intercept EntityManger events New: IHarnessAware to allow for ViewModel setup when executed inside of the Development Harness New: Improved design time stability New: Support for add-in development New: CoroutineFns.To...NicAudio: NicAudio 2.0.5: Minor change to accept special DTS stereo modes (LtRt, AB,...)NDepend TFS 2010 integration: version 0.5.0 beta 1: Only the activity and the VS plugin are avalaible right now. 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• Using the ASP.NET Cache to cache data in a Model or Business Object layer, without a dependency on System.Web in the layer - Part One.

  - by Rhames

  ASP.NET applications can make use of the System.Web.Caching.Cache object to cache data and prevent repeated expensive calls to a database or other store. However, ideally an application should make use of caching at the point where data is retrieved from the database, which typically is inside a Business Objects or Model layer. One of the key features of using a UI pattern such as Model-View-Presenter (MVP) or Model-View-Controller (MVC) is that the Model and Presenter (or Controller) layers are developed without any knowledge of the UI layer. Introducing a dependency on System.Web into the Model layer would break this independence of the Model from the View. This article gives a solution to this problem, using dependency injection to inject the caching implementation into the Model layer at runtime. This allows caching to be used within the Model layer, without any knowledge of the actual caching mechanism that will be used. Create a sample application to use the caching solution Create a test SQL Server database This solution uses a SQL Server database with the same Sales data used in my previous post on calculating running totals. The advantage of using this data is that it gives nice slow queries that will exaggerate the effect of using caching! To create the data, first create a new SQL database called CacheSample. Next run the following script to create the Sale table and populate it: USE CacheSample GO   CREATE TABLE Sale(DayCount smallint, Sales money) CREATE CLUSTERED INDEX ndx_DayCount ON Sale(DayCount) go INSERT Sale VALUES (1,120) INSERT Sale VALUES (2,60) INSERT Sale VALUES (3,125) INSERT Sale VALUES (4,40)   DECLARE @DayCount smallint, @Sales money SET @DayCount = 5 SET @Sales = 10   WHILE @DayCount < 5000  BEGIN  INSERT Sale VALUES (@DayCount,@Sales)  SET @DayCount = @DayCount + 1  SET @Sales = @Sales + 15  END Next create a stored procedure to calculate the running total, and return a specified number of rows from the Sale table, using the following script: USE [CacheSample] GO   SET ANSI_NULLS ON GO   SET QUOTED_IDENTIFIER ON GO   -- ============================================= -- Author:        Robin -- Create date: -- Description:   -- ============================================= CREATE PROCEDURE [dbo].[spGetRunningTotals]       -- Add the parameters for the stored procedure here       @HighestDayCount smallint = null AS BEGIN       -- SET NOCOUNT ON added to prevent extra result sets from       -- interfering with SELECT statements.       SET NOCOUNT ON;         IF @HighestDayCount IS NULL             SELECT @HighestDayCount = MAX(DayCount) FROM dbo.Sale                   DECLARE @SaleTbl TABLE (DayCount smallint, Sales money, RunningTotal money)         DECLARE @DayCount smallint,                   @Sales money,                   @RunningTotal money         SET @RunningTotal = 0       SET @DayCount = 0         DECLARE rt_cursor CURSOR       FOR       SELECT DayCount, Sales       FROM Sale       ORDER BY DayCount         OPEN rt_cursor         FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales         WHILE @@FETCH_STATUS = 0 AND @DayCount <= @HighestDayCount        BEGIN        SET @RunningTotal = @RunningTotal + @Sales        INSERT @SaleTbl VALUES (@DayCount,@Sales,@RunningTotal)        FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales        END         CLOSE rt_cursor       DEALLOCATE rt_cursor         SELECT DayCount, Sales, RunningTotal       FROM @SaleTbl   END   GO   Create the Sample ASP.NET application In Visual Studio create a new solution and add a class library project called CacheSample.BusinessObjects and an ASP.NET web application called CacheSample.UI. The CacheSample.BusinessObjects project will contain a single class to represent a Sale data item, with all the code to retrieve the sales from the database included in it for simplicity (normally I would at least have a separate Repository or other object that is responsible for retrieving data, and probably a data access layer as well, but for this sample I want to keep it simple). The C# code for the Sale class is shown below: using System; using System.Collections.Generic; using System.Data; using System.Data.SqlClient;   namespace CacheSample.BusinessObjects {     public class Sale     {         public Int16 DayCount { get; set; }         public decimal Sales { get; set; }         public decimal RunningTotal { get; set; }           public static IEnumerable<Sale> GetSales(int? highestDayCount)         {             List<Sale> sales = new List<Sale>();               SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt);             if (highestDayCount.HasValue)                 highestDayCountParameter.Value = highestDayCount;             else                 highestDayCountParameter.Value = DBNull.Value;               string connectionStr = System.Configuration.ConfigurationManager .ConnectionStrings["CacheSample"].ConnectionString;               using(SqlConnection sqlConn = new SqlConnection(connectionStr))             using (SqlCommand sqlCmd = sqlConn.CreateCommand())             {                 sqlCmd.CommandText = "spGetRunningTotals";                 sqlCmd.CommandType = CommandType.StoredProcedure;                 sqlCmd.Parameters.Add(highestDayCountParameter);                   sqlConn.Open();                   using (SqlDataReader dr = sqlCmd.ExecuteReader())                 {                     while (dr.Read())                     {                         Sale newSale = new Sale();                         newSale.DayCount = dr.GetInt16(0);                         newSale.Sales = dr.GetDecimal(1);                         newSale.RunningTotal = dr.GetDecimal(2);                           sales.Add(newSale);                     }                 }             }               return sales;         }     } }   The static GetSale() method makes a call to the spGetRunningTotals stored procedure and then reads each row from the returned SqlDataReader into an instance of the Sale class, it then returns a List of the Sale objects, as IEnnumerable<Sale>. A reference to System.Configuration needs to be added to the CacheSample.BusinessObjects project so that the connection string can be read from the web.config file. In the CacheSample.UI ASP.NET project, create a single web page called ShowSales.aspx, and make this the default start up page. This page will contain a single button to call the GetSales() method and a label to display the results. The html mark up and the C# code behind are shown below: ShowSales.aspx <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowSales.aspx.cs" Inherits="CacheSample.UI.ShowSales" %>   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">   <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server">     <title>Cache Sample - Show All Sales</title> </head> <body>     <form id="form1" runat="server">     <div>         <asp:Button ID="btnTest1" runat="server" onclick="btnTest1_Click"             Text="Get All Sales" />         &nbsp;&nbsp;&nbsp;         <asp:Label ID="lblResults" runat="server"></asp:Label>         </div>     </form> </body> </html>   ShowSales.aspx.cs using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls;   using CacheSample.BusinessObjects;   namespace CacheSample.UI {     public partial class ShowSales : System.Web.UI.Page     {         protected void Page_Load(object sender, EventArgs e)         {         }           protected void btnTest1_Click(object sender, EventArgs e)         {             System.Diagnostics.Stopwatch stopWatch = new System.Diagnostics.Stopwatch();             stopWatch.Start();               var sales = Sale.GetSales(null);               var lastSales = sales.Last();               stopWatch.Stop();               lblResults.Text = string.Format( "Count of Sales: {0}, Last DayCount: {1}, Total Sales: {2}. Query took {3} ms", sales.Count(), lastSales.DayCount, lastSales.RunningTotal, stopWatch.ElapsedMilliseconds);         }       } }   Finally we need to add a connection string to the CacheSample SQL Server database, called CacheSample, to the web.config file: <?xmlversion="1.0"?>   <configuration>    <connectionStrings>     <addname="CacheSample"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample"          providerName="System.Data.SqlClient" />  </connectionStrings>    <system.web>     <compilationdebug="true"targetFramework="4.0" />  </system.web>   </configuration>   Run the application and click the button a few times to see how long each call to the database takes. On my system, each query takes about 450ms. Next I shall look at a solution to use the ASP.NET caching to cache the data returned by the query, so that subsequent requests to the GetSales() method are much faster. Adding Data Caching Support I am going to create my caching support in a separate project called CacheSample.Caching, so the next step is to add a class library to the solution. We shall be using the application configuration to define the implementation of our caching system, so we need a reference to System.Configuration adding to the project. ICacheProvider<T> Interface The first step in adding caching to our application is to define an interface, called ICacheProvider, in the CacheSample.Caching project, with methods to retrieve any data from the cache or to retrieve the data from the data source if it is not present in the cache. Dependency Injection will then be used to inject an implementation of this interface at runtime, allowing the users of the interface (i.e. the CacheSample.BusinessObjects project) to be completely unaware of how the caching is actually implemented. As data of any type maybe retrieved from the data source, it makes sense to use generics in the interface, with a generic type parameter defining the data type associated with a particular instance of the cache interface implementation. The C# code for the ICacheProvider interface is shown below: using System; using System.Collections.Generic;   namespace CacheSample.Caching {     public interface ICacheProvider     {     }       public interface ICacheProvider<T> : ICacheProvider     {         T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry);           IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry);     } }   The empty non-generic interface will be used as a type in a Dictionary generic collection later to store instances of the ICacheProvider<T> implementation for reuse, I prefer to use a base interface when doing this, as I think the alternative of using object makes for less clear code. The ICacheProvider<T> interface defines two overloaded Fetch methods, the difference between these is that one will return a single instance of the type T and the other will return an IEnumerable<T>, providing support for easy caching of collections of data items. Both methods will take a key parameter, which will uniquely identify the cached data, a delegate of type Func<T> or Func<IEnumerable<T>> which will provide the code to retrieve the data from the store if it is not present in the cache, and absolute or relative expiry policies to define when a cached item should expire. Note that at present there is no support for cache dependencies, but I shall be showing a method of adding this in part two of this article. CacheProviderFactory Class We need a mechanism of creating instances of our ICacheProvider<T> interface, using Dependency Injection to get the implementation of the interface. To do this we shall create a CacheProviderFactory static class in the CacheSample.Caching project. This factory will provide a generic static method called GetCacheProvider<T>(), which shall return instances of ICacheProvider<T>. We can then call this factory method with the relevant data type (for example the Sale class in the CacheSample.BusinessObject project) to get a instance of ICacheProvider for that type (e.g. call CacheProviderFactory.GetCacheProvider<Sale>() to get the ICacheProvider<Sale> implementation). The C# code for the CacheProviderFactory is shown below: using System; using System.Collections.Generic;   using CacheSample.Caching.Configuration;   namespace CacheSample.Caching {     public static class CacheProviderFactory     {         private static Dictionary<Type, ICacheProvider> cacheProviders = new Dictionary<Type, ICacheProvider>();         private static object syncRoot = new object();           ///<summary>         /// Factory method to create or retrieve an implementation of the  /// ICacheProvider interface for type <typeparamref name="T"/>.         ///</summary>         ///<typeparam name="T">  /// The type that this cache provider instance will work with  ///</typeparam>         ///<returns>An instance of the implementation of ICacheProvider for type  ///<typeparamref name="T"/>, as specified by the application  /// configuration</returns>         public static ICacheProvider<T> GetCacheProvider<T>()         {             ICacheProvider<T> cacheProvider = null;             // Get the Type reference for the type parameter T             Type typeOfT = typeof(T);               // Lock the access to the cacheProviders dictionary             // so multiple threads can work with it             lock (syncRoot)             {                 // First check if an instance of the ICacheProvider implementation  // already exists in the cacheProviders dictionary for the type T                 if (cacheProviders.ContainsKey(typeOfT))                     cacheProvider = (ICacheProvider<T>)cacheProviders[typeOfT];                 else                 {                     // There is not already an instance of the ICacheProvider in       // cacheProviders for the type T                     // so we need to create one                       // Get the Type reference for the application's implementation of       // ICacheProvider from the configuration                     Type cacheProviderType = Type.GetType(CacheProviderConfigurationSection.Current. CacheProviderType);                     if (cacheProviderType != null)                     {                         // Now get a Type reference for the Cache Provider with the                         // type T generic parameter                         Type typeOfCacheProviderTypeForT = cacheProviderType.MakeGenericType(new Type[] { typeOfT });                         if (typeOfCacheProviderTypeForT != null)                         {                             // Create the instance of the Cache Provider and add it to // the cacheProviders dictionary for future use                             cacheProvider = (ICacheProvider<T>)Activator. CreateInstance(typeOfCacheProviderTypeForT);                             cacheProviders.Add(typeOfT, cacheProvider);                         }                     }                 }             }               return cacheProvider;                 }     } }   As this code uses Activator.CreateInstance() to create instances of the ICacheProvider<T> implementation, which is a slow process, the factory class maintains a Dictionary of the previously created instances so that a cache provider needs to be created only once for each type. The type of the implementation of ICacheProvider<T> is read from a custom configuration section in the application configuration file, via the CacheProviderConfigurationSection class, which is described below. CacheProviderConfigurationSection Class The implementation of ICacheProvider<T> will be specified in a custom configuration section in the application’s configuration. To handle this create a folder in the CacheSample.Caching project called Configuration, and add a class called CacheProviderConfigurationSection to this folder. This class will extend the System.Configuration.ConfigurationSection class, and will contain a single string property called CacheProviderType. The C# code for this class is shown below: using System; using System.Configuration;   namespace CacheSample.Caching.Configuration {     internal class CacheProviderConfigurationSection : ConfigurationSection     {         public static CacheProviderConfigurationSection Current         {             get             {                 return (CacheProviderConfigurationSection) ConfigurationManager.GetSection("cacheProvider");             }         }           [ConfigurationProperty("type", IsRequired=true)]         public string CacheProviderType         {             get             {                 return (string)this["type"];             }         }     } }   Adding Data Caching to the Sales Class We now have enough code in place to add caching to the GetSales() method in the CacheSample.BusinessObjects.Sale class, even though we do not yet have an implementation of the ICacheProvider<T> interface. We need to add a reference to the CacheSample.Caching project to CacheSample.BusinessObjects so that we can use the ICacheProvider<T> interface within the GetSales() method. Once the reference is added, we can first create a unique string key based on the method name and the parameter value, so that the same cache key is used for repeated calls to the method with the same parameter values. Then we get an instance of the cache provider for the Sales type, using the CacheProviderFactory, and pass the existing code to retrieve the data from the database as the retrievalMethod delegate in a call to the Cache Provider Fetch() method. The C# code for the modified GetSales() method is shown below: public static IEnumerable<Sale> GetSales(int? highestDayCount) {     string cacheKey = string.Format("CacheSample.BusinessObjects.GetSalesWithCache({0})", highestDayCount);       return CacheSample.Caching.CacheProviderFactory. GetCacheProvider<Sale>().Fetch(cacheKey,         delegate()         {             List<Sale> sales = new List<Sale>();               SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt);             if (highestDayCount.HasValue)                 highestDayCountParameter.Value = highestDayCount;             else                 highestDayCountParameter.Value = DBNull.Value;               string connectionStr = System.Configuration.ConfigurationManager. ConnectionStrings["CacheSample"].ConnectionString;               using (SqlConnection sqlConn = new SqlConnection(connectionStr))             using (SqlCommand sqlCmd = sqlConn.CreateCommand())             {                 sqlCmd.CommandText = "spGetRunningTotals";                 sqlCmd.CommandType = CommandType.StoredProcedure;                 sqlCmd.Parameters.Add(highestDayCountParameter);                   sqlConn.Open();                   using (SqlDataReader dr = sqlCmd.ExecuteReader())                 {                     while (dr.Read())                     {                         Sale newSale = new Sale();                         newSale.DayCount = dr.GetInt16(0);                         newSale.Sales = dr.GetDecimal(1);                         newSale.RunningTotal = dr.GetDecimal(2);                           sales.Add(newSale);                     }                 }             }               return sales;         },         null,         new TimeSpan(0, 10, 0)); }     This example passes the code to retrieve the Sales data from the database to the Cache Provider as an anonymous method, however it could also be written as a lambda. The main advantage of using an anonymous function (method or lambda) is that the code inside the anonymous function can access the parameters passed to the GetSales() method. Finally the absolute expiry is set to null, and the relative expiry set to 10 minutes, to indicate that the cache entry should be removed 10 minutes after the last request for the data. As the ICacheProvider<T> has a Fetch() method that returns IEnumerable<T>, we can simply return the results of the Fetch() method to the caller of the GetSales() method. This should be all that is needed for the GetSales() method to now retrieve data from a cache after the first time the data has be retrieved from the database. Implementing a ASP.NET Cache Provider The final step is to actually implement the ICacheProvider<T> interface, and add the implementation details to the web.config file for the dependency injection. The cache provider implementation needs to have access to System.Web. Therefore it could be placed in the CacheSample.UI project, or in its own project that has a reference to System.Web. Implementing the Cache Provider in a separate project is my favoured approach. Create a new project inside the solution called CacheSample.CacheProvider, and add references to System.Web and CacheSample.Caching to this project. Add a class to the project called AspNetCacheProvider. Make the class a generic class by adding the generic parameter <T> and indicate that the class implements ICacheProvider<T>. The C# code for the AspNetCacheProvider class is shown below: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Caching;   using CacheSample.Caching;   namespace CacheSample.CacheProvider {     public class AspNetCacheProvider<T> : ICacheProvider<T>     {         #region ICacheProvider<T> Members           public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry);         }           public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry);         }           #endregion           #region Helper Methods           private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             U value;             if (!TryGetValue<U>(key, out value))             {                 value = retrieveData();                 if (!absoluteExpiry.HasValue)                     absoluteExpiry = Cache.NoAbsoluteExpiration;                   if (!relativeExpiry.HasValue)                     relativeExpiry = Cache.NoSlidingExpiration;                   HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value);             }             return value;         }           private bool TryGetValue<U>(string key, out U value)         {             object cachedValue = HttpContext.Current.Cache.Get(key);             if (cachedValue == null)             {                 value = default(U);                 return false;             }             else             {                 try                 {                     value = (U)cachedValue;                     return true;                 }                 catch                 {                     value = default(U);                     return false;                 }             }         }           #endregion       } }   The two interface Fetch() methods call a private method called FetchAndCache(). This method first checks for a element in the HttpContext.Current.Cache with the specified cache key, and if so tries to cast this to the specified type (either T or IEnumerable<T>). If the cached element is found, the FetchAndCache() method simply returns it. If it is not found in the cache, the method calls the retrievalMethod delegate to get the data from the data source, and then adds this to the HttpContext.Current.Cache. The final step is to add the AspNetCacheProvider class to the relevant custom configuration section in the CacheSample.UI.Web.Config file. To do this there needs to be a <configSections> element added as the first element in <configuration>. This will match a custom section called <cacheProvider> with the CacheProviderConfigurationSection. Then we add a <cacheProvider> element, with a type property set to the fully qualified assembly name of the AspNetCacheProvider class, as shown below: <?xmlversion="1.0"?>   <configuration>  <configSections>     <sectionname="cacheProvider" type="CacheSample.Base.Configuration.CacheProviderConfigurationSection, CacheSample.Base" />  </configSections>    <connectionStrings>     <addname="CacheSample"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample"          providerName="System.Data.SqlClient" />  </connectionStrings>    <cacheProvidertype="CacheSample.CacheProvider.AspNetCacheProvider`1, CacheSample.CacheProvider, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">  </cacheProvider>    <system.web>     <compilationdebug="true"targetFramework="4.0" />  </system.web>   </configuration>   One point to note is that the fully qualified assembly name of the AspNetCacheProvider class includes the notation `1 after the class name, which indicates that it is a generic class with a single generic type parameter. The CacheSample.UI project needs to have references added to CacheSample.Caching and CacheSample.CacheProvider so that the actual application is aware of the relevant cache provider implementation. Conclusion After implementing this solution, you should have a working cache provider mechanism, that will allow the middle and data access layers to implement caching support when retrieving data, without any knowledge of the actually caching implementation. If the UI is not ASP.NET based, if for example it is Winforms or WPF, the implementation of ICacheProvider<T> would be written around whatever technology is available. It could even be a standalone caching system that takes full responsibility for adding and removing items from a global store. The next part of this article will show how this caching mechanism may be extended to provide support for cache dependencies, such as the System.Web.Caching.SqlCacheDependency. Another possible extension would be to cache the cache provider implementations instead of storing them in a static Dictionary in the CacheProviderFactory. This would prevent a build up of seldom used cache providers in the application memory, as they could be removed from the cache if not used often enough, although in reality there are probably unlikely to be vast numbers of cache provider implementation instances, as most applications do not have a massive number of business object or model types.

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• Snow Leopard doesn't repair permissions, despite showing / saying its fixed them?

  - by Jules

  Sometime ago, I used carbon copy as I was replacing my hard drive in my Mac Mini running Snow Leopard. Afterwards, on my new drive I had some permission problems. I've tried several times running a repair permissions / repair disk from disk util. It shows that there are problems and I think it says its correceted the problems. However the problems remain, what can I do to fix them ? It doesn't seem to cause me any problems, that I can tell EDIT Repairing permissions for “Macintosh HD” Permissions differ on "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/Italian.lproj/UIAgent.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/Italian.lproj/UIAgent.nib". Permissions differ on "System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Classes/jconsole.jar", should be -rw-r--r-- , they are lrwxr-xr-x . Repaired "System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Classes/jconsole.jar". User differs on "System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Home/lib", should be 95, user is 0. Repaired "System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Home/lib". User differs on "System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Libraries", should be 95, user is 0. Repaired "System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Libraries". Permissions differ on "System/Library/Frameworks/JavaVM.framework/Versions/A/Resources/Deploy.bundle/Contents/Home/lib/security/cacerts", should be -rw-r--r-- , they are lrwxr-xr-x . Repaired "System/Library/Frameworks/JavaVM.framework/Versions/A/Resources/Deploy.bundle/Contents/Home/lib/security/cacerts". Permissions differ on "System/Library/Frameworks/JavaVM.framework/Versions/A/Resources/Deploy.bundle/Contents/Resources/Java/deploy.jar", should be -rw-r--r-- , they are lrwxr-xr-x . Repaired "System/Library/Frameworks/JavaVM.framework/Versions/A/Resources/Deploy.bundle/Contents/Resources/Java/deploy.jar". Permissions differ on "System/Library/Frameworks/JavaVM.framework/Versions/A/Resources/Deploy.bundle/Contents/Resources/Java/libdeploy.jnilib", should be -rwxr-xr-x , they are lrwxr-xr-x . Repaired "System/Library/Frameworks/JavaVM.framework/Versions/A/Resources/Deploy.bundle/Contents/Resources/Java/libdeploy.jnilib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreenLeopard386.app/Contents/Resources/Italian.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreenLeopard386.app/Contents/Resources/Italian.lproj/MainMenu.nib". Permissions differ on "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/zh_TW.lproj/RemoteDesktopMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/zh_TW.lproj/RemoteDesktopMenu.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/zh_TW.lproj/UIAgent.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/zh_TW.lproj/UIAgent.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/zh_TW.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/zh_TW.lproj/MainMenu.nib". Permissions differ on "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/zh_CN.lproj/RemoteDesktopMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/zh_CN.lproj/RemoteDesktopMenu.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/zh_CN.lproj/UIAgent.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/zh_CN.lproj/UIAgent.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/zh_CN.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/zh_CN.lproj/MainMenu.nib". Permissions differ on "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/ko.lproj/RemoteDesktopMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/ko.lproj/RemoteDesktopMenu.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/ko.lproj/UIAgent.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/ko.lproj/UIAgent.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/ko.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/ko.lproj/MainMenu.nib". Permissions differ on "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/Dutch.lproj/RemoteDesktopMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/Dutch.lproj/RemoteDesktopMenu.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/Dutch.lproj/UIAgent.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/Dutch.lproj/UIAgent.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/Dutch.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/Dutch.lproj/MainMenu.nib". Permissions differ on "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/Italian.lproj/RemoteDesktopMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/Italian.lproj/RemoteDesktopMenu.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/Italian.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/Italian.lproj/MainMenu.nib". Permissions differ on "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/Spanish.lproj/RemoteDesktopMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/Spanish.lproj/RemoteDesktopMenu.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/Spanish.lproj/UIAgent.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/Spanish.lproj/UIAgent.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/Spanish.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/Spanish.lproj/MainMenu.nib". Permissions differ on "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/French.lproj/RemoteDesktopMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/French.lproj/RemoteDesktopMenu.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/French.lproj/UIAgent.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/French.lproj/UIAgent.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/French.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/French.lproj/MainMenu.nib". Permissions differ on "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/German.lproj/RemoteDesktopMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/German.lproj/RemoteDesktopMenu.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/German.lproj/UIAgent.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/German.lproj/UIAgent.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/German.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/German.lproj/MainMenu.nib". Permissions differ on "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/Japanese.lproj/RemoteDesktopMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/Japanese.lproj/RemoteDesktopMenu.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/Japanese.lproj/UIAgent.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/Japanese.lproj/UIAgent.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/Japanese.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/Japanese.lproj/MainMenu.nib". Permissions differ on "System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Resources/JavaPluginCocoa.bundle/Contents/Resources/Java/deploy.jar", should be -rw-r--r-- , they are lrwxr-xr-x . Repaired "System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Resources/JavaPluginCocoa.bundle/Contents/Resources/Java/deploy.jar". Permissions differ on "System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Resources/JavaPluginCocoa.bundle/Contents/Resources/Java/libdeploy.jnilib", should be -rwxr-xr-x , they are lrwxr-xr-x . Repaired "System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Resources/JavaPluginCocoa.bundle/Contents/Resources/Java/libdeploy.jnilib". Permissions differ on "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/English.lproj/RemoteDesktopMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/Menu Extras/RemoteDesktop.menu/Contents/Resources/English.lproj/RemoteDesktopMenu.nib". Warning: SUID file "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAgent" has been modified and will not be repaired. Permissions differ on "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/English.lproj/UIAgent.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Support/Remote Desktop Message.app/Contents/Resources/English.lproj/UIAgent.nib". Permissions differ on "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/English.lproj/MainMenu.nib", should be drwxr-xr-x , they are -rwxr-xr-x . Repaired "System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Support/LockScreen.app/Contents/Resources/English.lproj/MainMenu.nib". Group differs on "private/var/log/kernel.log", should be 80, group is 0. Permissions differ on "private/var/log/kernel.log", should be -rw-r----- , they are -rw-r--r-- . Repaired "private/var/log/kernel.log". Group differs on "private/var/log/secure.log", should be 80, group is 0. Permissions differ on "private/var/log/secure.log", should be -rw-r----- , they are -rw-r--r-- . Repaired "private/var/log/secure.log". Group differs on "private/var/log/system.log", should be 80, group is 0. Permissions differ on "private/var/log/system.log", should be -rw-r----- , they are -rw-r--r-- . Repaired "private/var/log/system.log". Permissions repair complete

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• org-sort multi: date/time (?d ?t) | priority (?p) | title (?a)

  - by lawlist

  Is anyone aware of an org-sort function / modification that can refile / organize a group of TODO so that it sorts them by three (3) criteria: first sort by due date, second sort by priority, and third sort by by title of the task? EDIT: I believe that org-sort by deadline (?d) has a bug that cannot properly handle undated tasks. I am working on a workaround (i.e., moving the undated todo to a different heading before the deadline (?d) sort occurs), but perhaps the best thing to do would be to try and fix the original sorting function. Development of the workaround can be found in this thread (i.e., moving the undated tasks to a different heading in one fell swoop): How to automate org-refile for multiple todo EDIT: Apparently, the following code (ancient history) that I found on the internet was eventually modified and included as a part of org-sort-entries. Unfortunately, undated todo are not properly sorted when sorting by deadline -- i.e., they are mixed in with the dated todo. ;; multiple sort (defun org-sort-multi (&rest sort-types) "Multiple sorts on a certain level of an outline tree, or plain list items. SORT-TYPES is a list where each entry is either a character or a cons pair (BOOL . CHAR), where BOOL is whether or not to sort case-sensitively, and CHAR is one of the characters defined in `org-sort-entries-or-items'. Entries are applied in back to front order. Example: To sort first by TODO status, then by priority, then by date, then alphabetically (case-sensitive) use the following call: (org-sort-multi '(?d ?p ?t (t . ?a)))" (interactive) (dolist (x (nreverse sort-types)) (when (char-valid-p x) (setq x (cons nil x))) (condition-case nil (org-sort-entries (car x) (cdr x)) (error nil)))) ;; sort current level (defun lawlist-sort (&rest sort-types) "Sort the current org level. SORT-TYPES is a list where each entry is either a character or a cons pair (BOOL . CHAR), where BOOL is whether or not to sort case-sensitively, and CHAR is one of the characters defined in `org-sort-entries-or-items'. Entries are applied in back to front order. Defaults to \"?o ?p\" which is sorted by TODO status, then by priority" (interactive) (when (equal mode-name "Org") (let ((sort-types (or sort-types (if (or (org-entry-get nil "TODO") (org-entry-get nil "PRIORITY")) '(?d ?t ?p) ;; date, time, priority '((nil . ?a)))))) (save-excursion (outline-up-heading 1) (let ((start (point)) end) (while (and (not (bobp)) (not (eobp)) (<= (point) start)) (condition-case nil (outline-forward-same-level 1) (error (outline-up-heading 1)))) (unless (> (point) start) (goto-char (point-max))) (setq end (point)) (goto-char start) (apply 'org-sort-multi sort-types) (goto-char end) (when (eobp) (forward-line -1)) (when (looking-at "^\\s-*$") ;; (delete-line) ) (goto-char start) ;; (dotimes (x ) (org-cycle)) ))))) EDIT: Here is a more modern version of multi-sort, which is likely based upon further development of the above-code: (defun org-sort-all () (interactive) (save-excursion (goto-char (point-min)) (while (re-search-forward "^\* " nil t) (goto-char (match-beginning 0)) (condition-case err (progn (org-sort-entries t ?a) (org-sort-entries t ?p) (org-sort-entries t ?o) (forward-line)) (error nil))) (goto-char (point-min)) (while (re-search-forward "\* PROJECT " nil t) (goto-char (line-beginning-position)) (ignore-errors (org-sort-entries t ?a) (org-sort-entries t ?p) (org-sort-entries t ?o)) (forward-line)))) EDIT: The best option will be to fix sorting of deadlines (?d) so that undated todo are moved to the bottom of the outline, instead of mixed in with the dated todo. Here is an excerpt from the current org.el included within Emacs Trunk (as of July 1, 2013): (defun org-sort (with-case) "Call `org-sort-entries', `org-table-sort-lines' or `org-sort-list'. Optional argument WITH-CASE means sort case-sensitively." (interactive "P") (cond ((org-at-table-p) (org-call-with-arg 'org-table-sort-lines with-case)) ((org-at-item-p) (org-call-with-arg 'org-sort-list with-case)) (t (org-call-with-arg 'org-sort-entries with-case)))) (defun org-sort-remove-invisible (s) (remove-text-properties 0 (length s) org-rm-props s) (while (string-match org-bracket-link-regexp s) (setq s (replace-match (if (match-end 2) (match-string 3 s) (match-string 1 s)) t t s))) s) (defvar org-priority-regexp) ; defined later in the file (defvar org-after-sorting-entries-or-items-hook nil "Hook that is run after a bunch of entries or items have been sorted. When children are sorted, the cursor is in the parent line when this hook gets called. When a region or a plain list is sorted, the cursor will be in the first entry of the sorted region/list.") (defun org-sort-entries (&optional with-case sorting-type getkey-func compare-func property) "Sort entries on a certain level of an outline tree. If there is an active region, the entries in the region are sorted. Else, if the cursor is before the first entry, sort the top-level items. Else, the children of the entry at point are sorted. Sorting can be alphabetically, numerically, by date/time as given by a time stamp, by a property or by priority. The command prompts for the sorting type unless it has been given to the function through the SORTING-TYPE argument, which needs to be a character, \(?n ?N ?a ?A ?t ?T ?s ?S ?d ?D ?p ?P ?o ?O ?r ?R ?f ?F). Here is the precise meaning of each character: n Numerically, by converting the beginning of the entry/item to a number. a Alphabetically, ignoring the TODO keyword and the priority, if any. o By order of TODO keywords. t By date/time, either the first active time stamp in the entry, or, if none exist, by the first inactive one. s By the scheduled date/time. d By deadline date/time. c By creation time, which is assumed to be the first inactive time stamp at the beginning of a line. p By priority according to the cookie. r By the value of a property. Capital letters will reverse the sort order. If the SORTING-TYPE is ?f or ?F, then GETKEY-FUNC specifies a function to be called with point at the beginning of the record. It must return either a string or a number that should serve as the sorting key for that record. Comparing entries ignores case by default. However, with an optional argument WITH-CASE, the sorting considers case as well." (interactive "P") (let ((case-func (if with-case 'identity 'downcase)) (cmstr ;; The clock marker is lost when using `sort-subr', let's ;; store the clocking string. (when (equal (marker-buffer org-clock-marker) (current-buffer)) (save-excursion (goto-char org-clock-marker) (looking-back "^.*") (match-string-no-properties 0)))) start beg end stars re re2 txt what tmp) ;; Find beginning and end of region to sort (cond ((org-region-active-p) ;; we will sort the region (setq end (region-end) what "region") (goto-char (region-beginning)) (if (not (org-at-heading-p)) (outline-next-heading)) (setq start (point))) ((or (org-at-heading-p) (condition-case nil (progn (org-back-to-heading) t) (error nil))) ;; we will sort the children of the current headline (org-back-to-heading) (setq start (point) end (progn (org-end-of-subtree t t) (or (bolp) (insert "\n")) (org-back-over-empty-lines) (point)) what "children") (goto-char start) (show-subtree) (outline-next-heading)) (t ;; we will sort the top-level entries in this file (goto-char (point-min)) (or (org-at-heading-p) (outline-next-heading)) (setq start (point)) (goto-char (point-max)) (beginning-of-line 1) (when (looking-at ".*?\\S-") ;; File ends in a non-white line (end-of-line 1) (insert "\n")) (setq end (point-max)) (setq what "top-level") (goto-char start) (show-all))) (setq beg (point)) (if (>= beg end) (error "Nothing to sort")) (looking-at "\\(\\*+\\)") (setq stars (match-string 1) re (concat "^" (regexp-quote stars) " +") re2 (concat "^" (regexp-quote (substring stars 0 -1)) "[ \t\n]") txt (buffer-substring beg end)) (if (not (equal (substring txt -1) "\n")) (setq txt (concat txt "\n"))) (if (and (not (equal stars "*")) (string-match re2 txt)) (error "Region to sort contains a level above the first entry")) (unless sorting-type (message "Sort %s: [a]lpha [n]umeric [p]riority p[r]operty todo[o]rder [f]unc [t]ime [s]cheduled [d]eadline [c]reated A/N/P/R/O/F/T/S/D/C means reversed:" what) (setq sorting-type (read-char-exclusive)) (and (= (downcase sorting-type) ?f) (setq getkey-func (org-icompleting-read "Sort using function: " obarray 'fboundp t nil nil)) (setq getkey-func (intern getkey-func))) (and (= (downcase sorting-type) ?r) (setq property (org-icompleting-read "Property: " (mapcar 'list (org-buffer-property-keys t)) nil t)))) (message "Sorting entries...") (save-restriction (narrow-to-region start end) (let ((dcst (downcase sorting-type)) (case-fold-search nil) (now (current-time))) (sort-subr (/= dcst sorting-type) ;; This function moves to the beginning character of the "record" to ;; be sorted. (lambda nil (if (re-search-forward re nil t) (goto-char (match-beginning 0)) (goto-char (point-max)))) ;; This function moves to the last character of the "record" being ;; sorted. (lambda nil (save-match-data (condition-case nil (outline-forward-same-level 1) (error (goto-char (point-max)))))) ;; This function returns the value that gets sorted against. (lambda nil (cond ((= dcst ?n) (if (looking-at org-complex-heading-regexp) (string-to-number (match-string 4)) nil)) ((= dcst ?a) (if (looking-at org-complex-heading-regexp) (funcall case-func (match-string 4)) nil)) ((= dcst ?t) (let ((end (save-excursion (outline-next-heading) (point)))) (if (or (re-search-forward org-ts-regexp end t) (re-search-forward org-ts-regexp-both end t)) (org-time-string-to-seconds (match-string 0)) (org-float-time now)))) ((= dcst ?c) (let ((end (save-excursion (outline-next-heading) (point)))) (if (re-search-forward (concat "^[ \t]*\\[" org-ts-regexp1 "\\]") end t) (org-time-string-to-seconds (match-string 0)) (org-float-time now)))) ((= dcst ?s) (let ((end (save-excursion (outline-next-heading) (point)))) (if (re-search-forward org-scheduled-time-regexp end t) (org-time-string-to-seconds (match-string 1)) (org-float-time now)))) ((= dcst ?d) (let ((end (save-excursion (outline-next-heading) (point)))) (if (re-search-forward org-deadline-time-regexp end t) (org-time-string-to-seconds (match-string 1)) (org-float-time now)))) ((= dcst ?p) (if (re-search-forward org-priority-regexp (point-at-eol) t) (string-to-char (match-string 2)) org-default-priority)) ((= dcst ?r) (or (org-entry-get nil property) "")) ((= dcst ?o) (if (looking-at org-complex-heading-regexp) (- 9999 (length (member (match-string 2) org-todo-keywords-1))))) ((= dcst ?f) (if getkey-func (progn (setq tmp (funcall getkey-func)) (if (stringp tmp) (setq tmp (funcall case-func tmp))) tmp) (error "Invalid key function `%s'" getkey-func))) (t (error "Invalid sorting type `%c'" sorting-type)))) nil (cond ((= dcst ?a) 'string<) ((= dcst ?f) compare-func) ((member dcst '(?p ?t ?s ?d ?c)) '<))))) (run-hooks 'org-after-sorting-entries-or-items-hook) ;; Reset the clock marker if needed (when cmstr (save-excursion (goto-char start) (search-forward cmstr nil t) (move-marker org-clock-marker (point)))) (message "Sorting entries...done"))) (defun org-do-sort (table what &optional with-case sorting-type) "Sort TABLE of WHAT according to SORTING-TYPE. The user will be prompted for the SORTING-TYPE if the call to this function does not specify it. WHAT is only for the prompt, to indicate what is being sorted. The sorting key will be extracted from the car of the elements of the table. If WITH-CASE is non-nil, the sorting will be case-sensitive." (unless sorting-type (message "Sort %s: [a]lphabetic, [n]umeric, [t]ime. A/N/T means reversed:" what) (setq sorting-type (read-char-exclusive))) (let ((dcst (downcase sorting-type)) extractfun comparefun) ;; Define the appropriate functions (cond ((= dcst ?n) (setq extractfun 'string-to-number comparefun (if (= dcst sorting-type) '< '>))) ((= dcst ?a) (setq extractfun (if with-case (lambda(x) (org-sort-remove-invisible x)) (lambda(x) (downcase (org-sort-remove-invisible x)))) comparefun (if (= dcst sorting-type) 'string< (lambda (a b) (and (not (string< a b)) (not (string= a b))))))) ((= dcst ?t) (setq extractfun (lambda (x) (if (or (string-match org-ts-regexp x) (string-match org-ts-regexp-both x)) (org-float-time (org-time-string-to-time (match-string 0 x))) 0)) comparefun (if (= dcst sorting-type) '< '>))) (t (error "Invalid sorting type `%c'" sorting-type))) (sort (mapcar (lambda (x) (cons (funcall extractfun (car x)) (cdr x))) table) (lambda (a b) (funcall comparefun (car a) (car b))))))

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• Can't get simple Apache VHost up and running

  - by TK Kocheran

  Unfortunately, I can't seem to get a simple Apache VHost online. I used to simply have one VHost which bound to all: <VirtualHost *:80>, but this isn't appropriate for security anymore. I need to have one VHost for localhost requests (ie my dev server) and one for incoming requests via my domain name. Here's my new VHost: NameVirtualHost domain1.com <VirtualHost domain1.com:80> DocumentRoot /var/www ServerName domain1.com </VirtualHost> <VirtualHost domain2.com:80> DocumentRoot /var/www ServerName domain2.com </VirtualHost> After I restart my server, I see the following errors in my log: [Wed Feb 16 11:26:36 2011] [error] [client ####.###.###.###] File does not exist: /htdocs [Wed Feb 16 11:26:36 2011] [error] [client ####.###.###.###] File does not exist: /htdocs What am I doing wrong? EDIT As per the answer give below, I have modified my configuration. Here are my configuration files: /etc/apache2/ports.conf: Listen 80 <IfModule mod_ssl.c> # If you add NameVirtualHost *:443 here, you will also have to change # the VirtualHost statement in /etc/apache2/sites-available/default-ssl # to <VirtualHost *:443> # Server Name Indication for SSL named virtual hosts is currently not # supported by MSIE on Windows XP. Listen 443 </IfModule> <IfModule mod_gnutls.c> Listen 443 </IfModule> Here are my actual defined sites: /etc/apache2/sites-enabled/000-localhost: NameVirtualHost 127.0.0.1:80 <VirtualHost 127.0.0.1:80> ServerAdmin ######### DocumentRoot /var/www <Directory /> Options FollowSymLinks AllowOverride None </Directory> <Directory /var/www/> Options Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> ErrorLog /var/log/apache2/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog /var/log/apache2/access.log combined Alias /doc/ "/usr/share/doc/" <Directory "/usr/share/doc/"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order deny,allow Deny from all Allow from 127.0.0.0/255.0.0.0 ::1/128 </Directory> RewriteEngine On RewriteLog "/var/log/apache2/mod_rewrite.log" RewriteLogLevel 9 <Location /> <Limit GET POST PUT> order allow,deny allow from all deny from 65.34.248.110 deny from 69.122.239.3 deny from 58.218.199.147 deny from 65.34.248.110 </Limit> </Location> </VirtualHost> /etc/apache2/sites-enabled/001-rfkrocktk.dyndns.org: NameVirtualHost rfkrocktk.dyndns.org:80 <VirtualHost rfkrocktk.dyndns.org:80> DocumentRoot /var/www ServerName rfkrocktk.dyndns.org </VirtualHost> And, just for kicks, my main file: /etc/apache2/apache2.conf: # # Based upon the NCSA server configuration files originally by Rob McCool. # # This is the main Apache server configuration file. It contains the # configuration directives that give the server its instructions. # See http://httpd.apache.org/docs/2.2/ for detailed information about # the directives. # # Do NOT simply read the instructions in here without understanding # what they do. They're here only as hints or reminders. If you are unsure # consult the online docs. You have been warned. # # The configuration directives are grouped into three basic sections: # 1. Directives that control the operation of the Apache server process as a # whole (the 'global environment'). # 2. Directives that define the parameters of the 'main' or 'default' server, # which responds to requests that aren't handled by a virtual host. # These directives also provide default values for the settings # of all virtual hosts. # 3. Settings for virtual hosts, which allow Web requests to be sent to # different IP addresses or hostnames and have them handled by the # same Apache server process. # # Configuration and logfile names: If the filenames you specify for many # of the server's control files begin with "/" (or "drive:/" for Win32), the # server will use that explicit path. If the filenames do *not* begin # with "/", the value of ServerRoot is prepended -- so "/var/log/apache2/foo.log" # with ServerRoot set to "" will be interpreted by the # server as "//var/log/apache2/foo.log". # ### Section 1: Global Environment # # The directives in this section affect the overall operation of Apache, # such as the number of concurrent requests it can handle or where it # can find its configuration files. # # # ServerRoot: The top of the directory tree under which the server's # configuration, error, and log files are kept. # # NOTE! If you intend to place this on an NFS (or otherwise network) # mounted filesystem then please read the LockFile documentation (available # at <URL:http://httpd.apache.org/docs-2.1/mod/mpm_common.html#lockfile>); # you will save yourself a lot of trouble. # # Do NOT add a slash at the end of the directory path. # ServerRoot "/etc/apache2" # # The accept serialization lock file MUST BE STORED ON A LOCAL DISK. # #<IfModule !mpm_winnt.c> #<IfModule !mpm_netware.c> LockFile /var/lock/apache2/accept.lock #</IfModule> #</IfModule> # # PidFile: The file in which the server should record its process # identification number when it starts. # This needs to be set in /etc/apache2/envvars # PidFile ${APACHE_PID_FILE} # # Timeout: The number of seconds before receives and sends time out. # Timeout 300 # # KeepAlive: Whether or not to allow persistent connections (more than # one request per connection). Set to "Off" to deactivate. # KeepAlive On # # MaxKeepAliveRequests: The maximum number of requests to allow # during a persistent connection. Set to 0 to allow an unlimited amount. # We recommend you leave this number high, for maximum performance. # MaxKeepAliveRequests 100 # # KeepAliveTimeout: Number of seconds to wait for the next request from the # same client on the same connection. # KeepAliveTimeout 15 ## ## Server-Pool Size Regulation (MPM specific) ## # prefork MPM # StartServers: number of server processes to start # MinSpareServers: minimum number of server processes which are kept spare # MaxSpareServers: maximum number of server processes which are kept spare # MaxClients: maximum number of server processes allowed to start # MaxRequestsPerChild: maximum number of requests a server process serves <IfModule mpm_prefork_module> StartServers 5 MinSpareServers 5 MaxSpareServers 10 MaxClients 150 MaxRequestsPerChild 0 </IfModule> # worker MPM # StartServers: initial number of server processes to start # MaxClients: maximum number of simultaneous client connections # MinSpareThreads: minimum number of worker threads which are kept spare # MaxSpareThreads: maximum number of worker threads which are kept spare # ThreadsPerChild: constant number of worker threads in each server process # MaxRequestsPerChild: maximum number of requests a server process serves <IfModule mpm_worker_module> StartServers 2 MinSpareThreads 25 MaxSpareThreads 75 ThreadLimit 64 ThreadsPerChild 25 MaxClients 150 MaxRequestsPerChild 0 </IfModule> # event MPM # StartServers: initial number of server processes to start # MaxClients: maximum number of simultaneous client connections # MinSpareThreads: minimum number of worker threads which are kept spare # MaxSpareThreads: maximum number of worker threads which are kept spare # ThreadsPerChild: constant number of worker threads in each server process # MaxRequestsPerChild: maximum number of requests a server process serves <IfModule mpm_event_module> StartServers 2 MaxClients 150 MinSpareThreads 25 MaxSpareThreads 75 ThreadLimit 64 ThreadsPerChild 25 MaxRequestsPerChild 0 </IfModule> # These need to be set in /etc/apache2/envvars User ${APACHE_RUN_USER} Group ${APACHE_RUN_GROUP} # # AccessFileName: The name of the file to look for in each directory # for additional configuration directives. See also the AllowOverride # directive. # AccessFileName .htaccess # # The following lines prevent .htaccess and .htpasswd files from being # viewed by Web clients. # <Files ~ "^\.ht"> Order allow,deny Deny from all Satisfy all </Files> # # DefaultType is the default MIME type the server will use for a document # if it cannot otherwise determine one, such as from filename extensions. # If your server contains mostly text or HTML documents, "text/plain" is # a good value. If most of your content is binary, such as applications # or images, you may want to use "application/octet-stream" instead to # keep browsers from trying to display binary files as though they are # text. # DefaultType text/plain # # HostnameLookups: Log the names of clients or just their IP addresses # e.g., www.apache.org (on) or 204.62.129.132 (off). # The default is off because it'd be overall better for the net if people # had to knowingly turn this feature on, since enabling it means that # each client request will result in AT LEAST one lookup request to the # nameserver. # HostnameLookups Off # ErrorLog: The location of the error log file. # If you do not specify an ErrorLog directive within a <VirtualHost> # container, error messages relating to that virtual host will be # logged here. If you *do* define an error logfile for a <VirtualHost> # container, that host's errors will be logged there and not here. # ErrorLog /var/log/apache2/error.log # # LogLevel: Control the number of messages logged to the error_log. # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. # LogLevel warn # Include module configuration: Include /etc/apache2/mods-enabled/*.load Include /etc/apache2/mods-enabled/*.conf # Include all the user configurations: Include /etc/apache2/httpd.conf # Include ports listing Include /etc/apache2/ports.conf # # The following directives define some format nicknames for use with # a CustomLog directive (see below). # If you are behind a reverse proxy, you might want to change %h into %{X-Forwarded-For}i # LogFormat "%v:%p %h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined LogFormat "%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined LogFormat "%h %l %u %t \"%r\" %>s %O" common LogFormat "%{Referer}i -> %U" referer LogFormat "%{User-agent}i" agent # # Define an access log for VirtualHosts that don't define their own logfile CustomLog /var/log/apache2/other_vhosts_access.log vhost_combined # Include of directories ignores editors' and dpkg's backup files, # see README.Debian for details. # Include generic snippets of statements Include /etc/apache2/conf.d/ # Include the virtual host configurations: Include /etc/apache2/sites-enabled/ what else do I need to do to fix it? Should I be telling apache to listen on 127.0.0.1:80, or isn't it already listening there?

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• Command does not execute in crontab while command itself works just fine

  - by fuzzybee

  I have this script from Colin Johnson on Github - https://github.com/colinbjohnson/aws-missing-tools/tree/master/ec2-automate-backup It seems great. I have modified it to send email to myself every time an EBS snapshot is created or deleted. The following works like a charm ec2-automate-backup.sh -v "vol-myvolumeid" -k 3 However, it does not execute at all as part of my crontab (I didn't receive any emails) #some command that got commented out */5 * * * * ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3; * * * * * date /root/logs/crontab.log; */5 * * * * date /root/logs/crontab2.log Please note that the 2nd and 3rd execute just fines as I can see the date and time in log files. What could I have missed here? The full ec2-automate-backup.sh is as follows: #!/bin/bash - # Author: Colin Johnson / [email protected] # Date: 2012-09-24 # Version 0.1 # License Type: GNU GENERAL PUBLIC LICENSE, Version 3 # #confirms that executables required for succesful script execution are available prerequisite_check() { for prerequisite in basename ec2-create-snapshot ec2-create-tags ec2-describe-snapshots ec2-delete-snapshot date do #use of "hash" chosen as it is a shell builtin and will add programs to hash table, possibly speeding execution. Use of type also considered - open to suggestions. hash $prerequisite &> /dev/null if [[ $? == 1 ]] #has exits with exit status of 70, executable was not found then echo "In order to use `basename $0`, the executable \"$prerequisite\" must be installed." 1>&2 | mailx -s "Error happened 0" [email protected] ; exit 70 fi done } #get_EBS_List gets a list of available EBS instances depending upon the selection_method of EBS selection that is provided by user input get_EBS_List() { case $selection_method in volumeid) if [[ -z $volumeid ]] then echo "The selection method \"volumeid\" (which is $app_name's default selection_method of operation or requested by using the -s volumeid parameter) requires a volumeid (-v volumeid) for operation. Correct usage is as follows: \"-v vol-6d6a0527\",\"-s volumeid -v vol-6d6a0527\" or \"-v \"vol-6d6a0527 vol-636a0112\"\" if multiple volumes are to be selected." 1>&2 | mailx -s "Error happened 1" [email protected] ; exit 64 fi ebs_selection_string="$volumeid" ;; tag) if [[ -z $tag ]] then echo "The selected selection_method \"tag\" (-s tag) requires a valid tag (-t key=value) for operation. Correct usage is as follows: \"-s tag -t backup=true\" or \"-s tag -t Name=my_tag.\"" 1>&2 | mailx -s "Error happened 2" [email protected] ; exit 64 fi ebs_selection_string="--filter tag:$tag" ;; *) echo "If you specify a selection_method (-s selection_method) for selecting EBS volumes you must select either \"volumeid\" (-s volumeid) or \"tag\" (-s tag)." 1>&2 | mailx -s "Error happened 3" [email protected] ; exit 64 ;; esac #creates a list of all ebs volumes that match the selection string from above ebs_backup_list_complete=`ec2-describe-volumes --show-empty-fields --region $region $ebs_selection_string 2>&1` #takes the output of the previous command ebs_backup_list_result=`echo $?` if [[ $ebs_backup_list_result -gt 0 ]] then echo -e "An error occured when running ec2-describe-volumes. The error returned is below:\n$ebs_backup_list_complete" 1>&2 | mailx -s "Error happened 4" [email protected] ; exit 70 fi ebs_backup_list=`echo "$ebs_backup_list_complete" | grep ^VOLUME | cut -f 2` #code to right will output list of EBS volumes to be backed up: echo -e "Now outputting ebs_backup_list:\n$ebs_backup_list" } create_EBS_Snapshot_Tags() { #snapshot tags holds all tags that need to be applied to a given snapshot - by aggregating tags we ensure that ec2-create-tags is called only onece snapshot_tags="" #if $name_tag_create is true then append ec2ab_${ebs_selected}_$date_current to the variable $snapshot_tags if $name_tag_create then ec2_snapshot_resource_id=`echo "$ec2_create_snapshot_result" | cut -f 2` snapshot_tags="$snapshot_tags --tag Name=ec2ab_${ebs_selected}_$date_current" fi #if $purge_after_days is true, then append $purge_after_date to the variable $snapshot_tags if [[ -n $purge_after_days ]] then snapshot_tags="$snapshot_tags --tag PurgeAfter=$purge_after_date --tag PurgeAllow=true" fi #if $snapshot_tags is not zero length then set the tag on the snapshot using ec2-create-tags if [[ -n $snapshot_tags ]] then echo "Tagging Snapshot $ec2_snapshot_resource_id with the following Tags:" ec2-create-tags $ec2_snapshot_resource_id --region $region $snapshot_tags #echo "Snapshot tags successfully created" | mailx -s "Snapshot tags successfully created" [email protected] fi } date_command_get() { #finds full path to date binary date_binary_full_path=`which date` #command below is used to determine if date binary is gnu, macosx or other date_binary_file_result=`file -b $date_binary_full_path` case $date_binary_file_result in "Mach-O 64-bit executable x86_64") date_binary="macosx" ;; "ELF 64-bit LSB executable, x86-64, version 1 (SYSV)"*) date_binary="gnu" ;; *) date_binary="unknown" ;; esac #based on the installed date binary the case statement below will determine the method to use to determine "purge_after_days" in the future case $date_binary in gnu) date_command="date -d +${purge_after_days}days -u +%Y-%m-%d" ;; macosx) date_command="date -v+${purge_after_days}d -u +%Y-%m-%d" ;; unknown) date_command="date -d +${purge_after_days}days -u +%Y-%m-%d" ;; *) date_command="date -d +${purge_after_days}days -u +%Y-%m-%d" ;; esac } purge_EBS_Snapshots() { #snapshot_tag_list is a string that contains all snapshots with either the key PurgeAllow or PurgeAfter set snapshot_tag_list=`ec2-describe-tags --show-empty-fields --region $region --filter resource-type=snapshot --filter key=PurgeAllow,PurgeAfter` #snapshot_purge_allowed is a list of all snapshot_ids with PurgeAllow=true snapshot_purge_allowed=`echo "$snapshot_tag_list" | grep .*PurgeAllow'\t'true | cut -f 3` for snapshot_id_evaluated in $snapshot_purge_allowed do #gets the "PurgeAfter" date which is in UTC with YYYY-MM-DD format (or %Y-%m-%d) purge_after_date=`echo "$snapshot_tag_list" | grep .*$snapshot_id_evaluated'\t'PurgeAfter.* | cut -f 5` #if purge_after_date is not set then we have a problem. Need to alter user. if [[ -z $purge_after_date ]] #Alerts user to the fact that a Snapshot was found with PurgeAllow=true but with no PurgeAfter date. then echo "A Snapshot with the Snapshot ID $snapshot_id_evaluated has the tag \"PurgeAllow=true\" but does not have a \"PurgeAfter=YYYY-MM-DD\" date. $app_name is unable to determine if $snapshot_id_evaluated should be purged." 1>&2 | mailx -s "Error happened 5" [email protected] else #convert both the date_current and purge_after_date into epoch time to allow for comparison date_current_epoch=`date -j -f "%Y-%m-%d" "$date_current" "+%s"` purge_after_date_epoch=`date -j -f "%Y-%m-%d" "$purge_after_date" "+%s"` #perform compparison - if $purge_after_date_epoch is a lower number than $date_current_epoch than the PurgeAfter date is earlier than the current date - and the snapshot can be safely removed if [[ $purge_after_date_epoch < $date_current_epoch ]] then echo "The snapshot \"$snapshot_id_evaluated\" with the Purge After date of $purge_after_date will be deleted." ec2-delete-snapshot --region $region $snapshot_id_evaluated echo "Old snapshots successfully deleted for $volumeid" | mailx -s "Old snapshots successfully deleted for $volumeid" [email protected] fi fi done } #calls prerequisitecheck function to ensure that all executables required for script execution are available prerequisite_check app_name=`basename $0` #sets defaults selection_method="volumeid" region="ap-southeast-1" #date_binary allows a user to set the "date" binary that is installed on their system and, therefore, the options that will be given to the date binary to perform date calculations date_binary="" #sets the "Name" tag set for a snapshot to false - using "Name" requires that ec2-create-tags be called in addition to ec2-create-snapshot name_tag_create=false #sets the Purge Snapshot feature to false - this feature will eventually allow the removal of snapshots that have a "PurgeAfter" tag that is earlier than current date purge_snapshots=false #handles options processing while getopts :s:r:v:t:k:pn opt do case $opt in s) selection_method="$OPTARG";; r) region="$OPTARG";; v) volumeid="$OPTARG";; t) tag="$OPTARG";; k) purge_after_days="$OPTARG";; n) name_tag_create=true;; p) purge_snapshots=true;; *) echo "Error with Options Input. Cause of failure is most likely that an unsupported parameter was passed or a parameter was passed without a corresponding option." 1>&2 ; exit 64;; esac done #sets date variable date_current=`date -u +%Y-%m-%d` #sets the PurgeAfter tag to the number of days that a snapshot should be retained if [[ -n $purge_after_days ]] then #if the date_binary is not set, call the date_command_get function if [[ -z $date_binary ]] then date_command_get fi purge_after_date=`$date_command` echo "Snapshots taken by $app_name will be eligible for purging after the following date: $purge_after_date." fi #get_EBS_List gets a list of EBS instances for which a snapshot is desired. The list of EBS instances depends upon the selection_method that is provided by user input get_EBS_List #the loop below is called once for each volume in $ebs_backup_list - the currently selected EBS volume is passed in as "ebs_selected" for ebs_selected in $ebs_backup_list do ec2_snapshot_description="ec2ab_${ebs_selected}_$date_current" ec2_create_snapshot_result=`ec2-create-snapshot --region $region -d $ec2_snapshot_description $ebs_selected 2>&1` if [[ $? != 0 ]] then echo -e "An error occured when running ec2-create-snapshot. The error returned is below:\n$ec2_create_snapshot_result" 1>&2 ; exit 70 else ec2_snapshot_resource_id=`echo "$ec2_create_snapshot_result" | cut -f 2` echo "Snapshots successfully created for volume $volumeid" | mailx -s "Snapshots successfully created for $volumeid" [email protected] fi create_EBS_Snapshot_Tags done #if purge_snapshots is true, then run purge_EBS_Snapshots function if $purge_snapshots then echo "Snapshot Purging is Starting Now." purge_EBS_Snapshots fi cron log Oct 23 10:24:01 ip-10-130-153-227 CROND[28214]: (root) CMD (root (ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3;)) Oct 23 10:24:01 ip-10-130-153-227 CROND[28215]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:25:01 ip-10-130-153-227 CROND[28228]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:25:01 ip-10-130-153-227 CROND[28229]: (root) CMD (date >> /root/logs/crontab2.log) Oct 23 10:26:01 ip-10-130-153-227 CROND[28239]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:27:01 ip-10-130-153-227 CROND[28247]: (root) CMD (root (ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3;)) Oct 23 10:27:01 ip-10-130-153-227 CROND[28248]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:28:01 ip-10-130-153-227 CROND[28263]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:29:01 ip-10-130-153-227 CROND[28275]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:30:01 ip-10-130-153-227 CROND[28292]: (root) CMD (root (ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3;)) Oct 23 10:30:01 ip-10-130-153-227 CROND[28293]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:30:01 ip-10-130-153-227 CROND[28294]: (root) CMD (date >> /root/logs/crontab2.log) Oct 23 10:31:01 ip-10-130-153-227 CROND[28312]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:32:01 ip-10-130-153-227 CROND[28319]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:33:01 ip-10-130-153-227 CROND[28325]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:33:01 ip-10-130-153-227 CROND[28324]: (root) CMD (root (ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3;)) Oct 23 10:34:01 ip-10-130-153-227 CROND[28345]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:35:01 ip-10-130-153-227 CROND[28362]: (root) CMD (date >> /root/logs/crontab.log;) Oct 23 10:35:01 ip-10-130-153-227 CROND[28363]: (root) CMD (date >> /root/logs/crontab2.log) Mails to root From [email protected] Tue Oct 23 06:00:01 2012 Return-Path: <[email protected]> Date: Tue, 23 Oct 2012 06:00:01 GMT From: [email protected] (Cron Daemon) To: [email protected] Subject: Cron <root@ip-10-130-153-227> root ec2-automate-backup.sh -v "vol-fb2fbcdf" -k 3 Content-Type: text/plain; charset=UTF-8 Auto-Submitted: auto-generated X-Cron-Env: <SHELL=/bin/sh> X-Cron-Env: <HOME=/root> X-Cron-Env: <PATH=/usr/bin:/bin> X-Cron-Env: <LOGNAME=root> X-Cron-Env: <USER=root> Status: R /bin/sh: root: command not found

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• puma init.d for centos 6 fails with runuser: user /var/log/puma.log does not exist

  - by Rubytastic

  Trying to get a init.d/puma to work on Centos 6. It throws error runuser: user /var/log/puma.log does not exist I run this from the /srv/books/current folder but it fails. I tried to debug the values but not quite get what is missing and why it throws this error. #! /bin/sh # puma - this script starts and stops the puma daemon # # chkconfig: - 85 15 # description: Puma # processname: puma # config: /etc/puma.conf # pidfile: /srv/books/current/tmp/pids/puma.pid # Author: Darío Javier Cravero &lt;[email protected]> # # Do NOT "set -e" # Original script https://github.com/puma/puma/blob/master/tools/jungle/puma # It was modified here by Stanislaw Pankevich <[email protected]> # to run on CentOS 5.5 boxes. # Script works perfectly on CentOS 5: script uses its native daemon(). # Puma is being stopped/restarted by sending signals, control app is not used. # Source function library. . /etc/rc.d/init.d/functions # Source networking configuration. . /etc/sysconfig/network # Check that networking is up. [ "$NETWORKING" = "no" ] && exit 0 # PATH should only include /usr/* if it runs after the mountnfs.sh script PATH=/usr/local/bin:/usr/local/sbin/:/sbin:/usr/sbin:/bin:/usr/bin DESC="Puma rack web server" NAME=puma DAEMON=$NAME SCRIPTNAME=/etc/init.d/$NAME CONFIG=/etc/puma.conf JUNGLE=`cat $CONFIG` RUNPUMA=/usr/local/bin/run-puma # Skipping the following non-CentOS string # Load the VERBOSE setting and other rcS variables # . /lib/init/vars.sh # CentOS does not have these functions natively log_daemon_msg() { echo "$@"; } log_end_msg() { [ $1 -eq 0 ] && RES=OK; logger ${RES:=FAIL}; } # Define LSB log_* functions. # Depend on lsb-base (>= 3.0-6) to ensure that this file is present. . /lib/lsb/init-functions # # Function that performs a clean up of puma.* files # cleanup() { echo "Cleaning up puma temporary files..." echo $1; PIDFILE=$1/tmp/puma/puma.pid STATEFILE=$1/tmp/puma/puma.state SOCKFILE=$1/tmp/puma/puma.sock rm -f $PIDFILE $STATEFILE $SOCKFILE } # # Function that starts the jungle # do_start() { log_daemon_msg "=> Running the jungle..." for i in $JUNGLE; do dir=`echo $i | cut -d , -f 1` user=`echo $i | cut -d , -f 2` config_file=`echo $i | cut -d , -f 3` if [ "$config_file" = "" ]; then config_file="$dir/puma/config.rb" fi log_file=`echo $i | cut -d , -f 4` if [ "$log_file" = "" ]; then log_file="$dir/puma/puma.log" fi do_start_one $dir $user $config_file $log_file done } do_start_one() { PIDFILE=$1/puma/puma.pid if [ -e $PIDFILE ]; then PID=`cat $PIDFILE` # If the puma isn't running, run it, otherwise restart it. if [ "`ps -A -o pid= | grep -c $PID`" -eq 0 ]; then do_start_one_do $1 $2 $3 $4 else do_restart_one $1 fi else do_start_one_do $1 $2 $3 $4 fi } do_start_one_do() { log_daemon_msg "--> Woke up puma $1" log_daemon_msg "user $2" log_daemon_msg "log to $4" cleanup $1; daemon --user $2 $RUNPUMA $1 $3 $4 } # # Function that stops the jungle # do_stop() { log_daemon_msg "=> Putting all the beasts to bed..." for i in $JUNGLE; do dir=`echo $i | cut -d , -f 1` do_stop_one $dir done } # # Function that stops the daemon/service # do_stop_one() { log_daemon_msg "--> Stopping $1" PIDFILE=$1/tmp/puma/puma.pid STATEFILE=$1/tmp/puma/puma.state echo $PIDFILE if [ -e $PIDFILE ]; then PID=`cat $PIDFILE` echo "Pid:" echo $PID if [ "`ps -A -o pid= | grep -c $PID`" -eq 0 ]; then log_daemon_msg "---> Puma $1 isn't running." else log_daemon_msg "---> About to kill PID `cat $PIDFILE`" # pumactl --state $STATEFILE stop # Many daemons don't delete their pidfiles when they exit. kill -9 $PID fi cleanup $1 else log_daemon_msg "---> No puma here..." fi return 0 } # # Function that restarts the jungle # do_restart() { for i in $JUNGLE; do dir=`echo $i | cut -d , -f 1` do_restart_one $dir done } # # Function that sends a SIGUSR2 to the daemon/service # do_restart_one() { PIDFILE=$1/tmp/puma/puma.pid i=`grep $1 $CONFIG` dir=`echo $i | cut -d , -f 1` if [ -e $PIDFILE ]; then log_daemon_msg "--> About to restart puma $1" # pumactl --state $dir/tmp/puma/state restart kill -s USR2 `cat $PIDFILE` # TODO Check if process exist else log_daemon_msg "--> Your puma was never playing... Let's get it out there first" user=`echo $i | cut -d , -f 2` config_file=`echo $i | cut -d , -f 3` if [ "$config_file" = "" ]; then config_file="$dir/config/puma.rb" fi log_file=`echo $i | cut -d , -f 4` if [ "$log_file" = "" ]; then log_file="$dir/log/puma.log" fi do_start_one $dir $user $config_file $log_file fi return 0 } # # Function that statuss then jungle # do_status() { for i in $JUNGLE; do dir=`echo $i | cut -d , -f 1` do_status_one $dir done } # # Function that sends a SIGUSR2 to the daemon/service # do_status_one() { PIDFILE=$1/tmp/puma/pid i=`grep $1 $CONFIG` dir=`echo $i | cut -d , -f 1` if [ -e $PIDFILE ]; then log_daemon_msg "--> About to status puma $1" pumactl --state $dir/tmp/puma/state stats # kill -s USR2 `cat $PIDFILE` # TODO Check if process exist else log_daemon_msg "--> $1 isn't there :(..." fi return 0 } do_add() { str="" # App's directory if [ -d "$1" ]; then if [ "`grep -c "^$1" $CONFIG`" -eq 0 ]; then str=$1 else echo "The app is already being managed. Remove it if you want to update its config." exit 1 fi else echo "The directory $1 doesn't exist." exit 1 fi # User to run it as if [ "`grep -c "^$2:" /etc/passwd`" -eq 0 ]; then echo "The user $2 doesn't exist." exit 1 else str="$str,$2" fi # Config file if [ "$3" != "" ]; then if [ -e $3 ]; then str="$str,$3" else echo "The config file $3 doesn't exist." exit 1 fi fi # Log file if [ "$4" != "" ]; then str="$str,$4" fi # Add it to the jungle echo $str >> $CONFIG log_daemon_msg "Added a Puma to the jungle: $str. You still have to start it though." } do_remove() { if [ "`grep -c "^$1" $CONFIG`" -eq 0 ]; then echo "There's no app $1 to remove." else # Stop it first. do_stop_one $1 # Remove it from the config. sed -i "\\:^$1:d" $CONFIG log_daemon_msg "Removed a Puma from the jungle: $1." fi } case "$1" in start) [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME" if [ "$#" -eq 1 ]; then do_start else i=`grep $2 $CONFIG` dir=`echo $i | cut -d , -f 1` user=`echo $i | cut -d , -f 2` config_file=`echo $i | cut -d , -f 3` if [ "$config_file" = "" ]; then config_file="$dir/config/puma.rb" fi log_file=`echo $i | cut -d , -f 4` if [ "$log_file" = "" ]; then log_file="$dir/log/puma.log" fi do_start_one $dir $user $config_file $log_file fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; stop) [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME" if [ "$#" -eq 1 ]; then do_stop else i=`grep $2 $CONFIG` dir=`echo $i | cut -d , -f 1` do_stop_one $dir fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; status) # TODO Implement. log_daemon_msg "Status $DESC" "$NAME" if [ "$#" -eq 1 ]; then do_status else i=`grep $2 $CONFIG` dir=`echo $i | cut -d , -f 1` do_status_one $dir fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; restart) log_daemon_msg "Restarting $DESC" "$NAME" if [ "$#" -eq 1 ]; then do_restart else i=`grep $2 $CONFIG` dir=`echo $i | cut -d , -f 1` do_restart_one $dir fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; add) if [ "$#" -lt 3 ]; then echo "Please, specifiy the app's directory and the user that will run it at least." echo " Usage: $SCRIPTNAME add /path/to/app user /path/to/app/config/puma.rb /path/to/app/config/log/puma.log" echo " config and log are optionals." exit 1 else do_add $2 $3 $4 $5 fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; remove) if [ "$#" -lt 2 ]; then echo "Please, specifiy the app's directory to remove." exit 1 else do_remove $2 fi case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; *) echo "Usage:" >&2 echo " Run the jungle: $SCRIPTNAME {start|stop|status|restart}" >&2 echo " Add a Puma: $SCRIPTNAME add /path/to/app user /path/to/app/config/puma.rb /path/to/app/config/log/puma.log" echo " config and log are optionals." echo " Remove a Puma: $SCRIPTNAME remove /path/to/app" echo " On a Puma: $SCRIPTNAME {start|stop|status|restart} PUMA-NAME" >&2 exit 3 ;; esac :

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• Memory leak involving jQuery Ajax requests

  - by Eli Courtwright

  I have a webpage that's leaking memory in both IE8 and Firefox; the memory usage displayed in the Windows Process Explorer just keeps growing over time. The following page requests the "unplanned.json" url, which is a static file that never changes (though I do set my Cache-control HTTP header to no-cache to make sure that the Ajax request always goes through). When it gets the results, it clears out an HTML table, loops over the json array it got back from the server, and dynamically adds a row to an HTML table for each entry in the array. Then it waits 2 seconds and repeats this process. Here's the entire webpage: <html> <head> <title>Test Page</title> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js"></script> </head> <body> <script type="text/javascript"> function kickoff() { $.getJSON("unplanned.json", resetTable); } function resetTable(rows) { $("#content tbody").empty(); for(var i=0; i<rows.length; i++) { $("<tr>" + "<td>" + rows[i].mpe_name + "</td>" + "<td>" + rows[i].bin + "</td>" + "<td>" + rows[i].request_time + "</td>" + "<td>" + rows[i].filtered_delta + "</td>" + "<td>" + rows[i].failed_delta + "</td>" + "</tr>").appendTo("#content tbody"); } setTimeout(kickoff, 2000); } $(kickoff); </script> <table id="content" border="1" style="width:100% ; text-align:center"> <thead><tr> <th>MPE</th> <th>Bin</th> <th>When</th> <th>Filtered</th> <th>Failed</th> </tr></thead> <tbody></tbody> </table> </body> </html> If it helps, here's an example of the json I'm sending back (it's this exact array wuith thousands of entries instead of just one): [ { mpe_name: "DBOSS-995", request_time: "09/18/2009 11:51:06", bin: 4, filtered_delta: 1, failed_delta: 1 } ] EDIT: I've accepted Toran's extremely helpful answer, but I feel I should post some additional code, since his removefromdom jQuery plugin has some limitations: It only removes individual elements. So you can't give it a query like `$("#content tbody tr")` and expect it to remove all of the elements you've specified. Any element that you remove with it must have an `id` attribute. So if I want to remove my `tbody`, then I must assign an `id` to my `tbody` tag or else it will give an error. It removes the element itself and all of its descendants, so if you simply want to empty that element then you'll have to re-create it afterwards (or modify the plugin to empty instead of remove). So here's my page above modified to use Toran's plugin. For the sake of simplicity I didn't apply any of the general performance advice offered by Peter. Here's the page which now no longer memory leaks: <html> <head> <title>Test Page</title> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js"></script> </head> <body> <script type="text/javascript"> <!-- $.fn.removefromdom = function(s) { if (!this) return; var el = document.getElementById(this.attr("id")); if (!el) return; var bin = document.getElementById("IELeakGarbageBin"); //before deleting el, recursively delete all of its children. while (el.childNodes.length > 0) { if (!bin) { bin = document.createElement("DIV"); bin.id = "IELeakGarbageBin"; document.body.appendChild(bin); } bin.appendChild(el.childNodes[el.childNodes.length - 1]); bin.innerHTML = ""; } el.parentNode.removeChild(el); if (!bin) { bin = document.createElement("DIV"); bin.id = "IELeakGarbageBin"; document.body.appendChild(bin); } bin.appendChild(el); bin.innerHTML = ""; }; var resets = 0; function kickoff() { $.getJSON("unplanned.json", resetTable); } function resetTable(rows) { $("#content tbody").removefromdom(); $("#content").append('<tbody id="id_field_required"></tbody>'); for(var i=0; i<rows.length; i++) { $("#content tbody").append("<tr><td>" + rows[i].mpe_name + "</td>" + "<td>" + rows[i].bin + "</td>" + "<td>" + rows[i].request_time + "</td>" + "<td>" + rows[i].filtered_delta + "</td>" + "<td>" + rows[i].failed_delta + "</td></tr>"); } resets++; $("#message").html("Content set this many times: " + resets); setTimeout(kickoff, 2000); } $(kickoff); // --> </script> <div id="message" style="color:red"></div> <table id="content" border="1" style="width:100% ; text-align:center"> <thead><tr> <th>MPE</th> <th>Bin</th> <th>When</th> <th>Filtered</th> <th>Failed</th> </tr></thead> <tbody id="id_field_required"></tbody> </table> </body> </html> FURTHER EDIT: I'll leave my question unchanged, though it's worth noting that this memory leak has nothing to do with Ajax. In fact, the following code would memory leak just the same and be just as easily solved with Toran's removefromdom jQuery plugin: function resetTable() { $("#content tbody").empty(); for(var i=0; i<1000; i++) { $("#content tbody").append("<tr><td>" + "DBOSS-095" + "</td>" + "<td>" + 4 + "</td>" + "<td>" + "09/18/2009 11:51:06" + "</td>" + "<td>" + 1 + "</td>" + "<td>" + 1 + "</td></tr>"); } setTimeout(resetTable, 2000); } $(resetTable);

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• Combining MVVM Light Toolkit and Unity 2.0

  - by Alan Cordner

  This is more of a commentary than a question, though feedback would be nice. I have been tasked to create the user interface for a new project we are doing. We want to use WPF and I wanted to learn all of the modern UI design techniques available. Since I am fairly new to WPF I have been researching what is available. I think I have pretty much settled on using MVVM Light Toolkit (mainly because of its "Blendability" and the EventToCommand behavior!), but I wanted to incorporate IoC also. So, here is what I have come up with. I have modified the default ViewModelLocator class in a MVVM Light project to use a UnityContainer to handle dependency injections. Considering I didn't know what 90% of these terms meant 3 months ago, I think I'm on the right track. // Example of MVVM Light Toolkit ViewModelLocator class that implements Microsoft // Unity 2.0 Inversion of Control container to resolve ViewModel dependencies. using Microsoft.Practices.Unity; namespace MVVMLightUnityExample { public class ViewModelLocator { public static UnityContainer Container { get; set; } #region Constructors static ViewModelLocator() { if (Container == null) { Container = new UnityContainer(); // register all dependencies required by view models Container .RegisterType<IDialogService, ModalDialogService>(new ContainerControlledLifetimeManager()) .RegisterType<ILoggerService, LogFileService>(new ContainerControlledLifetimeManager()) ; } } /// <summary> /// Initializes a new instance of the ViewModelLocator class. /// </summary> public ViewModelLocator() { ////if (ViewModelBase.IsInDesignModeStatic) ////{ //// // Create design time view models ////} ////else ////{ //// // Create run time view models ////} CreateMain(); } #endregion #region MainViewModel private static MainViewModel _main; /// <summary> /// Gets the Main property. /// </summary> public static MainViewModel MainStatic { get { if (_main == null) { CreateMain(); } return _main; } } /// <summary> /// Gets the Main property. /// </summary> [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "This non-static member is needed for data binding purposes.")] public MainViewModel Main { get { return MainStatic; } } /// <summary> /// Provides a deterministic way to delete the Main property. /// </summary> public static void ClearMain() { _main.Cleanup(); _main = null; } /// <summary> /// Provides a deterministic way to create the Main property. /// </summary> public static void CreateMain() { if (_main == null) { // allow Unity to resolve the view model and hold onto reference _main = Container.Resolve<MainViewModel>(); } } #endregion #region OrderViewModel // property to hold the order number (injected into OrderViewModel() constructor when resolved) public static string OrderToView { get; set; } /// <summary> /// Gets the OrderViewModel property. /// </summary> public static OrderViewModel OrderViewModelStatic { get { // allow Unity to resolve the view model // do not keep local reference to the instance resolved because we need a new instance // each time - the corresponding View is a UserControl that can be used multiple times // within a single window/view // pass current value of OrderToView parameter to constructor! return Container.Resolve<OrderViewModel>(new ParameterOverride("orderNumber", OrderToView)); } } /// <summary> /// Gets the OrderViewModel property. /// </summary> [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "This non-static member is needed for data binding purposes.")] public OrderViewModel Order { get { return OrderViewModelStatic; } } #endregion /// <summary> /// Cleans up all the resources. /// </summary> public static void Cleanup() { ClearMain(); Container = null; } } } And the MainViewModel class showing dependency injection usage: using GalaSoft.MvvmLight; using Microsoft.Practices.Unity; namespace MVVMLightUnityExample { public class MainViewModel : ViewModelBase { private IDialogService _dialogs; private ILoggerService _logger; /// <summary> /// Initializes a new instance of the MainViewModel class. This default constructor calls the /// non-default constructor resolving the interfaces used by this view model. /// </summary> public MainViewModel() : this(ViewModelLocator.Container.Resolve<IDialogService>(), ViewModelLocator.Container.Resolve<ILoggerService>()) { if (IsInDesignMode) { // Code runs in Blend --> create design time data. } else { // Code runs "for real" } } /// <summary> /// Initializes a new instance of the MainViewModel class. /// Interfaces are automatically resolved by the IoC container. /// </summary> /// <param name="dialogs">Interface to dialog service</param> /// <param name="logger">Interface to logger service</param> public MainViewModel(IDialogService dialogs, ILoggerService logger) { _dialogs = dialogs; _logger = logger; if (IsInDesignMode) { // Code runs in Blend --> create design time data. _dialogs.ShowMessage("Running in design-time mode!", "Injection Constructor", DialogButton.OK, DialogImage.Information); _logger.WriteLine("Running in design-time mode!"); } else { // Code runs "for real" _dialogs.ShowMessage("Running in run-time mode!", "Injection Constructor", DialogButton.OK, DialogImage.Information); _logger.WriteLine("Running in run-time mode!"); } } public override void Cleanup() { // Clean up if needed _dialogs = null; _logger = null; base.Cleanup(); } } } And the OrderViewModel class: using GalaSoft.MvvmLight; using Microsoft.Practices.Unity; namespace MVVMLightUnityExample { /// <summary> /// This class contains properties that a View can data bind to. /// <para> /// Use the <strong>mvvminpc</strong> snippet to add bindable properties to this ViewModel. /// </para> /// <para> /// You can also use Blend to data bind with the tool's support. /// </para> /// <para> /// See http://www.galasoft.ch/mvvm/getstarted /// </para> /// </summary> public class OrderViewModel : ViewModelBase { private const string testOrderNumber = "123456"; private Order _order; /// <summary> /// Initializes a new instance of the OrderViewModel class. /// </summary> public OrderViewModel() : this(testOrderNumber) { } /// <summary> /// Initializes a new instance of the OrderViewModel class. /// </summary> public OrderViewModel(string orderNumber) { if (IsInDesignMode) { // Code runs in Blend --> create design time data. _order = new Order(orderNumber, "My Company", "Our Address"); } else { _order = GetOrder(orderNumber); } } public override void Cleanup() { // Clean own resources if needed _order = null; base.Cleanup(); } } } And the code that could be used to display an order view for a specific order: public void ShowOrder(string orderNumber) { // pass the order number to show to ViewModelLocator to be injected //into the constructor of the OrderViewModel instance ViewModelLocator.OrderToShow = orderNumber; View.OrderView orderView = new View.OrderView(); } These examples have been stripped down to show only the IoC ideas. It took a lot of trial and error, searching the internet for examples, and finding out that the Unity 2.0 documentation is lacking (at best) to come up with this solution. Let me know if you think it could be improved.

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