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• Varnish default.vcl grace period

  - by Vladimir

  These are my settings for a grace period (/etc/varnish/default.vcl) sub vcl_recv { .... set req.grace = 360000s; ... } sub vcl_fetch { ... set beresp.grace = 360000s; ... } I tested Varnish using localhost and nodejs as a server. I started localhost, the site was up. Then I disconnected server and the site got disconnected in less than 2 min. It says: Error 503 Service Unavailable Service Unavailable Guru Meditation: XID: 1890127100 Varnish cache server Could you tell me what could be the problem? sub vcl_fetch { if (beresp.ttl < 120s) { ##std.log("Adjusting TTL"); set beresp.ttl = 36000s; ##120s; } # Do not cache the object if the backend application does not want us to. if (beresp.http.Cache-Control ~ "(no-cache|no-store|private|must-revalidate)") { return(hit_for_pass); } # Do not cache the object if the status is not in the 200s if (beresp.status >= 300) { # Remove the Set-Cookie header #remove beresp.http.Set-Cookie; return(hit_for_pass); } # # Everything below here should be cached # # Remove the Set-Cookie header ####remove beresp.http.Set-Cookie; # Set the grace time ## set beresp.grace = 1s; //change this to minutes in case of app shutdown set beresp.grace = 360000s; ## 10 hour - reduce if it has negative impact # Static assets - browser caches tpiphem for a long time. if (req.url ~ "\.(css|js|.js|jpg|jpeg|gif|ico|png)\??\d*$") { /* Remove Expires from backend, it's not long enough */ unset beresp.http.expires; /* Set the clients TTL on this object */ set beresp.http.cache-control = "public, max-age=31536000"; /* marker for vcl_deliver to reset Age: */ set beresp.http.magicmarker = "1"; } else { set beresp.http.Cache-Control = "private, max-age=0, must-revalidate"; set beresp.http.Pragma = "no-cache"; } if (req.url ~ "\.(css|js|min|)\??\d*$") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } ##do not duplicate these settings if (req.url ~ ".css") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } if (req.url ~ ".js") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } if (req.url ~ ".min") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } ## If the request to the backend returns a code other than 200, restart the loop ## If the number of restarts reaches the value of the parameter max_restarts, ## the request will be error'ed. max_restarts defaults to 4. This prevents ## an eternal loop in the event that, e.g., the object does not exist at all. if (beresp.status != 200 && beresp.status != 403 && beresp.status != 404) { return(restart); } if (beresp.status == 302) { return(deliver); } # Never cache posts if (req.url ~ "\/post\/" || req.url ~ "\/submit\/" || req.url ~ "\/ask\/" || req.url ~ "\/add\/") { return(hit_for_pass); } ##check this setting to ensure that it does not cause issues for browsers with no gzip if (beresp.http.content-type ~ "text") { set beresp.do_gzip = true; } if (beresp.http.Set-Cookie) { return(deliver); } ##if (req.url == "/index.html") { set beresp.do_esi = true; ##} ## check if this is needed or should be used # return(deliver); the object return(deliver); } sub vcl_recv { ##avoid leeching of images call hot_link; set req.grace = 360000s; ##2m ## if one backend is down - use another if (req.restarts == 0) { set req.backend = cache_director; ##we can specify individual VMs } else if (req.restarts == 1) { set req.backend = cache_director; } ## post calls should not be cached - add cookie for these requests if using micro-caching # Pass requests that are not GET or HEAD if (req.request != "GET" && req.request != "HEAD") { return(pass); ## return(pass) goes to backend - not cache } # Don't cache the result of a redirect if (req.http.Referer ~ "redir" || req.http.Origin ~ "jumpto") { return(pass); } # Don't cache the result of a redirect (asking for logon) if (req.http.Referer ~ "post" || req.http.Referer ~ "submit" || req.http.Referer ~ "add" || req.http.Referer ~ "ask") { return(pass); } # Never cache posts - ensure that we do not use these strings in our URLs' that need to be cached if (req.url ~ "\/post\/" || req.url ~ "\/submit\/" || req.url ~ "\/ask\/" || req.url ~ "\/add\/") { return(pass); } ## if (req.http.Authorization || req.http.Cookie) { if (req.http.Authorization) { /* Not cacheable by default */ return (pass); } # Handle compression correctly. Different browsers send different # "Accept-Encoding" headers, even though they mostly all support the same # compression mechanisms. By consolidating these compression headers into # a consistent format, we can reduce the size of the cache and get more hits. # @see: http:// varnish.projects.linpro.no/wiki/FAQ/Compression if (req.http.Accept-Encoding) { if (req.url ~ "\.(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg|ico)$") { # No point in compressing these remove req.http.Accept-Encoding; } else if (req.http.Accept-Encoding ~ "gzip") { # If the browser supports it, we'll use gzip. set req.http.Accept-Encoding = "gzip"; } else if (req.http.Accept-Encoding ~ "deflate") { # Next, try deflate if it is supported. set req.http.Accept-Encoding = "deflate"; } else { # Unknown algorithm. Remove it and send unencoded. unset req.http.Accept-Encoding; } } # lookup graphics, css, js & ico files in the cache if (req.url ~ "\.(png|gif|jpg|jpeg|css|.js|ico)$") { return(lookup); } ##added on 0918 - check if it causes issues with user specific content if (req.request == "GET" && req.http.cookie) { return(lookup); } # Pipe requests that are non-RFC2616 or CONNECT which is weird. if (req.request != "GET" && req.request != "HEAD" && req.request != "PUT" && req.request != "POST" && req.request != "TRACE" && req.request != "OPTIONS" && req.request != "DELETE") { ##closing connection and calling pipe return(pipe); } ##purge content via localhost only if (req.request == "PURGE") { if (!client.ip ~ purge) { error 405 "Not allowed."; } return(lookup); } ## do we need this? ## return(lookup); }

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• ProFTPd server on Ubuntu getting access denied message when successfully authenticated?

  - by exxoid

  I have a Ubuntu box with a ProFTPD 1.3.4a Server, when I try to log in via my FTP Client I cannot do anything as it does not allow me to list directories; I have tried logging in as root and as a regular user and tried accessing different paths within the FTP Server. The error I get in my FTP Client is: Status: Retrieving directory listing... Command: CDUP Response: 250 CDUP command successful Command: PWD Response: 257 "/var" is the current directory Command: PASV Response: 227 Entering Passive Mode (172,16,4,22,237,205). Command: MLSD Response: 550 Access is denied. Error: Failed to retrieve directory listing Any idea? Here is the config of my proftpd: # # /etc/proftpd/proftpd.conf -- This is a basic ProFTPD configuration file. # To really apply changes, reload proftpd after modifications, if # it runs in daemon mode. It is not required in inetd/xinetd mode. # # Includes DSO modules Include /etc/proftpd/modules.conf # Set off to disable IPv6 support which is annoying on IPv4 only boxes. UseIPv6 off # If set on you can experience a longer connection delay in many cases. IdentLookups off ServerName "Drupal Intranet" ServerType standalone ServerIdent on "FTP Server ready" DeferWelcome on # Set the user and group that the server runs as User nobody Group nogroup MultilineRFC2228 on DefaultServer on ShowSymlinks on TimeoutNoTransfer 600 TimeoutStalled 600 TimeoutIdle 1200 DisplayLogin welcome.msg DisplayChdir .message true ListOptions "-l" DenyFilter \*.*/ # Use this to jail all users in their homes # DefaultRoot ~ # Users require a valid shell listed in /etc/shells to login. # Use this directive to release that constrain. # RequireValidShell off # Port 21 is the standard FTP port. Port 21 # In some cases you have to specify passive ports range to by-pass # firewall limitations. Ephemeral ports can be used for that, but # feel free to use a more narrow range. # PassivePorts 49152 65534 # If your host was NATted, this option is useful in order to # allow passive tranfers to work. You have to use your public # address and opening the passive ports used on your firewall as well. # MasqueradeAddress 1.2.3.4 # This is useful for masquerading address with dynamic IPs: # refresh any configured MasqueradeAddress directives every 8 hours <IfModule mod_dynmasq.c> # DynMasqRefresh 28800 </IfModule> # To prevent DoS attacks, set the maximum number of child processes # to 30. If you need to allow more than 30 concurrent connections # at once, simply increase this value. Note that this ONLY works # in standalone mode, in inetd mode you should use an inetd server # that allows you to limit maximum number of processes per service # (such as xinetd) MaxInstances 30 # Set the user and group that the server normally runs at. # Umask 022 is a good standard umask to prevent new files and dirs # (second parm) from being group and world writable. Umask 022 022 # Normally, we want files to be overwriteable. AllowOverwrite on # Uncomment this if you are using NIS or LDAP via NSS to retrieve passwords: # PersistentPasswd off # This is required to use both PAM-based authentication and local passwords AuthPAMConfig proftpd AuthOrder mod_auth_pam.c* mod_auth_unix.c # Be warned: use of this directive impacts CPU average load! # Uncomment this if you like to see progress and transfer rate with ftpwho # in downloads. That is not needed for uploads rates. # UseSendFile off TransferLog /var/log/proftpd/xferlog SystemLog /var/log/proftpd/proftpd.log # Logging onto /var/log/lastlog is enabled but set to off by default #UseLastlog on # In order to keep log file dates consistent after chroot, use timezone info # from /etc/localtime. If this is not set, and proftpd is configured to # chroot (e.g. DefaultRoot or <Anonymous>), it will use the non-daylight # savings timezone regardless of whether DST is in effect. #SetEnv TZ :/etc/localtime <IfModule mod_quotatab.c> QuotaEngine off </IfModule> <IfModule mod_ratio.c> Ratios off </IfModule> # Delay engine reduces impact of the so-called Timing Attack described in # http://www.securityfocus.com/bid/11430/discuss # It is on by default. <IfModule mod_delay.c> DelayEngine on </IfModule> <IfModule mod_ctrls.c> ControlsEngine off ControlsMaxClients 2 ControlsLog /var/log/proftpd/controls.log ControlsInterval 5 ControlsSocket /var/run/proftpd/proftpd.sock </IfModule> <IfModule mod_ctrls_admin.c> AdminControlsEngine off </IfModule> # # Alternative authentication frameworks # #Include /etc/proftpd/ldap.conf #Include /etc/proftpd/sql.conf # # This is used for FTPS connections # #Include /etc/proftpd/tls.conf # # Useful to keep VirtualHost/VirtualRoot directives separated # #Include /etc/proftpd/virtuals.con # A basic anonymous configuration, no upload directories. # <Anonymous ~ftp> # User ftp # Group nogroup # # We want clients to be able to login with "anonymous" as well as "ftp" # UserAlias anonymous ftp # # Cosmetic changes, all files belongs to ftp user # DirFakeUser on ftp # DirFakeGroup on ftp # # RequireValidShell off # # # Limit the maximum number of anonymous logins # MaxClients 10 # # # We want 'welcome.msg' displayed at login, and '.message' displayed # # in each newly chdired directory. # DisplayLogin welcome.msg # DisplayChdir .message # # # Limit WRITE everywhere in the anonymous chroot # <Directory *> # <Limit WRITE> # DenyAll # </Limit> # </Directory> # # # Uncomment this if you're brave. # # <Directory incoming> # # # Umask 022 is a good standard umask to prevent new files and dirs # # # (second parm) from being group and world writable. # # Umask 022 022 # # <Limit READ WRITE> # # DenyAll # # </Limit> # # <Limit STOR> # # AllowAll # # </Limit> # # </Directory> # # </Anonymous> # Include other custom configuration files Include /etc/proftpd/conf.d/ UseReverseDNS off <Global> RootLogin on UseFtpUsers on ServerIdent on DefaultChdir /var/www DeleteAbortedStores on LoginPasswordPrompt on AccessGrantMsg "You have been authenticated successfully." </Global> Any idea what could be wrong? Thanks for your help!

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• How to diagnose failing 6Gbps SATA connection?

  - by whitequark

  I have a Samsung RC530 notebook and OCZ Vertex-3 6Gbps SATA SSD working in AHCI mode. # dmesg | grep DMI SAMSUNG ELECTRONICS CO., LTD. RC530/RC730/RC530/RC730, BIOS 03WD.M008.20110927.PSA 09/27/2011 # lspci -nn 00:1f.2 SATA controller [0106]: Intel Corporation 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller [8086:1c03] (rev 04) # sdparm -a /dev/sda /dev/sda: ATA OCZ-VERTEX3 2.15 At the boot, the following messages are present in dmesg (I am running Debian wheezy @ Linux 3.2.8): # dmesg | grep -iE '(ata|ahci)' [ 5.179783] ahci 0000:00:1f.2: version 3.0 [ 5.179802] ahci 0000:00:1f.2: PCI INT B -> GSI 19 (level, low) -> IRQ 19 [ 5.179864] ahci 0000:00:1f.2: irq 42 for MSI/MSI-X [ 5.195424] ahci 0000:00:1f.2: AHCI 0001.0300 32 slots 6 ports 6 Gbps 0x5 impl SATA mode [ 5.195429] ahci 0000:00:1f.2: flags: 64bit ncq sntf pm led clo pio slum part ems apst [ 5.195436] ahci 0000:00:1f.2: setting latency timer to 64 [ 5.204035] scsi0 : ahci [ 5.204301] scsi1 : ahci [ 5.204447] scsi2 : ahci [ 5.204592] scsi3 : ahci [ 5.204682] scsi4 : ahci [ 5.204799] scsi5 : ahci [ 5.204917] ata1: SATA max UDMA/133 abar m2048@0xf7c06000 port 0xf7c06100 irq 42 [ 5.204920] ata2: DUMMY [ 5.204923] ata3: SATA max UDMA/133 abar m2048@0xf7c06000 port 0xf7c06200 irq 42 [ 5.204924] ata4: DUMMY [ 5.204926] ata5: DUMMY [ 5.204927] ata6: DUMMY [ 5.523039] ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 300) [ 5.525911] ata3.00: ATAPI: TSSTcorp CDDVDW SN-208BB, SC00, max UDMA/100 [ 5.531006] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300) [ 5.533703] ata3.00: configured for UDMA/100 [ 5.542790] ata1.00: ATA-8: OCZ-VERTEX3, 2.15, max UDMA/133 [ 5.542800] ata1.00: 117231408 sectors, multi 16: LBA48 NCQ (depth 31/32), AA [ 5.552751] ata1.00: configured for UDMA/133 [ 5.553050] scsi 0:0:0:0: Direct-Access ATA OCZ-VERTEX3 2.15 PQ: 0 ANSI: 5 [ 5.559621] scsi 2:0:0:0: CD-ROM TSSTcorp CDDVDW SN-208BB SC00 PQ: 0 ANSI: 5 [ 5.564059] sd 0:0:0:0: [sda] 117231408 512-byte logical blocks: (60.0 GB/55.8 GiB) [ 5.564127] sd 0:0:0:0: [sda] Write Protect is off [ 5.564131] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 [ 5.564158] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 5.564582] sda: sda1 [ 5.564810] sd 0:0:0:0: [sda] Attached SCSI disk [ 5.572006] sr0: scsi3-mmc drive: 16x/24x writer dvd-ram cd/rw xa/form2 cdda tray [ 5.572010] cdrom: Uniform CD-ROM driver Revision: 3.20 [ 5.572189] sr 2:0:0:0: Attached scsi CD-ROM sr0 [ 6.717181] ata1.00: exception Emask 0x50 SAct 0x1 SErr 0x280900 action 0x6 frozen [ 6.717238] ata1.00: irq_stat 0x08000000, interface fatal error [ 6.717291] ata1: SError: { UnrecovData HostInt 10B8B BadCRC } [ 6.717342] ata1.00: failed command: READ FPDMA QUEUED [ 6.717395] ata1.00: cmd 60/50:00:20:39:58/00:00:00:00:00/40 tag 0 ncq 40960 in [ 6.717396] res 40/00:00:20:39:58/00:00:00:00:00/40 Emask 0x50 (ATA bus error) [ 6.717503] ata1.00: status: { DRDY } [ 6.717553] ata1: hard resetting link [ 7.033417] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300) [ 7.055234] ata1.00: configured for UDMA/133 [ 7.055262] ata1: EH complete [ 7.147280] ata1.00: exception Emask 0x10 SAct 0xf8 SErr 0x280100 action 0x6 frozen [ 7.147340] ata1.00: irq_stat 0x08000000, interface fatal error [ 7.147393] ata1: SError: { UnrecovData 10B8B BadCRC } [ 7.147460] ata1.00: failed command: READ FPDMA QUEUED [ 7.147529] ata1.00: cmd 60/08:18:88:17:41/00:00:02:00:00/40 tag 3 ncq 4096 in [ 7.147531] res 40/00:38:50:99:64/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.147691] ata1.00: status: { DRDY } [ 7.147754] ata1.00: failed command: READ FPDMA QUEUED [ 7.147821] ata1.00: cmd 60/00:20:f8:42:4c/01:00:02:00:00/40 tag 4 ncq 131072 in [ 7.147822] res 40/00:38:50:99:64/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.147977] ata1.00: status: { DRDY } [ 7.148036] ata1.00: failed command: READ FPDMA QUEUED [ 7.148100] ata1.00: cmd 60/50:28:f8:43:4c/00:00:02:00:00/40 tag 5 ncq 40960 in [ 7.148101] res 40/00:38:50:99:64/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.148255] ata1.00: status: { DRDY } [ 7.148315] ata1.00: failed command: READ FPDMA QUEUED [ 7.148379] ata1.00: cmd 60/00:30:50:98:64/01:00:02:00:00/40 tag 6 ncq 131072 in [ 7.148380] res 40/00:38:50:99:64/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.148534] ata1.00: status: { DRDY } [ 7.148593] ata1.00: failed command: READ FPDMA QUEUED [ 7.148657] ata1.00: cmd 60/00:38:50:99:64/01:00:02:00:00/40 tag 7 ncq 131072 in [ 7.148658] res 40/00:38:50:99:64/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.148813] ata1.00: status: { DRDY } [ 7.148875] ata1: hard resetting link [ 7.464842] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300) [ 7.486794] ata1.00: configured for UDMA/133 [ 7.486822] ata1: EH complete [ 7.546395] ata1.00: exception Emask 0x10 SAct 0x2f SErr 0x280100 action 0x6 frozen [ 7.546470] ata1.00: irq_stat 0x08000000, interface fatal error [ 7.546531] ata1: SError: { UnrecovData 10B8B BadCRC } [ 7.546588] ata1.00: failed command: READ FPDMA QUEUED [ 7.546648] ata1.00: cmd 60/00:00:e0:4b:61/01:00:02:00:00/40 tag 0 ncq 131072 in [ 7.546649] res 40/00:28:e0:4c:61/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.546794] ata1.00: status: { DRDY } [ 7.546847] ata1.00: failed command: READ FPDMA QUEUED [ 7.546906] ata1.00: cmd 60/00:08:90:2f:48/01:00:02:00:00/40 tag 1 ncq 131072 in [ 7.546907] res 40/00:28:e0:4c:61/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.547053] ata1.00: status: { DRDY } [ 7.547106] ata1.00: failed command: READ FPDMA QUEUED [ 7.547165] ata1.00: cmd 60/00:10:90:30:48/01:00:02:00:00/40 tag 2 ncq 131072 in [ 7.547166] res 40/00:28:e0:4c:61/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.547310] ata1.00: status: { DRDY } [ 7.547363] ata1.00: failed command: READ FPDMA QUEUED [ 7.547422] ata1.00: cmd 60/00:18:50:c7:64/01:00:02:00:00/40 tag 3 ncq 131072 in [ 7.547423] res 40/00:28:e0:4c:61/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.547568] ata1.00: status: { DRDY } [ 7.547621] ata1.00: failed command: READ FPDMA QUEUED [ 7.547681] ata1.00: cmd 60/00:28:e0:4c:61/01:00:02:00:00/40 tag 5 ncq 131072 in [ 7.547682] res 40/00:28:e0:4c:61/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.547825] ata1.00: status: { DRDY } [ 7.547882] ata1: hard resetting link [ 7.864408] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300) [ 7.886351] ata1.00: configured for UDMA/133 [ 7.886375] ata1: EH complete [ 7.890012] ata1: limiting SATA link speed to 3.0 Gbps [ 7.890016] ata1.00: exception Emask 0x10 SAct 0x7 SErr 0x280100 action 0x6 frozen [ 7.890093] ata1.00: irq_stat 0x08000000, interface fatal error [ 7.890152] ata1: SError: { UnrecovData 10B8B BadCRC } [ 7.890210] ata1.00: failed command: READ FPDMA QUEUED [ 7.890272] ata1.00: cmd 60/00:00:90:33:48/01:00:02:00:00/40 tag 0 ncq 131072 in [ 7.890273] res 40/00:10:e0:4f:61/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.890418] ata1.00: status: { DRDY } [ 7.890472] ata1.00: failed command: READ FPDMA QUEUED [ 7.890530] ata1.00: cmd 60/00:08:90:34:48/01:00:02:00:00/40 tag 1 ncq 131072 in [ 7.890531] res 40/00:10:e0:4f:61/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.890672] ata1.00: status: { DRDY } [ 7.890724] ata1.00: failed command: READ FPDMA QUEUED [ 7.890781] ata1.00: cmd 60/78:10:e0:4f:61/00:00:02:00:00/40 tag 2 ncq 61440 in [ 7.890782] res 40/00:10:e0:4f:61/00:00:02:00:00/40 Emask 0x10 (ATA bus error) [ 7.890925] ata1.00: status: { DRDY } [ 7.890981] ata1: hard resetting link [ 8.208021] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 320) [ 8.230100] ata1.00: configured for UDMA/133 [ 8.230124] ata1: EH complete Looks like the SATA interface tries to use 6Gbps link, then fails miserably and Linux fallbacks to 3Gbps. This is somewhat fine for me, as the system boots successfully each time and works under high load (cd linux-3.2.8; make -j16). I've also ran memtest86+ and it did not find any errors. What concerns me more is that Grub sometimes takes a long time to load the images and/or fails to load itself completely. The error is consistent and is probablistic: that is, each time I boot I have a certain chance to fail. Actually, I have a slight suspiction on the cause of the failure. Look at the cabling: What kind of engineer does it this way? Nah. Even 1Gbps Ethernet hardly tolerates cables bent over a small angle, and there you have 6Gbps SATA. How cound I determine and fix the cause of errors and/or switch the link to 3Gbps mode permanently?

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• What's the best name for a non-mutating "add" method on an immutable collection?

  - by Jon Skeet

  Sorry for the waffly title - if I could come up with a concise title, I wouldn't have to ask the question. Suppose I have an immutable list type. It has an operation Foo(x) which returns a new immutable list with the specified argument as an extra element at the end. So to build up a list of strings with values "Hello", "immutable", "world" you could write: var empty = new ImmutableList<string>(); var list1 = empty.Foo("Hello"); var list2 = list1.Foo("immutable"); var list3 = list2.Foo("word"); (This is C# code, and I'm most interested in a C# suggestion if you feel the language is important. It's not fundamentally a language question, but the idioms of the language may be important.) The important thing is that the existing lists are not altered by Foo - so empty.Count would still return 0. Another (more idiomatic) way of getting to the end result would be: var list = new ImmutableList<string>().Foo("Hello"); .Foo("immutable"); .Foo("word"); My question is: what's the best name for Foo? EDIT 3: As I reveal later on, the name of the type might not actually be ImmutableList<T>, which makes the position clear. Imagine instead that it's TestSuite and that it's immutable because the whole of the framework it's a part of is immutable... (End of edit 3) Options I've come up with so far: Add: common in .NET, but implies mutation of the original list Cons: I believe this is the normal name in functional languages, but meaningless to those without experience in such languages Plus: my favourite so far, it doesn't imply mutation to me. Apparently this is also used in Haskell but with slightly different expectations (a Haskell programmer might expect it to add two lists together rather than adding a single value to the other list). With: consistent with some other immutable conventions, but doesn't have quite the same "additionness" to it IMO. And: not very descriptive. Operator overload for + : I really don't like this much; I generally think operators should only be applied to lower level types. I'm willing to be persuaded though! The criteria I'm using for choosing are: Gives the correct impression of the result of the method call (i.e. that it's the original list with an extra element) Makes it as clear as possible that it doesn't mutate the existing list Sounds reasonable when chained together as in the second example above Please ask for more details if I'm not making myself clear enough... EDIT 1: Here's my reasoning for preferring Plus to Add. Consider these two lines of code: list.Add(foo); list.Plus(foo); In my view (and this is a personal thing) the latter is clearly buggy - it's like writing "x + 5;" as a statement on its own. The first line looks like it's okay, until you remember that it's immutable. In fact, the way that the plus operator on its own doesn't mutate its operands is another reason why Plus is my favourite. Without the slight ickiness of operator overloading, it still gives the same connotations, which include (for me) not mutating the operands (or method target in this case). EDIT 2: Reasons for not liking Add. Various answers are effectively: "Go with Add. That's what DateTime does, and String has Replace methods etc which don't make the immutability obvious." I agree - there's precedence here. However, I've seen plenty of people call DateTime.Add or String.Replace and expect mutation. There are loads of newsgroup questions (and probably SO ones if I dig around) which are answered by "You're ignoring the return value of String.Replace; strings are immutable, a new string gets returned." Now, I should reveal a subtlety to the question - the type might not actually be an immutable list, but a different immutable type. In particular, I'm working on a benchmarking framework where you add tests to a suite, and that creates a new suite. It might be obvious that: var list = new ImmutableList<string>(); list.Add("foo"); isn't going to accomplish anything, but it becomes a lot murkier when you change it to: var suite = new TestSuite<string, int>(); suite.Add(x => x.Length); That looks like it should be okay. Whereas this, to me, makes the mistake clearer: var suite = new TestSuite<string, int>(); suite.Plus(x => x.Length); That's just begging to be: var suite = new TestSuite<string, int>().Plus(x => x.Length); Ideally, I would like my users not to have to be told that the test suite is immutable. I want them to fall into the pit of success. This may not be possible, but I'd like to try. I apologise for over-simplifying the original question by talking only about an immutable list type. Not all collections are quite as self-descriptive as ImmutableList<T> :)

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• Sorting/Paginating/Filtering Complex Multi-AR Object Tables in Rails

  - by Matt Rogish

  I have a complex table pulled from a multi-ActiveRecord object array. This listing is a combined display of all of a particular user's "favorite" items (songs, messages, blog postings, whatever). Each of these items is a full-fledged AR object. My goal is to present the user with a simplified search, sort, and pagination interface. The user need not know that the Song has a singer, and that the Message has an author -- to the end user both entries in the table will be displayed as "User". Thus, the search box will simply be a dropdown list asking them which to search on (User name, created at, etc.). Internally, I would need to convert that to the appropriate object search, combine the results, and display. I can, separately, do pagination (mislav will_paginate), sorting, and filtering, but together I'm having some problems combining them. For example, if I paginate the combined list of items, the pagination plugin handles it just fine. It is not efficient since the pagination is happening in the app vs. the DB, but let's assume the intended use-case would indicate the vast majority of the users will have less than 30 favorited items and all other behavior, server capabilities, etc. indicates this will not be a bottleneck. However, if I wish to sort the list I cannot sort it via the pagination plugin because it relies on the assumption that the result set is derived from a single SQL query, and also that the field name is consistent throughout. Thus, I must sort the merged array via ruby, e.g. @items.sort_by{ |i| i.whatever } But, since the items do not share common names, I must first interrogate the object and then call the correct sort by. For example, if the user wishes to sort by user name, if the sorted object is a message, I sort by author but if the object is a song, I sort by singer. This is all very gross and feels quite un-ruby-like. This same problem comes into play with the filter. If the user filters on the "parent item" (the message's thread, the song's album), I must translate that to the appropriate collection object method. Also gross. This is not the exact set-up but is close enough. Note that this is a legacy app so changing it is quite difficult, although not impossible. Also, yes there is some DRY that can be done, but don't focus on the style or elegance of the following code. Style/elegance of the SOLUTION is important, however! :D models: class User < ActiveRecord::Base ... has_and_belongs_to_many :favorite_messages, :class_name => "Message" has_and_belongs_to_many :favorite_songs, :class_name => "Song" has_many :authored_messages, :class_name => "Message" has_many :sung_songs, :class_name => "Song" end class Message < ActiveRecord::Base has_and_belongs_to_many :favorite_messages belongs_to :author, :class_name => "User" belongs_to :thread end class Song < ActiveRecord::Base has_and_belongs_to_many :favorite_songs belongs_to :singer, :class_name => "User" belongs_to :album end controller: def show u = User.find 123 @items = Array.new @items << u.favorite_messages @items << u.favorite_songs # etc. etc. @items.flatten! @items = @items.sort_by{ |i| i.created_at } @items = @items.paginate :page => params[:page], :per_page => 20 end def search # Assume user is searching for username like 'Bob' u = User.find 123 @items = Array.new @items << u.favorite_messages.find( :all, :conditions => "LOWER( author ) LIKE LOWER('%bob%')" ) @items << u.favorite_songs.find( :all, :conditions => "LOWER( singer ) LIKE ... " ) # etc. etc. @items.flatten! @items = @items.sort_by{ |i| determine appropriate sorting based on user selection } @items = @items.paginate :page => params[:page], :per_page => 20 end view: #index.html.erb ... <table> <tr> <th>Title (sort ASC/DESC links)</th> <th>Created By (sort ASC/DESC links))</th> <th>Collection Title (sort ASC/DESC links)</th> <th>Created At (sort ASC/DESC links)</th> </tr> <% @items.each |item| do %> <%= render { :partial => "message", :locals => item } if item.is_a? Message %> <%= render { :partial => "song", :locals => item } if item.is_a? Song %> <%end%> ... </table> #message.html.erb # shorthand, not real ruby print out message title, author name, thread title, message created at #song.html.erb # shorthand print out song title, singer name, album title, song created at

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• How to match ColdFusion encryption with Java 1.4.2?

  - by JohnTheBarber

  * sweet - thanks to Edward Smith for the CF Technote that indicated the key from ColdFusion was Base64 encoded. See generateKey() for the 'fix' My task is to use Java 1.4.2 to match the results a given ColdFusion code sample for encryption. Known/given values: A 24-byte key A 16-byte salt (IVorSalt) Encoding is Hex Encryption algorithm is AES/CBC/PKCS5Padding A sample clear-text value The encrypted value of the sample clear-text after going through the ColdFusion code Assumptions: Number of iterations not specified in the ColdFusion code so I assume only one iteration 24-byte key so I assume 192-bit encryption Given/working ColdFusion encryption code sample: <cfset ThisSalt = "16byte-salt-here"> <cfset ThisAlgorithm = "AES/CBC/PKCS5Padding"> <cfset ThisKey = "a-24byte-key-string-here"> <cfset thisAdjustedNow = now()> <cfset ThisDateTimeVar = DateFormat( thisAdjustedNow , "yyyymmdd" )> <cfset ThisDateTimeVar = ThisDateTimeVar & TimeFormat( thisAdjustedNow , "HHmmss" )> <cfset ThisTAID = ThisDateTimeVar & "|" & someOtherData> <cfset ThisTAIDEnc = Encrypt( ThisTAID , ThisKey , ThisAlgorithm , "Hex" , ThisSalt)> My Java 1.4.2 encryption/decryption code swag: package so.example; import java.security.*; import javax.crypto.Cipher; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.SecretKeySpec; import org.apache.commons.codec.binary.*; public class SO_AES192 { private static final String _AES = "AES"; private static final String _AES_CBC_PKCS5Padding = "AES/CBC/PKCS5Padding"; private static final String KEY_VALUE = "a-24byte-key-string-here"; private static final String SALT_VALUE = "16byte-salt-here"; private static final int ITERATIONS = 1; private static IvParameterSpec ivParameterSpec; public static String encryptHex(String value) throws Exception { Key key = generateKey(); Cipher c = Cipher.getInstance(_AES_CBC_PKCS5Padding); ivParameterSpec = new IvParameterSpec(SALT_VALUE.getBytes()); c.init(Cipher.ENCRYPT_MODE, key, ivParameterSpec); String valueToEncrypt = null; String eValue = value; for (int i = 0; i < ITERATIONS; i++) { // valueToEncrypt = SALT_VALUE + eValue; // pre-pend salt - Length > sample length valueToEncrypt = eValue; // don't pre-pend salt Length = sample length byte[] encValue = c.doFinal(valueToEncrypt.getBytes()); eValue = Hex.encodeHexString(encValue); } return eValue; } public static String decryptHex(String value) throws Exception { Key key = generateKey(); Cipher c = Cipher.getInstance(_AES_CBC_PKCS5Padding); ivParameterSpec = new IvParameterSpec(SALT_VALUE.getBytes()); c.init(Cipher.DECRYPT_MODE, key, ivParameterSpec); String dValue = null; char[] valueToDecrypt = value.toCharArray(); for (int i = 0; i < ITERATIONS; i++) { byte[] decordedValue = Hex.decodeHex(valueToDecrypt); byte[] decValue = c.doFinal(decordedValue); // dValue = new String(decValue).substring(SALT_VALUE.length()); // when salt is pre-pended dValue = new String(decValue); // when salt is not pre-pended valueToDecrypt = dValue.toCharArray(); } return dValue; } private static Key generateKey() throws Exception { // Key key = new SecretKeySpec(KEY_VALUE.getBytes(), _AES); // this was wrong Key key = new SecretKeySpec(new BASE64Decoder().decodeBuffer(keyValueString), _AES); // had to un-Base64 the 'known' 24-byte key. return key; } } I cannot create a matching encrypted value nor decrypt a given encrypted value. My guess is it's something to do with how I'm handling the initial vector/salt. I'm not very crypto-savvy but I'm thinking I should be able to take the sample clear-text and produce the same encrypted value in Java as ColdFusion produced. I am able to encrypt/decrypt my own data with my Java code (so I'm consistent) but I cannot match nor decrypt the ColdFusion sample encrypted value. I have access to a local webservice that can test the encrypted output. The given ColdFusion output sample passes/decrypts fine (of course). If I try to decrypt the same sample with my Java code (using the actual key and salt) I get a "Given final block not properly padded" error. I get the same net result when I pass my attempt at encryption (using the actual key and salt) to the test webservice. Any Ideas?

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• Performance of delegate and method group

  - by BlueFox

  Hi I was investigating the performance hit of creating Cachedependency objects, so I wrote a very simple test program as follows: using System; using System.Collections.Generic; using System.Diagnostics; using System.Web.Caching; namespace Test { internal class Program { private static readonly string[] keys = new[] {"Abc"}; private static readonly int MaxIteration = 10000000; private static void Main(string[] args) { Debug.Print("first set"); test7(); test6(); test5(); test4(); test3(); test2(); Debug.Print("second set"); test2(); test3(); test4(); test5(); test6(); test7(); } private static void test2() { DateTime start = DateTime.Now; var list = new List<CacheDependency>(); for (int i = 0; i < MaxIteration; i++) { list.Add(new CacheDependency(null, keys)); } Debug.Print("test2 Time: " + (DateTime.Now - start)); } private static void test3() { DateTime start = DateTime.Now; var list = new List<Func<CacheDependency>>(); for (int i = 0; i < MaxIteration; i++) { list.Add(() => new CacheDependency(null, keys)); } Debug.Print("test3 Time: " + (DateTime.Now - start)); } private static void test4() { var p = new Program(); DateTime start = DateTime.Now; var list = new List<Func<CacheDependency>>(); for (int i = 0; i < MaxIteration; i++) { list.Add(p.GetDep); } Debug.Print("test4 Time: " + (DateTime.Now - start)); } private static void test5() { var p = new Program(); DateTime start = DateTime.Now; var list = new List<Func<CacheDependency>>(); for (int i = 0; i < MaxIteration; i++) { list.Add(() => { return p.GetDep(); }); } Debug.Print("test5 Time: " + (DateTime.Now - start)); } private static void test6() { DateTime start = DateTime.Now; var list = new List<Func<CacheDependency>>(); for (int i = 0; i < MaxIteration; i++) { list.Add(GetDepSatic); } Debug.Print("test6 Time: " + (DateTime.Now - start)); } private static void test7() { DateTime start = DateTime.Now; var list = new List<Func<CacheDependency>>(); for (int i = 0; i < MaxIteration; i++) { list.Add(() => { return GetDepSatic(); }); } Debug.Print("test7 Time: " + (DateTime.Now - start)); } private CacheDependency GetDep() { return new CacheDependency(null, keys); } private static CacheDependency GetDepSatic() { return new CacheDependency(null, keys); } } } But I can't understand why these result looks like this: first set test7 Time: 00:00:00.4840277 test6 Time: 00:00:02.2041261 test5 Time: 00:00:00.1910109 test4 Time: 00:00:03.1401796 test3 Time: 00:00:00.1820105 test2 Time: 00:00:08.5394884 second set test2 Time: 00:00:07.7324423 test3 Time: 00:00:00.1830105 test4 Time: 00:00:02.3561347 test5 Time: 00:00:00.1750100 test6 Time: 00:00:03.2941884 test7 Time: 00:00:00.1850106 In particular: 1. Why is test4 and test6 much slower than their delegate version? I also noticed that Resharper specifically has a comment on the delegate version suggesting change test5 and test7 to "Covert to method group". Which is the same as test4 and test6 but they're actually slower? 2. I don't seem a consistent performance difference when calling test4 and test6, shouldn't static calls to be always faster?

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• Swing object: first setText() gets "stuck" when using Mac Java SE 6

  - by Tim

  Hi there, I am a Java newbie trying to maintain an application that works fine under J2SE 5.0 (32- and 64-bit) but has a very specific problem when run under Java SE 6 64-bit: [Tims-MPB:~] tlynch% java -version java version "1.6.0_15" Java(TM) SE Runtime Environment (build 1.6.0_15-b03-226) Java HotSpot(TM) 64-Bit Server VM (build 14.1-b02-92, mixed mode) The application is cross-platform and reportedly works correctly on Java SE 6 under Windows, though I haven't been able to verify that myself. The program uses a JTextField for some text entry and a JLabel to indicate the text to be entered. The first time the showDialog() method is called to set the label text and display the dialog, it works correctly, but subsequent calls all result in the display of the label from the initial invocation rather than the one most recently specified via setText(). public void showDialog(String msgText) { System.out.println("set ChatDialog: " + msgText); jLabel1.setText(msgText); jLabel1.repaint(); // I added this; it didn't help System.out.println("get ChatDialog: " + jLabel1.getText()); super.setVisible(true); } [the full text of the class is provided below] The added printlns validate that expected text is passed to the label's setText() method and is confirmed by retrieving it using getText(), but what shows up on the screen/GUI is always the text from the very first time the method was called for the object. A similar issue is observed with a JTextArea used to label another dialog box. These problem are consistent across multiple Mac systems running Java SE 6 under OS 10.5.x and 10.6.x, but they are never observed when one reverts to J2SE 5.0. If there is some background information pertinent to this problem that I have omitted, please let me know. Any insights or advice appreciated. package gui; import java.awt.*; import java.awt.event.KeyEvent; import javax.swing.*; // Referenced classes of package gui: // MyJPanel, ChatDialog_jTextField1_keyAdapter, WarWindow public class ChatDialog extends JDialog { public ChatDialog(JFrame parent, WarWindow w) { super(parent, true); text = ""; borderLayout1 = new BorderLayout(); jPanel1 = new MyJPanel(); borderLayout2 = new BorderLayout(); jPanel2 = new MyJPanel(); jPanel3 = new MyJPanel(); jLabel1 = new JLabel(); jTextField1 = new JTextField(); warWindow = w; try { jbInit(); } catch(Exception exception) { System.out.println("Problem with ChatDialog init"); exception.printStackTrace(); } return; } public String getText() { return text; } void jTextField1_keyPressed(KeyEvent e) { int id = e.getKeyCode(); switch(id) { case 10: // '\n' text = jTextField1.getText(); setVisible(false); break; } } private void jbInit() throws Exception { setLocation(232, 450); setSize(560, 60); setModal(true); setResizable(false); setUndecorated(true); getContentPane().setLayout(borderLayout1); jPanel1.setLayout(borderLayout2); jPanel2.setMinimumSize(new Dimension(10, 20)); jPanel2.setPreferredSize(new Dimension(10, 20)); jLabel1.setPreferredSize(new Dimension(380, 15)); jLabel1.setHorizontalAlignment(0); jLabel1.setText("Chat Message"); jTextField1.setPreferredSize(new Dimension(520, 21)); jTextField1.setRequestFocusEnabled(false); jTextField1.addKeyListener(new ChatDialog_jTextField1_keyAdapter(this)); getContentPane().add(jPanel1, "Center"); jPanel1.add(jPanel2, "North"); jPanel2.add(jLabel1, null); jPanel1.add(jPanel3, "Center"); jPanel3.add(jTextField1, null); } public void setVisible(boolean b) { jTextField1.setText(""); super.setVisible(b); } public void showDialog(String msgText) { System.out.println("set ChatDialog: " + msgText); jLabel1.setText(msgText); jLabel1.repaint(); // I added this; it didn't help System.out.println("get ChatDialog: " + jLabel1.getText()); super.setVisible(true); } void this_keyPressed(KeyEvent e) { int id = e.getKeyCode(); switch(id) { case 10: // '\n' System.exit(88); break; } } BorderLayout borderLayout1; BorderLayout borderLayout2; JLabel jLabel1; JPanel jPanel1; JPanel jPanel2; JPanel jPanel3; JTextField jTextField1; String text; WarWindow warWindow; }

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• Different behavior for REF CURSOR between Oracle 10g and 11g when unique index present?

  - by wweicker

  Description I have an Oracle stored procedure that has been running for 7 or so years both locally on development instances and on multiple client test and production instances running Oracle 8, then 9, then 10, and recently 11. It has worked consistently until the upgrade to Oracle 11g. Basically, the procedure opens a reference cursor, updates a table then completes. In 10g the cursor will contain the expected results but in 11g the cursor will be empty. No DML or DDL changed after the upgrade to 11g. This behavior is consistent on every 10g or 11g instance I've tried (10.2.0.3, 10.2.0.4, 11.1.0.7, 11.2.0.1 - all running on Windows). The specific code is much more complicated but to explain the issue in somewhat realistic overview: I have some data in a header table and a bunch of child tables that will be output to PDF. The header table has a boolean (NUMBER(1) where 0 is false and 1 is true) column indicating whether that data has been processed yet. The view is limited to only show rows in that have not been processed (the view also joins on some other tables, makes some inline queries and function calls, etc). So at the time when the cursor is opened, the view shows one or more rows, then after the cursor is opened an update statement runs to flip the flag in the header table, a commit is issued, then the procedure completes. On 10g, the cursor opens, it contains the row, then the update statement flips the flag and running the procedure a second time would yield no data. On 11g, the cursor never contains the row, it's as if the cursor does not open until after the update statement runs. I'm concerned that something may have changed in 11g (hopefully a setting that can be configured) that might affect other procedures and other applications. What I'd like to know is whether anyone knows why the behavior is different between the two database versions and whether the issue can be resolved without code changes. Update 1: I managed to track the issue down to a unique constraint. It seems that when the unique constraint is present in 11g the issue is reproducible 100% of the time regardless of whether I'm running the real world code against the actual objects or the following simple example. Update 2: I was able to completely eliminate the view from the equation. I have updated the simple example to show the problem exists even when querying directly against the table. Simple Example CREATE TABLE tbl1 ( col1 VARCHAR2(10), col2 NUMBER(1) ); INSERT INTO tbl1 (col1, col2) VALUES ('TEST1', 0); /* View is no longer required to demonstrate the problem CREATE OR REPLACE VIEW vw1 (col1, col2) AS SELECT col1, col2 FROM tbl1 WHERE col2 = 0; */ CREATE OR REPLACE PACKAGE pkg1 AS TYPE refWEB_CURSOR IS REF CURSOR; PROCEDURE proc1 (crs OUT refWEB_CURSOR); END pkg1; CREATE OR REPLACE PACKAGE BODY pkg1 IS PROCEDURE proc1 (crs OUT refWEB_CURSOR) IS BEGIN OPEN crs FOR SELECT col1 FROM tbl1 WHERE col1 = 'TEST1' AND col2 = 0; UPDATE tbl1 SET col2 = 1 WHERE col1 = 'TEST1'; COMMIT; END proc1; END pkg1; Anonymous Block Demo DECLARE crs1 pkg1.refWEB_CURSOR; TYPE rectype1 IS RECORD ( col1 vw1.col1%TYPE ); rec1 rectype1; BEGIN pkg1.proc1 ( crs1 ); DBMS_OUTPUT.PUT_LINE('begin first test'); LOOP FETCH crs1 INTO rec1; EXIT WHEN crs1%NOTFOUND; DBMS_OUTPUT.PUT_LINE(rec1.col1); END LOOP; DBMS_OUTPUT.PUT_LINE('end first test'); END; /* After creating this index, the problem is seen */ CREATE UNIQUE INDEX unique_col1 ON tbl1 (col1); /* Reset data to initial values */ TRUNCATE TABLE tbl1; INSERT INTO tbl1 (col1, col2) VALUES ('TEST1', 0); DECLARE crs1 pkg1.refWEB_CURSOR; TYPE rectype1 IS RECORD ( col1 vw1.col1%TYPE ); rec1 rectype1; BEGIN pkg1.proc1 ( crs1 ); DBMS_OUTPUT.PUT_LINE('begin second test'); LOOP FETCH crs1 INTO rec1; EXIT WHEN crs1%NOTFOUND; DBMS_OUTPUT.PUT_LINE(rec1.col1); END LOOP; DBMS_OUTPUT.PUT_LINE('end second test'); END; Example of what the output on 10g would be:   begin first test   TEST1   end first test   begin second test   TEST1   end second test Example of what the output on 11g would be:   begin first test   TEST1   end first test   begin second test   end second test Clarification I can't remove the COMMIT because in the real world scenario the procedure is called from a web application. When the data provider on the front end calls the procedure it will issue an implicit COMMIT when disconnecting from the database anyways. So if I remove the COMMIT in the procedure then yes, the anonymous block demo would work but the real world scenario would not because the COMMIT would still happen. Question Why is 11g behaving differently? Is there anything I can do other than re-write the code?

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• .NET 3.5SP1 64-bit memory model vs. 32-bit memory model

  - by James Dunne

  As I understand it, the .NET memory model on a 32-bit machine guarantees 32-bit word writes and reads to be atomic operations but does not provide this guarantee on 64-bit words. I have written a quick tool to demonstrate this effect on a Windows XP 32-bit OS and am getting results consistent with that memory model description. However, I have taken this same tool's executable and run it on a Windows 7 Enterprise 64-bit OS and am getting wildly different results. Both the machines are identical specs just with different OSes installed. I would have expected that the .NET memory model would guarantee writes and reads to BOTH 32-bit and 64-bit words to be atomic on a 64-bit OS. I find results completely contrary to BOTH assumptions. 32-bit reads and writes are not demonstrated to be atomic on this OS. Can someone explain to me why this fails on a 64-bit OS? Tool code: using System; using System.Threading; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { var th = new Thread(new ThreadStart(RunThread)); var th2 = new Thread(new ThreadStart(RunThread)); int lastRecordedInt = 0; long lastRecordedLong = 0L; th.Start(); th2.Start(); while (!done) { int newIntValue = intValue; long newLongValue = longValue; if (lastRecordedInt > newIntValue) Console.WriteLine("BING(int)! {0} > {1}, {2}", lastRecordedInt, newIntValue, (lastRecordedInt - newIntValue)); if (lastRecordedLong > newLongValue) Console.WriteLine("BING(long)! {0} > {1}, {2}", lastRecordedLong, newLongValue, (lastRecordedLong - newLongValue)); lastRecordedInt = newIntValue; lastRecordedLong = newLongValue; } th.Join(); th2.Join(); Console.WriteLine("{0} =? {2}, {1} =? {3}", intValue, longValue, Int32.MaxValue / 2, (long)Int32.MaxValue + (Int32.MaxValue / 2)); } private static long longValue = Int32.MaxValue; private static int intValue; private static bool done = false; static void RunThread() { for (int i = 0; i < Int32.MaxValue / 4; ++i) { ++longValue; ++intValue; } done = true; } } } Results on Windows XP 32-bit: Windows XP 32-bit Intel Core2 Duo P8700 @ 2.53GHz BING(long)! 2161093208 > 2161092246, 962 BING(long)! 2162448397 > 2161273312, 1175085 BING(long)! 2270110050 > 2270109040, 1010 BING(long)! 2270115061 > 2270110059, 5002 BING(long)! 2558052223 > 2557528157, 524066 BING(long)! 2571660540 > 2571659563, 977 BING(long)! 2646433569 > 2646432557, 1012 BING(long)! 2660841714 > 2660840732, 982 BING(long)! 2661795522 > 2660841715, 953807 BING(long)! 2712855281 > 2712854239, 1042 BING(long)! 2737627472 > 2735210929, 2416543 1025780885 =? 1073741823, 3168207035 =? 3221225470 Notice how BING(int) is never written and demonstrates that 32-bit reads/writes are atomic on this 32-bit OS. Results on Windows 7 Enterprise 64-bit: Windows 7 Enterprise 64-bit Intel Core2 Duo P8700 @ 2.53GHz BING(long)! 2208482159 > 2208121217, 360942 BING(int)! 280292777 > 279704627, 588150 BING(int)! 308158865 > 308131694, 27171 BING(long)! 2549116628 > 2548884894, 231734 BING(int)! 534815527 > 534708027, 107500 BING(int)! 545113548 > 544270063, 843485 BING(long)! 2710030799 > 2709941968, 88831 BING(int)! 668662394 > 667539649, 1122745 1006355562 =? 1073741823, 3154727581 =? 3221225470 Notice that BING(long) AND BING(int) are both displayed! Why are the 32-bit operations failing, let alone the 64-bit ones?

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• How does Ocaml decide precedence for user-defined operators?

  - by forefinger

  I want nice operators for complex arithmetic to make my code more readable. Ocaml has a Complex module, so I just want to add operators that call those functions. The most intuitive way for me is to make a new complex operator from all of the usual operators by appending '&' to the operator symbol. Thus +& and *& will be complex addition and multiplication. I would also like ~& to be complex conjugation. If I'm going to use these operators, I want them to associate the same way that normal arithmetic associates. Based on the following sessions, they are automatically behaving the way I want, but I would like to understand why, so that I don't get horrible bugs when I introduce more operators. My current guess is that their precedence is done by lexically sorting the operator symbols according to an ordering that is consistent with normal arithmetic precedence. But I cannot confirm this. Session one: # open Complex;; # let (+&) a b = add a b;; val ( +& ) : Complex.t -> Complex.t -> Complex.t = <fun> # let ( *&) a b = mul a b;; val ( *& ) : Complex.t -> Complex.t -> Complex.t = <fun> # one +& zero *& one +& zero *& one;; - : Complex.t = {re = 1.; im = 0.} # zero +& one *& zero +& one *& zero;; - : Complex.t = {re = 0.; im = 0.} # i +& i *& i +& i *& i *& i;; - : Complex.t = {re = -1.; im = 0.} Session two: # open Complex;; # let ( *&) a b = mul a b;; val ( *& ) : Complex.t -> Complex.t -> Complex.t = <fun> # let (+&) a b = add a b;; val ( +& ) : Complex.t -> Complex.t -> Complex.t = <fun> # one +& zero *& one +& zero *& one;; - : Complex.t = {re = 1.; im = 0.} # zero +& one *& zero +& one *& zero;; - : Complex.t = {re = 0.; im = 0.} # i +& i *& i +& i *& i *& i;; - : Complex.t = {re = -1.; im = 0.} # let (~&) a = conj a;; val ( ~& ) : Complex.t -> Complex.t = <fun> # (one +& i) *& ~& (one +& i);; - : Complex.t = {re = 2.; im = 0.}

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• Creating STA COM compatible ASP.NET Applications

  - by Rick Strahl

  When building ASP.NET applications that interface with old school COM objects like those created with VB6 or Visual FoxPro (MTDLL), it's extremely important that the threads that are serving requests use Single Threaded Apartment Threading. STA is a COM built-in technology that allows essentially single threaded components to operate reliably in a multi-threaded environment. STA's guarantee that COM objects instantiated on a specific thread stay on that specific thread and any access to a COM object from another thread automatically marshals that thread to the STA thread. The end effect is that you can have multiple threads, but a COM object instance lives on a fixed never changing thread. ASP.NET by default uses MTA (multi-threaded apartment) threads which are truly free spinning threads that pay no heed to COM object marshaling. This is vastly more efficient than STA threading which has a bit of overhead in determining whether it's OK to run code on a given thread or whether some sort of thread/COM marshaling needs to occur. MTA COM components can be very efficient, but STA COM components in a multi-threaded environment always tend to have a fair amount of overhead. It's amazing how much COM Interop I still see today so while it seems really old school to be talking about this topic, it's actually quite apropos for me as I have many customers using legacy COM systems that need to interface with other .NET applications. In this post I'm consolidating some of the hacks I've used to integrate with various ASP.NET technologies when using STA COM Components. STA in ASP.NET Support for STA threading in the ASP.NET framework is fairly limited. Specifically only the original ASP.NET WebForms technology supports STA threading directly via its STA Page Handler implementation or what you might know as ASPCOMPAT mode. For WebForms running STA components is as easy as specifying the ASPCOMPAT attribute in the @Page tag:<%@ Page Language="C#" AspCompat="true" %> which runs the page in STA mode. Removing it runs in MTA mode. Simple. Unfortunately all other ASP.NET technologies built on top of the core ASP.NET engine do not support STA natively. So if you want to use STA COM components in MVC or with class ASMX Web Services, there's no automatic way like the ASPCOMPAT keyword available. So what happens when you run an STA COM component in an MTA application? In low volume environments - nothing much will happen. The COM objects will appear to work just fine as there are no simultaneous thread interactions and the COM component will happily run on a single thread or multiple single threads one at a time. So for testing running components in MTA environments may appear to work just fine. However as load increases and threads get re-used by ASP.NET COM objects will end up getting created on multiple different threads. This can result in crashes or hangs, or data corruption in the STA components which store their state in thread local storage on the STA thread. If threads overlap this global store can easily get corrupted which in turn causes problems. STA ensures that any COM object instance loaded always stays on the same thread it was instantiated on. What about COM+? COM+ is supposed to address the problem of STA in MTA applications by providing an abstraction with it's own thread pool manager for COM objects. It steps in to the COM instantiation pipeline and hands out COM instances from its own internally maintained STA Thread pool. This guarantees that the COM instantiation threads are STA threads if using STA components. COM+ works, but in my experience the technology is very, very slow for STA components. It adds a ton of overhead and reduces COM performance noticably in load tests in IIS. COM+ can make sense in some situations but for Web apps with STA components it falls short. In addition there's also the need to ensure that COM+ is set up and configured on the target machine and the fact that components have to be registered in COM+. COM+ also keeps components up at all times, so if a component needs to be replaced the COM+ package needs to be unloaded (same is true for IIS hosted components but it's more common to manage that). COM+ is an option for well established components, but native STA support tends to provide better performance and more consistent usability, IMHO. STA for non supporting ASP.NET Technologies As mentioned above only WebForms supports STA natively. However, by utilizing the WebForms ASP.NET Page handler internally it's actually possible to trick various other ASP.NET technologies and let them work with STA components. This is ugly but I've used each of these in various applications and I've had minimal problems making them work with FoxPro STA COM components which is about as dififcult as it gets for COM Interop in .NET. In this post I summarize several STA workarounds that enable you to use STA threading with these ASP.NET Technologies: ASMX Web Services ASP.NET MVC WCF Web Services ASP.NET Web API ASMX Web Services I start with classic ASP.NET ASMX Web Services because it's the easiest mechanism that allows for STA modification. It also clearly demonstrates how the WebForms STA Page Handler is the key technology to enable the various other solutions to create STA components. Essentially the way this works is to override the WebForms Page class and hijack it's init functionality for processing requests. Here's what this looks like for Web Services:namespace FoxProAspNet { public class WebServiceStaHandler : System.Web.UI.Page, IHttpAsyncHandler { protected override void OnInit(EventArgs e) { IHttpHandler handler = new WebServiceHandlerFactory().GetHandler( this.Context, this.Context.Request.HttpMethod, this.Context.Request.FilePath, this.Context.Request.PhysicalPath); handler.ProcessRequest(this.Context); this.Context.ApplicationInstance.CompleteRequest(); } public IAsyncResult BeginProcessRequest( HttpContext context, AsyncCallback cb, object extraData) { return this.AspCompatBeginProcessRequest(context, cb, extraData); } public void EndProcessRequest(IAsyncResult result) { this.AspCompatEndProcessRequest(result); } } public class AspCompatWebServiceStaHandlerWithSessionState : WebServiceStaHandler, IRequiresSessionState { } } This class overrides the ASP.NET WebForms Page class which has a little known AspCompatBeginProcessRequest() and AspCompatEndProcessRequest() method that is responsible for providing the WebForms ASPCOMPAT functionality. These methods handle routing requests to STA threads. Note there are two classes - one that includes session state and one that does not. If you plan on using ASP.NET Session state use the latter class, otherwise stick to the former. This maps to the EnableSessionState page setting in WebForms. This class simply hooks into this functionality by overriding the BeginProcessRequest and EndProcessRequest methods and always forcing it into the AspCompat methods. The way this works is that BeginProcessRequest() fires first to set up the threads and starts intializing the handler. As part of that process the OnInit() method is fired which is now already running on an STA thread. The code then creates an instance of the actual WebService handler factory and calls its ProcessRequest method to start executing which generates the Web Service result. Immediately after ProcessRequest the request is stopped with Application.CompletRequest() which ensures that the rest of the Page handler logic doesn't fire. This means that even though the fairly heavy Page class is overridden here, it doesn't end up executing any of its internal processing which makes this code fairly efficient. In a nutshell, we're highjacking the Page HttpHandler and forcing it to process the WebService process handler in the context of the AspCompat handler behavior. Hooking up the Handler Because the above is an HttpHandler implementation you need to hook up the custom handler and replace the standard ASMX handler. To do this you need to modify the web.config file (here for IIS 7 and IIS Express): <configuration> <system.webServer> <handlers> <remove name="WebServiceHandlerFactory-Integrated-4.0" /> <add name="Asmx STA Web Service Handler" path="*.asmx" verb="*" type="FoxProAspNet.WebServiceStaHandler" precondition="integrated"/> </handlers> </system.webServer> </configuration> (Note: The name for the WebServiceHandlerFactory-Integrated-4.0 might be slightly different depending on your server version. Check the IIS Handler configuration in the IIS Management Console for the exact name or simply remove the handler from the list there which will propagate to your web.config). For IIS 5 & 6 (Windows XP/2003) or the Visual Studio Web Server use:<configuration> <system.web> <httpHandlers> <remove path="*.asmx" verb="*" /> <add path="*.asmx" verb="*" type="FoxProAspNet.WebServiceStaHandler" /> </httpHandlers> </system.web></configuration> To test, create a new ASMX Web Service and create a method like this: [WebService(Namespace = "http://foxaspnet.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] public class FoxWebService : System.Web.Services.WebService { [WebMethod] public string HelloWorld() { return "Hello World. Threading mode is: " + System.Threading.Thread.CurrentThread.GetApartmentState(); } } Run this before you put in the web.config configuration changes and you should get: Hello World. Threading mode is: MTA Then put the handler mapping into Web.config and you should see: Hello World. Threading mode is: STA And you're on your way to using STA COM components. It's a hack but it works well! I've used this with several high volume Web Service installations with various customers and it's been fast and reliable. ASP.NET MVC ASP.NET MVC has quickly become the most popular ASP.NET technology, replacing WebForms for creating HTML output. MVC is more complex to get started with, but once you understand the basic structure of how requests flow through the MVC pipeline it's easy to use and amazingly flexible in manipulating HTML requests. In addition, MVC has great support for non-HTML output sources like JSON and XML, making it an excellent choice for AJAX requests without any additional tools. Unlike WebForms ASP.NET MVC doesn't support STA threads natively and so some trickery is needed to make it work with STA threads as well. MVC gets its handler implementation through custom route handlers using ASP.NET's built in routing semantics. To work in an STA handler requires working in the Page Handler as part of the Route Handler implementation. As with the Web Service handler the first step is to create a custom HttpHandler that can instantiate an MVC request pipeline properly:public class MvcStaThreadHttpAsyncHandler : Page, IHttpAsyncHandler, IRequiresSessionState { private RequestContext _requestContext; public MvcStaThreadHttpAsyncHandler(RequestContext requestContext) { if (requestContext == null) throw new ArgumentNullException("requestContext"); _requestContext = requestContext; } public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData) { return this.AspCompatBeginProcessRequest(context, cb, extraData); } protected override void OnInit(EventArgs e) { var controllerName = _requestContext.RouteData.GetRequiredString("controller"); var controllerFactory = ControllerBuilder.Current.GetControllerFactory(); var controller = controllerFactory.CreateController(_requestContext, controllerName); if (controller == null) throw new InvalidOperationException("Could not find controller: " + controllerName); try { controller.Execute(_requestContext); } finally { controllerFactory.ReleaseController(controller); } this.Context.ApplicationInstance.CompleteRequest(); } public void EndProcessRequest(IAsyncResult result) { this.AspCompatEndProcessRequest(result); } public override void ProcessRequest(HttpContext httpContext) { throw new NotSupportedException("STAThreadRouteHandler does not support ProcessRequest called (only BeginProcessRequest)"); } } This handler code figures out which controller to load and then executes the controller. MVC internally provides the information needed to route to the appropriate method and pass the right parameters. Like the Web Service handler the logic occurs in the OnInit() and performs all the processing in that part of the request. Next, we need a RouteHandler that can actually pick up this handler. Unlike the Web Service handler where we simply registered the handler, MVC requires a RouteHandler to pick up the handler. RouteHandlers look at the URL's path and based on that decide on what handler to invoke. The route handler is pretty simple - all it does is load our custom handler: public class MvcStaThreadRouteHandler : IRouteHandler { public IHttpHandler GetHttpHandler(RequestContext requestContext) { if (requestContext == null) throw new ArgumentNullException("requestContext"); return new MvcStaThreadHttpAsyncHandler(requestContext); } } At this point you can instantiate this route handler and force STA requests to MVC by specifying a route. The following sets up the ASP.NET Default Route:Route mvcRoute = new Route("{controller}/{action}/{id}", new RouteValueDictionary( new { controller = "Home", action = "Index", id = UrlParameter.Optional }), new MvcStaThreadRouteHandler()); RouteTable.Routes.Add(mvcRoute);   To make this code a little easier to work with and mimic the behavior of the routes.MapRoute() functionality extension method that MVC provides, here is an extension method for MapMvcStaRoute(): public static class RouteCollectionExtensions { public static void MapMvcStaRoute(this RouteCollection routeTable, string name, string url, object defaults = null) { Route mvcRoute = new Route(url, new RouteValueDictionary(defaults), new MvcStaThreadRouteHandler()); RouteTable.Routes.Add(mvcRoute); } } With this the syntax to add  route becomes a little easier and matches the MapRoute() method:RouteTable.Routes.MapMvcStaRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); The nice thing about this route handler, STA Handler and extension method is that it's fully self contained. You can put all three into a single class file and stick it into your Web app, and then simply call MapMvcStaRoute() and it just works. Easy! To see whether this works create an MVC controller like this: public class ThreadTestController : Controller { public string ThreadingMode() { return Thread.CurrentThread.GetApartmentState().ToString(); } } Try this test both with only the MapRoute() hookup in the RouteConfiguration in which case you should get MTA as the value. Then change the MapRoute() call to MapMvcStaRoute() leaving all the parameters the same and re-run the request. You now should see STA as the result. You're on your way using STA COM components reliably in ASP.NET MVC. WCF Web Services running through IIS WCF Web Services provide a more robust and wider range of services for Web Services. You can use WCF over HTTP, TCP, and Pipes, and WCF services support WS* secure services. There are many features in WCF that go way beyond what ASMX can do. But it's also a bit more complex than ASMX. As a basic rule if you need to serve straight SOAP Services over HTTP I 'd recommend sticking with the simpler ASMX services especially if COM is involved. If you need WS* support or want to serve data over non-HTTP protocols then WCF makes more sense. WCF is not my forte but I found a solution from Scott Seely on his blog that describes the progress and that seems to work well. I'm copying his code below so this STA information is all in one place and quickly explain. Scott's code basically works by creating a custom OperationBehavior which can be specified via an [STAOperation] attribute on every method. Using his attribute you end up with a class (or Interface if you separate the contract and class) that looks like this: [ServiceContract] public class WcfService { [OperationContract] public string HelloWorldMta() { return Thread.CurrentThread.GetApartmentState().ToString(); } // Make sure you use this custom STAOperationBehavior // attribute to force STA operation of service methods [STAOperationBehavior] [OperationContract] public string HelloWorldSta() { return Thread.CurrentThread.GetApartmentState().ToString(); } } Pretty straight forward. The latter method returns STA while the former returns MTA. To make STA work every method needs to be marked up. The implementation consists of the attribute and OperationInvoker implementation. Here are the two classes required to make this work from Scott's post:public class STAOperationBehaviorAttribute : Attribute, IOperationBehavior { public void AddBindingParameters(OperationDescription operationDescription, System.ServiceModel.Channels.BindingParameterCollection bindingParameters) { } public void ApplyClientBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.ClientOperation clientOperation) { // If this is applied on the client, well, it just doesn’t make sense. // Don’t throw in case this attribute was applied on the contract // instead of the implementation. } public void ApplyDispatchBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.DispatchOperation dispatchOperation) { // Change the IOperationInvoker for this operation. dispatchOperation.Invoker = new STAOperationInvoker(dispatchOperation.Invoker); } public void Validate(OperationDescription operationDescription) { if (operationDescription.SyncMethod == null) { throw new InvalidOperationException("The STAOperationBehaviorAttribute " + "only works for synchronous method invocations."); } } } public class STAOperationInvoker : IOperationInvoker { IOperationInvoker _innerInvoker; public STAOperationInvoker(IOperationInvoker invoker) { _innerInvoker = invoker; } public object[] AllocateInputs() { return _innerInvoker.AllocateInputs(); } public object Invoke(object instance, object[] inputs, out object[] outputs) { // Create a new, STA thread object[] staOutputs = null; object retval = null; Thread thread = new Thread( delegate() { retval = _innerInvoker.Invoke(instance, inputs, out staOutputs); }); thread.SetApartmentState(ApartmentState.STA); thread.Start(); thread.Join(); outputs = staOutputs; return retval; } public IAsyncResult InvokeBegin(object instance, object[] inputs, AsyncCallback callback, object state) { // We don’t handle async… throw new NotImplementedException(); } public object InvokeEnd(object instance, out object[] outputs, IAsyncResult result) { // We don’t handle async… throw new NotImplementedException(); } public bool IsSynchronous { get { return true; } } } The key in this setup is the Invoker and the Invoke method which creates a new thread and then fires the request on this new thread. Because this approach creates a new thread for every request it's not super efficient. There's a bunch of overhead involved in creating the thread and throwing it away after each thread, but it'll work for low volume requests and insure each thread runs in STA mode. If better performance is required it would be useful to create a custom thread manager that can pool a number of STA threads and hand off threads as needed rather than creating new threads on every request. If your Web Service needs are simple and you need only to serve standard SOAP 1.x requests, I would recommend sticking with ASMX services. It's easier to set up and work with and for STA component use it'll be significantly better performing since ASP.NET manages the STA thread pool for you rather than firing new threads for each request. One nice thing about Scotts code is though that it works in any WCF environment including self hosting. It has no dependency on ASP.NET or WebForms for that matter. STA - If you must STA components are a  pain in the ass and thankfully there isn't too much stuff out there anymore that requires it. But when you need it and you need to access STA functionality from .NET at least there are a few options available to make it happen. Each of these solutions is a bit hacky, but they work - I've used all of them in production with good results with FoxPro components. I hope compiling all of these in one place here makes it STA consumption a little bit easier. I feel your pain :-) Resources Download STA Handler Code Examples Scott Seely's original STA WCF OperationBehavior Article© Rick Strahl, West Wind Technologies, 2005-2012Posted in FoxPro   ASP.NET  .NET  COM   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Rounded Corners and Shadows &ndash; Dialogs with CSS

  - by Rick Strahl

  Well, it looks like we’ve finally arrived at a place where at least all of the latest versions of main stream browsers support rounded corners and box shadows. The two CSS properties that make this possible are box-shadow and box-radius. Both of these CSS Properties now supported in all the major browsers as shown in this chart from QuirksMode: In it’s simplest form you can use box-shadow and border radius like this: .boxshadow { -moz-box-shadow: 3px 3px 5px #535353; -webkit-box-shadow: 3px 3px 5px #535353; box-shadow: 3px 3px 5px #535353; } .roundbox { -moz-border-radius: 6px 6px 6px 6px; -webkit-border-radius: 6px; border-radius: 6px 6px 6px 6px; } box-shadow: horizontal-shadow-pixels vertical-shadow-pixels blur-distance shadow-color box-shadow attributes specify the the horizontal and vertical offset of the shadow, the blur distance (to give the shadow a smooth soft look) and a shadow color. The spec also supports multiple shadows separated by commas using the attributes above but we’re not using that functionality here. box-radius: top-left-radius top-right-radius bottom-right-radius bottom-left-radius border-radius takes a pixel size for the radius for each corner going clockwise. CSS 3 also specifies each of the individual corner elements such as border-top-left-radius, but support for these is much less prevalent so I would recommend not using them for now until support improves. Instead use the single box-radius to specify all corners. Browser specific Support in older Browsers Notice that there are two variations: The actual CSS 3 properties (box-shadow and box-radius) and the browser specific ones (-moz, –webkit prefixes for FireFox and Chrome/Safari respectively) which work in slightly older versions of modern browsers before official CSS 3 support was added. The goal is to spread support as widely as possible and the prefix versions extend the range slightly more to those browsers that provided early support for these features. Notice that box-shadow and border-radius are used after the browser specific versions to ensure that the latter versions get precedence if the browser supports both (last assignment wins). Use the .boxshadow and .roundbox Styles in HTML To use these two styles create a simple rounded box with a shadow you can use HTML like this: <!-- Simple Box with rounded corners and shadow --> <div class="roundbox boxshadow" style="width: 550px; border: solid 2px steelblue"> <div class="boxcontenttext"> Simple Rounded Corner Box. </div> </div> which looks like this in the browser: This works across browsers and it’s pretty sweet and simple. Watch out for nested Elements! There are a couple of things to be aware of however when using rounded corners. Specifically, you need to be careful when you nest other non-transparent content into the rounded box. For example check out what happens when I change the inside <div> to have a colored background: <!-- Simple Box with rounded corners and shadow --> <div class="roundbox boxshadow" style="width: 550px; border: solid 2px steelblue"> <div class="boxcontenttext" style="background: khaki;"> Simple Rounded Corner Box. </div> </div> which renders like this:   If you look closely you’ll find that the inside <div>’s corners are not rounded and so ‘poke out’ slightly over the rounded corners. It looks like the rounded corners are ‘broken’ up instead of a solid rounded line around the corner, which his pretty ugly. The bigger the radius the more drastic this effect becomes . To fix this issue the inner <div> also has have rounded corners at the same or slightly smaller radius than the outer <div>. The simple fix for this is to simply also apply the roundbox style to the inner <div> in addition to the boxcontenttext style already applied: <div class="boxcontenttext roundbox" style="background: khaki;"> The fixed display now looks proper: Separate Top and Bottom Elements This gets even a little more tricky if you have an element at the top or bottom only of the rounded box. What if you need to add something like a header or footer <div> that have non-transparent backgrounds which is a pretty common scenario? In those cases you want only the top or bottom corners rounded and not both. To make this work a couple of additional styles to round only the top and bottom corners can be created: .roundbox-top { -moz-border-radius: 4px 4px 0 0; -webkit-border-radius: 4px 4px 0 0; border-radius: 4px 4px 0 0; } .roundbox-bottom { -moz-border-radius: 0 0 4px 4px; -webkit-border-radius: 0 0 4px 4px; border-radius: 0 0 4px 4px; } Notice that radius used for the ‘inside’ rounding is smaller (4px) than the outside radius (6px). This is so the inner radius fills into the outer border – if you use the same size you may have some white space showing between inner and out rounded corners. Experiment with values to see what works – in my experimenting the behavior across browsers here is consistent (thankfully). These styles can be applied in addition to other styles to make only the top or bottom portions of an element rounded. For example imagine I have styles like this: .gridheader, .gridheaderbig, .gridheaderleft, .gridheaderright { padding: 4px 4px 4px 4px; background: #003399 url(images/vertgradient.png) repeat-x; text-align: center; font-weight: bold; text-decoration: none; color: khaki; } .gridheaderleft { text-align: left; } .gridheaderright { text-align: right; } .gridheaderbig { font-size: 135%; } If I just apply say gridheader by itself in HTML like this: <div class="roundbox boxshadow" style="width: 550px; border: solid 2px steelblue"> <div class="gridheaderleft">Box with a Header</div> <div class="boxcontenttext" style="background: khaki;"> Simple Rounded Corner Box. </div> </div> This results in a pretty funky display – again due to the fact that the inner elements render square rather than rounded corners: If you look close again you can see that both the header and the main content have square edges which jumps out at the eye. To fix this you can now apply the roundbox-top and roundbox-bottom to the header and content respectively: <div class="roundbox boxshadow" style="width: 550px; border: solid 2px steelblue"> <div class="gridheaderleft roundbox-top">Box with a Header</div> <div class="boxcontenttext roundbox-bottom" style="background: khaki;"> Simple Rounded Corner Box. </div> </div> Which now gives the proper display with rounded corners both on the top and bottom: All of this is sweet to be supported – at least by the newest browser – without having to resort to images and nasty JavaScripts solutions. While this is still not a mainstream feature yet for the majority of actually installed browsers, the majority of browser users are very likely to have this support as most browsers other than IE are actively pushing users to upgrade to newer versions. Since this is a ‘visual display only feature it degrades reasonably well in non-supporting browsers: You get an uninteresting square and non-shadowed browser box, but the display is still overall functional. The main sticking point – as always is Internet Explorer versions 8.0 and down as well as older versions of other browsers. With those browsers you get a functional view that is a little less interesting to look at obviously: but at least it’s still functional. Maybe that’s just one more incentive for people using older browsers to upgrade to a  more modern browser :-) Creating Dialog Related Styles In a lot of my AJAX based applications I use pop up windows which effectively work like dialogs. Using the simple CSS behaviors above, it’s really easy to create some fairly nice looking overlaid windows with nothing but CSS. Here’s what a typical ‘dialog’ I use looks like: The beauty of this is that it’s plain CSS – no plug-ins or images (other than the gradients which are optional) required. Add jQuery-ui draggable (or ww.jquery.js as shown below) and you have a nice simple inline implementation of a dialog represented by a simple <div> tag. Here’s the HTML for this dialog: <div id="divDialog" class="dialog boxshadow" style="width: 450px;"> <div class="dialog-header"> <div class="closebox"></div> User Sign-in </div> <div class="dialog-content"> <label>Username:</label> <input type="text" name="txtUsername" value=" " /> <label>Password</label> <input type="text" name="txtPassword" value=" " /> <hr /> <input type="button" id="btnLogin" value="Login" /> </div> <div class="dialog-statusbar">Ready</div> </div> Most of this behavior is driven by the ‘dialog’ styles which are fairly basic and easy to understand. They do use a few support images for the gradients which are provided in the sample I’ve provided. Here’s what the CSS looks like: .dialog { background: White; overflow: hidden; border: solid 1px steelblue; -moz-border-radius: 6px 6px 4px 4px; -webkit-border-radius: 6px 6px 4px 4px; border-radius: 6px 6px 3px 3px; } .dialog-header { background-image: url(images/dialogheader.png); background-repeat: repeat-x; text-align: left; color: cornsilk; padding: 5px; padding-left: 10px; font-size: 1.02em; font-weight: bold; position: relative; -moz-border-radius: 4px 4px 0px 0px; -webkit-border-radius: 4px 4px 0px 0px; border-radius: 4px 4px 0px 0px; } .dialog-top { -moz-border-radius: 4px 4px 0px 0px; -webkit-border-radius: 4px 4px 0px 0px; border-radius: 4px 4px 0px 0px; } .dialog-bottom { -moz-border-radius: 0 0 3px 3px; -webkit-border-radius: 0 0 3px 3px; border-radius: 0 0 3px 3px; } .dialog-content { padding: 15px; } .dialog-statusbar, .dialog-toolbar { background: #eeeeee; background-image: url(images/dialogstrip.png); background-repeat: repeat-x; padding: 5px; padding-left: 10px; border-top: solid 1px silver; border-bottom: solid 1px silver; font-size: 0.8em; } .dialog-statusbar { -moz-border-radius: 0 0 3px 3px; -webkit-border-radius: 0 0 3px 3px; border-radius: 0 0 3px 3px; padding-right: 10px; } .closebox { position: absolute; right: 2px; top: 2px; background-image: url(images/close.gif); background-repeat: no-repeat; width: 14px; height: 14px; cursor: pointer; opacity: 0.60; filter: alpha(opacity="80"); } .closebox:hover { opacity: 1; filter: alpha(opacity="100"); } The main style is the dialog class which is the outer box. It has the rounded border that serves as the outline. Note that I didn’t add the box-shadow to this style because in some situations I just want the rounded box in an inline display that doesn’t have a shadow so it’s still applied separately. dialog-header, then has the rounded top corners and displays a typical dialog heading format. dialog-bottom and dialog-top then provide the same functionality as roundbox-top and roundbox-bottom described earlier but are provided mainly in the stylesheet for consistency to match the dialog’s round edges and making it easier to  remember and find in Intellisense as it shows up in the same dialog- group. dialog-statusbar and dialog-toolbar are two elements I use a lot for floating windows – the toolbar serves for buttons and options and filters typically, while the status bar provides information specific to the floating window. Since the the status bar is always on the bottom of the dialog it automatically handles the rounding of the bottom corners. Finally there’s  closebox style which is to be applied to an empty <div> tag in the header typically. What this does is render a close image that is by default low-lighted with a low opacity value, and then highlights when hovered over. All you’d have to do handle the close operation is handle the onclick of the <div>. Note that the <div> right aligns so typically you should specify it before any other content in the header. Speaking of closable – some time ago I created a closable jQuery plug-in that basically automates this process and can be applied against ANY element in a page, automatically removing or closing the element with some simple script code. Using this you can leave out the <div> tag for closable and just do the following: To make the above dialog closable (and draggable) which makes it effectively and overlay window, you’d add jQuery.js and ww.jquery.js to the page: <script type="text/javascript" src="../../scripts/jquery.min.js"></script> <script type="text/javascript" src="../../scripts/ww.jquery.min.js"></script> and then simply call: <script type="text/javascript"> $(document).ready(function () { $("#divDialog") .draggable({ handle: ".dialog-header" }) .closable({ handle: ".dialog-header", closeHandler: function () { alert("Window about to be closed."); return true; // true closes - false leaves open } }); }); </script> * ww.jquery.js emulates base features in jQuery-ui’s draggable. If jQuery-ui is loaded its draggable version will be used instead and voila you have now have a draggable and closable window – here in mid-drag:   The dragging and closable behaviors are of course optional, but it’s the final touch that provides dialog like window behavior. Relief for older Internet Explorer Versions with CSS Pie If you want to get these features to work with older versions of Internet Explorer all the way back to version 6 you can check out CSS Pie. CSS Pie provides an Internet Explorer behavior file that attaches to specific CSS rules and simulates these behavior using script code in IE (mostly by implementing filters). You can simply add the behavior to each CSS style that uses box-shadow and border-radius like this: .boxshadow {     -moz-box-shadow: 3px 3px 5px #535353;     -webkit-box-shadow: 3px 3px 5px #535353;           box-shadow: 3px 3px 5px #535353;     behavior: url(scripts/PIE.htc);           } .roundbox {      -moz-border-radius: 6px 6px 6px 6px;     -webkit-border-radius: 6px;      border-radius: 6px 6px 6px 6px;     behavior: url(scripts/PIE.htc); } CSS Pie requires the PIE.htc on your server and referenced from each CSS style that needs it. Note that the url() for IE behaviors is NOT CSS file relative as other CSS resources, but rather PAGE relative , so if you have more than one folder you probably need to reference the HTC file with a fixed path like this: behavior: url(/MyApp/scripts/PIE.htc); in the style. Small price to pay, but a royal pain if you have a common CSS file you use in many applications. Once the PIE.htc file has been copied and you have applied the behavior to each style that uses these new features Internet Explorer will render rounded corners and box shadows! Yay! Hurray for box-shadow and border-radius All of this functionality is very welcome natively in the browser. If you think this is all frivolous visual candy, you might be right :-), but if you take a look on the Web and search for rounded corner solutions that predate these CSS attributes you’ll find a boatload of stuff from image files, to custom drawn content to Javascript solutions that play tricks with a few images. It’s sooooo much easier to have this functionality built in and I for one am glad to see that’s it’s finally becoming standard in the box. Still remember that when you use these new CSS features, they are not universal, and are not going to be really soon. Legacy browsers, especially old versions of Internet Explorer that can’t be updated will continue to be around and won’t work with this shiny new stuff. I say screw ‘em: Let them get a decent recent browser or see a degraded and ugly UI. We have the luxury with this functionality in that it doesn’t typically affect usability – it just doesn’t look as nice. Resources Download the Sample The sample includes the styles and images and sample page as well as ww.jquery.js for the draggable/closable example. Online Sample Check out the sample described in this post online. Closable and Draggable Documentation Documentation for the closeable and draggable plug-ins in ww.jquery.js. You can also check out the full documentation for all the plug-ins contained in ww.jquery.js here. © Rick Strahl, West Wind Technologies, 2005-2011Posted in HTML  CSS  

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• The broken Promise of the Mobile Web

  - by Rick Strahl

  High end mobile devices have been with us now for almost 7 years and they have utterly transformed the way we access information. Mobile phones and smartphones that have access to the Internet and host smart applications are in the hands of a large percentage of the population of the world. In many places even very remote, cell phones and even smart phones are a common sight. I’ll never forget when I was in India in 2011 I was up in the Southern Indian mountains riding an elephant out of a tiny local village, with an elephant herder in front riding atop of the elephant in front of us. He was dressed in traditional garb with the loin wrap and head cloth/turban as did quite a few of the locals in this small out of the way and not so touristy village. So we’re slowly trundling along in the forest and he’s lazily using his stick to guide the elephant and… 10 minutes in he pulls out his cell phone from his sash and starts texting. In the middle of texting a huge pig jumps out from the side of the trail and he takes a picture running across our path in the jungle! So yeah, mobile technology is very pervasive and it’s reached into even very buried and unexpected parts of this world. Apps are still King Apps currently rule the roost when it comes to mobile devices and the applications that run on them. If there’s something that you need on your mobile device your first step usually is to look for an app, not use your browser. But native app development remains a pain in the butt, with the requirement to have to support 2 or 3 completely separate platforms. There are solutions that try to bridge that gap. Xamarin is on a tear at the moment, providing their cross-device toolkit to build applications using C#. While Xamarin tools are impressive – and also *very* expensive – they only address part of the development madness that is app development. There are still specific device integration isssues, dealing with the different developer programs, security and certificate setups and all that other noise that surrounds app development. There’s also PhoneGap/Cordova which provides a hybrid solution that involves creating local HTML/CSS/JavaScript based applications, and then packaging them to run in a specialized App container that can run on most mobile device platforms using a WebView interface. This allows for using of HTML technology, but it also still requires all the set up, configuration of APIs, security keys and certification and submission and deployment process just like native applications – you actually lose many of the benefits that  Web based apps bring. The big selling point of Cordova is that you get to use HTML have the ability to build your UI once for all platforms and run across all of them – but the rest of the app process remains in place. Apps can be a big pain to create and manage especially when we are talking about specialized or vertical business applications that aren’t geared at the mainstream market and that don’t fit the ‘store’ model. If you’re building a small intra department application you don’t want to deal with multiple device platforms and certification etc. for various public or corporate app stores. That model is simply not a good fit both from the development and deployment perspective. Even for commercial, big ticket apps, HTML as a UI platform offers many advantages over native, from write-once run-anywhere, to remote maintenance, single point of management and failure to having full control over the application as opposed to have the app store overloads censor you. In a lot of ways Web based HTML/CSS/JavaScript applications have so much potential for building better solutions based on existing Web technologies for the very same reasons a lot of content years ago moved off the desktop to the Web. To me the Web as a mobile platform makes perfect sense, but the reality of today’s Mobile Web unfortunately looks a little different… Where’s the Love for the Mobile Web? Yet here we are in the middle of 2014, nearly 7 years after the first iPhone was released and brought the promise of rich interactive information at your fingertips, and yet we still don’t really have a solid mobile Web platform. I know what you’re thinking: “But we have lots of HTML/JavaScript/CSS features that allows us to build nice mobile interfaces”. I agree to a point – it’s actually quite possible to build nice looking, rich and capable Web UI today. We have media queries to deal with varied display sizes, CSS transforms for smooth animations and transitions, tons of CSS improvements in CSS 3 that facilitate rich layout, a host of APIs geared towards mobile device features and lately even a number of JavaScript framework choices that facilitate development of multi-screen apps in a consistent manner. Personally I’ve been working a lot with AngularJs and heavily modified Bootstrap themes to build mobile first UIs and that’s been working very well to provide highly usable and attractive UI for typical mobile business applications. From the pure UI perspective things actually look very good. Not just about the UI But it’s not just about the UI - it’s also about integration with the mobile device. When it comes to putting all those pieces together into what amounts to a consolidated platform to build mobile Web applications, I think we still have a ways to go… there are a lot of missing pieces to make it all work together and integrate with the device more smoothly, and more importantly to make it work uniformly across the majority of devices. I think there are a number of reasons for this. Slow Standards Adoption HTML standards implementations and ratification has been dreadfully slow, and browser vendors all seem to pick and choose different pieces of the technology they implement. The end result is that we have a capable UI platform that’s missing some of the infrastructure pieces to make it whole on mobile devices. There’s lots of potential but what is lacking that final 10% to build truly compelling mobile applications that can compete favorably with native applications. Some of it is the fragmentation of browsers and the slow evolution of the mobile specific HTML APIs. A host of mobile standards exist but many of the standards are in the early review stage and they have been there stuck for long periods of time and seem to move at a glacial pace. Browser vendors seem even slower to implement them, and for good reason – non-ratified standards mean that implementations may change and vendor implementations tend to be experimental and  likely have to be changed later. Neither Vendors or developers are not keen on changing standards. This is the typical chicken and egg scenario, but without some forward momentum from some party we end up stuck in the mud. It seems that either the standards bodies or the vendors need to carry the torch forward and that doesn’t seem to be happening quickly enough. Mobile Device Integration just isn’t good enough Current standards are not far reaching enough to address a number of the use case scenarios necessary for many mobile applications. While not every application needs to have access to all mobile device features, almost every mobile application could benefit from some integration with other parts of the mobile device platform. Integration with GPS, phone, media, messaging, notifications, linking and contacts system are benefits that are unique to mobile applications and could be widely used, but are mostly (with the exception of GPS) inaccessible for Web based applications today. Unfortunately trying to do most of this today only with a mobile Web browser is a losing battle. Aside from PhoneGap/Cordova’s app centric model with its own custom API accessing mobile device features and the token exception of the GeoLocation API, most device integration features are not widely supported by the current crop of mobile browsers. For example there’s no usable messaging API that allows access to SMS or contacts from HTML. Even obvious components like the Media Capture API are only implemented partially by mobile devices. There are alternatives and workarounds for some of these interfaces by using browser specific code, but that’s might ugly and something that I thought we were trying to leave behind with newer browser standards. But it’s not quite working out that way. It’s utterly perplexing to me that mobile standards like Media Capture and Streams, Media Gallery Access, Responsive Images, Messaging API, Contacts Manager API have only minimal or no traction at all today. Keep in mind we’ve had mobile browsers for nearly 7 years now, and yet we still have to think about how to get access to an image from the image gallery or the camera on some devices? Heck Windows Phone IE Mobile just gained the ability to upload images recently in the Windows 8.1 Update – that’s feature that HTML has had for 20 years! These are simple concepts and common problems that should have been solved a long time ago. It’s extremely frustrating to see build 90% of a mobile Web app with relative ease and then hit a brick wall for the remaining 10%, which often can be show stoppers. The remaining 10% have to do with platform integration, browser differences and working around the limitations that browsers and ‘pinned’ applications impose on HTML applications. The maddening part is that these limitations seem arbitrary as they could easily work on all mobile platforms. For example, SMS has a URL Moniker interface that sort of works on Android, works badly with iOS (only works if the address is already in the contact list) and not at all on Windows Phone. There’s no reason this shouldn’t work universally using the same interface – after all all phones have supported SMS since before the year 2000! But, it doesn’t have to be this way Change can happen very quickly. Take the GeoLocation API for example. Geolocation has taken off at the very beginning of the mobile device era and today it works well, provides the necessary security (a big concern for many mobile APIs), and is supported by just about all major mobile and even desktop browsers today. It handles security concerns via prompts to avoid unwanted access which is a model that would work for most other device APIs in a similar fashion. One time approval and occasional re-approval if code changes or caches expire. Simple and only slightly intrusive. It all works well, even though GeoLocation actually has some physical limitations, such as representing the current location when no GPS device is present. Yet this is a solved problem, where other APIs that are conceptually much simpler to implement have failed to gain any traction at all. Technically none of these APIs should be a problem to implement, but it appears that the momentum is just not there. Inadequate Web Application Linking and Activation Another important piece of the puzzle missing is the integration of HTML based Web applications. Today HTML based applications are not first class citizens on mobile operating systems. When talking about HTML based content there’s a big difference between content and applications. Content is great for search engine discovery and plain browser usage. Content is usually accessed intermittently and permanent linking is not so critical for this type of content.  But applications have different needs. Applications need to be started up quickly and must be easily switchable to support a multi-tasking user workflow. Therefore, it’s pretty crucial that mobile Web apps are integrated into the underlying mobile OS and work with the standard task management features. Unfortunately this integration is not as smooth as it should be. It starts with actually trying to find mobile Web applications, to ‘installing’ them onto a phone in an easily accessible manner in a prominent position. The experience of discovering a Mobile Web ‘App’ and making it sticky is by no means as easy or satisfying. Today the way you’d go about this is: Open the browser Search for a Web Site in the browser with your search engine of choice Hope that you find the right site Hope that you actually find a site that works for your mobile device Click on the link and run the app in a fully chrome’d browser instance (read tiny surface area) Pin the app to the home screen (with all the limitations outline above) Hope you pointed at the right URL when you pinned Even for you and me as developers, there are a few steps in there that are painful and annoying, but think about the average user. First figuring out how to search for a specific site or URL? And then pinning the app and hopefully from the right location? You’ve probably lost more than half of your audience at that point. This experience sucks. For developers too this process is painful since app developers can’t control the shortcut creation directly. This problem often gets solved by crazy coding schemes, with annoying pop-ups that try to get people to create shortcuts via fancy animations that are both annoying and add overhead to each and every application that implements this sort of thing differently. And that’s not the end of it - getting the link onto the home screen with an application icon varies quite a bit between browsers. Apple’s non-standard meta tags are prominent and they work with iOS and Android (only more recent versions), but not on Windows Phone. Windows Phone instead requires you to create an actual screen or rather a partial screen be captured for a shortcut in the tile manager. Who had that brilliant idea I wonder? Surprisingly Chrome on recent Android versions seems to actually get it right – icons use pngs, pinning is easy and pinned applications properly behave like standalone apps and retain the browser’s active page state and content. Each of the platforms has a different way to specify icons (WP doesn’t allow you to use an icon image at all), and the most widely used interface in use today is a bunch of Apple specific meta tags that other browsers choose to support. The question is: Why is there no standard implementation for installing shortcuts across mobile platforms using an official format rather than a proprietary one? Then there’s iOS and the crazy way it treats home screen linked URLs using a crazy hybrid format that is neither as capable as a Web app running in Safari nor a WebView hosted application. Moving off the Web ‘app’ link when switching to another app actually causes the browser and preview it to ‘blank out’ the Web application in the Task View (see screenshot on the right). Then, when the ‘app’ is reactivated it ends up completely restarting the browser with the original link. This is crazy behavior that you can’t easily work around. In some situations you might be able to store the application state and restore it using LocalStorage, but for many scenarios that involve complex data sources (like say Google Maps) that’s not a possibility. The only reason for this screwed up behavior I can think of is that it is deliberate to make Web apps a pain in the butt to use and forcing users trough the App Store/PhoneGap/Cordova route. App linking and management is a very basic problem – something that we essentially have solved in every desktop browser – yet on mobile devices where it arguably matters a lot more to have easy access to web content we have to jump through hoops to have even a remotely decent linking/activation experience across browsers. Where’s the Money? It’s not surprising that device home screen integration and Mobile Web support in general is in such dismal shape – the mobile OS vendors benefit financially from App store sales and have little to gain from Web based applications that bypass the App store and the cash cow that it presents. On top of that, platform specific vendor lock-in of both end users and developers who have invested in hardware, apps and consumables is something that mobile platform vendors actually aspire to. Web based interfaces that are cross-platform are the anti-thesis of that and so again it’s no surprise that the mobile Web is on a struggling path. But – that may be changing. More and more we’re seeing operations shifting to services that are subscription based or otherwise collect money for usage, and that may drive more progress into the Web direction in the end . Nothing like the almighty dollar to drive innovation forward. Do we need a Mobile Web App Store? As much as I dislike moderated experiences in today’s massive App Stores, they do at least provide one single place to look for apps for your device. I think we could really use some sort of registry, that could provide something akin to an app store for mobile Web apps, to make it easier to actually find mobile applications. This could take the form of a specialized search engine, or maybe a more formal store/registry like structure. Something like apt-get/chocolatey for Web apps. It could be curated and provide at least some feedback and reviews that might help with the integrity of applications. Coupled to that could be a native application on each platform that would allow searching and browsing of the registry and then also handle installation in the form of providing the home screen linking, plus maybe an initial security configuration that determines what features are allowed access to for the app. I’m not holding my breath. In order for this sort of thing to take off and gain widespread appeal, a lot of coordination would be required. And in order to get enough traction it would have to come from a well known entity – a mobile Web app store from a no name source is unlikely to gain high enough usage numbers to make a difference. In a way this would eliminate some of the freedom of the Web, but of course this would also be an optional search path in addition to the standard open Web search mechanisms to find and access content today. Security Security is a big deal, and one of the perceived reasons why so many IT professionals appear to be willing to go back to the walled garden of deployed apps is that Apps are perceived as safe due to the official review and curation of the App stores. Curated stores are supposed to protect you from malware, illegal and misleading content. It doesn’t always work out that way and all the major vendors have had issues with security and the review process at some time or another. Security is critical, but I also think that Web applications in general pose less of a security threat than native applications, by nature of the sandboxed browser and JavaScript environments. Web applications run externally completely and in the HTML and JavaScript sandboxes, with only a very few controlled APIs allowing access to device specific features. And as discussed earlier – security for any device interaction can be granted the same for mobile applications through a Web browser, as they can for native applications either via explicit policies loaded from the Web, or via prompting as GeoLocation does today. Security is important, but it’s certainly solvable problem for Web applications even those that need to access device hardware. Security shouldn’t be a reason for Web apps to be an equal player in mobile applications. Apps are winning, but haven’t we been here before? So now we’re finding ourselves back in an era of installed app, rather than Web based and managed apps. Only it’s even worse today than with Desktop applications, in that the apps are going through a gatekeeper that charges a toll and censors what you can and can’t do in your apps. Frankly it’s a mystery to me why anybody would buy into this model and why it’s lasted this long when we’ve already been through this process. It’s crazy… It’s really a shame that this regression is happening. We have the technology to make mobile Web apps much more prominent, but yet we’re basically held back by what seems little more than bureaucracy, partisan bickering and self interest of the major parties involved. Back in the day of the desktop it was Internet Explorer’s 98+%  market shareholding back the Web from improvements for many years – now it’s the combined mobile OS market in control of the mobile browsers. If mobile Web apps were allowed to be treated the same as native apps with simple ways to install and run them consistently and persistently, that would go a long way to making mobile applications much more usable and seriously viable alternatives to native apps. But as it is mobile apps have a severe disadvantage in placement and operation. There are a few bright spots in all of this. Mozilla’s FireFoxOs is embracing the Web for it’s mobile OS by essentially building every app out of HTML and JavaScript based content. It supports both packaged and certified package modes (that can be put into the app store), and Open Web apps that are loaded and run completely off the Web and can also cache locally for offline operation using a manifest. Open Web apps are treated as full class citizens in FireFoxOS and run using the same mechanism as installed apps. Unfortunately FireFoxOs is getting a slow start with minimal device support and specifically targeting the low end market. We can hope that this approach will change and catch on with other vendors, but that’s also an uphill battle given the conflict of interest with platform lock in that it represents. Recent versions of Android also seem to be working reasonably well with mobile application integration onto the desktop and activation out of the box. Although it still uses the Apple meta tags to find icons and behavior settings, everything at least works as you would expect – icons to the desktop on pinning, WebView based full screen activation, and reliable application persistence as the browser/app is treated like a real application. Hopefully iOS will at some point provide this same level of rudimentary Web app support. What’s also interesting to me is that Microsoft hasn’t picked up on the obvious need for a solid Web App platform. Being a distant third in the mobile OS war, Microsoft certainly has nothing to lose and everything to gain by using fresh ideas and expanding into areas that the other major vendors are neglecting. But instead Microsoft is trying to beat the market leaders at their own game, fighting on their adversary’s terms instead of taking a new tack. Providing a kick ass mobile Web platform that takes the lead on some of the proposed mobile APIs would be something positive that Microsoft could do to improve its miserable position in the mobile device market. Where are we at with Mobile Web? It sure sounds like I’m really down on the Mobile Web, right? I’ve built a number of mobile apps in the last year and while overall result and response has been very positive to what we were able to accomplish in terms of UI, getting that final 10% that required device integration dialed was an absolute nightmare on every single one of them. Big compromises had to be made and some features were left out or had to be modified for some devices. In two cases we opted to go the Cordova route in order to get the integration we needed, along with the extra pain involved in that process. Unless you’re not integrating with device features and you don’t care deeply about a smooth integration with the mobile desktop, mobile Web development is fraught with frustration. So, yes I’m frustrated! But it’s not for lack of wanting the mobile Web to succeed. I am still a firm believer that we will eventually arrive a much more functional mobile Web platform that allows access to the most common device features in a sensible way. It wouldn't be difficult for device platform vendors to make Web based applications first class citizens on mobile devices. But unfortunately it looks like it will still be some time before this happens. So, what’s your experience building mobile Web apps? Are you finding similar issues? Just giving up on raw Web applications and building PhoneGap apps instead? Completely skipping the Web and going native? Leave a comment for discussion. Resources Rick Strahl on DotNet Rocks talking about Mobile Web© Rick Strahl, West Wind Technologies, 2005-2014Posted in HTML5  Mobile   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Scrum in 5 Minutes

  - by Stephen.Walther

  The goal of this blog entry is to explain the basic concepts of Scrum in less than five minutes. You learn how Scrum can help a team of developers to successfully complete a complex software project. Product Backlog and the Product Owner Imagine that you are part of a team which needs to create a new website – for example, an e-commerce website. You have an overwhelming amount of work to do. You need to build (or possibly buy) a shopping cart, install an SSL certificate, create a product catalog, create a Facebook page, and at least a hundred other things that you have not thought of yet. According to Scrum, the first thing you should do is create a list. Place the highest priority items at the top of the list and the lower priority items lower in the list. For example, creating the shopping cart and buying the domain name might be high priority items and creating a Facebook page might be a lower priority item. In Scrum, this list is called the Product Backlog. How do you prioritize the items in the Product Backlog? Different stakeholders in the project might have different priorities. Gary, your division VP, thinks that it is crucial that the e-commerce site has a mobile app. Sally, your direct manager, thinks taking advantage of new HTML5 features is much more important. Multiple people are pulling you in different directions. According to Scrum, it is important that you always designate one person, and only one person, as the Product Owner. The Product Owner is the person who decides what items should be added to the Product Backlog and the priority of the items in the Product Backlog. The Product Owner could be the customer who is paying the bills, the project manager who is responsible for delivering the project, or a customer representative. The critical point is that the Product Owner must always be a single person and that single person has absolute authority over the Product Backlog. Sprints and the Sprint Backlog So now the developer team has a prioritized list of items and they can start work. The team starts implementing the first item in the Backlog — the shopping cart — and the team is making good progress. Unfortunately, however, half-way through the work of implementing the shopping cart, the Product Owner changes his mind. The Product Owner decides that it is much more important to create the product catalog before the shopping cart. With some frustration, the team switches their developmental efforts to focus on implementing the product catalog. However, part way through completing this work, once again the Product Owner changes his mind about the highest priority item. Getting work done when priorities are constantly shifting is frustrating for the developer team and it results in lower productivity. At the same time, however, the Product Owner needs to have absolute authority over the priority of the items which need to get done. Scrum solves this conflict with the concept of Sprints. In Scrum, a developer team works in Sprints. At the beginning of a Sprint the developers and the Product Owner agree on the items from the backlog which they will complete during the Sprint. This subset of items from the Product Backlog becomes the Sprint Backlog. During the Sprint, the Product Owner is not allowed to change the items in the Sprint Backlog. In other words, the Product Owner cannot shift priorities on the developer team during the Sprint. Different teams use Sprints of different lengths such as one month Sprints, two-week Sprints, and one week Sprints. For high-stress, time critical projects, teams typically choose shorter sprints such as one week sprints. For more mature projects, longer one month sprints might be more appropriate. A team can pick whatever Sprint length makes sense for them just as long as the team is consistent. You should pick a Sprint length and stick with it. Daily Scrum During a Sprint, the developer team needs to have meetings to coordinate their work on completing the items in the Sprint Backlog. For example, the team needs to discuss who is working on what and whether any blocking issues have been discovered. Developers hate meetings (well, sane developers hate meetings). Meetings take developers away from their work of actually implementing stuff as opposed to talking about implementing stuff. However, a developer team which never has meetings and never coordinates their work also has problems. For example, Fred might get stuck on a programming problem for days and never reach out for help even though Tom (who sits in the cubicle next to him) has already solved the very same problem. Or, both Ted and Fred might have started working on the same item from the Sprint Backlog at the same time. In Scrum, these conflicting needs – limiting meetings but enabling team coordination – are resolved with the idea of the Daily Scrum. The Daily Scrum is a meeting for coordinating the work of the developer team which happens once a day. To keep the meeting short, each developer answers only the following three questions: 1. What have you done since yesterday? 2. What do you plan to do today? 3. Any impediments in your way? During the Daily Scrum, developers are not allowed to talk about issues with their cat, do demos of their latest work, or tell heroic stories of programming problems overcome. The meeting must be kept short — typically about 15 minutes. Issues which come up during the Daily Scrum should be discussed in separate meetings which do not involve the whole developer team. Stories and Tasks Items in the Product or Sprint Backlog – such as building a shopping cart or creating a Facebook page – are often referred to as User Stories or Stories. The Stories are created by the Product Owner and should represent some business need. Unlike the Product Owner, the developer team needs to think about how a Story should be implemented. At the beginning of a Sprint, the developer team takes the Stories from the Sprint Backlog and breaks the stories into tasks. For example, the developer team might take the Create a Shopping Cart story and break it into the following tasks: · Enable users to add and remote items from shopping cart · Persist the shopping cart to database between visits · Redirect user to checkout page when Checkout button is clicked During the Daily Scrum, members of the developer team volunteer to complete the tasks required to implement the next Story in the Sprint Backlog. When a developer talks about what he did yesterday or plans to do tomorrow then the developer should be referring to a task. Stories are owned by the Product Owner and a story is all about business value. In contrast, the tasks are owned by the developer team and a task is all about implementation details. A story might take several days or weeks to complete. A task is something which a developer can complete in less than a day. Some teams get lazy about breaking stories into tasks. Neglecting to break stories into tasks can lead to “Never Ending Stories” If you don’t break a story into tasks, then you can’t know how much of a story has actually been completed because you don’t have a clear idea about the implementation steps required to complete the story. Scrumboard During the Daily Scrum, the developer team uses a Scrumboard to coordinate their work. A Scrumboard contains a list of the stories for the current Sprint, the tasks associated with each Story, and the state of each task. The developer team uses the Scrumboard so everyone on the team can see, at a glance, what everyone is working on. As a developer works on a task, the task moves from state to state and the state of the task is updated on the Scrumboard. Common task states are ToDo, In Progress, and Done. Some teams include additional task states such as Needs Review or Needs Testing. Some teams use a physical Scrumboard. In that case, you use index cards to represent the stories and the tasks and you tack the index cards onto a physical board. Using a physical Scrumboard has several disadvantages. A physical Scrumboard does not work well with a distributed team – for example, it is hard to share the same physical Scrumboard between Boston and Seattle. Also, generating reports from a physical Scrumboard is more difficult than generating reports from an online Scrumboard. Estimating Stories and Tasks Stakeholders in a project, the people investing in a project, need to have an idea of how a project is progressing and when the project will be completed. For example, if you are investing in creating an e-commerce site, you need to know when the site can be launched. It is not enough to just say that “the project will be done when it is done” because the stakeholders almost certainly have a limited budget to devote to the project. The people investing in the project cannot determine the business value of the project unless they can have an estimate of how long it will take to complete the project. Developers hate to give estimates. The reason that developers hate to give estimates is that the estimates are almost always completely made up. For example, you really don’t know how long it takes to build a shopping cart until you finish building a shopping cart, and at that point, the estimate is no longer useful. The problem is that writing code is much more like Finding a Cure for Cancer than Building a Brick Wall. Building a brick wall is very straightforward. After you learn how to add one brick to a wall, you understand everything that is involved in adding a brick to a wall. There is no additional research required and no surprises. If, on the other hand, I assembled a team of scientists and asked them to find a cure for cancer, and estimate exactly how long it will take, they would have no idea. The problem is that there are too many unknowns. I don’t know how to cure cancer, I need to do a lot of research here, so I cannot even begin to estimate how long it will take. So developers hate to provide estimates, but the Product Owner and other product stakeholders, have a legitimate need for estimates. Scrum resolves this conflict by using the idea of Story Points. Different teams use different units to represent Story Points. For example, some teams use shirt sizes such as Small, Medium, Large, and X-Large. Some teams prefer to use Coffee Cup sizes such as Tall, Short, and Grande. Finally, some teams like to use numbers from the Fibonacci series. These alternative units are converted into a Story Point value. Regardless of the type of unit which you use to represent Story Points, the goal is the same. Instead of attempting to estimate a Story in hours (which is doomed to failure), you use a much less fine-grained measure of work. A developer team is much more likely to be able to estimate that a Story is Small or X-Large than the exact number of hours required to complete the story. So you can think of Story Points as a compromise between the needs of the Product Owner and the developer team. When a Sprint starts, the developer team devotes more time to thinking about the Stories in a Sprint and the developer team breaks the Stories into Tasks. In Scrum, you estimate the work required to complete a Story by using Story Points and you estimate the work required to complete a task by using hours. The difference between Stories and Tasks is that you don’t create a task until you are just about ready to start working on a task. A task is something that you should be able to create within a day, so you have a much better chance of providing an accurate estimate of the work required to complete a task than a story. Burndown Charts In Scrum, you use Burndown charts to represent the remaining work on a project. You use Release Burndown charts to represent the overall remaining work for a project and you use Sprint Burndown charts to represent the overall remaining work for a particular Sprint. You create a Release Burndown chart by calculating the remaining number of uncompleted Story Points for the entire Product Backlog every day. The vertical axis represents Story Points and the horizontal axis represents time. A Sprint Burndown chart is similar to a Release Burndown chart, but it focuses on the remaining work for a particular Sprint. There are two different types of Sprint Burndown charts. You can either represent the remaining work in a Sprint with Story Points or with task hours (the following image, taken from Wikipedia, uses hours). When each Product Backlog Story is completed, the Release Burndown chart slopes down. When each Story or task is completed, the Sprint Burndown chart slopes down. Burndown charts typically do not always slope down over time. As new work is added to the Product Backlog, the Release Burndown chart slopes up. If new tasks are discovered during a Sprint, the Sprint Burndown chart will also slope up. The purpose of a Burndown chart is to give you a way to track team progress over time. If, halfway through a Sprint, the Sprint Burndown chart is still climbing a hill then you know that you are in trouble. Team Velocity Stakeholders in a project always want more work done faster. For example, the Product Owner for the e-commerce site wants the website to launch before tomorrow. Developers tend to be overly optimistic. Rarely do developers acknowledge the physical limitations of reality. So Project stakeholders and the developer team often collude to delude themselves about how much work can be done and how quickly. Too many software projects begin in a state of optimism and end in frustration as deadlines zoom by. In Scrum, this problem is overcome by calculating a number called the Team Velocity. The Team Velocity is a measure of the average number of Story Points which a team has completed in previous Sprints. Knowing the Team Velocity is important during the Sprint Planning meeting when the Product Owner and the developer team work together to determine the number of stories which can be completed in the next Sprint. If you know the Team Velocity then you can avoid committing to do more work than the team has been able to accomplish in the past, and your team is much more likely to complete all of the work required for the next Sprint. Scrum Master There are three roles in Scrum: the Product Owner, the developer team, and the Scrum Master. I’v e already discussed the Product Owner. The Product Owner is the one and only person who maintains the Product Backlog and prioritizes the stories. I’ve also described the role of the developer team. The members of the developer team do the work of implementing the stories by breaking the stories into tasks. The final role, which I have not discussed, is the role of the Scrum Master. The Scrum Master is responsible for ensuring that the team is following the Scrum process. For example, the Scrum Master is responsible for making sure that there is a Daily Scrum meeting and that everyone answers the standard three questions. The Scrum Master is also responsible for removing (non-technical) impediments which the team might encounter. For example, if the team cannot start work until everyone installs the latest version of Microsoft Visual Studio then the Scrum Master has the responsibility of working with management to get the latest version of Visual Studio as quickly as possible. The Scrum Master can be a member of the developer team. Furthermore, different people can take on the role of the Scrum Master over time. The Scrum Master, however, cannot be the same person as the Product Owner. Using SonicAgile SonicAgile (SonicAgile.com) is an online tool which you can use to manage your projects using Scrum. You can use the SonicAgile Product Backlog to create a prioritized list of stories. You can estimate the size of the Stories using different Story Point units such as Shirt Sizes and Coffee Cup sizes. You can use SonicAgile during the Sprint Planning meeting to select the Stories that you want to complete during a particular Sprint. You can configure Sprints to be any length of time. SonicAgile calculates Team Velocity automatically and displays a warning when you add too many stories to a Sprint. In other words, it warns you when it thinks you are overcommitting in a Sprint. SonicAgile also includes a Scrumboard which displays the list of Stories selected for a Sprint and the tasks associated with each story. You can drag tasks from one task state to another. Finally, SonicAgile enables you to generate Release Burndown and Sprint Burndown charts. You can use these charts to view the progress of your team. To learn more about SonicAgile, visit SonicAgile.com. Summary In this post, I described many of the basic concepts of Scrum. You learned how a Product Owner uses a Product Backlog to create a prioritized list of tasks. I explained why work is completed in Sprints so the developer team can be more productive. I also explained how a developer team uses the daily scrum to coordinate their work. You learned how the developer team uses a Scrumboard to see, at a glance, who is working on what and the state of each task. I also discussed Burndown charts. You learned how you can use both Release and Sprint Burndown charts to track team progress in completing a project. Finally, I described the crucial role of the Scrum Master – the person who is responsible for ensuring that the rules of Scrum are being followed. My goal was not to describe all of the concepts of Scrum. This post was intended to be an introductory overview. For a comprehensive explanation of Scrum, I recommend reading Ken Schwaber’s book Agile Project Management with Scrum: http://www.amazon.com/Agile-Project-Management-Microsoft-Professional/dp/073561993X/ref=la_B001H6ODMC_1_1?ie=UTF8&qid=1345224000&sr=1-1

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• ASP.NET Frameworks and Raw Throughput Performance

  - by Rick Strahl

  A few days ago I had a curious thought: With all these different technologies that the ASP.NET stack has to offer, what's the most efficient technology overall to return data for a server request? When I started this it was mere curiosity rather than a real practical need or result. Different tools are used for different problems and so performance differences are to be expected. But still I was curious to see how the various technologies performed relative to each just for raw throughput of the request getting to the endpoint and back out to the client with as little processing in the actual endpoint logic as possible (aka Hello World!). I want to clarify that this is merely an informal test for my own curiosity and I'm sharing the results and process here because I thought it was interesting. It's been a long while since I've done any sort of perf testing on ASP.NET, mainly because I've not had extremely heavy load requirements and because overall ASP.NET performs very well even for fairly high loads so that often it's not that critical to test load performance. This post is not meant to make a point  or even come to a conclusion which tech is better, but just to act as a reference to help understand some of the differences in perf and give a starting point to play around with this yourself. I've included the code for this simple project, so you can play with it and maybe add a few additional tests for different things if you like. Source Code on GitHub I looked at this data for these technologies: ASP.NET Web API ASP.NET MVC WebForms ASP.NET WebPages ASMX AJAX Services  (couldn't get AJAX/JSON to run on IIS8 ) WCF Rest Raw ASP.NET HttpHandlers It's quite a mixed bag, of course and the technologies target different types of development. What started out as mere curiosity turned into a bit of a head scratcher as the results were sometimes surprising. What I describe here is more to satisfy my curiosity more than anything and I thought it interesting enough to discuss on the blog :-) First test: Raw Throughput The first thing I did is test raw throughput for the various technologies. This is the least practical test of course since you're unlikely to ever create the equivalent of a 'Hello World' request in a real life application. The idea here is to measure how much time a 'NOP' request takes to return data to the client. So for this request I create the simplest Hello World request that I could come up for each tech. Http Handler The first is the lowest level approach which is an HTTP handler. public class Handler : IHttpHandler { public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; context.Response.Write("Hello World. Time is: " + DateTime.Now.ToString()); } public bool IsReusable { get { return true; } } } WebForms Next I added a couple of ASPX pages - one using CodeBehind and one using only a markup page. The CodeBehind page simple does this in CodeBehind without any markup in the ASPX page: public partial class HelloWorld_CodeBehind : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { Response.Write("Hello World. Time is: " + DateTime.Now.ToString() ); Response.End(); } } while the Markup page only contains some static output via an expression:<%@ Page Language="C#" AutoEventWireup="false" CodeBehind="HelloWorld_Markup.aspx.cs" Inherits="AspNetFrameworksPerformance.HelloWorld_Markup" %> Hello World. Time is <%= DateTime.Now %> ASP.NET WebPages WebPages is the freestanding Razor implementation of ASP.NET. Here's the simple HelloWorld.cshtml page:Hello World @DateTime.Now WCF REST WCF REST was the token REST implementation for ASP.NET before WebAPI and the inbetween step from ASP.NET AJAX. I'd like to forget that this technology was ever considered for production use, but I'll include it here. Here's an OperationContract class: [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class WcfService { [OperationContract] [WebGet] public Stream HelloWorld() { var data = Encoding.Unicode.GetBytes("Hello World" + DateTime.Now.ToString()); var ms = new MemoryStream(data); // Add your operation implementation here return ms; } } WCF REST can return arbitrary results by returning a Stream object and a content type. The code above turns the string result into a stream and returns that back to the client. ASP.NET AJAX (ASMX Services) I also wanted to test ASP.NET AJAX services because prior to WebAPI this is probably still the most widely used AJAX technology for the ASP.NET stack today. Unfortunately I was completely unable to get this running on my Windows 8 machine. Visual Studio 2012  removed adding of ASP.NET AJAX services, and when I tried to manually add the service and configure the script handler references it simply did not work - I always got a SOAP response for GET and POST operations. No matter what I tried I always ended up getting XML results even when explicitly adding the ScriptHandler. So, I didn't test this (but the code is there - you might be able to test this on a Windows 7 box). ASP.NET MVC Next up is probably the most popular ASP.NET technology at the moment: MVC. Here's the small controller: public class MvcPerformanceController : Controller { public ActionResult Index() { return View(); } public ActionResult HelloWorldCode() { return new ContentResult() { Content = "Hello World. Time is: " + DateTime.Now.ToString() }; } } ASP.NET WebAPI Next up is WebAPI which looks kind of similar to MVC. Except here I have to use a StringContent result to return the response: public class WebApiPerformanceController : ApiController { [HttpGet] public HttpResponseMessage HelloWorldCode() { return new HttpResponseMessage() { Content = new StringContent("Hello World. Time is: " + DateTime.Now.ToString(), Encoding.UTF8, "text/plain") }; } } Testing Take a minute to think about each of the technologies… and take a guess which you think is most efficient in raw throughput. The fastest should be pretty obvious, but the others - maybe not so much. The testing I did is pretty informal since it was mainly to satisfy my curiosity - here's how I did this: I used Apache Bench (ab.exe) from a full Apache HTTP installation to run and log the test results of hitting the server. ab.exe is a small executable that lets you hit a URL repeatedly and provides counter information about the number of requests, requests per second etc. ab.exe and the batch file are located in the \LoadTests folder of the project. An ab.exe command line  looks like this: ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorld which hits the specified URL 100,000 times with a load factor of 20 concurrent requests. This results in output like this:   It's a great way to get a quick and dirty performance summary. Run it a few times to make sure there's not a large amount of varience. You might also want to do an IISRESET to clear the Web Server. Just make sure you do a short test run to warm up the server first - otherwise your first run is likely to be skewed downwards. ab.exe also allows you to specify headers and provide POST data and many other things if you want to get a little more fancy. Here all tests are GET requests to keep it simple. I ran each test: 100,000 iterations Load factor of 20 concurrent connections IISReset before starting A short warm up run for API and MVC to make sure startup cost is mitigated Here is the batch file I used for the test: IISRESET REM make sure you add REM C:\Program Files (x86)\Apache Software Foundation\Apache2.2\bin REM to your path so ab.exe can be found REM Warm up ab.exe -n100 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldJsonab.exe -n100 -c20 http://localhost/aspnetperf/api/HelloWorldJson ab.exe -n100 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorld ab.exe -n100000 -c20 http://localhost/aspnetperf/handler.ashx > handler.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/HelloWorld_CodeBehind.aspx > AspxCodeBehind.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/HelloWorld_Markup.aspx > AspxMarkup.txt ab.exe -n100000 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorld > Wcf.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldCode > Mvc.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorld > WebApi.txt I ran each of these tests 3 times and took the average score for Requests/second, with the machine otherwise idle. I did see a bit of variance when running many tests but the values used here are the medians. Part of this has to do with the fact I ran the tests on my local machine - result would probably more consistent running the load test on a separate machine hitting across the network. I ran these tests locally on my laptop which is a Dell XPS with quad core Sandibridge I7-2720QM @ 2.20ghz and a fast SSD drive on Windows 8. CPU load during tests ran to about 70% max across all 4 cores (IOW, it wasn't overloading the machine). Ideally you can try running these tests on a separate machine hitting the local machine. If I remember correctly IIS 7 and 8 on client OSs don't throttle so the performance here should be Results Ok, let's cut straight to the chase. Below are the results from the tests… It's not surprising that the handler was fastest. But it was a bit surprising to me that the next fastest was WebForms and especially Web Forms with markup over a CodeBehind page. WebPages also fared fairly well. MVC and WebAPI are a little slower and the slowest by far is WCF REST (which again I find surprising). As mentioned at the start the raw throughput tests are not overly practical as they don't test scripting performance for the HTML generation engines or serialization performances of the data engines. All it really does is give you an idea of the raw throughput for the technology from time of request to reaching the endpoint and returning minimal text data back to the client which indicates full round trip performance. But it's still interesting to see that Web Forms performs better in throughput than either MVC, WebAPI or WebPages. It'd be interesting to try this with a few pages that actually have some parsing logic on it, but that's beyond the scope of this throughput test. But what's also amazing about this test is the sheer amount of traffic that a laptop computer is handling. Even the slowest tech managed 5700 requests a second, which is one hell of a lot of requests if you extrapolate that out over a 24 hour period. Remember these are not static pages, but dynamic requests that are being served. Another test - JSON Data Service Results The second test I used a JSON result from several of the technologies. I didn't bother running WebForms and WebPages through this test since that doesn't make a ton of sense to return data from the them (OTOH, returning text from the APIs didn't make a ton of sense either :-) In these tests I have a small Person class that gets serialized and then returned to the client. The Person class looks like this: public class Person { public Person() { Id = 10; Name = "Rick"; Entered = DateTime.Now; } public int Id { get; set; } public string Name { get; set; } public DateTime Entered { get; set; } } Here are the updated handler classes that use Person: Handler public class Handler : IHttpHandler { public void ProcessRequest(HttpContext context) { var action = context.Request.QueryString["action"]; if (action == "json") JsonRequest(context); else TextRequest(context); } public void TextRequest(HttpContext context) { context.Response.ContentType = "text/plain"; context.Response.Write("Hello World. Time is: " + DateTime.Now.ToString()); } public void JsonRequest(HttpContext context) { var json = JsonConvert.SerializeObject(new Person(), Formatting.None); context.Response.ContentType = "application/json"; context.Response.Write(json); } public bool IsReusable { get { return true; } } } This code adds a little logic to check for a action query string and route the request to an optional JSON result method. To generate JSON, I'm using the same JSON.NET serializer (JsonConvert.SerializeObject) used in Web API to create the JSON response. WCF REST   [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class WcfService { [OperationContract] [WebGet] public Stream HelloWorld() { var data = Encoding.Unicode.GetBytes("Hello World " + DateTime.Now.ToString()); var ms = new MemoryStream(data); // Add your operation implementation here return ms; } [OperationContract] [WebGet(ResponseFormat=WebMessageFormat.Json,BodyStyle=WebMessageBodyStyle.WrappedRequest)] public Person HelloWorldJson() { // Add your operation implementation here return new Person(); } } For WCF REST all I have to do is add a method with the Person result type.   ASP.NET MVC public class MvcPerformanceController : Controller { // // GET: /MvcPerformance/ public ActionResult Index() { return View(); } public ActionResult HelloWorldCode() { return new ContentResult() { Content = "Hello World. Time is: " + DateTime.Now.ToString() }; } public JsonResult HelloWorldJson() { return Json(new Person(), JsonRequestBehavior.AllowGet); } } For MVC all I have to do for a JSON response is return a JSON result. ASP.NET internally uses JavaScriptSerializer. ASP.NET WebAPI public class WebApiPerformanceController : ApiController { [HttpGet] public HttpResponseMessage HelloWorldCode() { return new HttpResponseMessage() { Content = new StringContent("Hello World. Time is: " + DateTime.Now.ToString(), Encoding.UTF8, "text/plain") }; } [HttpGet] public Person HelloWorldJson() { return new Person(); } [HttpGet] public HttpResponseMessage HelloWorldJson2() { var response = new HttpResponseMessage(HttpStatusCode.OK); response.Content = new ObjectContent<Person>(new Person(), GlobalConfiguration.Configuration.Formatters.JsonFormatter); return response; } } Testing and Results To run these data requests I used the following ab.exe commands:REM JSON RESPONSES ab.exe -n100000 -c20 http://localhost/aspnetperf/Handler.ashx?action=json > HandlerJson.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldJson > MvcJson.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorldJson > WebApiJson.txt ab.exe -n100000 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorldJson > WcfJson.txt The results from this test run are a bit interesting in that the WebAPI test improved performance significantly over returning plain string content. Here are the results:   The performance for each technology drops a little bit except for WebAPI which is up quite a bit! From this test it appears that WebAPI is actually significantly better performing returning a JSON response, rather than a plain string response. Snag with Apache Benchmark and 'Length Failures' I ran into a little snag with Apache Benchmark, which was reporting failures for my Web API requests when serializing. As the graph shows performance improved significantly from with JSON results from 5580 to 6530 or so which is a 15% improvement (while all others slowed down by 3-8%). However, I was skeptical at first because the WebAPI test reports showed a bunch of errors on about 10% of the requests. Check out this report: Notice the Failed Request count. What the hey? Is WebAPI failing on roughly 10% of requests when sending JSON? Turns out: No it's not! But it took some sleuthing to figure out why it reports these failures. At first I thought that Web API was failing, and so to make sure I re-ran the test with Fiddler attached and runiisning the ab.exe test by using the -X switch: ab.exe -n100 -c10 -X localhost:8888 http://localhost/aspnetperf/api/HelloWorldJson which showed that indeed all requests where returning proper HTTP 200 results with full content. However ab.exe was reporting the errors. After some closer inspection it turned out that the dates varying in size altered the response length in dynamic output. For example: these two results: {"Id":10,"Name":"Rick","Entered":"2012-09-04T10:57:24.841926-10:00"} {"Id":10,"Name":"Rick","Entered":"2012-09-04T10:57:24.8519262-10:00"} are different in length for the number which results in 68 and 69 bytes respectively. The same URL produces different result lengths which is what ab.exe reports. I didn't notice at first bit the same is happening when running the ASHX handler with JSON.NET result since it uses the same serializer that varies the milliseconds. Moral: You can typically ignore Length failures in Apache Benchmark and when in doubt check the actual output with Fiddler. Note that the other failure values are accurate though. Another interesting Side Note: Perf drops over Time As I was running these tests repeatedly I was finding that performance steadily dropped from a startup peak to a 10-15% lower stable level. IOW, with Web API I'd start out with around 6500 req/sec and in subsequent runs it keeps dropping until it would stabalize somewhere around 5900 req/sec occasionally jumping lower. For these tests this is why I did the IIS RESET and warm up for individual tests. This is a little puzzling. Looking at Process Monitor while the test are running memory very quickly levels out as do handles and threads, on the first test run. Subsequent runs everything stays stable, but the performance starts going downwards. This applies to all the technologies - Handlers, Web Forms, MVC, Web API - curious to see if others test this and see similar results. Doing an IISRESET then resets everything and performance starts off at peak again… Summary As I stated at the outset, these were informal to satiate my curiosity not to prove that any technology is better or even faster than another. While there clearly are differences in performance the differences (other than WCF REST which was by far the slowest and the raw handler which was by far the highest) are relatively minor, so there is no need to feel that any one technology is a runaway standout in raw performance. Choosing a technology is about more than pure performance but also about the adequateness for the job and the easy of implementation. The strengths of each technology will make for any minor performance difference we see in these tests. However, to me it's important to get an occasional reality check and compare where new technologies are heading. Often times old stuff that's been optimized and designed for a time of less horse power can utterly blow the doors off newer tech and simple checks like this let you compare. Luckily we're seeing that much of the new stuff performs well even in V1.0 which is great. To me it was very interesting to see Web API perform relatively badly with plain string content, which originally led me to think that Web API might not be properly optimized just yet. For those that caught my Tweets late last week regarding WebAPI's slow responses was with String content which is in fact considerably slower. Luckily where it counts with serialized JSON and XML WebAPI actually performs better. But I do wonder what would make generic string content slower than serialized code? This stresses another point: Don't take a single test as the final gospel and don't extrapolate out from a single set of tests. Certainly Twitter can make you feel like a fool when you post something immediate that hasn't been fleshed out a little more <blush>. Egg on my face. As a result I ended up screwing around with this for a few hours today to compare different scenarios. Well worth the time… I hope you found this useful, if not for the results, maybe for the process of quickly testing a few requests for performance and charting out a comparison. Now onwards with more serious stuff… Resources Source Code on GitHub Apache HTTP Server Project (ab.exe is part of the binary distribution)© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET  Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• 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 Tuesday, November 22, 2011

  CodePlex Daily Summary for Tuesday, November 22, 2011Popular ReleasesDeveloper Team Article System Management: DTASM v1.3: ?? ??? ???? 3 ????? ???? ???? ????? ??? : - ????? ?????? ????? ???? ?? ??? ???? ????? ?? ??? ? ?? ???? ?????? ???? ?? ???? ????? ?? . - ??? ?? ???? ????? ???? ????? ???? ???? ?? ????? , ?????? ????? ????? ?? ??? . - ??? ??????? ??? ??? ???? ?? ????? ????? ????? .VideoLan DotNet for WinForm, WPF & Silverlight 5: VideoLan DotNet for WinForm, WPF, SL5 - 2011.11.22: The new version contains Silverlight 5 library: Vlc.DotNet.Silverlight. A sample could be tested here The new version add and correct many features : Correction : Reinitialize some variables Deprecate : Logging API, since VLC 1.2 (08/20/2011) Add subitem in LocationMedia (for Youtube videos, ...) Update Wpf sample to use Youtube videos Many others correctionsSharePoint 2010 FBA Pack: SharePoint 2010 FBA Pack 1.2.0: Web parts are now fully customizable via html templates (Issue #323) FBA Pack is now completely localizable using resource files. Thank you David Chen for submitting the code as well as Chinese translations of the FBA Pack! The membership request web part now gives the option of having the user enter the password and removing the captcha (Issue # 447) The FBA Pack will now work in a zone that does not have FBA enabled (Another zone must have FBA enabled, and the zone must contain the me...SharePoint 2010 Education Demo Project: Release SharePoint SP1 for Education Solutions: This release includes updates to the Content Packs for SharePoint SP1. All Content Packs have been updated to install successfully under SharePoint SP1SQL Monitor - tracking sql server activities: SQLMon 4.1 alpha 6: 1. improved support for schema 2. added find reference when right click on object list 3. added object rename supportBugNET Issue Tracker: BugNET 0.9.126: First stable release of version 0.9. Upgrades from 0.8 are fully supported and upgrades to future releases will also be supported. This release is now compiled against the .NET 4.0 framework and is a requirement. Because of this the web.config has significantly changed. After upgrading, you will need to configure the authentication settings for user registration and anonymous access again. Please see our installation / upgrade instructions for more details: http://wiki.bugnetproject.c...Anno 2070 Assistant: v0.1.0 (STABLE): Version 0.1.0 Features Production Chains Eco Production Chains (Complete) Tycoon Production Chains (Disabled - Incomplete) Tech Production Chains (Disabled - Incomplete) Supply (Disabled - Incomplete) Calculator (Disabled - Incomplete) Building Layouts Eco Building Layouts (Complete) Tycoon Building Layouts (Disabled - Incomplete) Tech Building Layouts (Disabled - Incomplete) Credits (Complete)Free SharePoint 2010 Sites Templates: SharePoint Server 2010 Sites Templates: here is the list of sites templates to be downloadedVsTortoise - a TortoiseSVN add-in for Microsoft Visual Studio: VsTortoise Build 30 Beta: Note: This release does not work with custom VsTortoise toolbars. These get removed every time when you shutdown Visual Studio. (#7940) Build 30 (beta)New: Support for TortoiseSVN 1.7 added. (the download contains both setups, for TortoiseSVN 1.6 and 1.7) New: OpenModifiedDocumentDialog displays conflicted files now. New: OpenModifiedDocument allows to group items by changelist now. Fix: OpenModifiedDocumentDialog caused Visual Studio 2010 to freeze sometimes. Fix: The installer didn...nopCommerce. Open source shopping cart (ASP.NET MVC): nopcommerce 2.30: Highlight features & improvements: • Performance optimization. • Back in stock notifications. • Product special price support. • Catalog mode (based on customer role) To see the full list of fixes and changes please visit the release notes page (http://www.nopCommerce.com/releasenotes.aspx).WPF Converters: WPF Converters V1.2.0.0: support for enumerations, value types, and reference types in the expression converter's equality operators the expression converter now handles DependencyProperty.UnsetValue as argument values correctly (#4062) StyleCop conformance (more or less)Json.NET: Json.NET 4.0 Release 4: Change - JsonTextReader.Culture is now CultureInfo.InvariantCulture by default Change - KeyValurPairConverter no longer cares about the order of the key and value properties Change - Time zone conversions now use new TimeZoneInfo instead of TimeZone Fix - Fixed boolean values sometimes being capitalized when converting to XML Fix - Fixed error when deserializing ConcurrentDictionary Fix - Fixed serializing some Uris returning the incorrect value Fix - Fixed occasional error when...Media Companion: MC 3.423b 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) Replaced 'Rebuild' with 'Refresh' throughout entire code. Rebuild will now be known as Refresh. mc_com.exe has been fully updated TV Show Resolutions... Resolved issue #206 - having to hit save twice when updating runtime manually Shrunk cache size and lowered loading times f...Delta Engine: Delta Engine Beta Preview v0.9.1: v0.9.1 beta release with lots of refactoring, fixes, new samples and support for iOS, Android and WP7 (you need a Marketplace account however). If you want a binary release for the games (like v0.9.0), just say so in the Forum or here and we will quickly prepare one. It is just not much different from v0.9.0, so I left it out this time. See http://DeltaEngine.net/Wiki.Roadmap for details.SharpMap - Geospatial Application Framework for the CLR: SharpMap-0.9-AnyCPU-Trunk-2011.11.17: This is a build of SharpMap from the 0.9 development trunk as per 2011-11-17 For most applications the AnyCPU release is the recommended, but in case you need an x86 build that is included to. For some dataproviders (GDAL/OGR, SqLite, PostGis) you need to also referense the SharpMap.Extensions assembly For SqlServer Spatial you need to reference the SharpMap.SqlServerSpatial assemblyAJAX Control Toolkit: November 2011 Release: AJAX Control Toolkit Release Notes - November 2011 Release Version 51116November 2011 release of the AJAX Control Toolkit. AJAX Control Toolkit .NET 4 - Binary – AJAX Control Toolkit for .NET 4 and sample site (Recommended). AJAX Control Toolkit .NET 3.5 - Binary – AJAX Control Toolkit for .NET 3.5 and sample site (Recommended). Notes: - The current version of the AJAX Control Toolkit is not compatible with ASP.NET 2.0. The latest version that is compatible with ASP.NET 2.0 can be found h...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.36: Fix for issue #16908: string literals containing ASP.NET replacement syntax fail if the ASP.NET code contains the same character as the string literal delimiter. Also, we shouldn't be changing the delimiter for those literals or combining them with other literals; the developer may have specifically chosen the delimiter used because of possible content inserted by ASP.NET code. This logic is normally off; turn it on via the -aspnet command-line flag (or the Code.Settings.AllowEmbeddedAspNetBl...MVC Controls Toolkit: Mvc Controls Toolkit 1.5.5: Added: Now the DateRanteAttribute accepts complex expressions containing "Now" and "Today" as static minimum and maximum. Menu, MenuFor helpers capable of handling a "currently selected element". The developer can choose between using a standard nested menu based on a standard SimpleMenuItem class or specifying an item template based on a custom class. Added also helpers to build the tree structure containing all data items the menu takes infos from. Improved the pager. Now the developer ...SharpCompress - a fully native C# library for RAR, 7Zip, Zip, Tar, GZip, BZip2: SharpCompress 0.7: Reworked API to be more consistent. See Supported formats table. Added some more helper methods - e.g. OpenEntryStream (RarArchive/RarReader does not support this) Fixed up testsSilverlight Toolkit: Windows Phone Toolkit - Nov 2011 (7.1 SDK): This release is coming soon! What's new ListPicker once again works in a ScrollViewer LongListSelector bug fixes around OutOfRange exceptions, wrong ordering of items, grouping issues, and scrolling events. ItemTuple is now refactored to be the public type LongListSelectorItem to provide users better access to the values in selection changed handlers. PerformanceProgressBar binding fix for IsIndeterminate (item 9767 and others) There is no longer a GestureListener dependency with the C...New ProjectsAndrecorder: Andrecorder???Android???????,???????????????????,????????????????,????????!Android Tree Bulletin: Android bulletin reader in tree format.Bài t?p l?p môn HCI: Name: Ph?n m?m qu?n lý thu h?c phí tru?ng d?i h?c Công Nghi?p Hà N?i Basic Grid Collision sample in XNA: This project shows how to implement a basic grid collision in XNA. The project uses the XNA 4.0 framework and C#Club Manager: Club Manager is a web site for managing sport clubs / teams.Create email with encrypt text implement TEA encryption and Web Service: RahaTEA Mail is an application to send messages in secret. These applications implement TEA encryption and web serviceCRM 2011 Layers: Several .net layers to customize CRM 2011CTEF: China Tomorrow Education Foundation websitedns?????: ??c#???dns?????。????????，???????，??????。EAF: Extensibility Application FrameworkEnergy SBA: In order to compete with large companies for Federal contracts, small business need information. This application seeks to show standard methods of using remote APIs to integrate information into a Metro interface using services provided by the Small Business Administration (SBA)EPiOptimiser - Scan your EPiServer configuration to optimise start up times: EPiScanner scans your EPiServer configuration to optimise start ups by generating a recommended exclude list of assemblies to include in EPiServer framework config. It can be used on command line, as a custom build task or integrated into Visual Studio as an external tool.FreeIDS - Free Intrusion Detection System: Don't want someone to use your computer? Don't want to use a system password? Want to see when someone accessed your computer? Time/Date? FreeIDS is it!FtpServerAdministrator: FtpServerAdministrator makes it easier to administer some ftp server by code, although it can only be used for FileZilla server now. It's developed in C#.GreenPoint Online: Tools and components that help you customize an Office 365 / SharePoint Online Environment.HCC C# Workshop: This project contains the code for the exercises of the HCC C# WorkshopKsigDo - Real time view model syncing across user screens: KsigDo show real time view model syncing across user screens - using ASP.NET, Knockout and SignalR. Real time data syncing across user views *was* hard, especially in web applications. Most of the time, the second user needs to refresh the screen, to see the changes made by first user, or we need to implement some long polling that fetches the data and does the update manually. Now, with SignalR and Knockout, ASP.NET developers can take advantage of view model syncing across users, that...lineseven: ???????????????。Mail Size Labeler for GMail: A small utility that labels large e-mails on your gmail account. This utility scan you gmail account, and adds labels to large e-mail so you can clean your mailbox and free space. The labels this utility adds are: Size 1M-2M Size 2M-5M Size 5M-10M Size 10M-15M Size 15M plus Note: a single e-mail thread may get multiple labels if different e-mails of the thread fit different filters.MathService: Complex digits, standart class extentions etc.MyGameProject: gamesMySQL Connect 2 ASP.NET: Example project to show how to connect MySQL database to ASP.NET web project. IDE: Visual Studio 2010 Pro Programming language: C# Detailed information in the article here: http://epavlov.net/blog/2011/11/13/connect-to-mysql-in-visual-studio/ nl: Nutri Leaf Devomr.event.js: Simple js event injecterPastebin4DotNet: This project is an example of how to consume an API, in this case I consummed the Pastebin API.Pomelo: Pomelo is a website example.QuickDevFrameWork: ????????,??,??,????,ioc ?????postsharp?aopReadable Passphrase Generator: Generates passphrases which are (mostly) grammatically correct but nonsensical. These are easy to remember but difficult to guess (for humans or computers). Developed in C# with a KeePass plugin, console app and public API.Rosyama.ru for Windows Phone 7: ?????????? Windows Phone 7 ??? ???????? ???????? ?? ???? rosyama.ru. ?????????? ??????? ?????????? ? ???????? ????????? ???????. SimpleBatch: As the name suggests, this is a simple batch framework allowing you to define batch jobs in XML format. Thus far, contains a basic selection of processors such as the following; File Email SQL (SQL Server Client) SharePoint Document Library Custom ProcessorSite de Notícias: Projeto de faculdade que consiste na criação de um site de notícias.SPWikiProvisioning: Create update and delete SharePoint wiki pages using feature activation and deactivation handlers.SVN Automated Control With C#: I Created this libaray because I need to control Tortoise SVN automactically with out an interface for my own build server and could not find any resuilts on google to achive this task so I went about creating this libaray which dos most of the task's that I needed. I round that you could control SVN by command line so using that as my basic idear I went about coding the most common commands for SVN most of the commads are done but not all. if you like this libaray then please use it we...TremplinCMS: TremplinCMS is a CMS framework for ASP .NET 4.vlu0206sms: SMSMaker by team0206 developingWCF DataService RequestStream Access on webInvoke HTTP POST: This library provides access to the message body request stream of a WCF Data Service (formerly ADO.NET Data Service), which is not possible with the original WCF Data Service class. You are enabled passing data (e.g. Json, files) via HTTP POST to the request body. It uses the operation context (DbContext) provided by the DataService<T> class to get access to the resquest stream.WebOS: Welcome to join us to build our os projectWp7StarterDantas: Iniciando com Wp7WpfCollaborative3D: WpfCollaborative3DXNA Content Preprocessor: The XNA Content Preprocessor allows you to compile all of your XNA assets outside of your normal XNA project. This means more time building your game or app instead of your content.

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• Sniffing out SQL Code Smells: Inconsistent use of Symbolic names and Datatypes

  - by Phil Factor

  It is an awkward feeling. You’ve just delivered a database application that seems to be working fine in production, and you just run a few checks on it. You discover that there is a potential bug that, out of sheer good chance, hasn’t kicked in to produce an error; but it lurks, like a smoking bomb. Worse, maybe you find that the bug has started its evil work of corrupting the data, but in ways that nobody has, so far detected. You investigate, and find the damage. You are somehow going to have to repair it. Yes, it still very occasionally happens to me. It is not a nice feeling, and I do anything I can to prevent it happening. That’s why I’m interested in SQL code smells. SQL Code Smells aren’t necessarily bad practices, but just show you where to focus your attention when checking an application. Sometimes with databases the bugs can be subtle. SQL is rather like HTML: the language does its best to try to carry out your wishes, rather than to be picky about your bugs. Most of the time, this is a great benefit, but not always. One particular place where this can be detrimental is where you have implicit conversion between different data types. Most of the time it is completely harmless but we’re  concerned about the occasional time it isn’t. Let’s give an example: String truncation. Let’s give another even more frightening one, rounding errors on assignment to a number of different precision. Each requires a blog-post to explain in detail and I’m not now going to try. Just remember that it is not always a good idea to assign data to variables, parameters or even columns when they aren’t the same datatype, especially if you are relying on implicit conversion to work its magic.For details of the problem and the consequences, see here:  SR0014: Data loss might occur when casting from {Type1} to {Type2} . For any experienced Database Developer, this is a more frightening read than a Vampire Story. This is why one of the SQL Code Smells that makes me edgy, in my own or other peoples’ code, is to see parameters, variables and columns that have the same names and different datatypes. Whereas quite a lot of this is perfectly normal and natural, you need to check in case one of two things have gone wrong. Either sloppy naming, or mixed datatypes. Sure it is hard to remember whether you decided that the length of a log entry was 80 or 100 characters long, or the precision of a number. That is why a little check like this I’m going to show you is excellent for tidying up your code before you check it back into source Control! 1/ Checking Parameters only If you were just going to check parameters, you might just do this. It simply groups all the parameters, either input or output, of all the routines (e.g. stored procedures or functions) by their name and checks to see, in the HAVING clause, whether their data types are all the same. If not, it lists all the examples and their origin (the routine) Even this little check can occasionally be scarily revealing. ;WITH userParameter AS  ( SELECT   c.NAME AS ParameterName,  OBJECT_SCHEMA_NAME(c.object_ID) + '.' + OBJECT_NAME(c.object_ID) AS ObjectName,  t.name + ' '     + CASE     --we may have to put in the length            WHEN t.name IN ('char', 'varchar', 'nchar', 'nvarchar')             THEN '('               + CASE WHEN c.max_length = -1 THEN 'MAX'                ELSE CONVERT(VARCHAR(4),                    CASE WHEN t.name IN ('nchar', 'nvarchar')                      THEN c.max_length / 2 ELSE c.max_length                    END)                END + ')'         WHEN t.name IN ('decimal', 'numeric')             THEN '(' + CONVERT(VARCHAR(4), c.precision)                   + ',' + CONVERT(VARCHAR(4), c.Scale) + ')'         ELSE ''      END  --we've done with putting in the length      + CASE WHEN XML_collection_ID <> 0         THEN --deal with object schema names             '(' + CASE WHEN is_XML_Document = 1                    THEN 'DOCUMENT '                    ELSE 'CONTENT '                   END              + COALESCE(               (SELECT QUOTENAME(ss.name) + '.' + QUOTENAME(sc.name)                FROM sys.xml_schema_collections sc                INNER JOIN Sys.Schemas ss ON sc.schema_ID = ss.schema_ID                WHERE sc.xml_collection_ID = c.XML_collection_ID),'NULL') + ')'          ELSE ''         END        AS [DataType]  FROM sys.parameters c  INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID  WHERE OBJECT_SCHEMA_NAME(c.object_ID) <> 'sys'   AND parameter_id>0)SELECT CONVERT(CHAR(80),objectName+'.'+ParameterName),DataType FROM UserParameterWHERE ParameterName IN   (SELECT ParameterName FROM UserParameter    GROUP BY ParameterName    HAVING MIN(Datatype)<>MAX(DataType))ORDER BY ParameterName   so, in a very small example here, we have a @ClosingDelimiter variable that is only CHAR(1) when, by the looks of it, it should be up to ten characters long, or even worse, a function that should be a char(1) and seems to let in a string of ten characters. Worth investigating. Then we have a @Comment variable that can't decide whether it is a VARCHAR(2000) or a VARCHAR(MAX) 2/ Columns and Parameters Actually, once we’ve cleared up the mess we’ve made of our parameter-naming in the database we’re inspecting, we’re going to be more interested in listing both columns and parameters. We can do this by modifying the routine to list columns as well as parameters. Because of the slight complexity of creating the string version of the datatypes, we will create a fake table of both columns and parameters so that they can both be processed the same way. After all, we want the datatypes to match Unfortunately, parameters do not expose all the attributes we are interested in, such as whether they are nullable (oh yes, subtle bugs happen if this isn’t consistent for a datatype). We’ll have to leave them out for this check. Voila! A slight modification of the first routine ;WITH userObject AS  ( SELECT   Name AS DataName,--the actual name of the parameter or column ('@' removed)  --and the qualified object name of the routine  OBJECT_SCHEMA_NAME(ObjectID) + '.' + OBJECT_NAME(ObjectID) AS ObjectName,  --now the harder bit: the definition of the datatype.  TypeName + ' '     + CASE     --we may have to put in the length. e.g. CHAR (10)           WHEN TypeName IN ('char', 'varchar', 'nchar', 'nvarchar')             THEN '('               + CASE WHEN MaxLength = -1 THEN 'MAX'                ELSE CONVERT(VARCHAR(4),                    CASE WHEN TypeName IN ('nchar', 'nvarchar')                      THEN MaxLength / 2 ELSE MaxLength                    END)                END + ')'         WHEN TypeName IN ('decimal', 'numeric')--a BCD number!             THEN '(' + CONVERT(VARCHAR(4), Precision)                   + ',' + CONVERT(VARCHAR(4), Scale) + ')'         ELSE ''      END  --we've done with putting in the length      + CASE WHEN XML_collection_ID <> 0 --tush tush. XML         THEN --deal with object schema names             '(' + CASE WHEN is_XML_Document = 1                    THEN 'DOCUMENT '                    ELSE 'CONTENT '                   END              + COALESCE(               (SELECT TOP 1 QUOTENAME(ss.name) + '.' + QUOTENAME(sc.Name)                FROM sys.xml_schema_collections sc                INNER JOIN Sys.Schemas ss ON sc.schema_ID = ss.schema_ID                WHERE sc.xml_collection_ID = XML_collection_ID),'NULL') + ')'          ELSE ''         END        AS [DataType],       DataObjectType  FROM   (Select t.name AS TypeName, REPLACE(c.name,'@','') AS Name,          c.max_length AS MaxLength, c.precision AS [Precision],           c.scale AS [Scale], c.[Object_id] AS ObjectID, XML_collection_ID,          is_XML_Document,'P' AS DataobjectType  FROM sys.parameters c  INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID  AND parameter_id>0  UNION all  Select t.name AS TypeName, c.name AS Name, c.max_length AS MaxLength,          c.precision AS [Precision], c.scale AS [Scale],          c.[Object_id] AS ObjectID, XML_collection_ID,is_XML_Document,          'C' AS DataobjectType            FROM sys.columns c  INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID   WHERE OBJECT_SCHEMA_NAME(c.object_ID) <> 'sys'  )f)SELECT CONVERT(CHAR(80),objectName+'.'   + CASE WHEN DataobjectType ='P' THEN '@' ELSE '' END + DataName),DataType FROM UserObjectWHERE DataName IN   (SELECT DataName FROM UserObject   GROUP BY DataName    HAVING MIN(Datatype)<>MAX(DataType))ORDER BY DataName     Hmm. I can tell you I found quite a few minor issues with the various tabases I tested this on, and found some potential bugs that really leap out at you from the results. Here is the start of the result for AdventureWorks. Yes, AccountNumber is, for some reason, a Varchar(10) in the Customer table. Hmm. odd. Why is a city fifty characters long in that view?  The idea of the description of a colour being 256 characters long seems over-ambitious. Go down the list and you'll spot other mistakes. There are no bugs, but just mess. We started out with a listing to examine parameters, then we mixed parameters and columns. Our last listing is for a slightly more in-depth look at table columns. You’ll notice that we’ve delibarately removed the indication of whether a column is persisted, or is an identity column because that gives us false positives for our code smells. If you just want to browse your metadata for other reasons (and it can quite help in some circumstances) then uncomment them! ;WITH userColumns AS  ( SELECT   c.NAME AS columnName,  OBJECT_SCHEMA_NAME(c.object_ID) + '.' + OBJECT_NAME(c.object_ID) AS ObjectName,  REPLACE(t.name + ' '   + CASE WHEN is_computed = 1 THEN ' AS ' + --do DDL for a computed column          (SELECT definition FROM sys.computed_columns cc           WHERE cc.object_id = c.object_id AND cc.column_ID = c.column_ID)     --we may have to put in the length            WHEN t.Name IN ('char', 'varchar', 'nchar', 'nvarchar')             THEN '('               + CASE WHEN c.Max_Length = -1 THEN 'MAX'                ELSE CONVERT(VARCHAR(4),                    CASE WHEN t.Name IN ('nchar', 'nvarchar')                      THEN c.Max_Length / 2 ELSE c.Max_Length                    END)                END + ')'       WHEN t.name IN ('decimal', 'numeric')       THEN '(' + CONVERT(VARCHAR(4), c.precision) + ',' + CONVERT(VARCHAR(4), c.Scale) + ')'       ELSE ''      END + CASE WHEN c.is_rowguidcol = 1          THEN ' ROWGUIDCOL'          ELSE ''         END + CASE WHEN XML_collection_ID <> 0            THEN --deal with object schema names             '(' + CASE WHEN is_XML_Document = 1                THEN 'DOCUMENT '                ELSE 'CONTENT '               END + COALESCE((SELECT                QUOTENAME(ss.name) + '.' + QUOTENAME(sc.name)                FROM                sys.xml_schema_collections sc                INNER JOIN Sys.Schemas ss ON sc.schema_ID = ss.schema_ID                WHERE                sc.xml_collection_ID = c.XML_collection_ID),                'NULL') + ')'            ELSE ''           END + CASE WHEN is_identity = 1             THEN CASE WHEN OBJECTPROPERTY(object_id,                'IsUserTable') = 1 AND COLUMNPROPERTY(object_id,                c.name,                'IsIDNotForRepl') = 0 AND OBJECTPROPERTY(object_id,                'IsMSShipped') = 0                THEN ''                ELSE ' NOT FOR REPLICATION '               END             ELSE ''            END + CASE WHEN c.is_nullable = 0               THEN ' NOT NULL'               ELSE ' NULL'              END + CASE                WHEN c.default_object_id <> 0                THEN ' DEFAULT ' + object_Definition(c.default_object_id)                ELSE ''               END + CASE                WHEN c.collation_name IS NULL                THEN ''                WHEN c.collation_name <> (SELECT                collation_name                FROM                sys.databases                WHERE                name = DB_NAME()) COLLATE Latin1_General_CI_AS                THEN COALESCE(' COLLATE ' + c.collation_name,                '')                ELSE ''                END,'  ',' ') AS [DataType]FROM sys.columns c  INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID  WHERE OBJECT_SCHEMA_NAME(c.object_ID) <> 'sys')SELECT CONVERT(CHAR(80),objectName+'.'+columnName),DataType FROM UserColumnsWHERE columnName IN (SELECT columnName FROM UserColumns  GROUP BY columnName  HAVING MIN(Datatype)<>MAX(DataType))ORDER BY columnName If you take a look down the results against Adventureworks, you'll see once again that there are things to investigate, mostly, in the illustration, discrepancies between null and non-null datatypes So I here you ask, what about temporary variables within routines? If ever there was a source of elusive bugs, you'll find it there. Sadly, these temporary variables are not stored in the metadata so we'll have to find a more subtle way of flushing these out, and that will, I'm afraid, have to wait!

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• C#/.NET Little Wonders: The Generic Func Delegates

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Back in one of my three original “Little Wonders” Trilogy of posts, I had listed generic delegates as one of the Little Wonders of .NET.  Later, someone posted a comment saying said that they would love more detail on the generic delegates and their uses, since my original entry just scratched the surface of them. Last week, I began our look at some of the handy generic delegates built into .NET with a description of delegates in general, and the Action family of delegates.  For this week, I’ll launch into a look at the Func family of generic delegates and how they can be used to support generic, reusable algorithms and classes. Quick Delegate Recap Delegates are similar to function pointers in C++ in that they allow you to store a reference to a method.  They can store references to either static or instance methods, and can actually be used to chain several methods together in one delegate. Delegates are very type-safe and can be satisfied with any standard method, anonymous method, or a lambda expression.  They can also be null as well (refers to no method), so care should be taken to make sure that the delegate is not null before you invoke it. Delegates are defined using the keyword delegate, where the delegate’s type name is placed where you would typically place the method name: 1: // This delegate matches any method that takes string, returns nothing 2: public delegate void Log(string message); This delegate defines a delegate type named Log that can be used to store references to any method(s) that satisfies its signature (whether instance, static, lambda expression, etc.). Delegate instances then can be assigned zero (null) or more methods using the operator = which replaces the existing delegate chain, or by using the operator += which adds a method to the end of a delegate chain: 1: // creates a delegate instance named currentLogger defaulted to Console.WriteLine (static method) 2: Log currentLogger = Console.Out.WriteLine; 3:  4: // invokes the delegate, which writes to the console out 5: currentLogger("Hi Standard Out!"); 6:  7: // append a delegate to Console.Error.WriteLine to go to std error 8: currentLogger += Console.Error.WriteLine; 9:  10: // invokes the delegate chain and writes message to std out and std err 11: currentLogger("Hi Standard Out and Error!"); While delegates give us a lot of power, it can be cumbersome to re-create fairly standard delegate definitions repeatedly, for this purpose the generic delegates were introduced in various stages in .NET.  These support various method types with particular signatures. Note: a caveat with generic delegates is that while they can support multiple parameters, they do not match methods that contains ref or out parameters. If you want to a delegate to represent methods that takes ref or out parameters, you will need to create a custom delegate. We’ve got the Func… delegates Just like it’s cousin, the Action delegate family, the Func delegate family gives us a lot of power to use generic delegates to make classes and algorithms more generic.  Using them keeps us from having to define a new delegate type when need to make a class or algorithm generic. Remember that the point of the Action delegate family was to be able to perform an “action” on an item, with no return results.  Thus Action delegates can be used to represent most methods that take 0 to 16 arguments but return void.  You can assign a method The Func delegate family was introduced in .NET 3.5 with the advent of LINQ, and gives us the power to define a function that can be called on 0 to 16 arguments and returns a result.  Thus, the main difference between Action and Func, from a delegate perspective, is that Actions return nothing, but Funcs return a result. The Func family of delegates have signatures as follows: Func<TResult> – matches a method that takes no arguments, and returns value of type TResult. Func<T, TResult> – matches a method that takes an argument of type T, and returns value of type TResult. Func<T1, T2, TResult> – matches a method that takes arguments of type T1 and T2, and returns value of type TResult. Func<T1, T2, …, TResult> – and so on up to 16 arguments, and returns value of type TResult. These are handy because they quickly allow you to be able to specify that a method or class you design will perform a function to produce a result as long as the method you specify meets the signature. For example, let’s say you were designing a generic aggregator, and you wanted to allow the user to define how the values will be aggregated into the result (i.e. Sum, Min, Max, etc…).  To do this, we would ask the user of our class to pass in a method that would take the current total, the next value, and produce a new total.  A class like this could look like: 1: public sealed class Aggregator<TValue, TResult> 2: { 3: // holds method that takes previous result, combines with next value, creates new result 4: private Func<TResult, TValue, TResult> _aggregationMethod; 5:  6: // gets or sets the current result of aggregation 7: public TResult Result { get; private set; } 8:  9: // construct the aggregator given the method to use to aggregate values 10: public Aggregator(Func<TResult, TValue, TResult> aggregationMethod = null) 11: { 12: if (aggregationMethod == null) throw new ArgumentNullException("aggregationMethod"); 13:  14: _aggregationMethod = aggregationMethod; 15: } 16:  17: // method to add next value 18: public void Aggregate(TValue nextValue) 19: { 20: // performs the aggregation method function on the current result and next and sets to current result 21: Result = _aggregationMethod(Result, nextValue); 22: } 23: } Of course, LINQ already has an Aggregate extension method, but that works on a sequence of IEnumerable<T>, whereas this is designed to work more with aggregating single results over time (such as keeping track of a max response time for a service). We could then use this generic aggregator to find the sum of a series of values over time, or the max of a series of values over time (among other things): 1: // creates an aggregator that adds the next to the total to sum the values 2: var sumAggregator = new Aggregator<int, int>((total, next) => total + next); 3:  4: // creates an aggregator (using static method) that returns the max of previous result and next 5: var maxAggregator = new Aggregator<int, int>(Math.Max); So, if we were timing the response time of a web method every time it was called, we could pass that response time to both of these aggregators to get an idea of the total time spent in that web method, and the max time spent in any one call to the web method: 1: // total will be 13 and max 13 2: int responseTime = 13; 3: sumAggregator.Aggregate(responseTime); 4: maxAggregator.Aggregate(responseTime); 5:  6: // total will be 20 and max still 13 7: responseTime = 7; 8: sumAggregator.Aggregate(responseTime); 9: maxAggregator.Aggregate(responseTime); 10:  11: // total will be 40 and max now 20 12: responseTime = 20; 13: sumAggregator.Aggregate(responseTime); 14: maxAggregator.Aggregate(responseTime); The Func delegate family is useful for making generic algorithms and classes, and in particular allows the caller of the method or user of the class to specify a function to be performed in order to generate a result. What is the result of a Func delegate chain? If you remember, we said earlier that you can assign multiple methods to a delegate by using the += operator to chain them.  So how does this affect delegates such as Func that return a value, when applied to something like the code below? 1: Func<int, int, int> combo = null; 2:  3: // What if we wanted to aggregate the sum and max together? 4: combo += (total, next) => total + next; 5: combo += Math.Max; 6:  7: // what is the result? 8: var comboAggregator = new Aggregator<int, int>(combo); Well, in .NET if you chain multiple methods in a delegate, they will all get invoked, but the result of the delegate is the result of the last method invoked in the chain.  Thus, this aggregator would always result in the Math.Max() result.  The other chained method (the sum) gets executed first, but it’s result is thrown away: 1: // result is 13 2: int responseTime = 13; 3: comboAggregator.Aggregate(responseTime); 4:  5: // result is still 13 6: responseTime = 7; 7: comboAggregator.Aggregate(responseTime); 8:  9: // result is now 20 10: responseTime = 20; 11: comboAggregator.Aggregate(responseTime); So remember, you can chain multiple Func (or other delegates that return values) together, but if you do so you will only get the last executed result. Func delegates and co-variance/contra-variance in .NET 4.0 Just like the Action delegate, as of .NET 4.0, the Func delegate family is contra-variant on its arguments.  In addition, it is co-variant on its return type.  To support this, in .NET 4.0 the signatures of the Func delegates changed to: Func<out TResult> – matches a method that takes no arguments, and returns value of type TResult (or a more derived type). Func<in T, out TResult> – matches a method that takes an argument of type T (or a less derived type), and returns value of type TResult(or a more derived type). Func<in T1, in T2, out TResult> – matches a method that takes arguments of type T1 and T2 (or less derived types), and returns value of type TResult (or a more derived type). Func<in T1, in T2, …, out TResult> – and so on up to 16 arguments, and returns value of type TResult (or a more derived type). Notice the addition of the in and out keywords before each of the generic type placeholders.  As we saw last week, the in keyword is used to specify that a generic type can be contra-variant -- it can match the given type or a type that is less derived.  However, the out keyword, is used to specify that a generic type can be co-variant -- it can match the given type or a type that is more derived. On contra-variance, if you are saying you need an function that will accept a string, you can just as easily give it an function that accepts an object.  In other words, if you say “give me an function that will process dogs”, I could pass you a method that will process any animal, because all dogs are animals.  On the co-variance side, if you are saying you need a function that returns an object, you can just as easily pass it a function that returns a string because any string returned from the given method can be accepted by a delegate expecting an object result, since string is more derived.  Once again, in other words, if you say “give me a method that creates an animal”, I can pass you a method that will create a dog, because all dogs are animals. It really all makes sense, you can pass a more specific thing to a less specific parameter, and you can return a more specific thing as a less specific result.  In other words, pay attention to the direction the item travels (parameters go in, results come out).  Keeping that in mind, you can always pass more specific things in and return more specific things out. For example, in the code below, we have a method that takes a Func<object> to generate an object, but we can pass it a Func<string> because the return type of object can obviously accept a return value of string as well: 1: // since Func<object> is co-variant, this will access Func<string>, etc... 2: public static string Sequence(int count, Func<object> generator) 3: { 4: var builder = new StringBuilder(); 5:  6: for (int i=0; i<count; i++) 7: { 8: object value = generator(); 9: builder.Append(value); 10: } 11:  12: return builder.ToString(); 13: } Even though the method above takes a Func<object>, we can pass a Func<string> because the TResult type placeholder is co-variant and accepts types that are more derived as well: 1: // delegate that's typed to return string. 2: Func<string> stringGenerator = () => DateTime.Now.ToString(); 3:  4: // This will work in .NET 4.0, but not in previous versions 5: Sequence(100, stringGenerator); Previous versions of .NET implemented some forms of co-variance and contra-variance before, but .NET 4.0 goes one step further and allows you to pass or assign an Func<A, BResult> to a Func<Y, ZResult> as long as A is less derived (or same) as Y, and BResult is more derived (or same) as ZResult. Sidebar: The Func and the Predicate A method that takes one argument and returns a bool is generally thought of as a predicate.  Predicates are used to examine an item and determine whether that item satisfies a particular condition.  Predicates are typically unary, but you may also have binary and other predicates as well. Predicates are often used to filter results, such as in the LINQ Where() extension method: 1: var numbers = new[] { 1, 2, 4, 13, 8, 10, 27 }; 2:  3: // call Where() using a predicate which determines if the number is even 4: var evens = numbers.Where(num => num % 2 == 0); As of .NET 3.5, predicates are typically represented as Func<T, bool> where T is the type of the item to examine.  Previous to .NET 3.5, there was a Predicate<T> type that tended to be used (which we’ll discuss next week) and is still supported, but most developers recommend using Func<T, bool> now, as it prevents confusion with overloads that accept unary predicates and binary predicates, etc.: 1: // this seems more confusing as an overload set, because of Predicate vs Func 2: public static SomeMethod(Predicate<int> unaryPredicate) { } 3: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } 4:  5: // this seems more consistent as an overload set, since just uses Func 6: public static SomeMethod(Func<int, bool> unaryPredicate) { } 7: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } Also, even though Predicate<T> and Func<T, bool> match the same signatures, they are separate types!  Thus you cannot assign a Predicate<T> instance to a Func<T, bool> instance and vice versa: 1: // the same method, lambda expression, etc can be assigned to both 2: Predicate<int> isEven = i => (i % 2) == 0; 3: Func<int, bool> alsoIsEven = i => (i % 2) == 0; 4:  5: // but the delegate instances cannot be directly assigned, strongly typed! 6: // ERROR: cannot convert type... 7: isEven = alsoIsEven; 8:  9: // however, you can assign by wrapping in a new instance: 10: isEven = new Predicate<int>(alsoIsEven); 11: alsoIsEven = new Func<int, bool>(isEven); So, the general advice that seems to come from most developers is that Predicate<T> is still supported, but we should use Func<T, bool> for consistency in .NET 3.5 and above. Sidebar: Func as a Generator for Unit Testing One area of difficulty in unit testing can be unit testing code that is based on time of day.  We’d still want to unit test our code to make sure the logic is accurate, but we don’t want the results of our unit tests to be dependent on the time they are run. One way (of many) around this is to create an internal generator that will produce the “current” time of day.  This would default to returning result from DateTime.Now (or some other method), but we could inject specific times for our unit testing.  Generators are typically methods that return (generate) a value for use in a class/method. For example, say we are creating a CacheItem<T> class that represents an item in the cache, and we want to make sure the item shows as expired if the age is more than 30 seconds.  Such a class could look like: 1: // responsible for maintaining an item of type T in the cache 2: public sealed class CacheItem<T> 3: { 4: // helper method that returns the current time 5: private static Func<DateTime> _timeGenerator = () => DateTime.Now; 6:  7: // allows internal access to the time generator 8: internal static Func<DateTime> TimeGenerator 9: { 10: get { return _timeGenerator; } 11: set { _timeGenerator = value; } 12: } 13:  14: // time the item was cached 15: public DateTime CachedTime { get; private set; } 16:  17: // the item cached 18: public T Value { get; private set; } 19:  20: // item is expired if older than 30 seconds 21: public bool IsExpired 22: { 23: get { return _timeGenerator() - CachedTime > TimeSpan.FromSeconds(30.0); } 24: } 25:  26: // creates the new cached item, setting cached time to "current" time 27: public CacheItem(T value) 28: { 29: Value = value; 30: CachedTime = _timeGenerator(); 31: } 32: } Then, we can use this construct to unit test our CacheItem<T> without any time dependencies: 1: var baseTime = DateTime.Now; 2:  3: // start with current time stored above (so doesn't drift) 4: CacheItem<int>.TimeGenerator = () => baseTime; 5:  6: var target = new CacheItem<int>(13); 7:  8: // now add 15 seconds, should still be non-expired 9: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(15); 10:  11: Assert.IsFalse(target.IsExpired); 12:  13: // now add 31 seconds, should now be expired 14: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(31); 15:  16: Assert.IsTrue(target.IsExpired); Now we can unit test for 1 second before, 1 second after, 1 millisecond before, 1 day after, etc.  Func delegates can be a handy tool for this type of value generation to support more testable code.  Summary Generic delegates give us a lot of power to make truly generic algorithms and classes.  The Func family of delegates is a great way to be able to specify functions to calculate a result based on 0-16 arguments.  Stay tuned in the weeks that follow for other generic delegates in the .NET Framework!   Tweet Technorati Tags: .NET, C#, CSharp, Little Wonders, Generics, Func, Delegates

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• How to create Custom ListForm WebPart

  - by DipeshBhanani

  Mostly all who works extensively on SharePoint (including meJ) don’t like to use out-of-box list forms (DispForm.aspx, EditForm.aspx, NewForm.aspx) as interface. Actually these OOB list forms bind hands of developers for the customization. It gives headache to developers to add just one post back event, for a dropdown field and to populate other fields in NewForm.aspx or EditForm.aspx. On top of that clients always ask such stuff. So here I am going to give you guys a flight for SharePoint Customization world. In this blog, I will explain, how to create CustomListForm WebPart. In my next blogs, I am going to explain easy deployment of List Forms through features and last, guidance on using SharePoint web controls. 1.       First thing, create a class library project through Visual Studio and inherit the class with WebPart class.     public class CustomListForm : WebPart   2.       Declare the public variables and properties which we are going to use throughout the class. You will get to know these once you see them in use.         #region "Variable Declaration"           Table spTableCntl;         FormToolBar formToolBar;         Literal ltAlertMessage;         Guid SiteId;         Guid ListId;         int ItemId;         string ListName;           #endregion           #region "Properties"           SPControlMode _ControlMode = SPControlMode.New;         [Personalizable(PersonalizationScope.Shared),          WebBrowsable(true),          WebDisplayName("Control Mode"),          WebDescription("Set Control Mode"),          DefaultValue(""),          Category("Miscellaneous")]         public SPControlMode ControlMode         {             get { return _ControlMode; }             set { _ControlMode = value; }         }           #endregion     The property “ControlMode” is used to identify the mode of the List Form. The property is of type SPControlMode which is an enum type with values (Display, Edit, New and Invalid). When we will add this WebPart to DispForm.aspx, EditForm.aspx and NewForm.aspx, we will set the WebPart property “ControlMode” to Display, Edit and New respectively.     3.       Now, we need to override the CreateChildControl method and write code to manually add SharePoint Web Controls related to each list fields as well as ToolBar controls.         protected override void CreateChildControls()         {             base.CreateChildControls();               try             {                 SiteId = SPContext.Current.Site.ID;                 ListId = SPContext.Current.ListId;                 ListName = SPContext.Current.List.Title;                   if (_ControlMode == SPControlMode.Display || _ControlMode == SPControlMode.Edit)                     ItemId = SPContext.Current.ItemId;                   SPSecurity.RunWithElevatedPrivileges(delegate()                 {                     using (SPSite site = new SPSite(SiteId))                     {                         //creating a new SPSite with credentials of System Account                         using (SPWeb web = site.OpenWeb())                         {                               //<Custom Code for creating form controls>                         }                     }                 });             }             catch (Exception ex)             {                 ShowError(ex, "CreateChildControls");             }         }   Here we are assuming that we are developing this WebPart to plug into List Forms. Hence we will get the List Id and List Name from the current context. We can have Item Id only in case of Display and Edit Mode. We are putting our code into “RunWithElevatedPrivileges” to elevate privileges to System Account. Now, let’s get deep down into the main code and expand “//<Custom Code for creating form controls>”. Before initiating any SharePoint control, we need to set context of SharePoint web controls explicitly so that it will be instantiated with elevated System Account user. Following line does the job.     //To create SharePoint controls with new web object and System Account credentials     SPControl.SetContextWeb(Context, web);   First thing, let’s add main table as container for all controls.     //Table to render webpart     Table spTableMain = new Table();     spTableMain.CellPadding = 0;     spTableMain.CellSpacing = 0;     spTableMain.Width = new Unit(100, UnitType.Percentage);     this.Controls.Add(spTableMain);   Now we need to add Top toolbar with Save and Cancel button at top as you see in the below screen shot.       // Add Row and Cell for Top ToolBar     TableRow spRowTopToolBar = new TableRow();     spTableMain.Rows.Add(spRowTopToolBar);     TableCell spCellTopToolBar = new TableCell();     spRowTopToolBar.Cells.Add(spCellTopToolBar);     spCellTopToolBar.Width = new Unit(100, UnitType.Percentage);         ToolBar toolBarTop = (ToolBar)Page.LoadControl("/_controltemplates/ToolBar.ascx");     toolBarTop.CssClass = "ms-formtoolbar";     toolBarTop.ID = "toolBarTbltop";     toolBarTop.RightButtons.SeparatorHtml = "<td class=ms-separator> </td>";       if (_ControlMode != SPControlMode.Display)     {         SaveButton btnSave = new SaveButton();         btnSave.ControlMode = _ControlMode;         btnSave.ListId = ListId;           if (_ControlMode == SPControlMode.New)             btnSave.RenderContext = SPContext.GetContext(web);         else         {             btnSave.RenderContext = SPContext.GetContext(this.Context, ItemId, ListId, web);             btnSave.ItemContext = SPContext.GetContext(this.Context, ItemId, ListId, web);             btnSave.ItemId = ItemId;         }         toolBarTop.RightButtons.Controls.Add(btnSave);     }       GoBackButton goBackButtonTop = new GoBackButton();     toolBarTop.RightButtons.Controls.Add(goBackButtonTop);     goBackButtonTop.ControlMode = SPControlMode.Display;       spCellTopToolBar.Controls.Add(toolBarTop);   Here we have use “SaveButton” and “GoBackButton” which are internal SharePoint web controls for save and cancel functionality. I have set some of the properties of Save Button with if-else condition because we will not have Item Id in case of New Mode. Item Id property is used to identify which SharePoint List Item need to be saved. Now, add Form Toolbar to the page which contains “Attach File”, “Delete Item” etc buttons.       // Add Row and Cell for FormToolBar     TableRow spRowFormToolBar = new TableRow();     spTableMain.Rows.Add(spRowFormToolBar);     TableCell spCellFormToolBar = new TableCell();     spRowFormToolBar.Cells.Add(spCellFormToolBar);     spCellFormToolBar.Width = new Unit(100, UnitType.Percentage);       FormToolBar formToolBar = new FormToolBar();     formToolBar.ID = "formToolBar";     formToolBar.ListId = ListId;     if (_ControlMode == SPControlMode.New)         formToolBar.RenderContext = SPContext.GetContext(web);     else     {         formToolBar.RenderContext = SPContext.GetContext(this.Context, ItemId, ListId, web);         formToolBar.ItemContext = SPContext.GetContext(this.Context, ItemId, ListId, web);         formToolBar.ItemId = ItemId;     }     formToolBar.ControlMode = _ControlMode;     formToolBar.EnableViewState = true;       spCellFormToolBar.Controls.Add(formToolBar);     The ControlMode property will take care of which button to be displayed on the toolbar. E.g. “Attach files”, “Delete Item” in new/edit forms and “New Item”, “Edit Item”, “Delete Item”, “Manage Permissions” etc in display forms. Now add main section which contains form field controls.     //Create Form Field controls and add them in Table "spCellCntl"     CreateFieldControls(web);     //Add public variable "spCellCntl" containing all form controls to the page     spRowCntl.Cells.Add(spCellCntl);     spCellCntl.Width = new Unit(100, UnitType.Percentage);     spCellCntl.Controls.Add(spTableCntl);       //Add a Blank Row with height of 5px to render space between ToolBar table and Control table     TableRow spRowLine1 = new TableRow();     spTableMain.Rows.Add(spRowLine1);     TableCell spCellLine1 = new TableCell();     spRowLine1.Cells.Add(spCellLine1);     spCellLine1.Height = new Unit(5, UnitType.Pixel);     spCellLine1.Controls.Add(new LiteralControl("<IMG SRC='/_layouts/images/blank.gif' width=1 height=1 alt=''>"));       //Add Row and Cell for Form Controls Section     TableRow spRowCntl = new TableRow();     spTableMain.Rows.Add(spRowCntl);     TableCell spCellCntl = new TableCell();       //Create Form Field controls and add them in Table "spCellCntl"     CreateFieldControls(web);     //Add public variable "spCellCntl" containing all form controls to the page     spRowCntl.Cells.Add(spCellCntl);     spCellCntl.Width = new Unit(100, UnitType.Percentage);     spCellCntl.Controls.Add(spTableCntl);       TableRow spRowLine2 = new TableRow();     spTableMain.Rows.Add(spRowLine2);     TableCell spCellLine2 = new TableCell();     spRowLine2.Cells.Add(spCellLine2);     spCellLine2.CssClass = "ms-formline";     spCellLine2.Controls.Add(new LiteralControl("<IMG SRC='/_layouts/images/blank.gif' width=1 height=1 alt=''>"));       // Add Blank row with height of 5 pixel     TableRow spRowLine3 = new TableRow();     spTableMain.Rows.Add(spRowLine3);     TableCell spCellLine3 = new TableCell();     spRowLine3.Cells.Add(spCellLine3);     spCellLine3.Height = new Unit(5, UnitType.Pixel);     spCellLine3.Controls.Add(new LiteralControl("<IMG SRC='/_layouts/images/blank.gif' width=1 height=1 alt=''>"));   You can add bottom toolbar also to get same look and feel as OOB forms. I am not adding here as the blog will be much lengthy. At last, you need to write following lines to allow unsafe updates for Save and Delete button.     // Allow unsafe update on web for save button and delete button     if (this.Page.IsPostBack && this.Page.Request["__EventTarget"] != null         && (this.Page.Request["__EventTarget"].Contains("IOSaveItem")         || this.Page.Request["__EventTarget"].Contains("IODeleteItem")))     {         SPContext.Current.Web.AllowUnsafeUpdates = true;     }   So that’s all. We have finished writing Custom Code for adding field control. But something most important is skipped. In above code, I have called function “CreateFieldControls(web);” to add SharePoint field controls to the page. Let’s see the implementation of the function:     private void CreateFieldControls(SPWeb pWeb)     {         SPList listMain = pWeb.Lists[ListId];         SPFieldCollection fields = listMain.Fields;           //Main Table to render all fields         spTableCntl = new Table();         spTableCntl.BorderWidth = new Unit(0);         spTableCntl.CellPadding = 0;         spTableCntl.CellSpacing = 0;         spTableCntl.Width = new Unit(100, UnitType.Percentage);         spTableCntl.CssClass = "ms-formtable";           SPContext controlContext = SPContext.GetContext(this.Context, ItemId, ListId, pWeb);           foreach (SPField listField in fields)         {             string fieldDisplayName = listField.Title;             string fieldInternalName = listField.InternalName;               //Skip if the field is system field or hidden             if (listField.Hidden || listField.ShowInVersionHistory == false)                 continue;               //Skip if the control mode is display and field is read-only             if (_ControlMode != SPControlMode.Display && listField.ReadOnlyField == true)                 continue;               FieldLabel fieldLabel = new FieldLabel();             fieldLabel.FieldName = listField.InternalName;             fieldLabel.ListId = ListId;               BaseFieldControl fieldControl = listField.FieldRenderingControl;             fieldControl.ListId = ListId;             //Assign unique id using Field Internal Name             fieldControl.ID = string.Format("Field_{0}", fieldInternalName);             fieldControl.EnableViewState = true;               //Assign control mode             fieldLabel.ControlMode = _ControlMode;             fieldControl.ControlMode = _ControlMode;             switch (_ControlMode)             {                 case SPControlMode.New:                     fieldLabel.RenderContext = SPContext.GetContext(pWeb);                     fieldControl.RenderContext = SPContext.GetContext(pWeb);                     break;                 case SPControlMode.Edit:                 case SPControlMode.Display:                     fieldLabel.RenderContext = controlContext;                     fieldLabel.ItemContext = controlContext;                     fieldLabel.ItemId = ItemId;                       fieldControl.RenderContext = controlContext;                     fieldControl.ItemContext = controlContext;                     fieldControl.ItemId = ItemId;                     break;             }               //Add row to display a field row             TableRow spCntlRow = new TableRow();             spTableCntl.Rows.Add(spCntlRow);               //Add the cells for containing field lable and control             TableCell spCellLabel = new TableCell();             spCellLabel.Width = new Unit(30, UnitType.Percentage);             spCellLabel.CssClass = "ms-formlabel";             spCntlRow.Cells.Add(spCellLabel);             TableCell spCellControl = new TableCell();             spCellControl.Width = new Unit(70, UnitType.Percentage);             spCellControl.CssClass = "ms-formbody";             spCntlRow.Cells.Add(spCellControl);               //Add the control to the table cells             spCellLabel.Controls.Add(fieldLabel);             spCellControl.Controls.Add(fieldControl);               //Add description if there is any in case of New and Edit Mode             if (_ControlMode != SPControlMode.Display && listField.Description != string.Empty)             {                 FieldDescription fieldDesc = new FieldDescription();                 fieldDesc.FieldName = fieldInternalName;                 fieldDesc.ListId = ListId;                 spCellControl.Controls.Add(fieldDesc);             }               //Disable Name(Title) in Edit Mode             if (_ControlMode == SPControlMode.Edit && fieldDisplayName == "Name")             {                 TextBox txtTitlefield = (TextBox)fieldControl.Controls[0].FindControl("TextField");                 txtTitlefield.Enabled = false;             }         }         fields = null;     }   First of all, I have declared List object and got list fields in field collection object called “fields”. Then I have added a table for the container of all controls and assign CSS class as "ms-formtable" so that it gives consistent look and feel of SharePoint. Now it’s time to navigate through all fields and add them if required. Here we don’t need to add hidden or system fields. We also don’t want to display read-only fields in new and edit forms. Following lines does this job.             //Skip if the field is system field or hidden             if (listField.Hidden || listField.ShowInVersionHistory == false)                 continue;               //Skip if the control mode is display and field is read-only             if (_ControlMode != SPControlMode.Display && listField.ReadOnlyField == true)                 continue;   Let’s move to the next line of code.             FieldLabel fieldLabel = new FieldLabel();             fieldLabel.FieldName = listField.InternalName;             fieldLabel.ListId = ListId;               BaseFieldControl fieldControl = listField.FieldRenderingControl;             fieldControl.ListId = ListId;             //Assign unique id using Field Internal Name             fieldControl.ID = string.Format("Field_{0}", fieldInternalName);             fieldControl.EnableViewState = true;               //Assign control mode             fieldLabel.ControlMode = _ControlMode;             fieldControl.ControlMode = _ControlMode;   We have used “FieldLabel” control for displaying field title. The advantage of using Field Label is, SharePoint automatically adds red star besides field label to identify it as mandatory field if there is any. Here is most important part to understand. The “BaseFieldControl”. It will render the respective web controls according to type of the field. For example, if it’s single line of text, then Textbox, if it’s look up then it renders dropdown. Additionally, the “ControlMode” property tells compiler that which mode (display/edit/new) controls need to be rendered with. In display mode, it will render label with field value. In edit mode, it will render respective control with item value and in new mode it will render respective control with empty value. Please note that, it’s not always the case when dropdown field will be rendered for Lookup field or Choice field. You need to understand which controls are rendered for which list fields. I am planning to write a separate blog which I hope to publish it very soon. Moreover, we also need to assign list field specific properties like List Id, Field Name etc to identify which SharePoint List field is attached with the control.             switch (_ControlMode)             {                 case SPControlMode.New:                     fieldLabel.RenderContext = SPContext.GetContext(pWeb);                     fieldControl.RenderContext = SPContext.GetContext(pWeb);                     break;                 case SPControlMode.Edit:                 case SPControlMode.Display:                     fieldLabel.RenderContext = controlContext;                     fieldLabel.ItemContext = controlContext;                     fieldLabel.ItemId = ItemId;                       fieldControl.RenderContext = controlContext;                     fieldControl.ItemContext = controlContext;                     fieldControl.ItemId = ItemId;                     break;             }   Here, I have separate code for new mode and Edit/Display mode because we will not have Item Id to assign in New Mode. We also need to set CSS class for cell containing Label and Controls so that those controls get rendered with SharePoint theme.             spCellLabel.CssClass = "ms-formlabel";             spCellControl.CssClass = "ms-formbody";   “FieldDescription” control is used to add field description if there is any.    Now it’s time to add some more customization,               //Disable Name(Title) in Edit Mode             if (_ControlMode == SPControlMode.Edit && fieldDisplayName == "Name")             {                 TextBox txtTitlefield = (TextBox)fieldControl.Controls[0].FindControl("TextField");                 txtTitlefield.Enabled = false;             }   The above code will disable the title field in edit mode. You can add more code here to achieve more customization according to your requirement. Some of the examples are as follow:             //Adding post back event on UserField to auto populate some other dependent field             //in new mode and disable it in edit mode             if (_ControlMode != SPControlMode.Display && fieldDisplayName == "Manager")             {                 if (fieldControl.Controls[0].FindControl("UserField") != null)                 {                     PeopleEditor pplEditor = (PeopleEditor)fieldControl.Controls[0].FindControl("UserField");                     if (_ControlMode == SPControlMode.New)                         pplEditor.AutoPostBack = true;                     else                         pplEditor.Enabled = false;                 }             }               //Add JavaScript Event on Dropdown field. Don't forget to add the JavaScript function on the page.             if (_ControlMode == SPControlMode.Edit && fieldDisplayName == "Designation")             {                 DropDownList ddlCategory = (DropDownList)fieldControl.Controls[0];                 ddlCategory.Attributes.Add("onchange", string.Format("javascript:DropdownChangeEvent('{0}');return false;", ddlCategory.ClientID));             }    Following are the screenshots of my Custom ListForm WebPart. Let’s play a game, check out your OOB List forms of SharePoint, compare with these screens and find out differences.   DispForm.aspx:   EditForm.aspx:   NewForm.aspx:   Enjoy the SharePoint Soup!!! ­­­­­­­­­­­­­­­­­­­­

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• Partner Blog Series: PwC Perspectives - The Gotchas, The Do's and Don'ts for IDM Implementations

  - by Tanu Sood

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:12.0pt; mso-para-margin-left:0in; line-height:12.0pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Arial","sans-serif"; mso-ascii-font-family:Arial; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Arial; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} table.MsoTableMediumList1Accent6 {mso-style-name:"Medium List 1 - Accent 6"; mso-tstyle-rowband-size:1; mso-tstyle-colband-size:1; mso-style-priority:65; mso-style-unhide:no; border-top:solid #E0301E 1.0pt; mso-border-top-themecolor:accent6; border-left:none; border-bottom:solid #E0301E 1.0pt; mso-border-bottom-themecolor:accent6; border-right:none; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Georgia","serif"; color:black; mso-themecolor:text1; mso-ansi-language:EN-GB;} table.MsoTableMediumList1Accent6FirstRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:first-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:cell-none; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; font-family:"Verdana","sans-serif"; mso-ascii-font-family:Georgia; mso-ascii-theme-font:major-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:major-fareast; mso-hansi-font-family:Georgia; mso-hansi-theme-font:major-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:major-bidi;} table.MsoTableMediumList1Accent6LastRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:last-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:1.0pt solid #E0301E; mso-tstyle-border-top-themecolor:accent6; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; color:#968C6D; mso-themecolor:text2; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6FirstCol {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:first-column; mso-style-priority:65; mso-style-unhide:no; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6LastCol {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:last-column; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:1.0pt solid #E0301E; mso-tstyle-border-top-themecolor:accent6; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6OddColumn {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:odd-column; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-shading:#F7CBC7; mso-tstyle-shading-themecolor:accent6; mso-tstyle-shading-themetint:63;} table.MsoTableMediumList1Accent6OddRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:odd-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-shading:#F7CBC7; mso-tstyle-shading-themecolor:accent6; mso-tstyle-shading-themetint:63;} Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:12.0pt; mso-para-margin-left:0in; line-height:12.0pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Arial","sans-serif"; mso-ascii-font-family:Arial; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Arial; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} table.MsoTableMediumList1Accent6 {mso-style-name:"Medium List 1 - Accent 6"; mso-tstyle-rowband-size:1; mso-tstyle-colband-size:1; mso-style-priority:65; mso-style-unhide:no; border-top:solid #E0301E 1.0pt; mso-border-top-themecolor:accent6; border-left:none; border-bottom:solid #E0301E 1.0pt; mso-border-bottom-themecolor:accent6; border-right:none; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Georgia","serif"; color:black; mso-themecolor:text1; mso-ansi-language:EN-GB;} table.MsoTableMediumList1Accent6FirstRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:first-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:cell-none; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; font-family:"Arial Narrow","sans-serif"; mso-ascii-font-family:Georgia; mso-ascii-theme-font:major-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:major-fareast; mso-hansi-font-family:Georgia; mso-hansi-theme-font:major-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:major-bidi;} table.MsoTableMediumList1Accent6LastRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:last-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:1.0pt solid #E0301E; mso-tstyle-border-top-themecolor:accent6; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; color:#968C6D; mso-themecolor:text2; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6FirstCol {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:first-column; mso-style-priority:65; mso-style-unhide:no; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6LastCol {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:last-column; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:1.0pt solid #E0301E; mso-tstyle-border-top-themecolor:accent6; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6OddColumn {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:odd-column; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-shading:#F7CBC7; mso-tstyle-shading-themecolor:accent6; mso-tstyle-shading-themetint:63;} table.MsoTableMediumList1Accent6OddRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:odd-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-shading:#F7CBC7; mso-tstyle-shading-themecolor:accent6; mso-tstyle-shading-themetint:63;} It is generally accepted among business communities that technology by itself is not a silver bullet to all problems, but when it is combined with leading practices, strategy, careful planning and execution, it can create a recipe for success. This post attempts to highlight some of the best practices along with dos & don’ts that our practice has accumulated over the years in the identity & access management space in general, and also in the context of R2, in particular. Best Practices The following section illustrates the leading practices in “How” to plan, implement and sustain a successful OIM deployment, based on our collective experience. Planning is critical, but often overlooked A common approach to planning an IAM program that we identify with our clients is the three step process involving a current state assessment, a future state roadmap and an executable strategy to get there. It is extremely beneficial for clients to assess their current IAM state, perform gap analysis, document the recommended controls to address the gaps, align future state roadmap to business initiatives and get buy in from all stakeholders involved to improve the chances of success. When designing an enterprise-wide solution, the scalability of the technology must accommodate the future growth of the enterprise and the projected identity transactions over several years. Aligning the implementation schedule of OIM to related information technology projects increases the chances of success. As a baseline, it is recommended to match hardware specifications to the sizing guide for R2 published by Oracle. Adherence to this will help ensure that the hardware used to support OIM will not become a bottleneck as the adoption of new services increases. If your Organization has numerous connected applications that rely on reconciliation to synchronize the access data into OIM, consider hosting dedicated instances to handle reconciliation. Finally, ensure the use of clustered environment for development and have at least three total environments to help facilitate a controlled migration to production. If your Organization is planning to implement role based access control, we recommend performing a role mining exercise and consolidate your enterprise roles to keep them manageable. In addition, many Organizations have multiple approval flows to control access to critical roles, applications and entitlements. If your Organization falls into this category, we highly recommend that you limit the number of approval workflows to a small set. Most Organizations have operations managed across data centers with backend database synchronization, if your Organization falls into this category, ensure that the overall latency between the datacenters when replicating the databases is less than ten milliseconds to ensure that there are no front office performance impacts. Ingredients for a successful implementation During the development phase of your project, there are a number of guidelines that can be followed to help increase the chances for success. Most implementations cannot be completed without the use of customizations. If your implementation requires this, it’s a good practice to perform code reviews to help ensure quality and reduce code bottlenecks related to performance. We have observed at our clients that the development process works best when team members adhere to coding leading practices. Plan for time to correct coding defects and ensure developers are empowered to report their own bugs for maximum transparency. Many organizations struggle with defining a consistent approach to managing logs. This is particularly important due to the amount of information that can be logged by OIM. We recommend Oracle Diagnostics Logging (ODL) as an alternative to be used for logging. ODL allows log files to be formatted in XML for easy parsing and does not require a server restart when the log levels are changed during troubleshooting. Testing is a vital part of any large project, and an OIM R2 implementation is no exception. We suggest that at least one lower environment should use production-like data and connectors. Configurations should match as closely as possible. For example, use secure channels between OIM and target platforms in pre-production environments to test the configurations, the migration processes of certificates, and the additional overhead that encryption could impose. Finally, we ask our clients to perform database backups regularly and before any major change event, such as a patch or migration between environments. In the lowest environments, we recommend to have at least a weekly backup in order to prevent significant loss of time and effort. Similarly, if your organization is using virtual machines for one or more of the environments, it is recommended to take frequent snapshots so that rollbacks can occur in the event of improper configuration. Operate & sustain the solution to derive maximum benefits When migrating OIM R2 to production, it is important to perform certain activities that will help achieve a smoother transition. At our clients, we have seen that splitting the OIM tables into their own tablespaces by categories (physical tables, indexes, etc.) can help manage database growth effectively. If we notice that a client hasn’t enabled the Oracle-recommended indexing in the applicable database, we strongly suggest doing so to improve performance. Additionally, we work with our clients to make sure that the audit level is set to fit the organization’s auditing needs and sometimes even allocate UPA tables and indexes into their own table-space for better maintenance. Finally, many of our clients have set up schedules for reconciliation tables to be archived at regular intervals in order to keep the size of the database(s) reasonable and result in optimal database performance. For our clients that anticipate availability issues with target applications, we strongly encourage the use of the offline provisioning capabilities of OIM R2. This reduces the provisioning process for a given target application dependency on target availability and help avoid broken workflows. To account for this and other abnormalities, we also advocate that OIM’s monitoring controls be configured to alert administrators on any abnormal situations. Within OIM R2, we have begun advising our clients to utilize the ‘profile’ feature to encapsulate multiple commonly requested accounts, roles, and/or entitlements into a single item. By setting up a number of profiles that can be searched for and used, users will spend less time performing the same exact steps for common tasks. We advise our clients to follow the Oracle recommended guides for database and application server tuning which provides a good baseline configuration. It offers guidance on database connection pools, connection timeouts, user interface threads and proper handling of adapters/plug-ins. All of these can be important configurations that will allow faster provisioning and web page response times. Many of our clients have begun to recognize the value of data mining and a remediation process during the initial phases of an implementation (to help ensure high quality data gets loaded) and beyond (to support ongoing maintenance and business-as-usual processes). A successful program always begins with identifying the data elements and assigning a classification level based on criticality, risk, and availability. It should finish by following through with a remediation process. Dos & Don’ts Here are the most common dos and don'ts that we socialize with our clients, derived from our experience implementing the solution. Dos Don’ts Scope the project into phases with realistic goals. Look for quick wins to show success and value to the stake holders. Avoid “boiling the ocean” and trying to integrate all enterprise applications in the first phase. Establish an enterprise ID (universal unique ID across the enterprise) earlier in the program. Avoid major UI customizations that require code changes. Have a plan in place to patch during the project, which helps alleviate any major issues or roadblocks (product and database). Avoid publishing all the target entitlements if you don't anticipate their usage during access request. Assess your current state and prepare a roadmap to address your operations, tactical and strategic goals, align it with your business priorities. Avoid integrating non-production environments with your production target systems. Defer complex integrations to the later phases and take advantage of lessons learned from previous phases Avoid creating multiple accounts for the same user on the same system, if there is an opportunity to do so. Have an identity and access data quality initiative built into your plan to identify and remediate data related issues early on. Avoid creating complex approval workflows that would negative impact productivity and SLAs. Identify the owner of the identity systems with fair IdM knowledge and empower them with authority to make product related decisions. This will help ensure overcome any design hurdles. Avoid creating complex designs that are not sustainable long term and would need major overhaul during upgrades. Shadow your internal or external consulting resources during the implementation to build the necessary product skills needed to operate and sustain the solution. Avoid treating IAM as a point solution and have appropriate level of communication and training plan for the IT and business users alike. Conclusion In our experience, Identity programs will struggle with scope, proper resourcing, and more. We suggest that companies consider the suggestions discussed in this post and leverage them to help enable their identity and access program. This concludes PwC blog series on R2 for the month and we sincerely hope that the information we have shared thus far has been beneficial. For more information or if you have questions, you can reach out to Rex Thexton, Senior Managing Director, PwC and or Dharma Padala, Director, PwC. We look forward to hearing from you. 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Praveen Krishna is a Manager in the Advisory Security practice within PwC.  Over the last decade Praveen has helped clients plan, architect and implement Oracle identity solutions across diverse industries.  His experience includes delivering security across diverse topics like network, infrastructure, application and data where he brings a holistic point of view to problem solving. Scott MacDonald is a Director in the Advisory Security practice within PwC.  He has consulted for several clients across multiple industries including financial services, health care, automotive and retail.   Scott has 10 years of experience in delivering Identity Management solutions. John Misczak is a member of the Advisory Security practice within PwC.  He has experience implementing multiple Identity and Access Management solutions, specializing in Oracle Identity Manager and Business Process Engineering Language (BPEL).

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• program not working as expected!

  - by wilson88

  Can anyone just help spot why my program is not returning the expected output.related to my previous question.Am passing a vector by refrence, I want to see whats in the container before I copy them to another loaction.if u remove comments on loadRage, u will see bids are generated by the trader. #include <iostream> #include <vector> #include <string> #include <algorithm> #include <cstdlib> #include <iomanip> using namespace std; const int NUMSELLER = 1; const int NUMBUYER = 1; const int NUMBIDS = 20; const int MINQUANTITY = 1; const int MAXQUANTITY = 30; const int MINPRICE =100; const int MAXPRICE = 150; int s=0; int trdId; // Bid, simple container for values struct Bid { int bidId, trdId, qty, price; char type; // for sort and find. bool operator<(const Bid &other) const { return price < other.price; } bool operator==(int bidId) const { return this->bidId == bidId; } }; // alias to the list, make type consistent typedef vector<Bid> BidList; // this class generates bids! class Trader { private: int nextBidId; public: Trader(); Bid getNextBid(); Bid getNextBid(char type); // generate a number of bids void loadRange(BidList &, int size); void loadRange(BidList &, char type, int size); void setVector(); }; Trader::Trader() : nextBidId(1) {} #define RAND_RANGE(min, max) ((rand() % (max-min+1)) + min) Bid Trader::getNextBid() { char type = RAND_RANGE('A','B'); return getNextBid(type); } Bid Trader::getNextBid(char type) { for(int i = 0; i < NUMSELLER+NUMBUYER; i++) { // int trdId = RAND_RANGE(1,9); if (s<10){trdId=0;type='A';} else {trdId=1;type='B';} s++; int qty = RAND_RANGE(MINQUANTITY, MAXQUANTITY); int price = RAND_RANGE(MINPRICE, MAXPRICE); Bid bid = {nextBidId++, trdId, qty, price, type}; return bid; } } //void Trader::loadRange(BidList &list, int size) { // for (int i=0; i<size; i++) { list.push_back(getNextBid()); } //} // //void Trader::loadRange(BidList &list, char type, int size) { // for (int i=0; i<size; i++) { list.push_back(getNextBid(type)); } //} //---------------------------AUCTIONEER------------------------------------------- class Auctioneer { vector<Auctioneer> List; Trader trader; vector<Bid> list; public: Auctioneer(){}; void accept_bids(const BidList& bid); }; typedef vector<Auctioneer*> bidlist; void Auctioneer::accept_bids(const BidList& bid){ BidList list; //copy (BidList.begin(),BidList.end(),list); } //all the happy display commands void show(const Bid &bid) { cout << "\tBid\t(" << setw(3) << bid.bidId << "\t " << setw(3) << bid.trdId << "\t " << setw(3) << bid.type <<"\t " << setw(3) << bid.qty <<"\t " << setw(3) << bid.price <<")\t\n " ; } void show(const BidList &list) { cout << "\t\tBidID | TradID | Type | Qty | Price \n\n"; for(BidList::const_iterator itr=list.begin(); itr != list.end(); ++itr) { //cout <<"\t\t"; show(*itr); cout << endl; } cout << endl; } //search now checks for failure void show(const char *msg, const BidList &list) { cout << msg << endl; show(list); } void searchTest(BidList &list, int bidId) { cout << "Searching for Bid " << bidId << endl; BidList::const_iterator itr = find(list.begin(), list.end(), bidId); if (itr==list.end()) { cout << "Bid not found."; } else { cout << "Bid has been found. Its : "; show(*itr); } cout << endl; } //comparator function for price: returns true when x belongs before y bool compareBidList(Bid one, Bid two) { if (one.type == 'A' && two.type == 'B') return (one.price < two.price); return false; } void sort(BidList &bidlist) { sort(bidlist.begin(), bidlist.end(), compareBidList); } int main(int argc, char **argv) { Trader trader; BidList bidlist; Auctioneer auctioneer; //bidlist list; auctioneer.accept_bids(bidlist); //trader.loadRange(bidlist, NUMBIDS); show("Bids before sort:", bidlist); sort(bidlist); show("Bids after sort:", bidlist); system("pause"); return 0; }

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• SQLAuthority News – TechEd India – April 12-14, 2010 Bangalore – An Unforgettable Experience – An Op

  - by pinaldave

  TechEd India was one of the largest Technology events in India led by Microsoft. This event was attended by more than 3,000 technology enthusiasts, making it one of the most well-organized events of the year. Though I attempted to attend almost all the technology events here, I have not seen any bigger or better event in Indian subcontinents other than this. There are 21 Technical Tracks at Tech·Ed India 2010 that span more than 745 learning opportunities. I was fortunate enough to be a part of this whole event as a speaker and a delegate, as well. TechEd India Speaker Badge and A Token of Lifetime Hotel Selection I presented three different sessions at TechEd India and was also a part of panel discussion. (The details of the sessions are given at the end of this blog post.) Due to extensive traveling, I stay away from my family occasionally. For this reason, I took my wife – Nupur and daughter Shaivi (8 months old) to the event along with me. We stayed at the same hotel where the event was organized so as to maximize my time bonding with my family and to have more time in networking with technology community, at the same time. The hotel Lalit Ashok is the largest and most luxurious venue one can find in Bangalore, located in the middle of the city. The cost of the hotel was a bit pricey, but looking at all the advantages, I had decided to ask for a booking there. Hotel Lalit Ashok Nupur Dave and Shaivi Dave Arrival Day – DAY 0 – April 11, 2010 I reached the event a day earlier, and that was one wise decision for I was able to relax a bit and go over my presentation for the next day’s course. I am a kind of person who likes to get everything ready ahead of time. I was also able to enjoy a pleasant evening with several Microsoft employees and my family friends. I even checked out the location where I would be doing presentations the next day. I was fortunate enough to meet Bijoy Singhal from Microsoft who helped me out with a few of the logistics issues that occured the day before. I was not aware of the fact that the very next day he was going to be “The Man” of the TechEd 2010 event. Vinod Kumar from Microsoft was really very kind as he talked to me regarding my subsequent session. He gave me some suggestions which were really helpful that I was able to incorporate them during my presentation. Finally, I was able to meet Abhishek Kant from Microsoft; his valuable suggestions and unlimited passion have inspired many people like me to work with the Community. Pradipta from Microsoft was also around, being extremely busy with logistics; however, in those busy times, he did find some good spare time to have a chat with me and the other Community leaders. I also met Harish Ranganathan and Sachin Rathi, both from Microsoft. It was so interesting to listen to both of them talking about SharePoint. I just have no words to express my overwhelmed spirit because of all these passionate young guys - Pradipta,Vinod, Bijoy, Harish, Sachin and Ahishek (of course!). Map of TechEd India 2010 Event Day 1 – April 12, 2010 From morning until night time, today was truly a very busy day for me. I had two presentations and one panel discussion for the day. Needless to say, I had a few meetings to attend as well. The day started with a keynote from S. Somaseger where he announced the launch of Visual Studio 2010. The keynote area was really eye-catching because of the very large, bigger-than- life uniform screen. This was truly one to show. The title music of the keynote was very interesting and it featured Bijoy Singhal as the model. It was interesting to talk to him afterwards, when we laughed at jokes together about his modeling assignment. TechEd India Keynote Opening Featuring Bijoy TechEd India 2010 Keynote – S. Somasegar Time: 11:15pm – 11:45pm Session 1: True Lies of SQL Server – SQL Myth Buster Following the excellent keynote, I had my very first session on the subject of SQL Server Myth Buster. At first, I was a bit nervous as right after the keynote, for this was my very first session and during my presentation I saw lots of Microsoft Product Team members. Well, it really went well and I had a really good discussion with attendees of the session. I felt that a well begin was half-done and my confidence was regained. Right after the session, I met a few of my Community friends and had meaningful discussions with them on many subjects. The abstract of the session is as follows: In this 30-minute demo session, I am going to briefly demonstrate few SQL Server Myths and their resolutions as I back them up with some demo. This demo presentation is a must-attend for all developers and administrators who would come to the event. This is going to be a very quick yet fun session. Pinal Presenting session at TechEd India 2010 Time: 1:00 PM – 2:00 PM Lunch with Somasegar After the session I went to see my daughter, and then I headed right away to the lunch with S. Somasegar – the keynote speaker and senior vice president of the Developer Division at Microsoft. I really thank to Abhishek who made it possible for us. Because of his efforts, all the MVPs had the opportunity to meet such a legendary person and had to talk with them on Microsoft Technology. Though Somasegar is currently holding such a high position in Microsoft, he is very polite and a real gentleman, and how I wish that everybody in industry is like him. Believe me, if you spread love and kindness, then that is what you will receive back. As soon as lunch time was over, I ran to the session hall as my second presentation was about to start. Time: 2:30pm – 3:30pm Session 2: Master Data Services in Microsoft SQL Server 2008 R2 Business Intelligence is a subject which was widely talked about at TechEd. Everybody was interested in this subject, and I did not excuse myself from this great concept as well. I consider myself fortunate as I was presenting on the subject of Master Data Services at TechEd. When I had initially learned this subject, I had a bit of confusion about the usage of this tool. Later on, I decided that I would tackle about how we all developers and DBAs are not able to understand something so simple such as this, and even worst, creating confusion about the technology. During system designing, it is very important to have a reference material or master lookup tables. Well, I talked about the same subject and presented the session keeping that as my center talk. The session went very well and I received lots of interesting questions. I got many compliments for talking about this subject on the real-life scenario. I really thank Rushabh Mehta (CEO, Solid Quality Mentors India) for his supportive suggestions that helped me prepare the slide deck, as well as the subject. Pinal Presenting session at TechEd India 2010 The abstract of the session is as follows: SQL Server Master Data Services will ship with SQL Server 2008 R2 and will improve Microsoft’s platform appeal. This session provides an in-depth demonstration of MDS features and highlights important usage scenarios. Master Data Services enables consistent decision-making process by allowing you to create, manage and propagate changes from a single master view of your business entities. Also, MDS – Master Data-hub which is a vital component, helps ensure the consistency of reporting across systems and deliver faster and more accurate results across the enterprise. We will talk about establishing the basis for a centralized approach to defining, deploying, and managing master data in the enterprise. Pinal Presenting session at TechEd India 2010 The day was still not over for me. I had ran into several friends but we were not able keep our enthusiasm under control about all the rumors saying that SQL Server 2008 R2 was about to be launched tomorrow in the keynote. I then ran to my third and final technical event for the day- a panel discussion with the top technologies of India. Time: 5:00pm – 6:00pm Panel Discussion: Harness the power of Web – SEO and Technical Blogging As I have delivered two technical sessions by this time, I was a bit tired but  not less enthusiastic when I had to talk about Blog and Technology. We discussed many different topics there. I told them that the most important aspect for any blog is its content. We discussed in depth the issues with plagiarism and how to avoid it. Another topic of discussion was how we technology bloggers can create awareness in the Community about what the right kind of blogging is and what morally and technically wrong acts are. A couple of questions were raised about what type of liberty a person can have in terms of writing blogs. Well, it was generically agreed that a blog is mainly a representation of our ideas and thoughts; it should not be governed by external entities. As long as one is writing what they really want to say, but not providing incorrect information or not practicing plagiarism, a blogger should be allowed to express himself. This panel discussion was supposed to be over in an hour, but the interest of the participants was remarkable and so it was extended for 30 minutes more. Finally, we decided to bring to a close the discussion and agreed that we will continue the topic next year. TechEd India Panel Discussion on Web, Technology and SEO Surprisingly, the day was just beginning after doing all of these. By this time, I have almost met all the MVP who arrived at the event, as well as many Microsoft employees. There were lots of Community folks present, too. I decided that I would go to meet several friends from the Community and continue to communicate with me on SQLAuthority.com. I also met Abhishek Baxi and had a good talk with him regarding Win Mobile and Twitter. He also took a very quick video of me wherein I spoke in my mother’s tongue, Gujarati. It was funny that I talked in Gujarati almost all the day, but when I was talking in the interview I could not find the right Gujarati words to speak. I think we all think in English when we think about Technology, so as to address universality. After meeting them, I headed towards the Speakers’ Dinner. Time: 8:00 PM – onwards Speakers Dinner The Speakers’ dinner was indeed a wonderful opportunity for all the speakers to get together and relax. We talked so many different things, from XBOX to Hindi Movies, and from SQL to Samosas. I just could not express how much fun I had. After a long evening, when I returned tmy room and met Shaivi, I just felt instantly relaxed. Kids are really gifts from God. Today was a really long but exciting day. So many things happened in just one day: Visual Studio Lanch, lunch with Somasegar, 2 technical sessions, 1 panel discussion, community leaders meeting, speakers dinner and, last but not leas,t playing with my child! A perfect day! Day 2 – April 13, 2010 Today started with a bang with the excellent keynote by Kamal Hathi who launched SQL Server 2008 R2 in India and demonstrated the power of PowerPivot to all of us. 101 Million Rows in Excel brought lots of applause from the audience. Kamal Hathi Presenting Keynote at TechEd India 2010 The day was a bit easier one for me. I had no sessions today and no events planned. I had a few meetings planned for the second day of the event. I sat in the speaker’s lounge for half a day and met many people there. I attended nearly 9 different meetings today. The subjects of the meetings were very different. Here is a list of the topics of the Community-related meetings: SQL PASS and its involvement in India and subcontinents How to start community blogging Forums and developing aptitude towards technology Ahmedabad/Gandhinagar User Groups and their developments SharePoint and SQL Business Meeting – a client meeting Business Meeting – a potential performance tuning project Business Meeting – Solid Quality Mentors (SolidQ) And family friends Pinal Dave at TechEd India The day passed by so quickly during this meeting. In the evening, I headed to Partners Expo with friends and checked out few of the booths. I really wanted to talk about some of the products, but due to the freebies there was so much crowd that I finally decided to just take the contact details of the partner. I will now start sending them with my queries and, hopefully, I will have my questions answered. Nupur and Shaivi had also one meeting to attend; it was with our family friend Vijay Raj. Vijay is also a person who loves Technology and loves it more than anybody. I see him growing and learning every day, but still remaining as a ‘human’. I believe that if someone acquires as much knowledge as him, that person will become either a computer or cyborg. Here, Vijay is still a kind gentleman and is able to stay as our close family friend. Shaivi was really happy to play with Uncle Vijay. Pinal Dave and Vijay Raj Renuka Prasad, a Microsoft MVP, impressed me with his passion and knowledge of SQL. Every time he gives me credit for his success, I believe that he is very humble. He has way more certifications than me and has worked many more years with SQL compared to me. He is an excellent photographer as well. Most of the photos in this blog post have been taken by him. I told him if ever he wants to do a part time job, he can do the photography very well. Pinal Dave and Renuka Prasad I also met L Srividya from Microsoft, whom I was looking forward to meet. She is a bundle of knowledge that everyone would surely learn a lot from her. I was able to get a few minutes from her and well, I felt confident. She enlightened me with SQL Server BI concepts, domain management and SQL Server security and few other interesting details. I also had a wonderful time talking about SharePoint with fellow Solid Quality Mentor Joy Rathnayake. He is very passionate about SharePoint but when you talk .NET and SQL with him, he is still overwhelmingly knowledgeable. In fact, while talking to him, I figured out that the recent training he delivered was on SQL Server 2008 R2. I told him a joke that it hurts my ego as he is more popular now in SQL training and consulting than me. I am sure all of you agree that working with good people is a gift from God. I am fortunate enough to work with the best of the best Industry experts. It was a great pleasure to hang out with my Community friends – Ahswin Kini, HimaBindu Vejella, Vasudev G, Suprotim Agrawal, Dhananjay, Vikram Pendse, Mahesh Dhola, Mahesh Mitkari,  Manu Zacharia, Shobhan, Hardik Shah, Ashish Mohta, Manan, Subodh Sohani and Sanjay Shetty (of course!) .  (Please let me know if I have met you at the event and forgot your name to list here). Time: 8:00 PM – onwards Community Leaders Dinner After lots of meetings, I headed towards the Community Leaders dinner meeting and met almost all the folks I met in morning. The discussion was almost the same but the real good thing was that we were enjoying it. The food was really good. Nupur was invited in the event, but Shaivi could not come. When Nupur tried to enter the event, she was stopped as Shaivi did not have the pass to enter the dinner. Nupur expressed that Shaivi is only 8 months old and does not eat outside food as well and could not stay by herself at this age, but the door keeper did not agree and asked that without the entry details Shaivi could not go in, but Nupur could. Nupur called me on phone and asked me to help her out. By the time, I was outside; the organizer of the event reached to the door and happily approved Shaivi to join the party. Once in the party, Shaivi had lots of fun meeting so many people. Shaivi Dave and Abhishek Kant Dean Guida (Infragistics President and CEO) and Pinal Dave (SQLAuthority.com) Day 3 – April 14, 2010 Though, it was last day, I was very much excited today as I was about to present my very favorite session. Query Optimization and Performance Tuning is my domain expertise and I make my leaving by consulting and training the same. Today’s session was on the same subject and as an additional twist, another subject about Spatial Database was presented. I was always intrigued with Spatial Database and I have enjoyed learning about it; however, I have never thought about Spatial Indexing before it was decided that I will do this session. I really thank Solid Quality Mentor Dr. Greg Low for his assistance in helping me prepare the slide deck and also review the content. Furthermore, today was really what I call my ‘learning day’ . So far I had not attended any session in TechEd and I felt a bit down for that. Everybody spends their valuable time & money to learn something new and exciting in TechEd and I had not attended a single session at the moment thinking that it was already last day of the event. I did have a plan for the day and I attended two technical sessions before my session of spatial database. I attended 2 sessions of Vinod Kumar. Vinod is a natural storyteller and there was no doubt that his sessions would be jam-packed. People attended his sessions simply because Vinod is syhe speaker. He did not have a single time disappointed audience; he is truly a good speaker. He knows his stuff very well. I personally do not think that in India he can be compared to anyone for SQL. Time: 12:30pm-1:30pm SQL Server Query Optimization, Execution and Debugging Query Performance I really had a fun time attending this session. Vinod made this session very interactive. The entire audience really got into the presentation and started participating in the event. Vinod was presenting a small problem with Query Tuning, which any developer would have encountered and solved with their help in such a fashion that a developer feels he or she have already resolved it. In one question, I was the only one who was ready to answer and Vinod told me in a light tone that I am now allowed to answer it! The audience really found it very amusing. There was a huge crowd around Vinod after the session. Vinod – A master storyteller! Time: 3:45pm-4:45pm Data Recovery / consistency with CheckDB This session was much heavier than the earlier one, and I must say this is my most favorite session I EVER attended in India. In this TechEd I have only attended two sessions, but in my career, I have attended numerous technical sessions not only in India, but all over the world. This session had taken my breath away. One by one, Vinod took the different databases, and started to corrupt them in different ways. Each database has some unique ways to get corrupted. Once that was done, Vinod started to show the DBCC CEHCKDB and demonstrated how it can solve your problem. He finally fixed all the databases with this single tool. I do have a good knowledge of this subject, but let me honestly admit that I have learned a lot from this session. I enjoyed and cheered during this session along with other attendees. I had total satisfaction that, just like everyone, I took advantage of the event and learned something. I am now TECHnically EDucated. Pinal Dave and Vinod Kumar After two very interactive and informative SQL Sessions from Vinod Kumar, the next turn me presenting on Spatial Database and Indexing. I got once again nervous but Vinod told me to stay natural and do my presentation. Well, once I got a huge stage with a total of four projectors and a large crowd, I felt better. Time: 5:00pm-6:00pm Session 3: Developing with SQL Server Spatial and Deep Dive into Spatial Indexing Pinal Presenting session at TechEd India 2010 Pinal Presenting session at TechEd India 2010 I kicked off this session with Michael J Swart‘s beautiful spatial image. This session was the last one for the day but, to my surprise, I had more than 200+ attendees. Slowly, the rain was starting outside and I was worried that the hall would not be full; despite this, there was not a single seat available in the first five minutes of the session. Thanks to all of you for attending my presentation. I had demonstrated the map of world (and India) and quickly explained what  Geographic and Geometry data types in Spatial Database are. This session had interesting story of Indexing and Comparison, as well as how different traditional indexes are from spatial indexing. Pinal Presenting session at TechEd India 2010 Due to the heavy rain during this event, the power went off for about 22 minutes (just an accident – nobodies fault). During these minutes, there were no audio, no video and no light. I continued to address the mass of 200+ people without any audio device and PowerPoint. I must thank the audience because not a single person left from the session. They all stayed in their place, some moved closure to listen to me properly. I noticed that the curiosity and eagerness to learn new things was at the peak even though it was the very last session of the TechEd. Everybody wanted get the maximum knowledge out of this whole event. I was touched by the support from audience. They listened and participated in my session even without any kinds of technology (no ppt, no mike, no AC, nothing). During these 22 minutes, I had completed my theory verbally. Pinal Presenting session at TechEd India 2010 After a while, we got the projector back online and we continued with some exciting demos. Many thanks to Microsoft people who worked energetically in background to get the backup power for project up. I had a very interesting demo wherein I overlaid Bangalore and Hyderabad on the India Map and find their aerial distance between them. After finding the aerial distance, we browsed online and found that SQL Server estimates the exact aerial distance between these two cities, as compared to the factual distance. There was a huge applause from the crowd on the subject that SQL Server takes into the count of the curvature of the earth and finds the precise distances based on details. During the process of finding the distance, I demonstrated a few examples of the indexes where I expressed how one can use those indexes to find these distances and how they can improve the performance of similar query. I also demonstrated few examples wherein we were able to see in which data type the Index is most useful. We finished the demos with a few more internal stuff. Pinal Presenting session at TechEd India 2010 Despite all issues, I was mostly satisfied with my presentation. I think it was the best session I have ever presented at any conference. There was no help from Technology for a while, but I still got lots of appreciation at the end. When we ended the session, the applause from the audience was so loud that for a moment, the rain was not audible. I was truly moved by the dedication of the Technology enthusiasts. Pinal Dave After Presenting session at TechEd India 2010 The abstract of the session is as follows: The Microsoft SQL Server 2008 delivers new spatial data types that enable you to consume, use, and extend location-based data through spatial-enabled applications. Attend this session to learn how to use spatial functionality in next version of SQL Server to build and optimize spatial queries. This session outlines the new geography data type to store geodetic spatial data and perform operations on it, use the new geometry data type to store planar spatial data and perform operations on it, take advantage of new spatial indexes for high performance queries, use the new spatial results tab to quickly and easily view spatial query results directly from within Management Studio, extend spatial data capabilities by building or integrating location-enabled applications through support for spatial standards and specifications and much more. Time: 8:00 PM – onwards Dinner by Sponsors After the lively session during the day, there was another dinner party courtesy of one of the sponsors of TechEd. All the MVPs and several Community leaders were present at the dinner. I would like to express my gratitude to Abhishek Kant for organizing this wonderful event for us. It was a blast and really relaxing in all angles. We all stayed there for a long time and talked about our sweet and unforgettable memories of the event. Pinal Dave and Bijoy Singhal It was really one wonderful event. After writing this much, I say that I have no words to express about how much I enjoyed TechEd. However, it is true that I shared with you only 1% of the total activities I have done at the event. There were so many people I have met, yet were not mentioned here although I wanted to write their names here, too . Anyway, I have learned so many things and up until now, I am not able to get over all the fun I had in this event. Pinal Dave at TechEd India 2010 The Next Days – April 15, 2010 – till today I am still not able to get my mind out of the whole experience I had at TechEd India 2010. It was like a whole Microsoft Family working together to celebrate a happy occasion. TechEd India – Truly An Unforgettable Experience! Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, MVP, Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, SQLServer, T SQL, Technology Tagged: TechEd, TechEdIn

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• Using the West Wind Web Toolkit to set up AJAX and REST Services

  - by Rick Strahl

  I frequently get questions about which option to use for creating AJAX and REST backends for ASP.NET applications. There are many solutions out there to do this actually, but when I have a choice - not surprisingly - I fall back to my own tools in the West Wind West Wind Web Toolkit. I've talked a bunch about the 'in-the-box' solutions in the past so for a change in this post I'll talk about the tools that I use in my own and customer applications to handle AJAX and REST based access to service resources using the West Wind West Wind Web Toolkit. Let me preface this by saying that I like things to be easy. Yes flexible is very important as well but not at the expense of over-complexity. The goal I've had with my tools is make it drop dead easy, with good performance while providing the core features that I'm after, which are: Easy AJAX/JSON Callbacks Ability to return any kind of non JSON content (string, stream, byte[], images) Ability to work with both XML and JSON interchangeably for input/output Access endpoints via POST data, RPC JSON calls, GET QueryString values or Routing interface Easy to use generic JavaScript client to make RPC calls (same syntax, just what you need) Ability to create clean URLS with Routing Ability to use standard ASP.NET HTTP Stack for HTTP semantics It's all about options! In this post I'll demonstrate most of these features (except XML) in a few simple and short samples which you can download. So let's take a look and see how you can build an AJAX callback solution with the West Wind Web Toolkit. Installing the Toolkit Assemblies The easiest and leanest way of using the Toolkit in your Web project is to grab it via NuGet: West Wind Web and AJAX Utilities (Westwind.Web) and drop it into the project by right clicking in your Project and choosing Manage NuGet Packages from anywhere in the Project.   When done you end up with your project looking like this: What just happened? Nuget added two assemblies - Westwind.Web and Westwind.Utilities and the client ww.jquery.js library. It also added a couple of references into web.config: The default namespaces so they can be accessed in pages/views and a ScriptCompressionModule that the toolkit optionally uses to compress script resources served from within the assembly (namely ww.jquery.js and optionally jquery.js). Creating a new Service The West Wind Web Toolkit supports several ways of creating and accessing AJAX services, but for this post I'll stick to the lower level approach that works from any plain HTML page or of course MVC, WebForms, WebPages. There's also a WebForms specific control that makes this even easier but I'll leave that for another post. So, to create a new standalone AJAX/REST service we can create a new HttpHandler in the new project either as a pure class based handler or as a generic .ASHX handler. Both work equally well, but generic handlers don't require any web.config configuration so I'll use that here. In the root of the project add a Generic Handler. I'm going to call this one StockService.ashx. Once the handler has been created, edit the code and remove all of the handler body code. Then change the base class to CallbackHandler and add methods that have a [CallbackMethod] attribute. Here's the modified base handler implementation now looks like with an added HelloWorld method: using System; using Westwind.Web; namespace WestWindWebAjax { /// <summary> /// Handler implements CallbackHandler to provide REST/AJAX services /// </summary> public class SampleService : CallbackHandler { [CallbackMethod] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } } } Notice that the class inherits from CallbackHandler and that the HelloWorld service method is marked up with [CallbackMethod]. We're done here. Services Urlbased Syntax Once you compile, the 'service' is live can respond to requests. All CallbackHandlers support input in GET and POST formats, and can return results as JSON or XML. To check our fancy HelloWorld method we can now access the service like this: http://localhost/WestWindWebAjax/StockService.ashx?Method=HelloWorld&name=Rick which produces a default JSON response - in this case a string (wrapped in quotes as it's JSON): (note by default JSON will be downloaded by most browsers not displayed - various options are available to view JSON right in the browser) If I want to return the same data as XML I can tack on a &format=xml at the end of the querystring which produces: <string>Hello Rick. Time is: 11/1/2011 12:11:13 PM</string> Cleaner URLs with Routing Syntax If you want cleaner URLs for each operation you can also configure custom routes on a per URL basis similar to the way that WCF REST does. To do this you need to add a new RouteHandler to your application's startup code in global.asax.cs one for each CallbackHandler based service you create: protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); } With this code in place you can now add RouteUrl properties to any of your service methods. For the HelloWorld method that doesn't make a ton of sense but here is what a routed clean URL might look like in definition: [CallbackMethod(RouteUrl="stocks/HelloWorld/{name}")] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } The same URL I previously used now becomes a bit shorter and more readable with: http://localhost/WestWindWebAjax/HelloWorld/Rick It's an easy way to create cleaner URLs and still get the same functionality. Calling the Service with $.getJSON() Since the result produced is JSON you can now easily consume this data using jQuery's getJSON method. First we need a couple of scripts - jquery.js and ww.jquery.js in the page: <!DOCTYPE html> <html> <head> <link href="Css/Westwind.css" rel="stylesheet" type="text/css" /> <script src="scripts/jquery.min.js" type="text/javascript"></script> <script src="scripts/ww.jquery.min.js" type="text/javascript"></script> </head> <body> Next let's add a small HelloWorld example form (what else) that has a single textbox to type a name, a button and a div tag to receive the result: <fieldset> <legend>Hello World</legend> Please enter a name: <input type="text" name="txtHello" id="txtHello" value="" /> <input type="button" id="btnSayHello" value="Say Hello (POST)" /> <input type="button" id="btnSayHelloGet" value="Say Hello (GET)" /> <div id="divHelloMessage" class="errordisplay" style="display:none;width: 450px;" > </div> </fieldset> Then to call the HelloWorld method a little jQuery is used to hook the document startup and the button click followed by the $.getJSON call to retrieve the data from the server. <script type="text/javascript"> $(document).ready(function () { $("#btnSayHelloGet").click(function () { $.getJSON("SampleService.ashx", { Method: "HelloWorld", name: $("#txtHello").val() }, function (result) { $("#divHelloMessage") .text(result) .fadeIn(1000); }); });</script> .getJSON() expects a full URL to the endpoint of our service, which is the ASHX file. We can either provide a full URL (SampleService.ashx?Method=HelloWorld&name=Rick) or we can just provide the base URL and an object that encodes the query string parameters for us using an object map that has a property that matches each parameter for the server method. We can also use the clean URL routing syntax, but using the object parameter encoding actually is safer as the parameters will get properly encoded by jQuery. The result returned is whatever the result on the server method is - in this case a string. The string is applied to the divHelloMessage element and we're done. Obviously this is a trivial example, but it demonstrates the basics of getting a JSON response back to the browser. AJAX Post Syntax - using ajaxCallMethod() The previous example allows you basic control over the data that you send to the server via querystring parameters. This works OK for simple values like short strings, numbers and boolean values, but doesn't really work if you need to pass something more complex like an object or an array back up to the server. To handle traditional RPC type messaging where the idea is to map server side functions and results to a client side invokation, POST operations can be used. The easiest way to use this functionality is to use ww.jquery.js and the ajaxCallMethod() function. ww.jquery wraps jQuery's AJAX functions and knows implicitly how to call a CallbackServer method with parameters and parse the result. Let's look at another simple example that posts a simple value but returns something more interesting. Let's start with the service method: [CallbackMethod(RouteUrl="stocks/{symbol}")] public StockQuote GetStockQuote(string symbol) { Response.Cache.SetExpires(DateTime.UtcNow.Add(new TimeSpan(0, 2, 0))); StockServer server = new StockServer(); var quote = server.GetStockQuote(symbol); if (quote == null) throw new ApplicationException("Invalid Symbol passed."); return quote; } This sample utilizes a small StockServer helper class (included in the sample) that downloads a stock quote from Yahoo's financial site via plain HTTP GET requests and formats it into a StockQuote object. Lets create a small HTML block that lets us query for the quote and display it: <fieldset> <legend>Single Stock Quote</legend> Please enter a stock symbol: <input type="text" name="txtSymbol" id="txtSymbol" value="msft" /> <input type="button" id="btnStockQuote" value="Get Quote" /> <div id="divStockDisplay" class="errordisplay" style="display:none; width: 450px;"> <div class="label-left">Company:</div> <div id="stockCompany"></div> <div class="label-left">Last Price:</div> <div id="stockLastPrice"></div> <div class="label-left">Quote Time:</div> <div id="stockQuoteTime"></div> </div> </fieldset> The final result looks something like this:   Let's hook up the button handler to fire the request and fill in the data as shown: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").show().fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, HH:mm EST")); }, onPageError); }); So we point at SampleService.ashx and the GetStockQuote method, passing a single parameter of the input symbol value. Then there are two handlers for success and failure callbacks.  The success handler is the interesting part - it receives the stock quote as a result and assigns its values to various 'holes' in the stock display elements. The data that comes back over the wire is JSON and it looks like this: { "Symbol":"MSFT", "Company":"Microsoft Corpora", "OpenPrice":26.11, "LastPrice":26.01, "NetChange":0.02, "LastQuoteTime":"2011-11-03T02:00:00Z", "LastQuoteTimeString":"Nov. 11, 2011 4:20pm" } which is an object representation of the data. JavaScript can evaluate this JSON string back into an object easily and that's the reslut that gets passed to the success function. The quote data is then applied to existing page content by manually selecting items and applying them. There are other ways to do this more elegantly like using templates, but here we're only interested in seeing how the data is returned. The data in the object is typed - LastPrice is a number and QuoteTime is a date. Note about the date value: JavaScript doesn't have a date literal although the JSON embedded ISO string format used above  ("2011-11-03T02:00:00Z") is becoming fairly standard for JSON serializers. However, JSON parsers don't deserialize dates by default and return them by string. This is why the StockQuote actually returns a string value of LastQuoteTimeString for the same date. ajaxMethodCallback always converts dates properly into 'real' dates and the example above uses the real date value along with a .formatDate() data extension (also in ww.jquery.js) to display the raw date properly. Errors and Exceptions So what happens if your code fails? For example if I pass an invalid stock symbol to the GetStockQuote() method you notice that the code does this: if (quote == null) throw new ApplicationException("Invalid Symbol passed."); CallbackHandler automatically pushes the exception message back to the client so it's easy to pick up the error message. Regardless of what kind of error occurs: Server side, client side, protocol errors - any error will fire the failure handler with an error object parameter. The error is returned to the client via a JSON response in the error callback. In the previous examples I called onPageError which is a generic routine in ww.jquery that displays a status message on the bottom of the screen. But of course you can also take over the error handling yourself: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); }, function (error, xhr) { $("#divErrorDisplay").text(error.message).fadeIn(1000); }); }); The error object has a isCallbackError, message and  stackTrace properties, the latter of which is only populated when running in Debug mode, and this object is returned for all errors: Client side, transport and server side errors. Regardless of which type of error you get the same object passed (as well as the XHR instance optionally) which makes for a consistent error retrieval mechanism. Specifying HttpVerbs You can also specify HTTP Verbs that are allowed using the AllowedHttpVerbs option on the CallbackMethod attribute: [CallbackMethod(AllowedHttpVerbs=HttpVerbs.GET | HttpVerbs.POST)] public string HelloWorld(string name) { … } If you're building REST style API's this might be useful to force certain request semantics onto the client calling. For the above if call with a non-allowed HttpVerb the request returns a 405 error response along with a JSON (or XML) error object result. The default behavior is to allow all verbs access (HttpVerbs.All). Passing in object Parameters Up to now the parameters I passed were very simple. But what if you need to send something more complex like an object or an array? Let's look at another example now that passes an object from the client to the server. Keeping with the Stock theme here lets add a method called BuyOrder that lets us buy some shares for a stock. Consider the following service method that receives an StockBuyOrder object as a parameter: [CallbackMethod] public string BuyStock(StockBuyOrder buyOrder) { var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } public class StockBuyOrder { public string Symbol { get; set; } public int Quantity { get; set; } public DateTime BuyOn { get; set; } public StockBuyOrder() { BuyOn = DateTime.Now; } } This is a contrived do-nothing example that simply echoes back what was passed in, but it demonstrates how you can pass complex data to a callback method. On the client side we now have a very simple form that captures the three values on a form: <fieldset> <legend>Post a Stock Buy Order</legend> Enter a symbol: <input type="text" name="txtBuySymbol" id="txtBuySymbol" value="GLD" />&nbsp;&nbsp; Qty: <input type="text" name="txtBuyQty" id="txtBuyQty" value="10" style="width: 50px" />&nbsp;&nbsp; Buy on: <input type="text" name="txtBuyOn" id="txtBuyOn" value="<%= DateTime.Now.ToString("d") %>" style="width: 70px;" /> <input type="button" id="btnBuyStock" value="Buy Stock" /> <div id="divStockBuyMessage" class="errordisplay" style="display:none"></div> </fieldset> The completed form and demo then looks something like this:   The client side code that picks up the input values and assigns them to object properties and sends the AJAX request looks like this: $("#btnBuyStock").click(function () { // create an object map that matches StockBuyOrder signature var buyOrder = { Symbol: $("#txtBuySymbol").val(), Quantity: $("#txtBuyQty").val() * 1, // number Entered: new Date() } ajaxCallMethod("SampleService.ashx", "BuyStock", [buyOrder], function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError); }); The code creates an object and attaches the properties that match the server side object passed to the BuyStock method. Each property that you want to update needs to be included and the type must match (ie. string, number, date in this case). Any missing properties will not be set but also not cause any errors. Pass POST data instead of Objects In the last example I collected a bunch of values from form variables and stuffed them into object variables in JavaScript code. While that works, often times this isn't really helping - I end up converting my types on the client and then doing another conversion on the server. If lots of input controls are on a page and you just want to pick up the values on the server via plain POST variables - that can be done too - and it makes sense especially if you're creating and filling the client side object only to push data to the server. Let's add another method to the server that once again lets us buy a stock. But this time let's not accept a parameter but rather send POST data to the server. Here's the server method receiving POST data: [CallbackMethod] public string BuyStockPost() { StockBuyOrder buyOrder = new StockBuyOrder(); buyOrder.Symbol = Request.Form["txtBuySymbol"]; ; int qty; int.TryParse(Request.Form["txtBuyQuantity"], out qty); buyOrder.Quantity = qty; DateTime time; DateTime.TryParse(Request.Form["txtBuyBuyOn"], out time); buyOrder.BuyOn = time; // Or easier way yet //FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } Clearly we've made this server method take more code than it did with the object parameter. We've basically moved the parameter assignment logic from the client to the server. As a result the client code to call this method is now a bit shorter since there's no client side shuffling of values from the controls to an object. $("#btnBuyStockPost").click(function () { ajaxCallMethod("SampleService.ashx", "BuyStockPost", [], // Note: No parameters - function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError, // Force all page Form Variables to be posted { postbackMode: "Post" }); }); The client simply calls the BuyStockQuote method and pushes all the form variables from the page up to the server which parses them instead. The feature that makes this work is one of the options you can pass to the ajaxCallMethod() function: { postbackMode: "Post" }); which directs the function to include form variable POST data when making the service call. Other options include PostNoViewState (for WebForms to strip out WebForms crap vars), PostParametersOnly (default), None. If you pass parameters those are always posted to the server except when None is set. The above code can be simplified a bit by using the FormVariableBinder helper, which can unbind form variables directly into an object: FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); which replaces the manual Request.Form[] reading code. It receives the object to unbind into, a string of properties to skip, and an optional prefix which is stripped off form variables to match property names. The component is similar to the MVC model binder but it's independent of MVC. Returning non-JSON Data CallbackHandler also supports returning non-JSON/XML data via special return types. You can return raw non-JSON encoded strings like this: [CallbackMethod(ReturnAsRawString=true,ContentType="text/plain")] public string HelloWorldNoJSON(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } Calling this method results in just a plain string - no JSON encoding with quotes around the result. This can be useful if your server handling code needs to return a string or HTML result that doesn't fit well for a page or other UI component. Any string output can be returned. You can also return binary data. Stream, byte[] and Bitmap/Image results are automatically streamed back to the client. Notice that you should set the ContentType of the request either on the CallbackMethod attribute or using Response.ContentType. This ensures the Web Server knows how to display your binary response. Using a stream response makes it possible to return any of data. Streamed data can be pretty handy to return bitmap data from a method. The following is a method that returns a stock history graph for a particular stock over a provided number of years: [CallbackMethod(ContentType="image/png",RouteUrl="stocks/history/graph/{symbol}/{years}")] public Stream GetStockHistoryGraph(string symbol, int years = 2,int width = 500, int height=350) { if (width == 0) width = 500; if (height == 0) height = 350; StockServer server = new StockServer(); return server.GetStockHistoryGraph(symbol,"Stock History for " + symbol,width,height,years); } I can now hook this up into the JavaScript code when I get a stock quote. At the end of the process I can assign the URL to the service that returns the image into the src property and so force the image to display. Here's the changed code: $("#btnStockQuote").click(function () { var symbol = $("#txtSymbol").val(); ajaxCallMethod("SampleService.ashx", "GetStockQuote", [symbol], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); // display a stock chart $("#imgStockHistory").attr("src", "stocks/history/graph/" + symbol + "/2"); },onPageError); }); The resulting output then looks like this: The charting code uses the new ASP.NET 4.0 Chart components via code to display a bar chart of the 2 year stock data as part of the StockServer class which you can find in the sample download. The ability to return arbitrary data from a service is useful as you can see - in this case the chart is clearly associated with the service and it's nice that the graph generation can happen off a handler rather than through a page. Images are common resources, but output can also be PDF reports, zip files for downloads etc. which is becoming increasingly more common to be returned from REST endpoints and other applications. Why reinvent? Obviously the examples I've shown here are pretty basic in terms of functionality. But I hope they demonstrate the core features of AJAX callbacks that you need to work through in most applications which is simple: return data, send back data and potentially retrieve data in various formats. While there are other solutions when it comes down to making AJAX callbacks and servicing REST like requests, I like the flexibility my home grown solution provides. Simply put it's still the easiest solution that I've found that addresses my common use cases: AJAX JSON RPC style callbacks Url based access XML and JSON Output from single method endpoint XML and JSON POST support, querystring input, routing parameter mapping UrlEncoded POST data support on callbacks Ability to return stream/raw string data Essentially ability to return ANYTHING from Service and pass anything All these features are available in various solutions but not together in one place. I've been using this code base for over 4 years now in a number of projects both for myself and commercial work and it's served me extremely well. Besides the AJAX functionality CallbackHandler provides, it's also an easy way to create any kind of output endpoint I need to create. Need to create a few simple routines that spit back some data, but don't want to create a Page or View or full blown handler for it? Create a CallbackHandler and add a method or multiple methods and you have your generic endpoints.  It's a quick and easy way to add small code pieces that are pretty efficient as they're running through a pretty small handler implementation. I can have this up and running in a couple of minutes literally without any setup and returning just about any kind of data. Resources Download the Sample NuGet: Westwind Web and AJAX Utilities (Westwind.Web) ajaxCallMethod() Documentation Using the AjaxMethodCallback WebForms Control West Wind Web Toolkit Home Page West Wind Web Toolkit Source Code © Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  jQuery  AJAX   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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