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  • How to filter Backbone.js Collection and Rerender App View?

    - by Jeremy H.
    Is is a total Backbone.js noob question. I am working off of the ToDo Backbone.js example trying to build out a fairly simple single app interface. While the todo project is more about user input, this app is more about filtering the data based on the user options (click events). I am completely new to Backbone.js and Mongoose and have been unable to find a good example of what I am trying to do. I have been able to get my api to pull the data from the MongoDB collection and drop it into the Backbone.js collection which renders it in the app. What I cannot for the life of me figure out how to do is filter that data and re-render the app view. I am trying to filter by the "type" field in the document. Here is my script: (I am totally aware of some major refactoring needed, I am just rapid prototyping a concept.) $(function() { window.Job = Backbone.Model.extend({ idAttribute: "_id", defaults: function() { return { attachments: false } } }); window.JobsList = Backbone.Collection.extend({ model: Job, url: '/api/jobs', leads: function() { return this.filter(function(job){ return job.get('type') == "Lead"; }); } }); window.Jobs = new JobsList; window.JobView = Backbone.View.extend({ tagName: "div", className: "item", template: _.template($('#item-template').html()), initialize: function() { this.model.bind('change', this.render, this); this.model.bind('destroy', this.remove, this); }, render: function() { $(this.el).html(this.template(this.model.toJSON())); this.setText(); return this; }, setText: function() { var month=new Array(); month[0]="Jan"; month[1]="Feb"; month[2]="Mar"; month[3]="Apr"; month[4]="May"; month[5]="Jun"; month[6]="Jul"; month[7]="Aug"; month[8]="Sep"; month[9]="Oct"; month[10]="Nov"; month[11]="Dec"; var title = this.model.get('title'); var description = this.model.get('description'); var datemonth = this.model.get('datem'); var dateday = this.model.get('dated'); var jobtype = this.model.get('type'); var jobstatus = this.model.get('status'); var amount = this.model.get('amount'); var paymentstatus = this.model.get('paymentstatus') var type = this.$('.status .jobtype'); var status = this.$('.status .jobstatus'); this.$('.title a').text(title); this.$('.description').text(description); this.$('.date .month').text(month[datemonth]); this.$('.date .day').text(dateday); type.text(jobtype); status.text(jobstatus); if(amount > 0) this.$('.paymentamount').text(amount) if(paymentstatus) this.$('.paymentstatus').text(paymentstatus) if(jobstatus === 'New') { status.addClass('new'); } else if (jobstatus === 'Past Due') { status.addClass('pastdue') }; if(jobtype === 'Lead') { type.addClass('lead'); } else if (jobtype === '') { type.addClass(''); }; }, remove: function() { $(this.el).remove(); }, clear: function() { this.model.destroy(); } }); window.AppView = Backbone.View.extend({ el: $("#main"), events: { "click #leads .highlight" : "filterLeads" }, initialize: function() { Jobs.bind('add', this.addOne, this); Jobs.bind('reset', this.addAll, this); Jobs.bind('all', this.render, this); Jobs.fetch(); }, addOne: function(job) { var view = new JobView({model: job}); this.$("#activitystream").append(view.render().el); }, addAll: function() { Jobs.each(this.addOne); }, filterLeads: function() { // left here, this event fires but i need to figure out how to filter the activity list. } }); window.App = new AppView; });

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  • Stacking two pictures with captions side by side and centered in Wordpress

    - by Jim
    Hi all - this is driving me absolutely nuts. I'm not the most experienced with CSS, so I'm hoping it is something simple. I'm running Wordpress 2.9.2 with "The Morning After" theme. I am trying to write a post where I want to display two small pictures, with captions, side-by-side and centered in the middle of the page. Here is the HTML code I am using to display the images: [caption align="alignnone" width="150" caption="Protein rest"] <a href="http://www.mysite.com/wp-content/uploads/2008/06/protein-rest.jpg"> <img title="Mash during protein rest" src="http://www.mysite.com/wp-content/uploads/2008/06/protein-rest-150x144.jpg" alt="Mash during protein rest" width="150" height="144" /> </a>[/caption] [caption align="alignnone" width="143" caption="Saccharification rest" captionalign="center"] <a href="http://www.mysite.com/wp-content/uploads/2008/06/saccharification-rest.jpg"> <img title="Mash during saccharification rest" src="http://www.mysite.com/wp-content/uploads/2008/06/saccharification-rest-143x150.jpg" alt="Mash during saccharification rest" width="143" height="150" /> </a>[/caption] I tried using "aligncenter" and "alignleft" for the caption align - if I use "alignleft" the pictures are lined up perfectly, but all the way to the left of the page. If I use "aligncenter" the pics are in the center, but stacked one on top of the other. My first thought was to wrap the images in a div using: <div style="text-align:center;">image code</div> but that doesn't work. Now, if I wrap in a centered div like that and omit the [caption] tags, it works, but I need the captions. Those caption tags are translated by Wordpress into it's own div of class wp-caption. I've also tried wrapping each separate image in its own div within a parent centered div wrapper. Here is the pertinent parts of the style.css - please let me know if you need any other info, and if you can help me, I will postpone jumping off the nearest bridge! Thanks!! Style.css: .aligncenter, div.aligncenter { display: block; margin: 14px auto; } .alignleft { float: left; margin: 0 14px 10px 0; } .alignright { float: right; margin: 0 0 10px 14px; } .wp-caption { border: 1px solid #ddd; text-align: center; background-color: #f3f3f3; padding-top: 4px; /* optional rounded corners for browsers that support it */ -moz-border-radius: 3px; -khtml-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; } .wp-caption img { margin: 0; padding: 0; border: 0 none; } .wp-caption p.wp-caption-text { font-size: 11px; line-height: 14px; padding: 5px 4px 5px 5px; margin: 0; } PS - I am aware of the Gallery feature available in Wordpress, but would like to avoid it and would love to understand why wrapping in a div doesn't move the whole kit to the center. Finally, just for the sake of completeness, here is the source of the page when loaded using the div wrapper and image code as above (so you can see how Wordpress translates the caption tags): <div style="text-align:center;"> <div class="wp-caption alignnone" style="width: 160px"> <a href="http://www.mysite.com/wp-content/uploads/2008/06/protein-rest.jpg"> <img title="Mash during protein rest" src="http://www.mysite.com/wp-content/uploads/2008/06/protein-rest-150x144.jpg" alt="Mash during protein rest" width="150" height="144" /> </a> <p class="wp-caption-text" style="text-align:center">Protein rest</p> </div> <div class="wp-caption alignnone" style="width: 153px"> <a href="http://www.mysite.com/wp-content/uploads/2008/06/saccharification-rest.jpg"> <img title="Mash during saccharification rest" src="http://www.mysite.com/wp-content/uploads/2008/06/saccharification-rest-143x150.jpg" alt="Mash during saccharification rest" width="143" height="150" /> </a> <p class="wp-caption-text" style="text-align:center">Saccharification rest</p> </div> </div>

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  • z index background issue in IE

    - by Michael
    I have a jQuery tools scroller set up with controls managing two separate divs of info - one images, the other related text that needs to sit over the top of the images with a transparent bg image. I am using z-indexing to achieve this and am aware of IE's issues with this but am unable to sort it (tested in IE6-8). Image of the issue below: http://test.shakingpaper.com.au/not_working.png It seems that the overlayed div is taking on the containers white. Try as I might, I can't resolve this. HTML/CSS code below: <div id="content"> <div id="nav"></div> <div class="s4 slideshow"> <div> <img src="<?php bloginfo('stylesheet_directory'); ?>/images/hero_1_white.jpg" width="770" height="367" /> </div> <div> <img src="<?php bloginfo('stylesheet_directory'); ?>/images/hero_1_white.jpg" width="770" height="367" /> </div> <div> <img src="<?php bloginfo('stylesheet_directory'); ?>/images/hero_1_white.jpg" width="770" height="367" /> </div> </div> <div id="overlay_bg"></div> <div class="s4 information"> <div> <h1>Support</h1> <p>Quisque lacus quam, egestas ac tincidunt a, lacinia vel velit. Aenean facilisis nulla vitae.</p> <p><a href="#">Support Us</a></p> </div> <div> <h1>Events</h1> <p>Quisque lacegestas ac tincidunt a, lacinia vel velit. Aenean facilisis nulla vitae.</p> <p><a href="#">Read More</a></p> </div> <div> <h1>Regional</h1> <p>Quisque lacus quam, egestas ac tincidunt a, lacinia vel velit. Aenean facilisis nulla vitae.</p> <p><a href="#">Support Us</a></p> </div> </div> </div> <!-- end of content --> #content { height: auto; min-height: 300px !important; overflow: hidden; position:relative; margin-left: 27px; width: 770px; padding-bottom: 43px; } #nav { width: 60px; z-index: 10000; position: absolute; top:340px; left: 28px; } .s4 { width: 770px; height: 370px; overflow: hidden; } #nav a { background-color: transparent; background-image: url(images/transition.png); background-position: 0 0; text-indent: -1000em; width: 10px; height: 10px; display: block; float: left; margin-right: 5px; } #nav a.activeSlide { background-position: 0 -10px; } #overlay_bg { background: url(images/soild_block.png) no-repeat; width: 318px; height: 339px; z-index: 5000; position: absolute; top: 28px; } .information { position: absolute; top: 60px; left: 28px; z-index: 16000; width: 290px; height: 260px; color: #FFF; } .information h1 { font-size: 50px; font-style: italic; text-transform: uppercase; } .information p { font-size: 17px; line-height: 27px; margin-top: 37px; } .information a { font-size: 13px; padding-bottom: 2px; border-bottom: 1px solid; color: #FFF; text-transform: uppercase; font-style: italic; } .information a:hover { color: #000; } Any help would be greatly appreciated.

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  • Handling file upload in a non-blocking manner

    - by Kaliyug Antagonist
    The background thread is here Just to make objective clear - the user will upload a large file and must be redirected immediately to another page for proceeding different operations. But the file being large, will take time to be read from the controller's InputStream. So I unwillingly decided to fork a new Thread to handle this I/O. The code is as follows : The controller servlet /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse * response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub System.out.println("In Controller.doPost(...)"); TempModel tempModel = new TempModel(); tempModel.uploadSegYFile(request, response); System.out.println("Forwarding to Accepted.jsp"); /*try { Thread.sleep(1000 * 60); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); }*/ request.getRequestDispatcher("/jsp/Accepted.jsp").forward(request, response); } The model class package com.model; import java.io.IOException; import java.util.concurrent.ExecutionException; import java.util.concurrent.Future; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.utils.ProcessUtils; public class TempModel { public void uploadSegYFile(HttpServletRequest request, HttpServletResponse response) { // TODO Auto-generated method stub System.out.println("In TempModel.uploadSegYFile(...)"); /* * Trigger the upload/processing code in a thread, return immediately * and notify when the thread completes */ try { FileUploaderRunnable fileUploadRunnable = new FileUploaderRunnable( request.getInputStream()); /* * Future<FileUploaderRunnable> future = ProcessUtils.submitTask( * fileUploadRunnable, fileUploadRunnable); * * FileUploaderRunnable processed = future.get(); * * System.out.println("Is file uploaded : " + * processed.isFileUploaded()); */ Thread uploadThread = new Thread(fileUploadRunnable); uploadThread.start(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } /* * catch (InterruptedException e) { // TODO Auto-generated catch block * e.printStackTrace(); } catch (ExecutionException e) { // TODO * Auto-generated catch block e.printStackTrace(); } */ System.out.println("Returning from TempModel.uploadSegYFile(...)"); } } The Runnable package com.model; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.nio.ByteBuffer; import java.nio.channels.Channels; import java.nio.channels.ReadableByteChannel; public class FileUploaderRunnable implements Runnable { private boolean isFileUploaded = false; private InputStream inputStream = null; public FileUploaderRunnable(InputStream inputStream) { // TODO Auto-generated constructor stub this.inputStream = inputStream; } public void run() { // TODO Auto-generated method stub /* Read from InputStream. If success, set isFileUploaded = true */ System.out.println("Starting upload in a thread"); File outputFile = new File("D:/06c01_output.seg");/* * This will be changed * later */ FileOutputStream fos; ReadableByteChannel readable = Channels.newChannel(inputStream); ByteBuffer buffer = ByteBuffer.allocate(1000000); try { fos = new FileOutputStream(outputFile); while (readable.read(buffer) != -1) { fos.write(buffer.array()); buffer.clear(); } fos.flush(); fos.close(); readable.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } System.out.println("File upload thread completed"); } public boolean isFileUploaded() { return isFileUploaded; } } My queries/doubts : Spawning threads manually from the Servlet makes sense to me logically but scares me coding wise - the container isn't aware of these threads after all(I think so!) The current code is giving an Exception which is quite obvious - the stream is inaccessible as the doPost(...) method returns before the run() method completes : In Controller.doPost(...) In TempModel.uploadSegYFile(...) Returning from TempModel.uploadSegYFile(...) Forwarding to Accepted.jsp Starting upload in a thread Exception in thread "Thread-4" java.lang.NullPointerException at org.apache.coyote.http11.InternalInputBuffer.fill(InternalInputBuffer.java:512) at org.apache.coyote.http11.InternalInputBuffer.fill(InternalInputBuffer.java:497) at org.apache.coyote.http11.InternalInputBuffer$InputStreamInputBuffer.doRead(InternalInputBuffer.java:559) at org.apache.coyote.http11.AbstractInputBuffer.doRead(AbstractInputBuffer.java:324) at org.apache.coyote.Request.doRead(Request.java:422) at org.apache.catalina.connector.InputBuffer.realReadBytes(InputBuffer.java:287) at org.apache.tomcat.util.buf.ByteChunk.substract(ByteChunk.java:407) at org.apache.catalina.connector.InputBuffer.read(InputBuffer.java:310) at org.apache.catalina.connector.CoyoteInputStream.read(CoyoteInputStream.java:202) at java.nio.channels.Channels$ReadableByteChannelImpl.read(Unknown Source) at com.model.FileUploaderRunnable.run(FileUploaderRunnable.java:39) at java.lang.Thread.run(Unknown Source) Keeping in mind the point 1., does the use of Executor framework help me in anyway ? package com.utils; import java.util.concurrent.Future; import java.util.concurrent.ScheduledThreadPoolExecutor; public final class ProcessUtils { /* Ensure that no more than 2 uploads,processing req. are allowed */ private static final ScheduledThreadPoolExecutor threadPoolExec = new ScheduledThreadPoolExecutor( 2); public static <T> Future<T> submitTask(Runnable task, T result) { return threadPoolExec.submit(task, result); } } So how should I ensure that the user doesn't block and the stream remains accessible so that the (uploaded)file can be read from it?

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  • mysql: Bind on unix socket: Permission denied

    - by Alex
    Can't start mysql with: sudo /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 120222 13:40:48 mysqld_safe Starting mysqld daemon with databases from /srv/mysql/myDB 120222 13:40:54 mysqld_safe mysqld from pid file /srv/mysql/pids/mysqld-myDB.pid ended /srv/mysql/logs/mysqld-myDB.log: 120222 13:43:53 mysqld_safe Starting mysqld daemon with databases from /srv/mysql/myDB 120222 13:43:53 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld: Table 'plugin' is read only 120222 13:43:53 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 120222 13:43:53 InnoDB: Completed initialization of buffer pool 120222 13:43:53 InnoDB: Started; log sequence number 32 4232720908 120222 13:43:53 [ERROR] Can't start server : Bind on unix socket: Permission denied 120222 13:43:53 [ERROR] Do you already have another mysqld server running on socket: /srv/mysql/sockets/mysql-myDB.sock ? 120222 13:43:53 [ERROR] Aborting 120222 13:43:53 InnoDB: Starting shutdown... One instance mysqld is running: $ ps aux | grep mysql mysql 1093 0.0 0.2 169972 18700 ? Ssl 11:50 0:02 /usr/sbin/mysqld $ Port 3700 is available: $ netstat -a | grep 3700 $ Directory with sockets is empty: $ ls /srv/mysql/sockets/ $ There are all permissions: $ ls -l /srv/mysql/ total 20 drwxrwxrwx 2 mysql mysql 4096 2012-02-22 13:28 logs drwxrwxrwx 13 mysql mysql 4096 2012-02-22 13:44 myDB drwxrwxrwx 2 mysql mysql 4096 2012-02-22 12:55 pids drwxrwxrwx 2 mysql mysql 4096 2012-02-22 12:55 sockets drwxrwxrwx 2 mysql mysql 4096 2012-02-22 13:25 version Apparmor config: $cat /etc/apparmor.d/usr.sbin.mysqld # vim:syntax=apparmor # Last Modified: Tue Jun 19 17:37:30 2007 #include <tunables/global> /usr/sbin/mysqld flags=(complain) { #include <abstractions/base> #include <abstractions/nameservice> #include <abstractions/user-tmp> #include <abstractions/mysql> #include <abstractions/winbind> capability dac_override, capability sys_resource, capability setgid, capability setuid, network tcp, /etc/hosts.allow r, /etc/hosts.deny r, /etc/mysql/*.pem r, /etc/mysql/conf.d/ r, /etc/mysql/conf.d/* r, /etc/mysql/*.cnf r, /usr/lib/mysql/plugin/ r, /usr/lib/mysql/plugin/*.so* mr, /usr/sbin/mysqld mr, /usr/share/mysql/** r, /var/log/mysql.log rw, /var/log/mysql.err rw, /var/lib/mysql/ r, /var/lib/mysql/** rwk, /var/log/mysql/ r, /var/log/mysql/* rw, /{,var/}run/mysqld/mysqld.pid w, /{,var/}run/mysqld/mysqld.sock w, /srv/mysql/ r, /srv/mysql/** rwk, /sys/devices/system/cpu/ r, # Site-specific additions and overrides. See local/README for details. #include <local/usr.sbin.mysqld> } Any suggestions? UPD1: $ touch /srv/mysql/sockets/mysql-myDB.sock $ sudo chown mysql:mysql /srv/mysql/sockets/mysql-myDB.sock $ ls -l /srv/mysql/sockets/mysql-myDB.sock -rw-rw-r-- 1 mysql mysql 0 2012-02-22 14:29 /srv/mysql/sockets/mysql-myDB.sock $ sudo /usr/bin/mysqld_safe --datadir=/srv/mysql/myDB --log-error=/srv/mysql/logs/mysqld-myDB.log --pid-file=/srv/mysql/pids/mysqld-myDB.pid --user=mysql --socket=/srv/mysql/sockets/mysql-myDB.sock --port=3700 120222 14:30:18 mysqld_safe Can't log to error log and syslog at the same time. Remove all --log-error configuration options for --syslog to take effect. 120222 14:30:18 mysqld_safe Logging to '/srv/mysql/logs/mysqld-myDB.log'. 120222 14:30:18 mysqld_safe Starting mysqld daemon with databases from /srv/mysqlmyDB 120222 14:30:24 mysqld_safe mysqld from pid file /srv/mysql/pids/mysqld-myDB.pid ended $ ls -l /srv/mysql/sockets/mysql-myDB.sock ls: cannot access /srv/mysql/sockets/mysql-myDB.sock: No such file or directory $ UPD2: $ sudo netstat -lnp | grep mysql tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 1093/mysqld unix 2 [ ACC ] STREAM LISTENING 5912 1093/mysqld /var/run/mysqld/mysqld.sock $ sudo lsof | grep /srv/mysql/sockets/mysql-myDB.sock lsof: WARNING: can't stat() fuse.gvfs-fuse-daemon file system /home/sears/.gvfs Output information may be incomplete. UPD3: $ cat /etc/mysql/my.cnf # # The MySQL database server configuration file. # # You can copy this to one of: # - "/etc/mysql/my.cnf" to set global options, # - "~/.my.cnf" to set user-specific options. # # One can use all long options that the program supports. # Run program with --help to get a list of available options and with # --print-defaults to see which it would actually understand and use. # # For explanations see # http://dev.mysql.com/doc/mysql/en/server-system-variables.html # This will be passed to all mysql clients # It has been reported that passwords should be enclosed with ticks/quotes # escpecially if they contain "#" chars... # Remember to edit /etc/mysql/debian.cnf when changing the socket location. [client] port = 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. Both versions are currently parsed. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] # # * Basic Settings # # # * IMPORTANT # If you make changes to these settings and your system uses apparmor, you may # also need to also adjust /etc/apparmor.d/usr.sbin.mysqld. # user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp skip-external-locking # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. #bind-address = 127.0.0.1 # # * Fine Tuning # key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #max_connections = 100 #table_cache = 64 #thread_concurrency = 10 # # * Query Cache Configuration # query_cache_limit = 1M query_cache_size = 16M # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. # As of 5.1 you can enable the log at runtime! #general_log_file = /var/log/mysql/mysql.log #general_log = 1 log_error = /var/log/mysql/error.log # Here you can see queries with especially long duration #log_slow_queries = /var/log/mysql/mysql-slow.log #long_query_time = 2 #log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log expire_logs_days = 10 max_binlog_size = 100M #binlog_do_db = include_database_name #binlog_ignore_db = include_database_name # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 16M # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/

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  • openvpn: after changing to server mode, client does not create TUN device

    - by lurscher
    i had a previously working configuration with the config files used in a previous question However, i've changed this now to the following configuration using server mode, everything on the logs seem fine, however the client doesn't create any tun interface, so i don't have anything to connect to, presumably, i need to add or push some route commands, but i don't have any idea at this point what i need to do. I am posting all my relevant configuration files server.conf: dev tun server 10.8.117.0 255.255.255.0 ifconfig-pool-persist ipp.txt tls-server dh /home/lurscher/keys/dh1024.pem ca /home/lurscher/keys/ca.crt cert /home/lurscher/keys/vpnCh8TestServer.crt key /home/lurscher/keys/vpnCh8TestServer.key status openvpn-status.log log openvpn.log comp-lzo verb 3 and client.conf: dev tun remote my.server.com tls-client ca /home/chuckq/keys/ca.crt cert /home/chuckq/keys/vpnCh8TestClient.crt key /home/chuckq/keys/vpnCh8TestClient.key ns-cert-type server ; port 1194 ; user nobody ; group nogroup status openvpn-status.log log openvpn.log comp-lzo verb 3 the server ifconfig shows a tun device: tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:10.8.117.1 P-t-P:10.8.117.2 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:100 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) However the client ifconfig does not show any tun interface! $ ifconfig tun0 tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 POINTOPOINT NOARP MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:100 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) the client log says: Tue May 17 23:27:09 2011 OpenVPN 2.1.0 i686-pc-linux-gnu [SSL] [LZO2] [EPOLL] [PKCS11] [MH] [PF_INET6] [eurephia] built on Jul 12 2010 Tue May 17 23:27:09 2011 IMPORTANT: OpenVPN's default port number is now 1194, based on an official port number assignment by IANA. OpenVPN 2.0-beta16 and earlier used 5000 as the default port. Tue May 17 23:27:09 2011 NOTE: the current --script-security setting may allow this configuration to call user-defined scripts Tue May 17 23:27:09 2011 /usr/bin/openssl-vulnkey -q -b 1024 -m <modulus omitted> Tue May 17 23:27:09 2011 LZO compression initialized Tue May 17 23:27:09 2011 Control Channel MTU parms [ L:1542 D:138 EF:38 EB:0 ET:0 EL:0 ] Tue May 17 23:27:09 2011 TUN/TAP device tun0 opened Tue May 17 23:27:09 2011 TUN/TAP TX queue length set to 100 Tue May 17 23:27:09 2011 Data Channel MTU parms [ L:1542 D:1450 EF:42 EB:135 ET:0 EL:0 AF:3/1 ] Tue May 17 23:27:09 2011 Local Options hash (VER=V4): '41690919' Tue May 17 23:27:09 2011 Expected Remote Options hash (VER=V4): '530fdded' Tue May 17 23:27:09 2011 Socket Buffers: R=[114688->131072] S=[114688->131072] Tue May 17 23:27:09 2011 UDPv4 link local (bound): [undef] Tue May 17 23:27:09 2011 UDPv4 link remote: [AF_INET]192.168.0.101:1194 Tue May 17 23:27:09 2011 TLS: Initial packet from [AF_INET]192.168.0.101:1194, sid=8e8bdc33 f4275407 Tue May 17 23:27:09 2011 VERIFY OK: depth=1, /C=CA/ST=Out/L=There/O=Ubuntu/OU=Home/CN=Ubuntu_CA/name=lurscher/[email protected] Tue May 17 23:27:09 2011 VERIFY OK: nsCertType=SERVER Tue May 17 23:27:09 2011 VERIFY OK: depth=0, /C=CA/ST=Out/L=There/O=Ubuntu/OU=Home/CN=vpnCh8TestServer/name=lurscher/[email protected] Tue May 17 23:27:09 2011 Data Channel Encrypt: Cipher 'BF-CBC' initialized with 128 bit key Tue May 17 23:27:09 2011 Data Channel Encrypt: Using 160 bit message hash 'SHA1' for HMAC authentication Tue May 17 23:27:09 2011 Data Channel Decrypt: Cipher 'BF-CBC' initialized with 128 bit key Tue May 17 23:27:09 2011 Data Channel Decrypt: Using 160 bit message hash 'SHA1' for HMAC authentication Tue May 17 23:27:09 2011 Control Channel: TLSv1, cipher TLSv1/SSLv3 DHE-RSA-AES256-SHA, 1024 bit RSA Tue May 17 23:27:09 2011 [vpnCh8TestServer] Peer Connection Initiated with [AF_INET]192.168.0.101:1194 Tue May 17 23:27:10 2011 Initialization Sequence Completed the client status log: OpenVPN STATISTICS Updated,Tue May 17 23:30:09 2011 TUN/TAP read bytes,0 TUN/TAP write bytes,0 TCP/UDP read bytes,5604 TCP/UDP write bytes,4244 Auth read bytes,0 pre-compress bytes,0 post-compress bytes,0 pre-decompress bytes,0 post-decompress bytes,0 END and the server log says: Tue May 17 23:18:25 2011 OpenVPN 2.1.0 x86_64-pc-linux-gnu [SSL] [LZO2] [EPOLL] [PKCS11] [MH] [PF_INET6] [eurephia] built on Jul 12 2010 Tue May 17 23:18:25 2011 IMPORTANT: OpenVPN's default port number is now 1194, based on an official port number assignment by IANA. OpenVPN 2.0-beta16 and earlier used 5000 as the default port. Tue May 17 23:18:25 2011 WARNING: --keepalive option is missing from server config Tue May 17 23:18:25 2011 NOTE: your local LAN uses the extremely common subnet address 192.168.0.x or 192.168.1.x. Be aware that this might create routing conflicts if you connect to the VPN server from public locations such as internet cafes that use the same subnet. Tue May 17 23:18:25 2011 NOTE: the current --script-security setting may allow this configuration to call user-defined scripts Tue May 17 23:18:25 2011 Diffie-Hellman initialized with 1024 bit key Tue May 17 23:18:25 2011 /usr/bin/openssl-vulnkey -q -b 1024 -m <modulus omitted> Tue May 17 23:18:25 2011 TLS-Auth MTU parms [ L:1542 D:138 EF:38 EB:0 ET:0 EL:0 ] Tue May 17 23:18:25 2011 ROUTE default_gateway=192.168.0.1 Tue May 17 23:18:25 2011 TUN/TAP device tun0 opened Tue May 17 23:18:25 2011 TUN/TAP TX queue length set to 100 Tue May 17 23:18:25 2011 /sbin/ifconfig tun0 10.8.117.1 pointopoint 10.8.117.2 mtu 1500 Tue May 17 23:18:25 2011 /sbin/route add -net 10.8.117.0 netmask 255.255.255.0 gw 10.8.117.2 Tue May 17 23:18:25 2011 Data Channel MTU parms [ L:1542 D:1450 EF:42 EB:135 ET:0 EL:0 AF:3/1 ] Tue May 17 23:18:25 2011 Socket Buffers: R=[126976->131072] S=[126976->131072] Tue May 17 23:18:25 2011 UDPv4 link local (bound): [undef] Tue May 17 23:18:25 2011 UDPv4 link remote: [undef] Tue May 17 23:18:25 2011 MULTI: multi_init called, r=256 v=256 Tue May 17 23:18:25 2011 IFCONFIG POOL: base=10.8.117.4 size=62 Tue May 17 23:18:25 2011 IFCONFIG POOL LIST Tue May 17 23:18:25 2011 vpnCh8TestClient,10.8.117.4 Tue May 17 23:18:25 2011 Initialization Sequence Completed Tue May 17 23:27:22 2011 MULTI: multi_create_instance called Tue May 17 23:27:22 2011 192.168.0.104:1194 Re-using SSL/TLS context Tue May 17 23:27:22 2011 192.168.0.104:1194 LZO compression initialized Tue May 17 23:27:22 2011 192.168.0.104:1194 Control Channel MTU parms [ L:1542 D:138 EF:38 EB:0 ET:0 EL:0 ] Tue May 17 23:27:22 2011 192.168.0.104:1194 Data Channel MTU parms [ L:1542 D:1450 EF:42 EB:135 ET:0 EL:0 AF:3/1 ] Tue May 17 23:27:22 2011 192.168.0.104:1194 Local Options hash (VER=V4): '530fdded' Tue May 17 23:27:22 2011 192.168.0.104:1194 Expected Remote Options hash (VER=V4): '41690919' Tue May 17 23:27:22 2011 192.168.0.104:1194 TLS: Initial packet from [AF_INET]192.168.0.104:1194, sid=8972b565 79323f68 Tue May 17 23:27:22 2011 192.168.0.104:1194 VERIFY OK: depth=1, /C=CA/ST=Out/L=There/O=Ubuntu/OU=Home/CN=Ubuntu_CA/name=lurscher/[email protected] Tue May 17 23:27:22 2011 192.168.0.104:1194 VERIFY OK: depth=0, /C=CA/ST=Out/L=There/O=Ubuntu/OU=Home/CN=Ubuntu_CA/name=lurscher/[email protected] Tue May 17 23:27:22 2011 192.168.0.104:1194 Data Channel Encrypt: Cipher 'BF-CBC' initialized with 128 bit key Tue May 17 23:27:22 2011 192.168.0.104:1194 Data Channel Encrypt: Using 160 bit message hash 'SHA1' for HMAC authentication Tue May 17 23:27:22 2011 192.168.0.104:1194 Data Channel Decrypt: Cipher 'BF-CBC' initialized with 128 bit key Tue May 17 23:27:22 2011 192.168.0.104:1194 Data Channel Decrypt: Using 160 bit message hash 'SHA1' for HMAC authentication Tue May 17 23:27:22 2011 192.168.0.104:1194 Control Channel: TLSv1, cipher TLSv1/SSLv3 DHE-RSA-AES256-SHA, 1024 bit RSA Tue May 17 23:27:22 2011 192.168.0.104:1194 [vpnCh8TestClient] Peer Connection Initiated with [AF_INET]192.168.0.104:1194 Tue May 17 23:27:22 2011 vpnCh8TestClient/192.168.0.104:1194 MULTI: Learn: 10.8.117.6 -> vpnCh8TestClient/192.168.0.104:1194 Tue May 17 23:27:22 2011 vpnCh8TestClient/192.168.0.104:1194 MULTI: primary virtual IP for vpnCh8TestClient/192.168.0.104:1194: 10.8.117.6 finally, the server status log: OpenVPN CLIENT LIST Updated,Tue May 17 23:36:25 2011 Common Name,Real Address,Bytes Received,Bytes Sent,Connected Since vpnCh8TestClient,192.168.0.104:1194,4244,5604,Tue May 17 23:27:22 2011 ROUTING TABLE Virtual Address,Common Name,Real Address,Last Ref 10.8.117.6,vpnCh8TestClient,192.168.0.104:1194,Tue May 17 23:27:22 2011 GLOBAL STATS Max bcast/mcast queue length,0 END

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  • qemu-kvm virtual machine virtio network freeze under load

    - by Rick Koshi
    I'm having a problem with my virtual machines, where the network will freeze under heavy load. I'm using CentOS 6.2 as both host and guest, not using libvirt, just running qemu-kvm directly as follows: /usr/libexec/qemu-kvm \ -drive file=/data2/vm/rb-dev2-www1-vm.img,index=0,media=disk,cache=none,if=virtio \ -boot order=c \ -m 2G \ -smp cores=1,threads=2 \ -vga std \ -name rb-dev2-www1-vm \ -vnc :84,password \ -net nic,vlan=0,macaddr=52:54:20:00:00:54,model=virtio \ -net tap,vlan=0,ifname=tap84,script=/etc/qemu-ifup \ -monitor unix:/var/run/vm/rb-dev2-www1-vm.mon,server,nowait \ -rtc base=utc \ -device piix3-usb-uhci \ -device usb-tablet /etc/qemu-ifup (used by the above command) is a very simple script, containing the following: #!/bin/sh sudo /sbin/ifconfig $1 0.0.0.0 promisc up sudo /usr/sbin/brctl addif br0 $1 sleep 2 And here's the info on br0 and other interfaces: avl-host3 14# brctl show bridge name bridge id STP enabled interfaces br0 8000.180373f5521a no bond0 tap84 virbr0 8000.525400858961 yes virbr0-nic avl-host3 15# ip addr show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: em1: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc mq master bond0 state UP qlen 1000 link/ether 18:03:73:f5:52:1a brd ff:ff:ff:ff:ff:ff 3: em2: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc mq master bond0 state UP qlen 1000 link/ether 18:03:73:f5:52:1a brd ff:ff:ff:ff:ff:ff 4: em3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000 link/ether 18:03:73:f5:52:1e brd ff:ff:ff:ff:ff:ff 5: em4: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000 link/ether 18:03:73:f5:52:20 brd ff:ff:ff:ff:ff:ff 6: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP link/ether 18:03:73:f5:52:1a brd ff:ff:ff:ff:ff:ff inet6 fe80::1a03:73ff:fef5:521a/64 scope link valid_lft forever preferred_lft forever 7: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN link/ether 18:03:73:f5:52:1a brd ff:ff:ff:ff:ff:ff inet 172.16.1.46/24 brd 172.16.1.255 scope global br0 inet6 fe80::1a03:73ff:fef5:521a/64 scope link valid_lft forever preferred_lft forever 8: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN link/ether 52:54:00:85:89:61 brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 9: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 500 link/ether 52:54:00:85:89:61 brd ff:ff:ff:ff:ff:ff 12: tap84: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 500 link/ether ba:e8:9b:2a:ff:48 brd ff:ff:ff:ff:ff:ff inet6 fe80::b8e8:9bff:fe2a:ff48/64 scope link valid_lft forever preferred_lft forever bond0 is a bond of em1 and em2. virbr0 and virbr0-nic are vestigial interfaces left over from CentOS's default installation. They are unused (as far as I know). The guest runs perfectly until I run a large 'rsync', when the network will freeze after some seemingly-random time (usually under a minute). When it freezes, there is no network activity in or out of the guest. I can still connect to the guest's console via vnc, but it is unable to speak out its network interface. Any attempt to 'ping' from the guest gives a "Destination Host Unreachable" error for 3/4 packets and no reply for every fourth packet. Sometimes (perhaps two thirds of the time), I can bring the interface back to life by doing a "service network restart" from the guest's console. If this works (and if I do it before the rsync times out), the rsync will resume. Usually it will freeze again within a minute or two. If I repeat, the rsync will eventually finish, and I presume the machine goes back to waiting for another period of heavy load. Throughout the whole process, there are no console errors or relevant (that I can see) syslog messages on either guest or host machine. If the "service network restart" doesn't work the first time, trying again (and again and again) never seems to work. The command completes normally, with normal output, but the interface stays frozen. However, a soft reboot of the guest machine (without restarting qemu-kvm) always seems to bring it back. I am aware of the "lowest mac address" assignment problem, where the bridge takes on the mac address of the slave interface with the lowest mac address. This causes temporary network freezes, but is definitely not what's happening for me. My freezes are permanent until manual intervention, and you can see from the 'ip addr show' output above that the mac address being used by br0 is that of the physical ethernet. There are no other virtual machines running on the host. I've verified that each virtual machine on the subnet has its own unique mac address. I have rebuilt the guest machine several times, and I have tried this on three different host machines (identical hardware, built identically). Oddly, I do have one virtual host (the second of this series) which never seemed to have a problem. It never had its network freeze when it was running the same rsync during its build. It's particularly odd because it was the second build. The first, on a different host, did have the freezing problem, but the second did not. I assumed at the time that I had done something wrong with the first build, and that the problem was resolved. Unfortunately, the problem reappeared when I built the third VM. Also unfortunately, I can't do many tests with the working VM, as it's now in production use, and I'm hoping I can find the cause of this issue before that machine starts having problems. It's possible that I just got really lucky while running the rsync on the working machine, and that one time it didn't freeze. Of course it's possible that I somehow changed the build scripts without realizing it and re-broke something, but I can't find any such thing. In any case, I'm hoping someone has some idea what could cause this. Addendum: Preliminary tests suggest that I don't have the problem if I substitute e1000 for virtio in the first -net flag to qemu-kvm. I don't consider this a solution, but it is suitable for a stopgap. Has anyone else had (or better yet, solved) this problem with the virtio network driver?

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  • IIS Strategies for Accessing Secured Network Resources

    - by ErikE
    Problem: A user connects to a service on a machine, such as an IIS web site or a SQL Server database. The site or the database need to gain access to network resources such as file shares (the most common) or a database on a different server. Permission is denied. This is because the user the service is running under doesn't have network permissions in the first place, or if it does, it doesn't have rights to access the remote resource. I keep running into this problem over and over again and am tired of not having a really solid way of handling it. Here are some workarounds I'm aware of: Run IIS as a custom-created domain user who is granted high permissions If permissions are granted one file share at a time, then every time I want to read from a new share, I would have to ask a network admin to add it for me. Eventually, with many web sites reading from many shares, it is going to get really complicated. If permissions are just opened up wide for the user to access any file shares in our domain, then this seems like an unnecessary security surface area to present. This also applies to all the sites running on IIS, rather than just the selected site or virtual directory that needs the access, a further surface area problem. Still use the IUSR account but give it network permissions and set up the same user name on the remote resource (not a domain user, a local user) This also has its problems. For example, there's a file share I am using that I have full rights to for sharing, but I can't log in to the machine. So I have to find the right admin and ask him to do it for me. Any time something has to change, it's another request to an admin. Allow IIS users to connect as anonymous, but set the account used for anonymous access to a high-privilege one This is even worse than giving the IIS IUSR full privileges, because it means my web site can't use any kind of security in the first place. Connect using Kerberos, then delegate This sounds good in principle but has all sorts of problems. First of all, if you're using virtual web sites where the domain name you connect to the site with is not the base machine name (as we do frequently), then you have to set up a Service Principal Name on the webserver using Microsoft's SetSPN utility. It's complicated and apparently prone to errors. Also, you have to ask your network/domain admin to change security policy for both the web server and the domain account so they are "trusted for delegation." If you don't get everything perfectly right, suddenly your intended Kerberos authentication is NTLM instead, and you can only impersonate rather than delegate, and thus no reaching out over the network as the user. Also, this method can be problematic because sometimes you need the web site or database to have permissions that the connecting user doesn't have. Create a service or COM+ application that fetches the resource for the web site Services and COM+ packages are run with their own set of credentials. Running as a high-privilege user is okay since they can do their own security and deny requests that are not legitimate, putting control in the hands of the application developer instead of the network admin. Problems: I am using a COM+ package that does exactly this on Windows Server 2000 to deliver highly sensitive images to a secured web application. I tried moving the web site to Windows Server 2003 and was suddenly denied permission to instantiate the COM+ object, very likely registry permissions. I trolled around quite a bit and did not solve the problem, partly because I was reluctant to give the IUSR account full registry permissions. That seems like the same bad practice as just running IIS as a high-privilege user. Note: This is actually really simple. In a programming language of your choice, you create a class with a function that returns an instance of the object you want (an ADODB.Connection, for example), and build a dll, which you register as a COM+ object. In your web server-side code, you create an instance of the class and use the function, and since it is running under a different security context, calls to network resources work. Map drive letters to shares This could theoretically work, but in my mind it's not really a good long-term strategy. Even though mappings can be created with specific credentials, and this can be done by others than a network admin, this also is going to mean that there are either way too many shared drives (small granularity) or too much permission is granted to entire file servers (large granularity). Also, I haven't figured out how to map a drive so that the IUSR gets the drives. Mapping a drive is for the current user, I don't know the IUSR account password to log in as it and create the mappings. Move the resources local to the web server/database There are times when I've done this, especially with Access databases. Does the database have to live out on the file share? Sometimes, it was just easiest to move the database to the web server or to the SQL database server (so the linked server to it would work). But I don't think this is a great all-around solution, either. And it won't work when the resource is a service rather than a file. Move the service to the final web server/database I suppose I could run a web server on my SQL Server database, so the web site can connect to it using impersonation and make me happy. But do we really want random extra web servers on our database servers just so this is possible? No. Virtual directories in IIS I know that virtual directories can help make remote resources look as though they are local, and this supports using custom credentials for each virtual directory. I haven't been able to come up with, yet, how this would solve the problem for system calls. Users could reach file shares directly, but this won't help, say, classic ASP code access resources. I could use a URL instead of a file path to read remote data files in a web page, but this isn't going to help me make a connection to an Access database, a SQL server database, or any other resource that uses a connection library rather than being able to just read all the bytes and work with them. I wish there was some kind of "service tunnel" that I could create. Think about how a VPN makes remote resources look like they are local. With a richer aliasing mechanism, perhaps code-based, why couldn't even database connections occur under a defined security context? Why not a special Windows component that lets you specify, per user, what resources are available and what alternate credentials are used for the connection? File shares, databases, web sites, you name it. I guess I'm almost talking about a specialized local proxy server. Anyway, so there's my list. I may update it if I think of more. Does anyone have any ideas for me? My current problem today is, yet again, I need a web site to connect to an Access database on a file share. Here we go again...

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  • IIS Strategies for Accessing Secured Network Resources

    - by Emtucifor
    Problem: A user connects to a service on a machine, such as an IIS web site or a SQL Server database. The site or the database need to gain access to network resources such as file shares (the most common) or a database on a different server. Permission is denied. This is because the user the service is running as doesn't have network permissions in the first place, or if it does, it doesn't have rights to access the remote resource. I keep running into this problem over and over again and am tired of not having a really solid way of handling it. Here are some workarounds I'm aware of: Run IIS as a custom-created domain user who is granted high permissions If permissions are granted one file share at a time, then every time I want to read from a new share, I would have to ask a network admin to add it for me. Eventually, with many web sites reading from many shares, it is going to get really complicated. If permissions are just opened up wide for the user to access any file shares in our domain, then this seems like an unnecessary security surface area to present. This also applies to all the sites running on IIS, rather than just the selected site or virtual directory that needs the access, a further surface area problem. Still use the IUSR account but give it network permissions and set up the same user name on the remote resource (not a domain user, a local user) This also has its problems. For example, there's a file share I am using that I have full rights to for sharing, but I can't log in to the machine. So I have to find the right admin and ask him to do it for me. Any time something has to change, it's another request to an admin. Allow IIS users to connect as anonymous, but set the account used for anonymous access to a high-privilege one This is even worse than giving the IIS IUSR full privileges, because it means my web site can't use any kind of security in the first place. Connect using Kerberos, then delegate This sounds good in principle but has all sorts of problems. First of all, if you're using virtual web sites where the domain name you connect to the site with is not the base machine name (as we do frequently), then you have to set up a Service Principal Name on the webserver using Microsoft's SetSPN utility. It's complicated and apparently prone to errors. Also, you have to ask your network/domain admin to change security policy for the web server so it is "trusted for delegation." If you don't get everything perfectly right, suddenly your intended Kerberos authentication is NTLM instead, and you can only impersonate rather than delegate, and thus no reaching out over the network as the user. Also, this method can be problematic because sometimes you need the web site or database to have permissions that the connecting user doesn't have. Create a service or COM+ application that fetches the resource for the web site Services and COM+ packages are run with their own set of credentials. Running as a high-privilege user is okay since they can do their own security and deny requests that are not legitimate, putting control in the hands of the application developer instead of the network admin. Problems: I am using a COM+ package that does exactly this on Windows Server 2000 to deliver highly sensitive images to a secured web application. I tried moving the web site to Windows Server 2003 and was suddenly denied permission to instantiate the COM+ object, very likely registry permissions. I trolled around quite a bit and did not solve the problem, partly because I was reluctant to give the IUSR account full registry permissions. That seems like the same bad practice as just running IIS as a high-privilege user. Note: This is actually really simple. In a programming language of your choice, you create a class with a function that returns an instance of the object you want (an ADODB.Connection, for example), and build a dll, which you register as a COM+ object. In your web server-side code, you create an instance of the class and use the function, and since it is running under a different security context, calls to network resources work. Map drive letters to shares This could theoretically work, but in my mind it's not really a good long-term strategy. Even though mappings can be created with specific credentials, and this can be done by others than a network admin, this also is going to mean that there are either way too many shared drives (small granularity) or too much permission is granted to entire file servers (large granularity). Also, I haven't figured out how to map a drive so that the IUSR gets the drives. Mapping a drive is for the current user, I don't know the IUSR account password to log in as it and create the mappings. Move the resources local to the web server/database There are times when I've done this, especially with Access databases. Does the database have to live out on the file share? Sometimes, it was just easiest to move the database to the web server or to the SQL database server (so the linked server to it would work). But I don't think this is a great all-around solution, either. And it won't work when the resource is a service rather than a file. Move the service to the final web server/database I suppose I could run a web server on my SQL Server database, so the web site can connect to it using impersonation and make me happy. But do we really want random extra web servers on our database servers just so this is possible? No. Virtual directories in IIS I know that virtual directories can help make remote resources look as though they are local, and this supports using custom credentials for each virtual directory. I haven't been able to come up with, yet, how this would solve the problem for system calls. Users could reach file shares directly, but this won't help, say, classic ASP code access resources. I could use a URL instead of a file path to read remote data files in a web page, but this isn't going to help me make a connection to an Access database, a SQL server database, or any other resource that uses a connection library rather than being able to just read all the bytes and work with them. I wish there was some kind of "service tunnel" that I could create. Think about how a VPN makes remote resources look like they are local. With a richer aliasing mechanism, perhaps code-based, why couldn't even database connections occur under a defined security context? Why not a special Windows component that lets you specify, per user, what resources are available and what alternate credentials are used for the connection? File shares, databases, web sites, you name it. I guess I'm almost talking about a specialized local proxy server. Anyway, so there's my list. I may update it if I think of more. Does anyone have any ideas for me? My current problem today is, yet again, I need a web site to connect to an Access database on a file share. Here we go again...

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  • postfix: Temporary lookup failure

    - by mk_89
    I have followed the tutorials step by step for installing and configuring postfix https://help.ubuntu.com/community/Postfix https://help.ubuntu.com/community/PostfixBasicSetupHowto I am trying to test the services to whether Temporary lookup failure error telnet localhost 25 250 2.1.0 Ok rcpt to: fmaster@localhost 451 4.3.0 <fmaster@localhost>: Temporary lookup failure rcpt to: info@localhost 451 4.3.0 <info@localhost>: Temporary lookup failure I have tried searching the web but I have found no solutions, why am I getting this problem? mail.log Sep 24 01:03:05 bookcdb postfix/smtpd[21055]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <info@localhost>: Temporary lookup failure; from=<root@localhost> to=<info@localhost> proto=ESMTP helo=<localhost> Sep 24 01:03:19 bookcdb postfix/smtpd[21055]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <root@localhost>: Temporary lookup failure; from=<root@localhost> to=<root@localhost> proto=ESMTP helo=<localhost> Sep 24 01:08:19 bookcdb postfix/smtpd[21055]: timeout after RCPT from unknown[::1] Sep 24 01:08:19 bookcdb postfix/smtpd[21055]: disconnect from unknown[::1] Sep 24 01:10:49 bookcdb postfix/anvil[21059]: statistics: max connection rate 1/60s for (smtp:::1) at Sep 24 01:00:49 Sep 24 01:10:49 bookcdb postfix/anvil[21059]: statistics: max connection count 1 for (smtp:::1) at Sep 24 01:00:49 Sep 24 01:10:49 bookcdb postfix/anvil[21059]: statistics: max cache size 1 at Sep 24 01:00:49 Sep 24 01:15:36 bookcdb postfix/smtpd[22175]: error: open database /var/lib/mailman/data/aliases.db: No such file or directory Sep 24 01:15:36 bookcdb postfix/smtpd[22175]: warning: hostname localhost does not resolve to address ::1: No address associated with hostname Sep 24 01:15:36 bookcdb postfix/smtpd[22175]: connect from unknown[::1] Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: error: open database /etc/postfix/transport.db: No such file or directory Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport lookup error for "root@localhost" Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: transport_maps lookup failure Sep 24 01:15:59 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:15:59 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport lookup error for "fmaster@localhost" Sep 24 01:15:59 bookcdb postfix/trivial-rewrite[22195]: warning: transport_maps lookup failure Sep 24 01:15:59 bookcdb postfix/smtpd[22175]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <fmaster@localhost>: Temporary lookup failure; from=<root@localhost> to=<fmaster@localhost> proto=ESMTP helo=<localhost> Sep 24 01:16:30 postfix/smtpd[22175]: last message repeated 5 times Sep 24 01:16:30 bookcdb postfix/smtpd[22175]: disconnect from unknown[::1] Sep 24 01:19:50 bookcdb postfix/anvil[22177]: statistics: max connection rate 1/60s for (smtp:::1) at Sep 24 01:15:36 Sep 24 01:19:50 bookcdb postfix/anvil[22177]: statistics: max connection count 1 for (smtp:::1) at Sep 24 01:15:36 Sep 24 01:19:50 bookcdb postfix/anvil[22177]: statistics: max cache size 1 at Sep 24 01:15:36 Sep 24 01:20:32 bookcdb postfix/qmgr[21039]: D0C596E0B34: from=<[email protected]>, size=442, nrcpt=1 (queue active) Sep 24 01:20:32 bookcdb postfix/qmgr[21039]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 01:20:32 bookcdb postfix/error[22402]: D0C596E0B34: to=<[email protected]>, relay=none, delay=5369, delays=5369/0.01/0/0.09, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 01:24:16 bookcdb postfix/smtpd[22573]: error: open database /var/lib/mailman/data/aliases.db: No such file or directory Sep 24 01:24:16 bookcdb postfix/smtpd[22573]: warning: hostname localhost does not resolve to address ::1: No address associated with hostname Sep 24 01:24:16 bookcdb postfix/smtpd[22573]: connect from unknown[::1] Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: error: open database /etc/postfix/transport.db: No such file or directory Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "root@localhost" Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: transport_maps lookup failure Sep 24 01:25:14 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:25:14 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "[email protected]" Sep 24 01:25:14 bookcdb postfix/trivial-rewrite[22594]: warning: transport_maps lookup failure Sep 24 01:25:14 bookcdb postfix/smtpd[22573]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <[email protected]>: Temporary lookup failure; from=<root@localhost> to=<[email protected]> proto=ESMTP helo=<localhost> Sep 24 01:25:32 bookcdb postfix/qmgr[21039]: 2E5C36E0A07: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 01:25:32 bookcdb postfix/qmgr[21039]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 01:25:32 bookcdb postfix/qmgr[21039]: 0EA3A6E0ACC: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 01:25:32 bookcdb postfix/error[22631]: 2E5C36E0A07: to=<[email protected]>, orig_to=<root>, relay=none, delay=30203, delays=30203/0.01/0/0.1, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 01:25:32 bookcdb postfix/error[22632]: 0EA3A6E0ACC: to=<[email protected]>, orig_to=<root>, relay=none, delay=30115, delays=30115/0.01/0/0.11, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 01:25:58 bookcdb postfix/smtpd[22573]: warning: non-SMTP command from unknown[::1]: subject: fdf Sep 24 01:25:58 bookcdb postfix/smtpd[22573]: disconnect from unknown[::1] Sep 24 01:26:01 bookcdb postfix/smtpd[22573]: warning: hostname localhost does not resolve to address ::1: No address associated with hostname Sep 24 01:26:01 bookcdb postfix/smtpd[22573]: connect from unknown[::1] Sep 24 01:26:10 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:26:10 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "root@locahost" Sep 24 01:26:10 bookcdb postfix/trivial-rewrite[22594]: warning: transport_maps lookup failure Sep 24 01:26:37 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:26:37 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "fmaster@localhost" Sep 24 01:26:37 bookcdb postfix/trivial-rewrite[22594]: warning: transport_maps lookup failure Sep 24 01:26:37 bookcdb postfix/smtpd[22573]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <fmaster@localhost>: Temporary lookup failure; from=<root@locahost> to=<fmaster@localhost> proto=SMTP Sep 24 01:26:45 bookcdb postfix/smtpd[22573]: disconnect from unknown[::1] Sep 24 01:30:05 bookcdb postfix/anvil[22575]: statistics: max connection rate 1/60s for (smtp:::1) at Sep 24 01:24:16 Sep 24 01:30:05 bookcdb postfix/anvil[22575]: statistics: max connection count 1 for (smtp:::1) at Sep 24 01:24:16 Sep 24 01:30:05 bookcdb postfix/anvil[22575]: statistics: max cache size 1 at Sep 24 01:24:16 Sep 24 01:34:57 bookcdb dovecot: master: Dovecot v2.0.19 starting up (core dumps disabled) Sep 24 01:35:02 bookcdb amavis[1009]: starting. /usr/sbin/amavisd-new at mail.bookcdb.com amavisd-new-2.6.5 (20110407), Unicode aware Sep 24 01:35:02 bookcdb amavis[1009]: Perl version 5.014002 Sep 24 01:35:05 bookcdb amavis[1155]: Net::Server: Group Not Defined. Defaulting to EGID '114 114' Sep 24 01:35:05 bookcdb amavis[1155]: Net::Server: User Not Defined. Defaulting to EUID '108' Sep 24 01:35:05 bookcdb amavis[1155]: Module Amavis::Conf 2.208 Sep 24 01:35:05 bookcdb amavis[1155]: Module Archive::Zip 1.30 Sep 24 01:35:05 bookcdb amavis[1155]: Module BerkeleyDB 0.49 Sep 24 01:35:05 bookcdb amavis[1155]: Module Compress::Zlib 2.033 Sep 24 01:35:05 bookcdb amavis[1155]: Module Convert::TNEF 0.17 Sep 24 01:35:05 bookcdb amavis[1155]: Module Convert::UUlib 1.4 Sep 24 01:35:05 bookcdb amavis[1155]: Module Crypt::OpenSSL::RSA 0.27 Sep 24 01:35:05 bookcdb amavis[1155]: Module DB_File 1.821 Sep 24 01:35:05 bookcdb amavis[1155]: Module Digest::MD5 2.51 Sep 24 01:35:05 bookcdb amavis[1155]: Module Digest::SHA 5.61 Sep 24 01:35:05 bookcdb amavis[1155]: Module IO::Socket::INET6 2.69 Sep 24 01:35:05 bookcdb amavis[1155]: Module MIME::Entity 5.502 Sep 24 01:35:05 bookcdb amavis[1155]: Module MIME::Parser 5.502 Sep 24 01:35:05 bookcdb amavis[1155]: Module MIME::Tools 5.502 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::DKIM::Signer 0.39 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::DKIM::Verifier 0.39 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::Header 2.08 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::Internet 2.08 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::SPF v2.008 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::SpamAssassin 3.003002 Sep 24 01:35:05 bookcdb amavis[1155]: Module Net::DNS 0.66 Sep 24 01:35:05 bookcdb amavis[1155]: Module Net::Server 0.99 Sep 24 01:35:05 bookcdb amavis[1155]: Module NetAddr::IP 4.058 Sep 24 01:35:05 bookcdb amavis[1155]: Module Socket6 0.23 Sep 24 01:35:05 bookcdb amavis[1155]: Module Time::HiRes 1.972101 Sep 24 01:35:05 bookcdb amavis[1155]: Module URI 1.59 Sep 24 01:35:05 bookcdb amavis[1155]: Module Unix::Syslog 1.1 Sep 24 01:35:05 bookcdb amavis[1155]: Amavis::DB code loaded Sep 24 01:35:05 bookcdb amavis[1155]: Amavis::Cache code loaded Sep 24 01:35:05 bookcdb amavis[1155]: SQL base code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: SQL::Log code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: SQL::Quarantine NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: Lookup::SQL code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: Lookup::LDAP code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: AM.PDP-in proto code loaded Sep 24 01:35:05 bookcdb amavis[1155]: SMTP-in proto code loaded Sep 24 01:35:05 bookcdb amavis[1155]: Courier proto code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: SMTP-out proto code loaded Sep 24 01:35:05 bookcdb amavis[1155]: Pipe-out proto code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: BSMTP-out proto code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: Local-out proto code loaded Sep 24 01:35:05 bookcdb amavis[1155]: OS_Fingerprint code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: ANTI-VIRUS code loaded Sep 24 01:35:05 bookcdb amavis[1155]: ANTI-SPAM code loaded Sep 24 01:35:05 bookcdb amavis[1155]: ANTI-SPAM-EXT code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: ANTI-SPAM-C code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: ANTI-SPAM-SA code loaded Sep 24 01:35:05 bookcdb amavis[1155]: Unpackers code loaded Sep 24 01:35:05 bookcdb amavis[1155]: DKIM code loaded Sep 24 01:35:05 bookcdb amavis[1155]: Tools code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: Found $file at /usr/bin/file Sep 24 01:35:05 bookcdb amavis[1155]: No $altermime, not using it Sep 24 01:35:05 bookcdb amavis[1155]: Internal decoder for .mail Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .F Sep 24 01:35:05 bookcdb amavis[1155]: Found decoder for .Z at /bin/uncompress Sep 24 01:35:05 bookcdb amavis[1155]: Internal decoder for .gz Sep 24 01:35:05 bookcdb amavis[1155]: Found decoder for .bz2 at /bin/bzip2 -d Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .lzo tried: lzop -d Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .rpm tried: rpm2cpio.pl, rpm2cpio Sep 24 01:35:05 bookcdb amavis[1155]: Found decoder for .cpio at /bin/pax Sep 24 01:35:05 bookcdb amavis[1155]: Found decoder for .tar at /bin/pax Sep 24 01:35:05 bookcdb amavis[1155]: Found decoder for .deb at /usr/bin/ar Sep 24 01:35:05 bookcdb amavis[1155]: Internal decoder for .zip Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .7z tried: 7zr, 7za, 7z Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .rar tried: unrar-free Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .arj tried: arj, unarj Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .arc tried: nomarch, arc Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .zoo tried: zoo Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .lha Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .doc tried: ripole Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .cab tried: cabextract Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .tnef Sep 24 01:35:05 bookcdb amavis[1155]: Internal decoder for .tnef Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .exe tried: unrar-free; arj, unarj Sep 24 01:35:05 bookcdb amavis[1155]: Using primary internal av scanner code for ClamAV-clamd Sep 24 01:35:05 bookcdb amavis[1155]: Found secondary av scanner ClamAV-clamscan at /usr/bin/clamscan Sep 24 01:35:05 bookcdb amavis[1155]: Creating db in /var/lib/amavis/db/; BerkeleyDB 0.49, libdb 5.1 Sep 24 01:35:05 bookcdb postgrey[1219]: Process Backgrounded Sep 24 01:35:05 bookcdb postgrey[1219]: 2012/09/24-01:35:05 postgrey (type Net::Server::Multiplex) starting! pid(1219) Sep 24 01:35:05 bookcdb postgrey[1219]: Using default listen value of 128 Sep 24 01:35:05 bookcdb postgrey[1219]: Binding to TCP port 10023 on host localhost#012 Sep 24 01:35:05 bookcdb postgrey[1219]: Setting gid to "116 116" Sep 24 01:35:05 bookcdb postgrey[1219]: Setting uid to "110" Sep 24 01:35:06 bookcdb spamd[1231]: logger: removing stderr method Sep 24 01:35:08 bookcdb spamd[1233]: spamd: server started on port 783/tcp (running version 3.3.2) Sep 24 01:35:08 bookcdb spamd[1233]: spamd: server pid: 1233 Sep 24 01:35:08 bookcdb spamd[1233]: spamd: server successfully spawned child process, pid 1238 Sep 24 01:35:08 bookcdb spamd[1233]: spamd: server successfully spawned child process, pid 1240 Sep 24 01:35:08 bookcdb spamd[1233]: prefork: child states: SI Sep 24 01:35:08 bookcdb spamd[1233]: prefork: child states: II Sep 24 01:35:15 bookcdb postfix/master[1729]: daemon started -- version 2.9.3, configuration /etc/postfix Sep 24 01:36:08 bookcdb postfix/smtpd[1995]: error: open database /var/lib/mailman/data/aliases.db: No such file or directory Sep 24 01:36:08 bookcdb postfix/smtpd[1995]: warning: hostname localhost does not resolve to address ::1: No address associated with hostname Sep 24 01:36:08 bookcdb postfix/smtpd[1995]: connect from unknown[::1] Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: error: open database /etc/postfix/transport.db: No such file or directory Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport lookup error for "root@localhost" Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: transport_maps lookup failure Sep 24 01:37:00 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:37:00 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport lookup error for "fmaster@localhost" Sep 24 01:37:00 bookcdb postfix/trivial-rewrite[1999]: warning: transport_maps lookup failure Sep 24 01:37:00 bookcdb postfix/smtpd[1995]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <fmaster@localhost>: Temporary lookup failure; from=<root@localhost> to=<fmaster@localhost> proto=SMTP Sep 24 01:37:28 bookcdb dovecot: imap-login: Login: user=<mkadiri89>, method=PLAIN, rip=::1, lip=::1, mpid=2730, secured Sep 24 01:37:28 bookcdb dovecot: imap(mkadiri89): Disconnected: Logged out bytes=44/697 Sep 24 01:37:29 bookcdb dovecot: imap-login: Login: user=<mkadiri89>, method=PLAIN, rip=::1, lip=::1, mpid=2732, secured Sep 24 01:37:29 bookcdb dovecot: imap(mkadiri89): Disconnected: Logged out bytes=464/1303 Sep 24 01:37:29 bookcdb dovecot: imap-login: Login: user=<mkadiri89>, method=PLAIN, rip=::1, lip=::1, mpid=2734, secured Sep 24 01:37:29 bookcdb dovecot: imap(mkadiri89): Disconnected: Logged out bytes=117/1395 Sep 24 01:37:31 bookcdb dovecot: imap-login: Login: user=<mkadiri89>, method=PLAIN, rip=::1, lip=::1, mpid=2737, secured Sep 24 01:37:31 bookcdb dovecot: imap(mkadiri89): Disconnected: Logged out bytes=117/1395 Sep 24 01:37:49 bookcdb dovecot: imap-login: Login: user=<root>, method=PLAIN, rip=::1, lip=::1, mpid=2739, secured Sep 24 01:37:49 bookcdb dovecot: imap: Error: user root: Invalid settings in userdb: userdb returned 0 as uid Sep 24 01:37:49 bookcdb dovecot: imap: Error: Invalid user settings. Refer to server log for more information. Sep 24 01:37:54 bookcdb dovecot: imap-login: Login: user=<root>, method=PLAIN, rip=::1, lip=::1, mpid=2741, secured Sep 24 01:37:54 bookcdb dovecot: imap: Error: user root: Invalid settings in userdb: userdb returned 0 as uid Sep 24 01:37:54 bookcdb dovecot: imap: Error: Invalid user settings. Refer to server log for more information. Sep 24 01:38:04 bookcdb dovecot: imap-login: Login: user=<info>, method=PLAIN, rip=::1, lip=::1, mpid=2743, secured Sep 24 01:38:04 bookcdb dovecot: imap(info): Disconnected: Logged out bytes=44/697 Sep 24 01:38:04 bookcdb dovecot: imap-login: Login: user=<info>, method=PLAIN, rip=::1, lip=::1, mpid=2745, secured Sep 24 01:38:04 bookcdb dovecot: imap(info): Disconnected: Logged out bytes=464/1303 Sep 24 01:38:04 bookcdb dovecot: imap-login: Login: user=<info>, method=PLAIN, rip=::1, lip=::1, mpid=2747, secured Sep 24 01:38:04 bookcdb dovecot: imap(info): Disconnected: Logged out bytes=117/1395 Sep 24 01:38:55 bookcdb postfix/smtpd[1995]: disconnect from unknown[::1] Sep 24 01:38:58 bookcdb postfix/smtpd[1995]: warning: hostname localhost does not resolve to address ::1: No address associated with hostname Sep 24 01:38:58 bookcdb postfix/smtpd[1995]: connect from unknown[::1] Sep 24 01:39:11 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:39:11 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport lookup error for "info@localhost" Sep 24 01:39:11 bookcdb postfix/trivial-rewrite[1999]: warning: transport_maps lookup failure Sep 24 01:39:37 bookcdb postfix/smtpd[1995]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <fmaster@localhost>: Temporary lookup failure; from=<info@localhost> to=<fmaster@localhost> proto=SMTP Sep 24 01:39:47 bookcdb postfix/smtpd[1995]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <fmaster@localhost>: Temporary lookup failure; from=<info@localhost> to=<fmaster@localhost> proto=SMTP Sep 24 01:40:13 bookcdb postfix/smtpd[1995]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <info@localhost>: Temporary lookup failure; from=<info@localhost> to=<info@localhost> proto=SMTP Sep 24 01:43:08 bookcdb postfix/smtpd[1995]: disconnect from unknown[::1] Sep 24 01:46:08 bookcdb postfix/anvil[1998]: statistics: max connection rate 1/60s for (smtp:::1) at Sep 24 01:36:08 Sep 24 01:46:08 bookcdb postfix/anvil[1998]: statistics: max connection count 1 for (smtp:::1) at Sep 24 01:36:08 Sep 24 01:46:08 bookcdb postfix/anvil[1998]: statistics: max cache size 1 at Sep 24 01:36:08 Sep 24 01:48:05 bookcdb dovecot: imap-login: Login: user=<info>, method=PLAIN, rip=::1, lip=::1, mpid=2805, secured Sep 24 01:48:05 bookcdb dovecot: imap(info): Disconnected: Logged out bytes=85/681 Sep 24 01:51:30 bookcdb dovecot: imap-login: Login: user=<info>, method=PLAIN, rip=::1, lip=::1, mpid=2815, secured Sep 24 01:51:30 bookcdb dovecot: imap(info): Disconnected: Logged out bytes=117/1395 Sep 24 02:05:15 bookcdb postfix/qmgr[1745]: 2EA006E0B32: from=<[email protected]>, size=439, nrcpt=1 (queue active) Sep 24 02:05:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 02:05:15 bookcdb postfix/qmgr[1745]: E76996E09B2: from=<[email protected]>, size=439, nrcpt=1 (queue active) Sep 24 02:05:15 bookcdb postfix/error[2842]: 2EA006E0B32: to=<[email protected]>, relay=none, delay=8391, delays=8391/0.05/0/0.09, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 02:05:16 bookcdb postfix/error[2843]: E76996E09B2: to=<[email protected]>, relay=none, delay=8416, delays=8416/0.03/0/0.11, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 02:30:15 bookcdb postfix/qmgr[1745]: D0C596E0B34: from=<[email protected]>, size=442, nrcpt=1 (queue active) Sep 24 02:30:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 02:30:15 bookcdb postfix/error[2914]: D0C596E0B34: to=<[email protected]>, relay=none, delay=9551, delays=9551/0.01/0/0.08, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 02:35:15 bookcdb postfix/qmgr[1745]: 2E5C36E0A07: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 02:35:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 02:35:15 bookcdb postfix/qmgr[1745]: 0EA3A6E0ACC: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 02:35:15 bookcdb postfix/error[2926]: 2E5C36E0A07: to=<[email protected]>, orig_to=<root>, relay=none, delay=34386, delays=34386/0.03/0/0.1, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 02:35:15 bookcdb postfix/error[2927]: 0EA3A6E0ACC: to=<[email protected]>, orig_to=<root>, relay=none, delay=34299, delays=34298/0.02/0/0.12, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 03:15:15 bookcdb postfix/qmgr[1745]: 2EA006E0B32: from=<[email protected]>, size=439, nrcpt=1 (queue active) Sep 24 03:15:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 03:15:15 bookcdb postfix/qmgr[1745]: E76996E09B2: from=<[email protected]>, size=439, nrcpt=1 (queue active) Sep 24 03:15:15 bookcdb postfix/error[3025]: 2EA006E0B32: to=<[email protected]>, relay=none, delay=12590, delays=12590/0.01/0/0.07, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 03:15:15 bookcdb postfix/error[3026]: E76996E09B2: to=<[email protected]>, relay=none, delay=12616, delays=12616/0.01/0/0.09, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 03:40:15 bookcdb postfix/qmgr[1745]: D0C596E0B34: from=<[email protected]>, size=442, nrcpt=1 (queue active) Sep 24 03:40:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 03:40:15 bookcdb postfix/error[3097]: D0C596E0B34: to=<[email protected]>, relay=none, delay=13752, delays=13752/0.01/0/0.07, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 03:45:15 bookcdb postfix/qmgr[1745]: 2E5C36E0A07: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 03:45:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 03:45:15 bookcdb postfix/qmgr[1745]: 0EA3A6E0ACC: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 03:45:15 bookcdb postfix/error[3129]: 2E5C36E0A07: to=<[email protected]>, orig_to=<root>, relay=none, delay=38586, delays=38586/0.01/0/0.09, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 03:45:15 bookcdb postfix/error[3130]: 0EA3A6E0ACC: to=<[email protected]>, orig_to=<root>, relay=none, delay=38498, delays=38498/0.01/0/0.08, dsn=4.3.0, status=deferred (mail transport unavailable) postconf -n alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases, hash:/var/lib/mailman/data/aliases append_dot_mydomain = no biff = no broken_sasl_auth_clients = yes config_directory = /etc/postfix content_filter = smtp-amavis:[127.0.0.1]:10024 home_mailbox = Maildir/ inet_interfaces = all inet_protocols = all mailbox_command = mailbox_size_limit = 0 mailman_destination_recipient_limit = 1 mydestination = server1.bookcdb.com, bookcdb.com, localhost.bookcdb.com, localho st, bookcdb.com myhostname = server1.bookcdb.com mynetworks = 127.0.0.0/8 myorigin = /etc/mailname readme_directory = no recipient_delimiter = + relay_domains = lists.bookcdb.com relayhost = smtp_tls_note_starttls_offer = yes smtp_tls_security_level = may smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,rejec t_unauth_destination smtpd_sasl_auth_enable = yes smtpd_sasl_local_domain = smtpd_sasl_security_options = noanonymous smtpd_tls_CAfile = /etc/ssl/certs/cacert.pem smtpd_tls_auth_only = no smtpd_tls_cert_file = /etc/ssl/certs/smtpd.crt smtpd_tls_key_file = /etc/ssl/private/smtpd.key smtpd_tls_loglevel = 1 smtpd_tls_received_header = yes smtpd_tls_security_level = may smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtpd_tls_session_cache_timeout = 3600s smtpd_use_tls = yes tls_random_source = dev:/dev/urandom transport_maps = hash:/etc/postfix/transport

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  • Using FiddlerCore to capture HTTP Requests with .NET

    - by Rick Strahl
    Over the last few weeks I’ve been working on my Web load testing utility West Wind WebSurge. One of the key components of a load testing tool is the ability to capture URLs effectively so that you can play them back later under load. One of the options in WebSurge for capturing URLs is to use its built-in capture tool which acts as an HTTP proxy to capture any HTTP and HTTPS traffic from most Windows HTTP clients, including Web Browsers as well as standalone Windows applications and services. To make this happen, I used Eric Lawrence’s awesome FiddlerCore library, which provides most of the functionality of his desktop Fiddler application, all rolled into an easy to use library that you can plug into your own applications. FiddlerCore makes it almost too easy to capture HTTP content! For WebSurge I needed to capture all HTTP traffic in order to capture the full HTTP request – URL, headers and any content posted by the client. The result of what I ended up creating is this semi-generic capture form: In this post I’m going to demonstrate how easy it is to use FiddlerCore to build this HTTP Capture Form.  If you want to jump right in here are the links to get Telerik’s Fiddler Core and the code for the demo provided here. FiddlerCore Download FiddlerCore on NuGet Show me the Code (WebSurge Integration code from GitHub) Download the WinForms Sample Form West Wind Web Surge (example implementation in live app) Note that FiddlerCore is bound by a license for commercial usage – see license.txt in the FiddlerCore distribution for details. Integrating FiddlerCore FiddlerCore is a library that simply plugs into your application. You can download it from the Telerik site and manually add the assemblies to your project, or you can simply install the NuGet package via:       PM> Install-Package FiddlerCore The library consists of the FiddlerCore.dll as well as a couple of support libraries (CertMaker.dll and BCMakeCert.dll) that are used for installing SSL certificates. I’ll have more on SSL captures and certificate installation later in this post. But first let’s see how easy it is to use FiddlerCore to capture HTTP content by looking at how to build the above capture form. Capturing HTTP Content Once the library is installed it’s super easy to hook up Fiddler functionality. Fiddler includes a number of static class methods on the FiddlerApplication object that can be called to hook up callback events as well as actual start monitoring HTTP URLs. In the following code directly lifted from WebSurge, I configure a few filter options on Form level object, from the user inputs shown on the form by assigning it to a capture options object. In the live application these settings are persisted configuration values, but in the demo they are one time values initialized and set on the form. Once these options are set, I hook up the AfterSessionComplete event to capture every URL that passes through the proxy after the request is completed and start up the Proxy service:void Start() { if (tbIgnoreResources.Checked) CaptureConfiguration.IgnoreResources = true; else CaptureConfiguration.IgnoreResources = false; string strProcId = txtProcessId.Text; if (strProcId.Contains('-')) strProcId = strProcId.Substring(strProcId.IndexOf('-') + 1).Trim(); strProcId = strProcId.Trim(); int procId = 0; if (!string.IsNullOrEmpty(strProcId)) { if (!int.TryParse(strProcId, out procId)) procId = 0; } CaptureConfiguration.ProcessId = procId; CaptureConfiguration.CaptureDomain = txtCaptureDomain.Text; FiddlerApplication.AfterSessionComplete += FiddlerApplication_AfterSessionComplete; FiddlerApplication.Startup(8888, true, true, true); } The key lines for FiddlerCore are just the last two lines of code that include the event hookup code as well as the Startup() method call. Here I only hook up to the AfterSessionComplete event but there are a number of other events that hook various stages of the HTTP request cycle you can also hook into. Other events include BeforeRequest, BeforeResponse, RequestHeadersAvailable, ResponseHeadersAvailable and so on. In my case I want to capture the request data and I actually have several options to capture this data. AfterSessionComplete is the last event that fires in the request sequence and it’s the most common choice to capture all request and response data. I could have used several other events, but AfterSessionComplete is one place where you can look both at the request and response data, so this will be the most common place to hook into if you’re capturing content. The implementation of AfterSessionComplete is responsible for capturing all HTTP request headers and it looks something like this:private void FiddlerApplication_AfterSessionComplete(Session sess) { // Ignore HTTPS connect requests if (sess.RequestMethod == "CONNECT") return; if (CaptureConfiguration.ProcessId > 0) { if (sess.LocalProcessID != 0 && sess.LocalProcessID != CaptureConfiguration.ProcessId) return; } if (!string.IsNullOrEmpty(CaptureConfiguration.CaptureDomain)) { if (sess.hostname.ToLower() != CaptureConfiguration.CaptureDomain.Trim().ToLower()) return; } if (CaptureConfiguration.IgnoreResources) { string url = sess.fullUrl.ToLower(); var extensions = CaptureConfiguration.ExtensionFilterExclusions; foreach (var ext in extensions) { if (url.Contains(ext)) return; } var filters = CaptureConfiguration.UrlFilterExclusions; foreach (var urlFilter in filters) { if (url.Contains(urlFilter)) return; } } if (sess == null || sess.oRequest == null || sess.oRequest.headers == null) return; string headers = sess.oRequest.headers.ToString(); var reqBody = sess.GetRequestBodyAsString(); // if you wanted to capture the response //string respHeaders = session.oResponse.headers.ToString(); //var respBody = session.GetResponseBodyAsString(); // replace the HTTP line to inject full URL string firstLine = sess.RequestMethod + " " + sess.fullUrl + " " + sess.oRequest.headers.HTTPVersion; int at = headers.IndexOf("\r\n"); if (at < 0) return; headers = firstLine + "\r\n" + headers.Substring(at + 1); string output = headers + "\r\n" + (!string.IsNullOrEmpty(reqBody) ? reqBody + "\r\n" : string.Empty) + Separator + "\r\n\r\n"; BeginInvoke(new Action<string>((text) => { txtCapture.AppendText(text); UpdateButtonStatus(); }), output); } The code starts by filtering out some requests based on the CaptureOptions I set before the capture is started. These options/filters are applied when requests actually come in. This is very useful to help narrow down the requests that are captured for playback based on options the user picked. I find it useful to limit requests to a certain domain for captures, as well as filtering out some request types like static resources – images, css, scripts etc. This is of course optional, but I think it’s a common scenario and WebSurge makes good use of this feature. AfterSessionComplete like other FiddlerCore events, provides a Session object parameter which contains all the request and response details. There are oRequest and oResponse objects to hold their respective data. In my case I’m interested in the raw request headers and body only, as you can see in the commented code you can also retrieve the response headers and body. Here the code captures the request headers and body and simply appends the output to the textbox on the screen. Note that the Fiddler events are asynchronous, so in order to display the content in the UI they have to be marshaled back the UI thread with BeginInvoke, which here simply takes the generated headers and appends it to the existing textbox test on the form. As each request is processed, the headers are captured and appended to the bottom of the textbox resulting in a Session HTTP capture in the format that Web Surge internally supports, which is basically raw request headers with a customized 1st HTTP Header line that includes the full URL rather than a server relative URL. When the capture is done the user can either copy the raw HTTP session to the clipboard, or directly save it to file. This raw capture format is the same format WebSurge and also Fiddler use to import/export request data. While this code is application specific, it demonstrates the kind of logic that you can easily apply to the request capture process, which is one of the reasonsof why FiddlerCore is so powerful. You get to choose what content you want to look up as part of your own application logic and you can then decide how to capture or use that data as part of your application. The actual captured data in this case is only a string. The user can edit the data by hand or in the the case of WebSurge, save it to disk and automatically open the captured session as a new load test. Stopping the FiddlerCore Proxy Finally to stop capturing requests you simply disconnect the event handler and call the FiddlerApplication.ShutDown() method:void Stop() { FiddlerApplication.AfterSessionComplete -= FiddlerApplication_AfterSessionComplete; if (FiddlerApplication.IsStarted()) FiddlerApplication.Shutdown(); } As you can see, adding HTTP capture functionality to an application is very straight forward. FiddlerCore offers tons of features I’m not even touching on here – I suspect basic captures are the most common scenario, but a lot of different things can be done with FiddlerCore’s simple API interface. Sky’s the limit! The source code for this sample capture form (WinForms) is provided as part of this article. Adding Fiddler Certificates with FiddlerCore One of the sticking points in West Wind WebSurge has been that if you wanted to capture HTTPS/SSL traffic, you needed to have the full version of Fiddler and have HTTPS decryption enabled. Essentially you had to use Fiddler to configure HTTPS decryption and the associated installation of the Fiddler local client certificate that is used for local decryption of incoming SSL traffic. While this works just fine, requiring to have Fiddler installed and then using a separate application to configure the SSL functionality isn’t ideal. Fortunately FiddlerCore actually includes the tools to register the Fiddler Certificate directly using FiddlerCore. Why does Fiddler need a Certificate in the first Place? Fiddler and FiddlerCore are essentially HTTP proxies which means they inject themselves into the HTTP conversation by re-routing HTTP traffic to a special HTTP port (8888 by default for Fiddler) and then forward the HTTP data to the original client. Fiddler injects itself as the system proxy in using the WinInet Windows settings  which are the same settings that Internet Explorer uses and that are configured in the Windows and Internet Explorer Internet Settings dialog. Most HTTP clients running on Windows pick up and apply these system level Proxy settings before establishing new HTTP connections and that’s why most clients automatically work once Fiddler – or FiddlerCore/WebSurge are running. For plain HTTP requests this just works – Fiddler intercepts the HTTP requests on the proxy port and then forwards them to the original port (80 for HTTP and 443 for SSL typically but it could be any port). For SSL however, this is not quite as simple – Fiddler can easily act as an HTTPS/SSL client to capture inbound requests from the server, but when it forwards the request to the client it has to also act as an SSL server and provide a certificate that the client trusts. This won’t be the original certificate from the remote site, but rather a custom local certificate that effectively simulates an SSL connection between the proxy and the client. If there is no custom certificate configured for Fiddler the SSL request fails with a certificate validation error. The key for this to work is that a custom certificate has to be installed that the HTTPS client trusts on the local machine. For a much more detailed description of the process you can check out Eric Lawrence’s blog post on Certificates. If you’re using the desktop version of Fiddler you can install a local certificate into the Windows certificate store. Fiddler proper does this from the Options menu: This operation does several things: It installs the Fiddler Root Certificate It sets trust to this Root Certificate A new client certificate is generated for each HTTPS site monitored Certificate Installation with FiddlerCore You can also provide this same functionality using FiddlerCore which includes a CertMaker class. Using CertMaker is straight forward to use and it provides an easy way to create some simple helpers that can install and uninstall a Fiddler Root certificate:public static bool InstallCertificate() { if (!CertMaker.rootCertExists()) { if (!CertMaker.createRootCert()) return false; if (!CertMaker.trustRootCert()) return false; } return true; } public static bool UninstallCertificate() { if (CertMaker.rootCertExists()) { if (!CertMaker.removeFiddlerGeneratedCerts(true)) return false; } return true; } InstallCertificate() works by first checking whether the root certificate is already installed and if it isn’t goes ahead and creates a new one. The process of creating the certificate is a two step process – first the actual certificate is created and then it’s moved into the certificate store to become trusted. I’m not sure why you’d ever split these operations up since a cert created without trust isn’t going to be of much value, but there are two distinct steps. When you trigger the trustRootCert() method, a message box will pop up on the desktop that lets you know that you’re about to trust a local private certificate. This is a security feature to ensure that you really want to trust the Fiddler root since you are essentially installing a man in the middle certificate. It’s quite safe to use this generated root certificate, because it’s been specifically generated for your machine and thus is not usable from external sources, the only way to use this certificate in a trusted way is from the local machine. IOW, unless somebody has physical access to your machine, there’s no useful way to hijack this certificate and use it for nefarious purposes (see Eric’s post for more details). Once the Root certificate has been installed, FiddlerCore/Fiddler create new certificates for each site that is connected to with HTTPS. You can end up with quite a few temporary certificates in your certificate store. To uninstall you can either use Fiddler and simply uncheck the Decrypt HTTPS traffic option followed by the remove Fiddler certificates button, or you can use FiddlerCore’s CertMaker.removeFiddlerGeneratedCerts() which removes the root cert and any of the intermediary certificates Fiddler created. Keep in mind that when you uninstall you uninstall the certificate for both FiddlerCore and Fiddler, so use UninstallCertificate() with care and realize that you might affect the Fiddler application’s operation by doing so as well. When to check for an installed Certificate Note that the check to see if the root certificate exists is pretty fast, while the actual process of installing the certificate is a relatively slow operation that even on a fast machine takes a few seconds. Further the trust operation pops up a message box so you probably don’t want to install the certificate repeatedly. Since the check for the root certificate is fast, you can easily put a call to InstallCertificate() in any capture startup code – in which case the certificate installation only triggers when a certificate is in fact not installed. Personally I like to make certificate installation explicit – just like Fiddler does, so in WebSurge I use a small drop down option on the menu to install or uninstall the SSL certificate:   This code calls the InstallCertificate and UnInstallCertificate functions respectively – the experience with this is similar to what you get in Fiddler with the extra dialog box popping up to prompt confirmation for installation of the root certificate. Once the cert is installed you can then capture SSL requests. There’s a gotcha however… Gotcha: FiddlerCore Certificates don’t stick by Default When I originally tried to use the Fiddler certificate installation I ran into an odd problem. I was able to install the certificate and immediately after installation was able to capture HTTPS requests. Then I would exit the application and come back in and try the same HTTPS capture again and it would fail due to a missing certificate. CertMaker.rootCertExists() would return false after every restart and if re-installed the certificate a new certificate would get added to the certificate store resulting in a bunch of duplicated root certificates with different keys. What the heck? CertMaker and BcMakeCert create non-sticky CertificatesI turns out that FiddlerCore by default uses different components from what the full version of Fiddler uses. Fiddler uses a Windows utility called MakeCert.exe to create the Fiddler Root certificate. FiddlerCore however installs the CertMaker.dll and BCMakeCert.dll assemblies, which use a different crypto library (Bouncy Castle) for certificate creation than MakeCert.exe which uses the Windows Crypto API. The assemblies provide support for non-windows operation for Fiddler under Mono, as well as support for some non-Windows certificate platforms like iOS and Android for decryption. The bottom line is that the FiddlerCore provided bouncy castle assemblies are not sticky by default as the certificates created with them are not cached as they are in Fiddler proper. To get certificates to ‘stick’ you have to explicitly cache the certificates in Fiddler’s internal preferences. A cache aware version of InstallCertificate looks something like this:public static bool InstallCertificate() { if (!CertMaker.rootCertExists()) { if (!CertMaker.createRootCert()) return false; if (!CertMaker.trustRootCert()) return false; App.Configuration.UrlCapture.Cert = FiddlerApplication.Prefs.GetStringPref("fiddler.certmaker.bc.cert", null); App.Configuration.UrlCapture.Key = FiddlerApplication.Prefs.GetStringPref("fiddler.certmaker.bc.key", null); } return true; } public static bool UninstallCertificate() { if (CertMaker.rootCertExists()) { if (!CertMaker.removeFiddlerGeneratedCerts(true)) return false; } App.Configuration.UrlCapture.Cert = null; App.Configuration.UrlCapture.Key = null; return true; } In this code I store the Fiddler cert and private key in an application configuration settings that’s stored with the application settings (App.Configuration.UrlCapture object). These settings automatically persist when WebSurge is shut down. The values are read out of Fiddler’s internal preferences store which is set after a new certificate has been created. Likewise I clear out the configuration settings when the certificate is uninstalled. In order for these setting to be used you have to also load the configuration settings into the Fiddler preferences *before* a call to rootCertExists() is made. I do this in the capture form’s constructor:public FiddlerCapture(StressTestForm form) { InitializeComponent(); CaptureConfiguration = App.Configuration.UrlCapture; MainForm = form; if (!string.IsNullOrEmpty(App.Configuration.UrlCapture.Cert)) { FiddlerApplication.Prefs.SetStringPref("fiddler.certmaker.bc.key", App.Configuration.UrlCapture.Key); FiddlerApplication.Prefs.SetStringPref("fiddler.certmaker.bc.cert", App.Configuration.UrlCapture.Cert); }} This is kind of a drag to do and not documented anywhere that I could find, so hopefully this will save you some grief if you want to work with the stock certificate logic that installs with FiddlerCore. MakeCert provides sticky Certificates and the same functionality as Fiddler But there’s actually an easier way. If you want to skip the above Fiddler preference configuration code in your application you can choose to distribute MakeCert.exe instead of certmaker.dll and bcmakecert.dll. When you use MakeCert.exe, the certificates settings are stored in Windows so they are available without any custom configuration inside of your application. It’s easier to integrate and as long as you run on Windows and you don’t need to support iOS or Android devices is simply easier to deal with. To integrate into your project, you can remove the reference to CertMaker.dll (and the BcMakeCert.dll assembly) from your project. Instead copy MakeCert.exe into your output folder. To make sure MakeCert.exe gets pushed out, include MakeCert.exe in your project and set the Build Action to None, and Copy to Output Directory to Copy if newer. Note that the CertMaker.dll reference in the project has been removed and on disk the files for Certmaker.dll, as well as the BCMakeCert.dll files on disk. Keep in mind that these DLLs are resources of the FiddlerCore NuGet package, so updating the package may end up pushing those files back into your project. Once MakeCert.exe is distributed FiddlerCore checks for it first before using the assemblies so as long as MakeCert.exe exists it’ll be used for certificate creation (at least on Windows). Summary FiddlerCore is a pretty sweet tool, and it’s absolutely awesome that we get to plug in most of the functionality of Fiddler right into our own applications. A few years back I tried to build this sort of functionality myself for an app and ended up giving up because it’s a big job to get HTTP right – especially if you need to support SSL. FiddlerCore now provides that functionality as a turnkey solution that can be plugged into your own apps easily. The only downside is FiddlerCore’s documentation for more advanced features like certificate installation which is pretty sketchy. While for the most part FiddlerCore’s feature set is easy to work with without any documentation, advanced features are often not intuitive to gleam by just using Intellisense or the FiddlerCore help file reference (which is not terribly useful). While Eric Lawrence is very responsive on his forum and on Twitter, there simply isn’t much useful documentation on Fiddler/FiddlerCore available online. If you run into trouble the forum is probably the first place to look and then ask a question if you can’t find the answer. The best documentation you can find is Eric’s Fiddler Book which covers a ton of functionality of Fiddler and FiddlerCore. The book is a great reference to Fiddler’s feature set as well as providing great insights into the HTTP protocol. The second half of the book that gets into the innards of HTTP is an excellent read for anybody who wants to know more about some of the more arcane aspects and special behaviors of HTTP – it’s well worth the read. While the book has tons of information in a very readable format, it’s unfortunately not a great reference as it’s hard to find things in the book and because it’s not available online you can’t electronically search for the great content in it. But it’s hard to complain about any of this given the obvious effort and love that’s gone into this awesome product for all of these years. A mighty big thanks to Eric Lawrence  for having created this useful tool that so many of us use all the time, and also to Telerik for picking up Fiddler/FiddlerCore and providing Eric the resources to support and improve this wonderful tool full time and keeping it free for all. Kudos! Resources FiddlerCore Download FiddlerCore NuGet Fiddler Capture Sample Form Fiddler Capture Form in West Wind WebSurge (GitHub) Eric Lawrence’s Fiddler Book© Rick Strahl, West Wind Technologies, 2005-2014Posted in .NET  HTTP   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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  • Why is Java EE 6 better than Spring ?

    - by arungupta
    Java EE 6 was released over 2 years ago and now there are 14 compliant application servers. In all my talks around the world, a question that is frequently asked is Why should I use Java EE 6 instead of Spring ? There are already several blogs covering that topic: Java EE wins over Spring by Bill Burke Why will I use Java EE instead of Spring in new Enterprise Java projects in 2012 ? by Kai Waehner (more discussion on TSS) Spring to Java EE migration (Part 1 and 2, 3 and 4 coming as well) by David Heffelfinger Spring to Java EE - A Migration Experience by Lincoln Baxter Migrating Spring to Java EE 6 by Bert Ertman and Paul Bakker at NLJUG Moving from Spring to Java EE 6 - The Age of Frameworks is Over at TSS Java EE vs Spring Shootout by Rohit Kelapure and Reza Rehman at JavaOne 2011 Java EE 6 and the Ewoks by Murat Yener Definite excuse to avoid Spring forever - Bert Ertman and Arun Gupta I will try to share my perspective in this blog. First of all, I'd like to start with a note: Thank you Spring framework for filling the interim gap and providing functionality that is now included in the mainstream Java EE 6 application servers. The Java EE platform has evolved over the years learning from frameworks like Spring and provides all the functionality to build an enterprise application. Thank you very much Spring framework! While Spring was revolutionary in its time and is still very popular and quite main stream in the same way Struts was circa 2003, it really is last generation's framework - some people are even calling it legacy. However my theory is "code is king". So my approach is to build/take a simple Hello World CRUD application in Java EE 6 and Spring and compare the deployable artifacts. I started looking at the official tutorial Developing a Spring Framework MVC Application Step-by-Step but it is using the older version 2.5. I wasn't able to find any updated version in the current 3.1 release. Next, I downloaded Spring Tool Suite and thought that would provide some template samples to get started. A least a quick search did not show any handy tutorials - either video or text-based. So I searched and found a link to their SVN repository at src.springframework.org/svn/spring-samples/. I tried the "mvc-basic" sample and the generated WAR file was 4.43 MB. While it was named a "basic" sample it seemed to come with 19 different libraries bundled but it was what I could find: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/joda-time-jsptags-1.0.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar And it is not even using any database! The app deployed fine on GlassFish 3.1.2 but the "@Controller Example" link did not work as it was missing the context root. With a bit of tweaking I could deploy the application and assume that the account got created because no error was displayed in the browser or server log. Next I generated the WAR for "mvc-ajax" and the 5.1 MB WAR had 20 JARs (1 removed, 2 added): ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.6.4.jar./WEB-INF/lib/jackson-mapper-asl-1.6.4.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar 2 more JARs for just doing Ajax. Anyway, deploying this application gave the following error: Caused by: java.lang.NoSuchMethodError: org.codehaus.jackson.map.SerializationConfig.<init>(Lorg/codehaus/jackson/map/ClassIntrospector;Lorg/codehaus/jackson/map/AnnotationIntrospector;Lorg/codehaus/jackson/map/introspect/VisibilityChecker;Lorg/codehaus/jackson/map/jsontype/SubtypeResolver;)V    at org.springframework.samples.mvc.ajax.json.ConversionServiceAwareObjectMapper.<init>(ConversionServiceAwareObjectMapper.java:20)    at org.springframework.samples.mvc.ajax.json.JacksonConversionServiceConfigurer.postProcessAfterInitialization(JacksonConversionServiceConfigurer.java:40)    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:407) Seems like some incorrect repos in the "pom.xml". Next one is "mvc-showcase" and the 6.49 MB WAR now has 28 JARs as shown below: ./WEB-INF/lib/aopalliance-1.0.jar./WEB-INF/lib/aspectjrt-1.6.10.jar./WEB-INF/lib/commons-fileupload-1.2.2.jar./WEB-INF/lib/commons-io-2.0.1.jar./WEB-INF/lib/el-api-2.2.jar./WEB-INF/lib/hibernate-validator-4.1.0.Final.jar./WEB-INF/lib/jackson-core-asl-1.8.1.jar./WEB-INF/lib/jackson-mapper-asl-1.8.1.jar./WEB-INF/lib/javax.inject-1.jar./WEB-INF/lib/jcl-over-slf4j-1.6.1.jar./WEB-INF/lib/jdom-1.0.jar./WEB-INF/lib/joda-time-1.6.2.jar./WEB-INF/lib/jstl-api-1.2.jar./WEB-INF/lib/jstl-impl-1.2.jar./WEB-INF/lib/log4j-1.2.16.jar./WEB-INF/lib/rome-1.0.0.jar./WEB-INF/lib/slf4j-api-1.6.1.jar./WEB-INF/lib/slf4j-log4j12-1.6.1.jar./WEB-INF/lib/spring-aop-3.1.0.RELEASE.jar./WEB-INF/lib/spring-asm-3.1.0.RELEASE.jar./WEB-INF/lib/spring-beans-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-3.1.0.RELEASE.jar./WEB-INF/lib/spring-context-support-3.1.0.RELEASE.jar./WEB-INF/lib/spring-core-3.1.0.RELEASE.jar./WEB-INF/lib/spring-expression-3.1.0.RELEASE.jar./WEB-INF/lib/spring-web-3.1.0.RELEASE.jar./WEB-INF/lib/spring-webmvc-3.1.0.RELEASE.jar./WEB-INF/lib/validation-api-1.0.0.GA.jar The app at least deployed and showed results this time. But still no database! Next I tried building "jpetstore" and got the error: [ERROR] Failed to execute goal on project org.springframework.samples.jpetstore:Could not resolve dependencies for project org.springframework.samples:org.springframework.samples.jpetstore:war:1.0.0-SNAPSHOT: Failed to collect dependencies for [commons-fileupload:commons-fileupload:jar:1.2.1 (compile), org.apache.struts:com.springsource.org.apache.struts:jar:1.2.9 (compile), javax.xml.rpc:com.springsource.javax.xml.rpc:jar:1.1.0 (compile), org.apache.commons:com.springsource.org.apache.commons.dbcp:jar:1.2.2.osgi (compile), commons-io:commons-io:jar:1.3.2 (compile), hsqldb:hsqldb:jar:1.8.0.7 (compile), org.apache.tiles:tiles-core:jar:2.2.0 (compile), org.apache.tiles:tiles-jsp:jar:2.2.0 (compile), org.tuckey:urlrewritefilter:jar:3.1.0 (compile), org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-orm:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework:spring-context-support:jar:3.0.0.BUILD-SNAPSHOT (compile), org.springframework.webflow:spring-js:jar:2.0.7.RELEASE (compile), org.apache.ibatis:com.springsource.com.ibatis:jar:2.3.4.726 (runtime), com.caucho:com.springsource.com.caucho:jar:3.2.1 (compile), org.apache.axis:com.springsource.org.apache.axis:jar:1.4.0 (compile), javax.wsdl:com.springsource.javax.wsdl:jar:1.6.1 (compile), javax.servlet:jstl:jar:1.2 (runtime), org.aspectj:aspectjweaver:jar:1.6.5 (compile), javax.servlet:servlet-api:jar:2.5 (provided), javax.servlet.jsp:jsp-api:jar:2.1 (provided), junit:junit:jar:4.6 (test)]: Failed to read artifact descriptor for org.springframework:spring-webmvc:jar:3.0.0.BUILD-SNAPSHOT: Could not transfer artifact org.springframework:spring-webmvc:pom:3.0.0.BUILD-SNAPSHOT from/to JBoss repository (http://repository.jboss.com/maven2): Access denied to: http://repository.jboss.com/maven2/org/springframework/spring-webmvc/3.0.0.BUILD-SNAPSHOT/spring-webmvc-3.0.0.BUILD-SNAPSHOT.pom It appears the sample is broken - maybe I was pulling from the wrong repository - would be great if someone were to point me at a good target to use here. With a 50% hit on samples in this repository, I started searching through numerous blogs, most of which have either outdated information (using XML-heavy Spring 2.5), some piece of configuration (which is a typical "feature" of Spring) is missing, or too much complexity in the sample. I finally found this blog that worked like a charm. This blog creates a trivial Spring MVC 3 application using Hibernate and MySQL. This application performs CRUD operations on a single table in a database using typical Spring technologies.  I downloaded the sample code from the blog, deployed it on GlassFish 3.1.2 and could CRUD the "person" entity. The source code for this application can be downloaded here. More details on the application statistics below. And then I built a similar CRUD application in Java EE 6 using NetBeans wizards in a couple of minutes. The source code for the application can be downloaded here and the WAR here. The Spring Source Tool Suite may also offer similar wizard-driven capabilities but this blog focus primarily on comparing the runtimes. The lack of STS tutorials was slightly disappointing as well. NetBeans however has tons of text-based and video tutorials and tons of material even by the community. One more bit on the download size of tools bundle ... NetBeans 7.1.1 "All" is 211 MB (which includes GlassFish and Tomcat) Spring Tool Suite  2.9.0 is 347 MB (~ 65% bigger) This blog is not about the tooling comparison so back to the Java EE 6 version of the application .... In order to run the Java EE version on GlassFish, copy the MySQL Connector/J to glassfish3/glassfish/domains/domain1/lib/ext directory and create a JDBC connection pool and JDBC resource as: ./bin/asadmin create-jdbc-connection-pool --datasourceclassname \\ com.mysql.jdbc.jdbc2.optional.MysqlDataSource --restype \\ javax.sql.DataSource --property \\ portNumber=3306:user=mysql:password=mysql:databaseName=mydatabase \\ myConnectionPool ./bin/asadmin create-jdbc-resource --connectionpoolid myConnectionPool jdbc/myDataSource I generated WARs for the two projects and the table below highlights some differences between them: Java EE 6 Spring WAR File Size 0.021030 MB 10.87 MB (~516x) Number of files 20 53 (> 2.5x) Bundled libraries 0 36 Total size of libraries 0 12.1 MB XML files 3 5 LoC in XML files 50 (11 + 15 + 24) 129 (27 + 46 + 16 + 11 + 19) (~ 2.5x) Total .properties files 1 Bundle.properties 2 spring.properties, log4j.properties Cold Deploy 5,339 ms 11,724 ms Second Deploy 481 ms 6,261 ms Third Deploy 528 ms 5,484 ms Fourth Deploy 484 ms 5,576 ms Runtime memory ~73 MB ~101 MB Some points worth highlighting from the table ... 516x WAR file, 10x deployment time - With 12.1 MB of libraries (for a very basic application) bundled in your application, the WAR file size and the deployment time will naturally go higher. The WAR file for Spring-based application is 516x bigger and the deployment time is double during the first deployment and ~ 10x during subsequent deployments. The Java EE 6 application is fully portable and will run on any Java EE 6 compliant application server. 36 libraries in the WAR - There are 14 Java EE 6 compliant application servers today. Each of those servers provide all the functionality like transactions, dependency injection, security, persistence, etc typically required of an enterprise or web application. There is no need to bundle 36 libraries worth 12.1 MB for a trivial CRUD application. These 14 compliant application servers provide all the functionality baked in. Now you can also deploy these libraries in the container but then you don't get the "portability" offered by Spring in that case. Does your typical Spring deployment actually do that ? 3x LoC in XML - The number of XML files is about 1.6x and the LoC is ~ 2.5x. So much XML seems circa 2003 when the Java language had no annotations. The XML files can be further reduced, e.g. faces-config.xml can be replaced without providing i18n, but I just want to compare stock applications. Memory usage - Both the applications were deployed on default GlassFish 3.1.2 installation and any additional memory consumed as part of deployment/access was attributed to the application. This is by no means scientific but at least provides an initial ballpark. This area definitely needs more investigation. Another table that compares typical Java EE 6 compliant application servers and the custom-stack created for a Spring application ... Java EE 6 Spring Web Container ? 53 MB (tcServer 2.6.3 Developer Edition) Security ? 12 MB (Spring Security 3.1.0) Persistence ? 6.3 MB (Hibernate 4.1.0, required) Dependency Injection ? 5.3 MB (Framework) Web Services ? 796 KB (Spring WS 2.0.4) Messaging ? 3.4 MB (RabbitMQ Server 2.7.1) 936 KB (Java client 936) OSGi ? 1.3 MB (Spring OSGi 1.2.1) GlassFish and WebLogic (starting at 33 MB) 83.3 MB There are differentiating factors on both the stacks. But most of the functionality like security, persistence, and dependency injection is baked in a Java EE 6 compliant application server but needs to be individually managed and patched for a Spring application. This very quickly leads to a "stack explosion". The Java EE 6 servers are tested extensively on a variety of platforms in different combinations whereas a Spring application developer is responsible for testing with different JDKs, Operating Systems, Versions, Patches, etc. Oracle has both the leading OSS lightweight server with GlassFish and the leading enterprise Java server with WebLogic Server, both Java EE 6 and both with lightweight deployment options. The Web Container offered as part of a Java EE 6 application server not only deploys your enterprise Java applications but also provide operational management, diagnostics, and mission-critical capabilities required by your applications. The Java EE 6 platform also introduced the Web Profile which is a subset of the specifications from the entire platform. It is targeted at developers of modern web applications offering a reasonably complete stack, composed of standard APIs, and is capable out-of-the-box of addressing the needs of a large class of Web applications. As your applications grow, the stack can grow to the full Java EE 6 platform. The GlassFish Server Web Profile starting at 33MB (smaller than just the non-standard tcServer) provides most of the functionality typically required by a web application. WebLogic provides battle-tested functionality for a high throughput, low latency, and enterprise grade web application. No individual managing or patching, all tested and commercially supported for you! Note that VMWare does have a server, tcServer, but it is non-standard and not even certified to the level of the standard Web Profile most customers expect these days. Customers who choose this risk proprietary lock-in since VMWare does not seem to want to formally certify with either Java EE 6 Enterprise Platform or with Java EE 6 Web Profile but of course it would be great if they were to join the community and help their customers reduce the risk of deploying on VMWare software. Some more points to help you decide choose between Java EE 6 and Spring ... Freedom to choose container - There are 14 Java EE 6 compliant application servers today, with a variety of open source and commercial offerings. A Java EE 6 application can be deployed on any of those containers. So if you deployed your application on GlassFish today and would like to scale up with your demands then you can deploy the same application to WebLogic. And because of the portability of a Java EE 6 application, you can even take it a different vendor altogether. Spring requires a runtime which could be any of these app servers as well. But why use Spring when all the required functionality is already baked into the application server itself ? Spring also has a different definition of portability where they claim to bundle all the libraries in the WAR file and move to any application server. But we saw earlier how bloated that archive could be. The equivalent features in Spring runtime offerings (mainly tcServer) are not all open source, not as mature, and often require manual assembly.  Vendor choice - The Java EE 6 platform is created using the Java Community Process where all the big players like Oracle, IBM, RedHat, and Apache are conritbuting to make the platform successful. Each application server provides the basic Java EE 6 platform compliance and has its own competitive offerings. This allows you to choose an application server for deploying your Java EE 6 applications. If you are not happy with the support or feature of one vendor then you can move your application to a different vendor because of the portability promise offered by the platform. Spring is a set of products from a single company, one price book, one support organization, one sustaining organization, one sales organization, etc. If any of those cause a customer headache, where do you go ? Java EE, backed by multiple vendors, is a safer bet for those that are risk averse. Production support - With Spring, typically you need to get support from two vendors - VMWare and the container provider. With Java EE 6, all of this is typically provided by one vendor. For example, Oracle offers commercial support from systems, operating systems, JDK, application server, and applications on top of them. VMWare certainly offers complete production support but do you really want to put all your eggs in one basket ? Do you really use tcServer ? ;-) Maintainability - With Spring, you are likely building your own distribution with multiple JAR files, integrating, patching, versioning, etc of all those components. Spring's claim is that multiple JAR files allow you to go à la carte and pick the latest versions of different components. But who is responsible for testing whether all these versions work together ? Yep, you got it, its YOU! If something does not work, who patches and maintains the JARs ? Of course, you! Commercial support for such a configuration ? On your own! The Java EE application servers manage all of this for you and provide a well-tested and commercially supported bundle. While it is always good to realize that there is something new and improved that updates and replaces older frameworks like Spring, the good news is not only does a Java EE 6 container offer what is described here, most also will let you deploy and run your Spring applications on them while you go through an upgrade to a more modern architecture. End result, you get the best of both worlds - keeping your legacy investment but moving to a more agile, lightweight world of Java EE 6. A message to the Spring lovers ... The complexity in J2EE 1.2, 1.3, and 1.4 led to the genesis of Spring but that was in 2004. This is 2012 and the name has changed to "Java EE 6" :-) There are tons of improvements in the Java EE platform to make it easy-to-use and powerful. Some examples: Adding @Stateless on a POJO makes it an EJB EJBs can be packaged in a WAR with no special packaging or deployment descriptors "web.xml" and "faces-config.xml" are optional in most of the common cases Typesafe dependency injection is now part of the Java EE platform Add @Path on a POJO allows you to publish it as a RESTful resource EJBs can be used as backing beans for Facelets-driven JSF pages providing full MVC Java EE 6 WARs are known to be kilobytes in size and deployed in milliseconds Tons of other simplifications in the platform and application servers So if you moved away from J2EE to Spring many years ago and have not looked at Java EE 6 (which has been out since Dec 2009) then you should definitely try it out. Just be at least aware of what other alternatives are available instead of restricting yourself to one stack. Here are some workshops and screencasts worth trying: screencast #37 shows how to build an end-to-end application using NetBeans screencast #36 builds the same application using Eclipse javaee-lab-feb2012.pdf is a 3-4 hours self-paced hands-on workshop that guides you to build a comprehensive Java EE 6 application using NetBeans Each city generally has a "spring cleanup" program every year. It allows you to clean up the mess from your house. For your software projects, you don't need to wait for an annual event, just get started and reduce the technical debt now! Move away from your legacy Spring-based applications to a lighter and more modern approach of building enterprise Java applications using Java EE 6. Watch this beautiful presentation that explains how to migrate from Spring -> Java EE 6: List of files in the Java EE 6 project: ./index.xhtml./META-INF./person./person/Create.xhtml./person/Edit.xhtml./person/List.xhtml./person/View.xhtml./resources./resources/css./resources/css/jsfcrud.css./template.xhtml./WEB-INF./WEB-INF/classes./WEB-INF/classes/Bundle.properties./WEB-INF/classes/META-INF./WEB-INF/classes/META-INF/persistence.xml./WEB-INF/classes/org./WEB-INF/classes/org/javaee./WEB-INF/classes/org/javaee/javaeemysql./WEB-INF/classes/org/javaee/javaeemysql/AbstractFacade.class./WEB-INF/classes/org/javaee/javaeemysql/Person.class./WEB-INF/classes/org/javaee/javaeemysql/Person_.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$1.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController$PersonControllerConverter.class./WEB-INF/classes/org/javaee/javaeemysql/PersonController.class./WEB-INF/classes/org/javaee/javaeemysql/PersonFacade.class./WEB-INF/classes/org/javaee/javaeemysql/util./WEB-INF/classes/org/javaee/javaeemysql/util/JsfUtil.class./WEB-INF/classes/org/javaee/javaeemysql/util/PaginationHelper.class./WEB-INF/faces-config.xml./WEB-INF/web.xml List of files in the Spring 3.x project: ./META-INF ./META-INF/MANIFEST.MF./WEB-INF./WEB-INF/applicationContext.xml./WEB-INF/classes./WEB-INF/classes/log4j.properties./WEB-INF/classes/org./WEB-INF/classes/org/krams ./WEB-INF/classes/org/krams/tutorial ./WEB-INF/classes/org/krams/tutorial/controller ./WEB-INF/classes/org/krams/tutorial/controller/MainController.class ./WEB-INF/classes/org/krams/tutorial/domain ./WEB-INF/classes/org/krams/tutorial/domain/Person.class ./WEB-INF/classes/org/krams/tutorial/service ./WEB-INF/classes/org/krams/tutorial/service/PersonService.class ./WEB-INF/hibernate-context.xml ./WEB-INF/hibernate.cfg.xml ./WEB-INF/jsp ./WEB-INF/jsp/addedpage.jsp ./WEB-INF/jsp/addpage.jsp ./WEB-INF/jsp/deletedpage.jsp ./WEB-INF/jsp/editedpage.jsp ./WEB-INF/jsp/editpage.jsp ./WEB-INF/jsp/personspage.jsp ./WEB-INF/lib ./WEB-INF/lib/antlr-2.7.6.jar ./WEB-INF/lib/aopalliance-1.0.jar ./WEB-INF/lib/c3p0-0.9.1.2.jar ./WEB-INF/lib/cglib-nodep-2.2.jar ./WEB-INF/lib/commons-beanutils-1.8.3.jar ./WEB-INF/lib/commons-collections-3.2.1.jar ./WEB-INF/lib/commons-digester-2.1.jar ./WEB-INF/lib/commons-logging-1.1.1.jar ./WEB-INF/lib/dom4j-1.6.1.jar ./WEB-INF/lib/ejb3-persistence-1.0.2.GA.jar ./WEB-INF/lib/hibernate-annotations-3.4.0.GA.jar ./WEB-INF/lib/hibernate-commons-annotations-3.1.0.GA.jar ./WEB-INF/lib/hibernate-core-3.3.2.GA.jar ./WEB-INF/lib/javassist-3.7.ga.jar ./WEB-INF/lib/jstl-1.1.2.jar ./WEB-INF/lib/jta-1.1.jar ./WEB-INF/lib/junit-4.8.1.jar ./WEB-INF/lib/log4j-1.2.14.jar ./WEB-INF/lib/mysql-connector-java-5.1.14.jar ./WEB-INF/lib/persistence-api-1.0.jar ./WEB-INF/lib/slf4j-api-1.6.1.jar ./WEB-INF/lib/slf4j-log4j12-1.6.1.jar ./WEB-INF/lib/spring-aop-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-asm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-beans-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-context-support-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-core-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-expression-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-jdbc-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-orm-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-tx-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-web-3.0.5.RELEASE.jar ./WEB-INF/lib/spring-webmvc-3.0.5.RELEASE.jar ./WEB-INF/lib/standard-1.1.2.jar ./WEB-INF/lib/xml-apis-1.0.b2.jar ./WEB-INF/spring-servlet.xml ./WEB-INF/spring.properties ./WEB-INF/web.xml So, are you excited about Java EE 6 ? Want to get started now ? Here are some resources: Java EE 6 SDK (including runtime, samples, tutorials etc) GlassFish Server Open Source Edition 3.1.2 (Community) Oracle GlassFish Server 3.1.2 (Commercial) Java EE 6 using WebLogic 12c and NetBeans (Video) Java EE 6 with NetBeans and GlassFish (Video) Java EE with Eclipse and GlassFish (Video)

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  • Top things web developers should know about the Visual Studio 2013 release

    - by Jon Galloway
    ASP.NET and Web Tools for Visual Studio 2013 Release NotesASP.NET and Web Tools for Visual Studio 2013 Release NotesSummary for lazy readers: Visual Studio 2013 is now available for download on the Visual Studio site and on MSDN subscriber downloads) Visual Studio 2013 installs side by side with Visual Studio 2012 and supports round-tripping between Visual Studio versions, so you can try it out without committing to a switch Visual Studio 2013 ships with the new version of ASP.NET, which includes ASP.NET MVC 5, ASP.NET Web API 2, Razor 3, Entity Framework 6 and SignalR 2.0 The new releases ASP.NET focuses on One ASP.NET, so core features and web tools work the same across the platform (e.g. adding ASP.NET MVC controllers to a Web Forms application) New core features include new templates based on Bootstrap, a new scaffolding system, and a new identity system Visual Studio 2013 is an incredible editor for web files, including HTML, CSS, JavaScript, Markdown, LESS, Coffeescript, Handlebars, Angular, Ember, Knockdown, etc. Top links: Visual Studio 2013 content on the ASP.NET site are in the standard new releases area: http://www.asp.net/vnext ASP.NET and Web Tools for Visual Studio 2013 Release Notes Short intro videos on the new Visual Studio web editor features from Scott Hanselman and Mads Kristensen Announcing release of ASP.NET and Web Tools for Visual Studio 2013 post on the official .NET Web Development and Tools Blog Scott Guthrie's post: Announcing the Release of Visual Studio 2013 and Great Improvements to ASP.NET and Entity Framework Okay, for those of you who are still with me, let's dig in a bit. Quick web dev notes on downloading and installing Visual Studio 2013 I found Visual Studio 2013 to be a pretty fast install. According to Brian Harry's release post, installing over pre-release versions of Visual Studio is supported.  I've installed the release version over pre-release versions, and it worked fine. If you're only going to be doing web development, you can speed up the install if you just select Web Developer tools. Of course, as a good Microsoft employee, I'll mention that you might also want to install some of those other features, like the Store apps for Windows 8 and the Windows Phone 8.0 SDK, but they do download and install a lot of other stuff (e.g. the Windows Phone SDK sets up Hyper-V and downloads several GB's of VM's). So if you're planning just to do web development for now, you can pick just the Web Developer Tools and install the other stuff later. If you've got a fast internet connection, I recommend using the web installer instead of downloading the ISO. The ISO includes all the features, whereas the web installer just downloads what you're installing. Visual Studio 2013 development settings and color theme When you start up Visual Studio, it'll prompt you to pick some defaults. These are totally up to you -whatever suits your development style - and you can change them later. As I said, these are completely up to you. I recommend either the Web Development or Web Development (Code Only) settings. The only real difference is that Code Only hides the toolbars, and you can switch between them using Tools / Import and Export Settings / Reset. Web Development settings Web Development (code only) settings Usually I've just gone with Web Development (code only) in the past because I just want to focus on the code, although the Standard toolbar does make it easier to switch default web browsers. More on that later. Color theme Sigh. Okay, everyone's got their favorite colors. I alternate between Light and Dark depending on my mood, and I personally like how the low contrast on the window chrome in those themes puts the emphasis on my code rather than the tabs and toolbars. I know some people got pretty worked up over that, though, and wanted the blue theme back. I personally don't like it - it reminds me of ancient versions of Visual Studio that I don't want to think about anymore. So here's the thing: if you install Visual Studio Ultimate, it defaults to Blue. The other versions default to Light. If you use Blue, I won't criticize you - out loud, that is. You can change themes really easily - either Tools / Options / Environment / General, or the smart way: ctrl+q for quick launch, then type Theme and hit enter. Signing in During the first run, you'll be prompted to sign in. You don't have to - you can click the "Not now, maybe later" link at the bottom of that dialog. I recommend signing in, though. It's not hooked in with licensing or tracking the kind of code you write to sell you components. It is doing good things, like  syncing your Visual Studio settings between computers. More about that here. So, you don't have to, but I sure do. Overview of shiny new things in ASP.NET land There are a lot of good new things in ASP.NET. I'll list some of my favorite here, but you can read more on the ASP.NET site. One ASP.NET You've heard us talk about this for a while. The idea is that options are good, but choice can be a burden. When you start a new ASP.NET project, why should you have to make a tough decision - with long-term consequences - about how your application will work? If you want to use ASP.NET Web Forms, but have the option of adding in ASP.NET MVC later, why should that be hard? It's all ASP.NET, right? Ideally, you'd just decide that you want to use ASP.NET to build sites and services, and you could use the appropriate tools (the green blocks below) as you needed them. So, here it is. When you create a new ASP.NET application, you just create an ASP.NET application. Next, you can pick from some templates to get you started... but these are different. They're not "painful decision" templates, they're just some starting pieces. And, most importantly, you can mix and match. I can pick a "mostly" Web Forms template, but include MVC and Web API folders and core references. If you've tried to mix and match in the past, you're probably aware that it was possible, but not pleasant. ASP.NET MVC project files contained special project type GUIDs, so you'd only get controller scaffolding support in a Web Forms project if you manually edited the csproj file. Features in one stack didn't work in others. Project templates were painful choices. That's no longer the case. Hooray! I just did a demo in a presentation last week where I created a new Web Forms + MVC + Web API site, built a model, scaffolded MVC and Web API controllers with EF Code First, add data in the MVC view, viewed it in Web API, then added a GridView to the Web Forms Default.aspx page and bound it to the Model. In about 5 minutes. Sure, it's a simple example, but it's great to be able to share code and features across the whole ASP.NET family. Authentication In the past, authentication was built into the templates. So, for instance, there was an ASP.NET MVC 4 Intranet Project template which created a new ASP.NET MVC 4 application that was preconfigured for Windows Authentication. All of that authentication stuff was built into each template, so they varied between the stacks, and you couldn't reuse them. You didn't see a lot of changes to the authentication options, since they required big changes to a bunch of project templates. Now, the new project dialog includes a common authentication experience. When you hit the Change Authentication button, you get some common options that work the same way regardless of the template or reference settings you've made. These options work on all ASP.NET frameworks, and all hosting environments (IIS, IIS Express, or OWIN for self-host) The default is Individual User Accounts: This is the standard "create a local account, using username / password or OAuth" thing; however, it's all built on the new Identity system. More on that in a second. The one setting that has some configuration to it is Organizational Accounts, which lets you configure authentication using Active Directory, Windows Azure Active Directory, or Office 365. Identity There's a new identity system. We've taken the best parts of the previous ASP.NET Membership and Simple Identity systems, rolled in a lot of feedback and made big enhancements to support important developer concerns like unit testing and extensiblity. I've written long posts about ASP.NET identity, and I'll do it again. Soon. This is not that post. The short version is that I think we've finally got just the right Identity system. Some of my favorite features: There are simple, sensible defaults that work well - you can File / New / Run / Register / Login, and everything works. It supports standard username / password as well as external authentication (OAuth, etc.). It's easy to customize without having to re-implement an entire provider. It's built using pluggable pieces, rather than one large monolithic system. It's built using interfaces like IUser and IRole that allow for unit testing, dependency injection, etc. You can easily add user profile data (e.g. URL, twitter handle, birthday). You just add properties to your ApplicationUser model and they'll automatically be persisted. Complete control over how the identity data is persisted. By default, everything works with Entity Framework Code First, but it's built to support changes from small (modify the schema) to big (use another ORM, store your data in a document database or in the cloud or in XML or in the EXIF data of your desktop background or whatever). It's configured via OWIN. More on OWIN and Katana later, but the fact that it's built using OWIN means it's portable. You can find out more in the Authentication and Identity section of the ASP.NET site (and lots more content will be going up there soon). New Bootstrap based project templates The new project templates are built using Bootstrap 3. Bootstrap (formerly Twitter Bootstrap) is a front-end framework that brings a lot of nice benefits: It's responsive, so your projects will automatically scale to device width using CSS media queries. For example, menus are full size on a desktop browser, but on narrower screens you automatically get a mobile-friendly menu. The built-in Bootstrap styles make your standard page elements (headers, footers, buttons, form inputs, tables etc.) look nice and modern. Bootstrap is themeable, so you can reskin your whole site by dropping in a new Bootstrap theme. Since Bootstrap is pretty popular across the web development community, this gives you a large and rapidly growing variety of templates (free and paid) to choose from. Bootstrap also includes a lot of very useful things: components (like progress bars and badges), useful glyphicons, and some jQuery plugins for tooltips, dropdowns, carousels, etc.). Here's a look at how the responsive part works. When the page is full screen, the menu and header are optimized for a wide screen display: When I shrink the page down (this is all based on page width, not useragent sniffing) the menu turns into a nice mobile-friendly dropdown: For a quick example, I grabbed a new free theme off bootswatch.com. For simple themes, you just need to download the boostrap.css file and replace the /content/bootstrap.css file in your project. Now when I refresh the page, I've got a new theme: Scaffolding The big change in scaffolding is that it's one system that works across ASP.NET. You can create a new Empty Web project or Web Forms project and you'll get the Scaffold context menus. For release, we've got MVC 5 and Web API 2 controllers. We had a preview of Web Forms scaffolding in the preview releases, but they weren't fully baked for RTM. Look for them in a future update, expected pretty soon. This scaffolding system wasn't just changed to work across the ASP.NET frameworks, it's also built to enable future extensibility. That's not in this release, but should also hopefully be out soon. Project Readme page This is a small thing, but I really like it. When you create a new project, you get a Project_Readme.html page that's added to the root of your project and opens in the Visual Studio built-in browser. I love it. A long time ago, when you created a new project we just dumped it on you and left you scratching your head about what to do next. Not ideal. Then we started adding a bunch of Getting Started information to the new project templates. That told you what to do next, but you had to delete all of that stuff out of your website. It doesn't belong there. Not ideal. This is a simple HTML file that's not integrated into your project code at all. You can delete it if you want. But, it shows a lot of helpful links that are current for the project you just created. In the future, if we add new wacky project types, they can create readme docs with specific information on how to do appropriately wacky things. Side note: I really like that they used the internal browser in Visual Studio to show this content rather than popping open an HTML page in the default browser. I hate that. It's annoying. If you're doing that, I hope you'll stop. What if some unnamed person has 40 or 90 tabs saved in their browser session? When you pop open your "Thanks for installing my Visual Studio extension!" page, all eleventy billion tabs start up and I wish I'd never installed your thing. Be like these guys and pop stuff Visual Studio specific HTML docs in the Visual Studio browser. ASP.NET MVC 5 The biggest change with ASP.NET MVC 5 is that it's no longer a separate project type. It integrates well with the rest of ASP.NET. In addition to that and the other common features we've already looked at (Bootstrap templates, Identity, authentication), here's what's new for ASP.NET MVC. Attribute routing ASP.NET MVC now supports attribute routing, thanks to a contribution by Tim McCall, the author of http://attributerouting.net. With attribute routing you can specify your routes by annotating your actions and controllers. This supports some pretty complex, customized routing scenarios, and it allows you to keep your route information right with your controller actions if you'd like. Here's a controller that includes an action whose method name is Hiding, but I've used AttributeRouting to configure it to /spaghetti/with-nesting/where-is-waldo public class SampleController : Controller { [Route("spaghetti/with-nesting/where-is-waldo")] public string Hiding() { return "You found me!"; } } I enable that in my RouteConfig.cs, and I can use that in conjunction with my other MVC routes like this: public class RouteConfig { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapMvcAttributeRoutes(); routes.MapRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); } } You can read more about Attribute Routing in ASP.NET MVC 5 here. Filter enhancements There are two new additions to filters: Authentication Filters and Filter Overrides. Authentication filters are a new kind of filter in ASP.NET MVC that run prior to authorization filters in the ASP.NET MVC pipeline and allow you to specify authentication logic per-action, per-controller, or globally for all controllers. Authentication filters process credentials in the request and provide a corresponding principal. Authentication filters can also add authentication challenges in response to unauthorized requests. Override filters let you change which filters apply to a given action method or controller. Override filters specify a set of filter types that should not be run for a given scope (action or controller). This allows you to configure filters that apply globally but then exclude certain global filters from applying to specific actions or controllers. ASP.NET Web API 2 ASP.NET Web API 2 includes a lot of new features. Attribute Routing ASP.NET Web API supports the same attribute routing system that's in ASP.NET MVC 5. You can read more about the Attribute Routing features in Web API in this article. OAuth 2.0 ASP.NET Web API picks up OAuth 2.0 support, using security middleware running on OWIN (discussed below). This is great for features like authenticated Single Page Applications. OData Improvements ASP.NET Web API now has full OData support. That required adding in some of the most powerful operators: $select, $expand, $batch and $value. You can read more about OData operator support in this article by Mike Wasson. Lots more There's a huge list of other features, including CORS (cross-origin request sharing), IHttpActionResult, IHttpRequestContext, and more. I think the best overview is in the release notes. OWIN and Katana I've written about OWIN and Katana recently. I'm a big fan. OWIN is the Open Web Interfaces for .NET. It's a spec, like HTML or HTTP, so you can't install OWIN. The benefit of OWIN is that it's a community specification, so anyone who implements it can plug into the ASP.NET stack, either as middleware or as a host. Katana is the Microsoft implementation of OWIN. It leverages OWIN to wire up things like authentication, handlers, modules, IIS hosting, etc., so ASP.NET can host OWIN components and Katana components can run in someone else's OWIN implementation. Howard Dierking just wrote a cool article in MSDN magazine describing Katana in depth: Getting Started with the Katana Project. He had an interesting example showing an OWIN based pipeline which leveraged SignalR, ASP.NET Web API and NancyFx components in the same stack. If this kind of thing makes sense to you, that's great. If it doesn't, don't worry, but keep an eye on it. You're going to see some cool things happen as a result of ASP.NET becoming more and more pluggable. Visual Studio Web Tools Okay, this stuff's just crazy. Visual Studio has been adding some nice web dev features over the past few years, but they've really cranked it up for this release. Visual Studio is by far my favorite code editor for all web files: CSS, HTML, JavaScript, and lots of popular libraries. Stop thinking of Visual Studio as a big editor that you only use to write back-end code. Stop editing HTML and CSS in Notepad (or Sublime, Notepad++, etc.). Visual Studio starts up in under 2 seconds on a modern computer with an SSD. Misspelling HTML attributes or your CSS classes or jQuery or Angular syntax is stupid. It doesn't make you a better developer, it makes you a silly person who wastes time. Browser Link Browser Link is a real-time, two-way connection between Visual Studio and all connected browsers. It's only attached when you're running locally, in debug, but it applies to any and all connected browser, including emulators. You may have seen demos that showed the browsers refreshing based on changes in the editor, and I'll agree that's pretty cool. But it's really just the start. It's a two-way connection, and it's built for extensiblity. That means you can write extensions that push information from your running application (in IE, Chrome, a mobile emulator, etc.) back to Visual Studio. Mads and team have showed off some demonstrations where they enabled edit mode in the browser which updated the source HTML back on the browser. It's also possible to look at how the rendered HTML performs, check for compatibility issues, watch for unused CSS classes, the sky's the limit. New HTML editor The previous HTML editor had a lot of old code that didn't allow for improvements. The team rewrote the HTML editor to take advantage of the new(ish) extensibility features in Visual Studio, which then allowed them to add in all kinds of features - things like CSS Class and ID IntelliSense (so you type style="" and get a list of classes and ID's for your project), smart indent based on how your document is formatted, JavaScript reference auto-sync, etc. Here's a 3 minute tour from Mads Kristensen. The previous HTML editor had a lot of old code that didn't allow for improvements. The team rewrote the HTML editor to take advantage of the new(ish) extensibility features in Visual Studio, which then allowed them to add in all kinds of features - things like CSS Class and ID IntelliSense (so you type style="" and get a list of classes and ID's for your project), smart indent based on how your document is formatted, JavaScript reference auto-sync, etc. Lots more Visual Studio web dev features That's just a sampling - there's a ton of great features for JavaScript editing, CSS editing, publishing, and Page Inspector (which shows real-time rendering of your page inside Visual Studio). Here are some more short videos showing those features. Lots, lots more Okay, that's just a summary, and it's still quite a bit. Head on over to http://asp.net/vnext for more information, and download Visual Studio 2013 now to get started!

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  • An Introduction to Meteor

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

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  • Toorcon 15 (2013)

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

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

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

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  • 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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  • How to find and fix performance problems in ORM powered applications

    - by FransBouma
    Once in a while we get requests about how to fix performance problems with our framework. As it comes down to following the same steps and looking into the same things every single time, I decided to write a blogpost about it instead, so more people can learn from this and solve performance problems in their O/R mapper powered applications. In some parts it's focused on LLBLGen Pro but it's also usable for other O/R mapping frameworks, as the vast majority of performance problems in O/R mapper powered applications are not specific for a certain O/R mapper framework. Too often, the developer looks at the wrong part of the application, trying to fix what isn't a problem in that part, and getting frustrated that 'things are so slow with <insert your favorite framework X here>'. I'm in the O/R mapper business for a long time now (almost 10 years, full time) and as it's a small world, we O/R mapper developers know almost all tricks to pull off by now: we all know what to do to make task ABC faster and what compromises (because there are almost always compromises) to deal with if we decide to make ABC faster that way. Some O/R mapper frameworks are faster in X, others in Y, but you can be sure the difference is mainly a result of a compromise some developers are willing to deal with and others aren't. That's why the O/R mapper frameworks on the market today are different in many ways, even though they all fetch and save entities from and to a database. I'm not suggesting there's no room for improvement in today's O/R mapper frameworks, there always is, but it's not a matter of 'the slowness of the application is caused by the O/R mapper' anymore. Perhaps query generation can be optimized a bit here, row materialization can be optimized a bit there, but it's mainly coming down to milliseconds. Still worth it if you're a framework developer, but it's not much compared to the time spend inside databases and in user code: if a complete fetch takes 40ms or 50ms (from call to entity object collection), it won't make a difference for your application as that 10ms difference won't be noticed. That's why it's very important to find the real locations of the problems so developers can fix them properly and don't get frustrated because their quest to get a fast, performing application failed. Performance tuning basics and rules Finding and fixing performance problems in any application is a strict procedure with four prescribed steps: isolate, analyze, interpret and fix, in that order. It's key that you don't skip a step nor make assumptions: these steps help you find the reason of a problem which seems to be there, and how to fix it or leave it as-is. Skipping a step, or when you assume things will be bad/slow without doing analysis will lead to the path of premature optimization and won't actually solve your problems, only create new ones. The most important rule of finding and fixing performance problems in software is that you have to understand what 'performance problem' actually means. Most developers will say "when a piece of software / code is slow, you have a performance problem". But is that actually the case? If I write a Linq query which will aggregate, group and sort 5 million rows from several tables to produce a resultset of 10 rows, it might take more than a couple of milliseconds before that resultset is ready to be consumed by other logic. If I solely look at the Linq query, the code consuming the resultset of the 10 rows and then look at the time it takes to complete the whole procedure, it will appear to me to be slow: all that time taken to produce and consume 10 rows? But if you look closer, if you analyze and interpret the situation, you'll see it does a tremendous amount of work, and in that light it might even be extremely fast. With every performance problem you encounter, always do realize that what you're trying to solve is perhaps not a technical problem at all, but a perception problem. The second most important rule you have to understand is based on the old saying "Penny wise, Pound Foolish": the part which takes e.g. 5% of the total time T for a given task isn't worth optimizing if you have another part which takes a much larger part of the total time T for that same given task. Optimizing parts which are relatively insignificant for the total time taken is not going to bring you better results overall, even if you totally optimize that part away. This is the core reason why analysis of the complete set of application parts which participate in a given task is key to being successful in solving performance problems: No analysis -> no problem -> no solution. One warning up front: hunting for performance will always include making compromises. Fast software can be made maintainable, but if you want to squeeze as much performance out of your software, you will inevitably be faced with the dilemma of compromising one or more from the group {readability, maintainability, features} for the extra performance you think you'll gain. It's then up to you to decide whether it's worth it. In almost all cases it's not. The reason for this is simple: the vast majority of performance problems can be solved by implementing the proper algorithms, the ones with proven Big O-characteristics so you know the performance you'll get plus you know the algorithm will work. The time taken by the algorithm implementing code is inevitable: you already implemented the best algorithm. You might find some optimizations on the technical level but in general these are minor. Let's look at the four steps to see how they guide us through the quest to find and fix performance problems. Isolate The first thing you need to do is to isolate the areas in your application which are assumed to be slow. For example, if your application is a web application and a given page is taking several seconds or even minutes to load, it's a good candidate to check out. It's important to start with the isolate step because it allows you to focus on a single code path per area with a clear begin and end and ignore the rest. The rest of the steps are taken per identified problematic area. Keep in mind that isolation focuses on tasks in an application, not code snippets. A task is something that's started in your application by either another task or the user, or another program, and has a beginning and an end. You can see a task as a piece of functionality offered by your application.  Analyze Once you've determined the problem areas, you have to perform analysis on the code paths of each area, to see where the performance problems occur and which areas are not the problem. This is a multi-layered effort: an application which uses an O/R mapper typically consists of multiple parts: there's likely some kind of interface (web, webservice, windows etc.), a part which controls the interface and business logic, the O/R mapper part and the RDBMS, all connected with either a network or inter-process connections provided by the OS or other means. Each of these parts, including the connectivity plumbing, eat up a part of the total time it takes to complete a task, e.g. load a webpage with all orders of a given customer X. To understand which parts participate in the task / area we're investigating and how much they contribute to the total time taken to complete the task, analysis of each participating task is essential. Start with the code you wrote which starts the task, analyze the code and track the path it follows through your application. What does the code do along the way, verify whether it's correct or not. Analyze whether you have implemented the right algorithms in your code for this particular area. Remember we're looking at one area at a time, which means we're ignoring all other code paths, just the code path of the current problematic area, from begin to end and back. Don't dig in and start optimizing at the code level just yet. We're just analyzing. If your analysis reveals big architectural stupidity, it's perhaps a good idea to rethink the architecture at this point. For the rest, we're analyzing which means we collect data about what could be wrong, for each participating part of the complete application. Reviewing the code you wrote is a good tool to get deeper understanding of what is going on for a given task but ultimately it lacks precision and overview what really happens: humans aren't good code interpreters, computers are. We therefore need to utilize tools to get deeper understanding about which parts contribute how much time to the total task, triggered by which other parts and for example how many times are they called. There are two different kind of tools which are necessary: .NET profilers and O/R mapper / RDBMS profilers. .NET profiling .NET profilers (e.g. dotTrace by JetBrains or Ants by Red Gate software) show exactly which pieces of code are called, how many times they're called, and the time it took to run that piece of code, at the method level and sometimes even at the line level. The .NET profilers are essential tools for understanding whether the time taken to complete a given task / area in your application is consumed by .NET code, where exactly in your code, the path to that code, how many times that code was called by other code and thus reveals where hotspots are located: the areas where a solution can be found. Importantly, they also reveal which areas can be left alone: remember our penny wise pound foolish saying: if a profiler reveals that a group of methods are fast, or don't contribute much to the total time taken for a given task, ignore them. Even if the code in them is perhaps complex and looks like a candidate for optimization: you can work all day on that, it won't matter.  As we're focusing on a single area of the application, it's best to start profiling right before you actually activate the task/area. Most .NET profilers support this by starting the application without starting the profiling procedure just yet. You navigate to the particular part which is slow, start profiling in the profiler, in your application you perform the actions which are considered slow, and afterwards you get a snapshot in the profiler. The snapshot contains the data collected by the profiler during the slow action, so most data is produced by code in the area to investigate. This is important, because it allows you to stay focused on a single area. O/R mapper and RDBMS profiling .NET profilers give you a good insight in the .NET side of things, but not in the RDBMS side of the application. As this article is about O/R mapper powered applications, we're also looking at databases, and the software making it possible to consume the database in your application: the O/R mapper. To understand which parts of the O/R mapper and database participate how much to the total time taken for task T, we need different tools. There are two kind of tools focusing on O/R mappers and database performance profiling: O/R mapper profilers and RDBMS profilers. For O/R mapper profilers, you can look at LLBLGen Prof by hibernating rhinos or the Linq to Sql/LLBLGen Pro profiler by Huagati. Hibernating rhinos also have profilers for other O/R mappers like NHibernate (NHProf) and Entity Framework (EFProf) and work the same as LLBLGen Prof. For RDBMS profilers, you have to look whether the RDBMS vendor has a profiler. For example for SQL Server, the profiler is shipped with SQL Server, for Oracle it's build into the RDBMS, however there are also 3rd party tools. Which tool you're using isn't really important, what's important is that you get insight in which queries are executed during the task / area we're currently focused on and how long they took. Here, the O/R mapper profilers have an advantage as they collect the time it took to execute the query from the application's perspective so they also collect the time it took to transport data across the network. This is important because a query which returns a massive resultset or a resultset with large blob/clob/ntext/image fields takes more time to get transported across the network than a small resultset and a database profiler doesn't take this into account most of the time. Another tool to use in this case, which is more low level and not all O/R mappers support it (though LLBLGen Pro and NHibernate as well do) is tracing: most O/R mappers offer some form of tracing or logging system which you can use to collect the SQL generated and executed and often also other activity behind the scenes. While tracing can produce a tremendous amount of data in some cases, it also gives insight in what's going on. Interpret After we've completed the analysis step it's time to look at the data we've collected. We've done code reviews to see whether we've done anything stupid and which parts actually take place and if the proper algorithms have been implemented. We've done .NET profiling to see which parts are choke points and how much time they contribute to the total time taken to complete the task we're investigating. We've performed O/R mapper profiling and RDBMS profiling to see which queries were executed during the task, how many queries were generated and executed and how long they took to complete, including network transportation. All this data reveals two things: which parts are big contributors to the total time taken and which parts are irrelevant. Both aspects are very important. The parts which are irrelevant (i.e. don't contribute significantly to the total time taken) can be ignored from now on, we won't look at them. The parts which contribute a lot to the total time taken are important to look at. We now have to first look at the .NET profiler results, to see whether the time taken is consumed in our own code, in .NET framework code, in the O/R mapper itself or somewhere else. For example if most of the time is consumed by DbCommand.ExecuteReader, the time it took to complete the task is depending on the time the data is fetched from the database. If there was just 1 query executed, according to tracing or O/R mapper profilers / RDBMS profilers, check whether that query is optimal, uses indexes or has to deal with a lot of data. Interpret means that you follow the path from begin to end through the data collected and determine where, along the path, the most time is contributed. It also means that you have to check whether this was expected or is totally unexpected. My previous example of the 10 row resultset of a query which groups millions of rows will likely reveal that a long time is spend inside the database and almost no time is spend in the .NET code, meaning the RDBMS part contributes the most to the total time taken, the rest is compared to that time, irrelevant. Considering the vastness of the source data set, it's expected this will take some time. However, does it need tweaking? Perhaps all possible tweaks are already in place. In the interpret step you then have to decide that further action in this area is necessary or not, based on what the analysis results show: if the analysis results were unexpected and in the area where the most time is contributed to the total time taken is room for improvement, action should be taken. If not, you can only accept the situation and move on. In all cases, document your decision together with the analysis you've done. If you decide that the perceived performance problem is actually expected due to the nature of the task performed, it's essential that in the future when someone else looks at the application and starts asking questions you can answer them properly and new analysis is only necessary if situations changed. Fix After interpreting the analysis results you've concluded that some areas need adjustment. This is the fix step: you're actively correcting the performance problem with proper action targeted at the real cause. In many cases related to O/R mapper powered applications it means you'll use different features of the O/R mapper to achieve the same goal, or apply optimizations at the RDBMS level. It could also mean you apply caching inside your application (compromise memory consumption over performance) to avoid unnecessary re-querying data and re-consuming the results. After applying a change, it's key you re-do the analysis and interpretation steps: compare the results and expectations with what you had before, to see whether your actions had any effect or whether it moved the problem to a different part of the application. Don't fall into the trap to do partly analysis: do the full analysis again: .NET profiling and O/R mapper / RDBMS profiling. It might very well be that the changes you've made make one part faster but another part significantly slower, in such a way that the overall problem hasn't changed at all. Performance tuning is dealing with compromises and making choices: to use one feature over the other, to accept a higher memory footprint, to go away from the strict-OO path and execute queries directly onto the RDBMS, these are choices and compromises which will cross your path if you want to fix performance problems with respect to O/R mappers or data-access and databases in general. In most cases it's not a big issue: alternatives are often good choices too and the compromises aren't that hard to deal with. What is important is that you document why you made a choice, a compromise: which analysis data, which interpretation led you to the choice made. This is key for good maintainability in the years to come. Most common performance problems with O/R mappers Below is an incomplete list of common performance problems related to data-access / O/R mappers / RDBMS code. It will help you with fixing the hotspots you found in the interpretation step. SELECT N+1: (Lazy-loading specific). Lazy loading triggered performance bottlenecks. Consider a list of Orders bound to a grid. You have a Field mapped onto a related field in Order, Customer.CompanyName. Showing this column in the grid will make the grid fetch (indirectly) for each row the Customer row. This means you'll get for the single list not 1 query (for the orders) but 1+(the number of orders shown) queries. To solve this: use eager loading using a prefetch path to fetch the customers with the orders. SELECT N+1 is easy to spot with an O/R mapper profiler or RDBMS profiler: if you see a lot of identical queries executed at once, you have this problem. Prefetch paths using many path nodes or sorting, or limiting. Eager loading problem. Prefetch paths can help with performance, but as 1 query is fetched per node, it can be the number of data fetched in a child node is bigger than you think. Also consider that data in every node is merged on the client within the parent. This is fast, but it also can take some time if you fetch massive amounts of entities. If you keep fetches small, you can use tuning parameters like the ParameterizedPrefetchPathThreshold setting to get more optimal queries. Deep inheritance hierarchies of type Target Per Entity/Type. If you use inheritance of type Target per Entity / Type (each type in the inheritance hierarchy is mapped onto its own table/view), fetches will join subtype- and supertype tables in many cases, which can lead to a lot of performance problems if the hierarchy has many types. With this problem, keep inheritance to a minimum if possible, or switch to a hierarchy of type Target Per Hierarchy, which means all entities in the inheritance hierarchy are mapped onto the same table/view. Of course this has its own set of drawbacks, but it's a compromise you might want to take. Fetching massive amounts of data by fetching large lists of entities. LLBLGen Pro supports paging (and limiting the # of rows returned), which is often key to process through large sets of data. Use paging on the RDBMS if possible (so a query is executed which returns only the rows in the page requested). When using paging in a web application, be sure that you switch server-side paging on on the datasourcecontrol used. In this case, paging on the grid alone is not enough: this can lead to fetching a lot of data which is then loaded into the grid and paged there. Keep note that analyzing queries for paging could lead to the false assumption that paging doesn't occur, e.g. when the query contains a field of type ntext/image/clob/blob and DISTINCT can't be applied while it should have (e.g. due to a join): the datareader will do DISTINCT filtering on the client. this is a little slower but it does perform paging functionality on the data-reader so it won't fetch all rows even if the query suggests it does. Fetch massive amounts of data because blob/clob/ntext/image fields aren't excluded. LLBLGen Pro supports field exclusion for queries. You can exclude fields (also in prefetch paths) per query to avoid fetching all fields of an entity, e.g. when you don't need them for the logic consuming the resultset. Excluding fields can greatly reduce the amount of time spend on data-transport across the network. Use this optimization if you see that there's a big difference between query execution time on the RDBMS and the time reported by the .NET profiler for the ExecuteReader method call. Doing client-side aggregates/scalar calculations by consuming a lot of data. If possible, try to formulate a scalar query or group by query using the projection system or GetScalar functionality of LLBLGen Pro to do data consumption on the RDBMS server. It's far more efficient to process data on the RDBMS server than to first load it all in memory, then traverse the data in-memory to calculate a value. Using .ToList() constructs inside linq queries. It might be you use .ToList() somewhere in a Linq query which makes the query be run partially in-memory. Example: var q = from c in metaData.Customers.ToList() where c.Country=="Norway" select c; This will actually fetch all customers in-memory and do an in-memory filtering, as the linq query is defined on an IEnumerable<T>, and not on the IQueryable<T>. Linq is nice, but it can often be a bit unclear where some parts of a Linq query might run. Fetching all entities to delete into memory first. To delete a set of entities it's rather inefficient to first fetch them all into memory and then delete them one by one. It's more efficient to execute a DELETE FROM ... WHERE query on the database directly to delete the entities in one go. LLBLGen Pro supports this feature, and so do some other O/R mappers. It's not always possible to do this operation in the context of an O/R mapper however: if an O/R mapper relies on a cache, these kind of operations are likely not supported because they make it impossible to track whether an entity is actually removed from the DB and thus can be removed from the cache. Fetching all entities to update with an expression into memory first. Similar to the previous point: it is more efficient to update a set of entities directly with a single UPDATE query using an expression instead of fetching the entities into memory first and then updating the entities in a loop, and afterwards saving them. It might however be a compromise you don't want to take as it is working around the idea of having an object graph in memory which is manipulated and instead makes the code fully aware there's a RDBMS somewhere. Conclusion Performance tuning is almost always about compromises and making choices. It's also about knowing where to look and how the systems in play behave and should behave. The four steps I provided should help you stay focused on the real problem and lead you towards the solution. Knowing how to optimally use the systems participating in your own code (.NET framework, O/R mapper, RDBMS, network/services) is key for success as well as knowing what's going on inside the application you built. I hope you'll find this guide useful in tracking down performance problems and dealing with them in a useful way.  

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  • Ancillary Objects: Separate Debug ELF Files For Solaris

    - by Ali Bahrami
    We introduced a new object ELF object type in Solaris 11 Update 1 called the Ancillary Object. This posting describes them, using material originally written during their development, the PSARC arc case, and the Solaris Linker and Libraries Manual. ELF objects contain allocable sections, which are mapped into memory at runtime, and non-allocable sections, which are present in the file for use by debuggers and observability tools, but which are not mapped or used at runtime. Typically, all of these sections exist within a single object file. Ancillary objects allow them to instead go into a separate file. There are different reasons given for wanting such a feature. One can debate whether the added complexity is worth the benefit, and in most cases it is not. However, one important case stands out — customers with very large 32-bit objects who are not ready or able to make the transition to 64-bits. We have customers who build extremely large 32-bit objects. Historically, the debug sections in these objects have used the stabs format, which is limited, but relatively compact. In recent years, the industry has transitioned to the powerful but verbose DWARF standard. In some cases, the size of these debug sections is large enough to push the total object file size past the fundamental 4GB limit for 32-bit ELF object files. The best, and ultimately only, solution to overly large objects is to transition to 64-bits. However, consider environments where: Hundreds of users may be executing the code on large shared systems. (32-bits use less memory and bus bandwidth, and on sparc runs just as fast as 64-bit code otherwise). Complex finely tuned code, where the original authors may no longer be available. Critical production code, that was expensive to qualify and bring online, and which is otherwise serving its intended purpose without issue. Users in these risk adverse and/or high scale categories have good reasons to push 32-bits objects to the limit before moving on. Ancillary objects offer these users a longer runway. Design The design of ancillary objects is intended to be simple, both to help human understanding when examining elfdump output, and to lower the bar for debuggers such as dbx to support them. The primary and ancillary objects have the same set of section headers, with the same names, in the same order (i.e. each section has the same index in both files). A single added section of type SHT_SUNW_ANCILLARY is added to both objects, containing information that allows a debugger to identify and validate both files relative to each other. Given one of these files, the ancillary section allows you to identify the other. Allocable sections go in the primary object, and non-allocable ones go into the ancillary object. A small set of non-allocable objects, notably the symbol table, are copied into both objects. As noted above, most sections are only written to one of the two objects, but both objects have the same section header array. The section header in the file that does not contain the section data is tagged with the SHF_SUNW_ABSENT section header flag to indicate its placeholder status. Compiler writers and others who produce objects can set the SUNW_SHF_PRIMARY section header flag to mark non-allocable sections that should go to the primary object rather than the ancillary. If you don't request an ancillary object, the Solaris ELF format is unchanged. Users who don't use ancillary objects do not pay for the feature. This is important, because they exist to serve a small subset of our users, and must not complicate the common case. If you do request an ancillary object, the runtime behavior of the primary object will be the same as that of a normal object. There is no added runtime cost. The primary and ancillary object together represent a logical single object. This is facilitated by the use of a single set of section headers. One can easily imagine a tool that can merge a primary and ancillary object into a single file, or the reverse. (Note that although this is an interesting intellectual exercise, we don't actually supply such a tool because there's little practical benefit above and beyond using ld to create the files). Among the benefits of this approach are: There is no need for per-file symbol tables to reflect the contents of each file. The same symbol table that would be produced for a standard object can be used. The section contents are identical in either case — there is no need to alter data to accommodate multiple files. It is very easy for a debugger to adapt to these new files, and the processing involved can be encapsulated in input/output routines. Most of the existing debugger implementation applies without modification. The limit of a 4GB 32-bit output object is now raised to 4GB of code, and 4GB of debug data. There is also the future possibility (not currently supported) to support multiple ancillary objects, each of which could contain up to 4GB of additional debug data. It must be noted however that the 32-bit DWARF debug format is itself inherently 32-bit limited, as it uses 32-bit offsets between debug sections, so the ability to employ multiple ancillary object files may not turn out to be useful. Using Ancillary Objects (From the Solaris Linker and Libraries Guide) By default, objects contain both allocable and non-allocable sections. Allocable sections are the sections that contain executable code and the data needed by that code at runtime. Non-allocable sections contain supplemental information that is not required to execute an object at runtime. These sections support the operation of debuggers and other observability tools. The non-allocable sections in an object are not loaded into memory at runtime by the operating system, and so, they have no impact on memory use or other aspects of runtime performance no matter their size. For convenience, both allocable and non-allocable sections are normally maintained in the same file. However, there are situations in which it can be useful to separate these sections. To reduce the size of objects in order to improve the speed at which they can be copied across wide area networks. To support fine grained debugging of highly optimized code requires considerable debug data. In modern systems, the debugging data can easily be larger than the code it describes. The size of a 32-bit object is limited to 4 Gbytes. In very large 32-bit objects, the debug data can cause this limit to be exceeded and prevent the creation of the object. To limit the exposure of internal implementation details. Traditionally, objects have been stripped of non-allocable sections in order to address these issues. Stripping is effective, but destroys data that might be needed later. The Solaris link-editor can instead write non-allocable sections to an ancillary object. This feature is enabled with the -z ancillary command line option. $ ld ... -z ancillary[=outfile] ...By default, the ancillary file is given the same name as the primary output object, with a .anc file extension. However, a different name can be provided by providing an outfile value to the -z ancillary option. When -z ancillary is specified, the link-editor performs the following actions. All allocable sections are written to the primary object. In addition, all non-allocable sections containing one or more input sections that have the SHF_SUNW_PRIMARY section header flag set are written to the primary object. All remaining non-allocable sections are written to the ancillary object. The following non-allocable sections are written to both the primary object and ancillary object. .shstrtab The section name string table. .symtab The full non-dynamic symbol table. .symtab_shndx The symbol table extended index section associated with .symtab. .strtab The non-dynamic string table associated with .symtab. .SUNW_ancillary Contains the information required to identify the primary and ancillary objects, and to identify the object being examined. The primary object and all ancillary objects contain the same array of sections headers. Each section has the same section index in every file. Although the primary and ancillary objects all define the same section headers, the data for most sections will be written to a single file as described above. If the data for a section is not present in a given file, the SHF_SUNW_ABSENT section header flag is set, and the sh_size field is 0. This organization makes it possible to acquire a full list of section headers, a complete symbol table, and a complete list of the primary and ancillary objects from either of the primary or ancillary objects. The following example illustrates the underlying implementation of ancillary objects. An ancillary object is created by adding the -z ancillary command line option to an otherwise normal compilation. The file utility shows that the result is an executable named a.out, and an associated ancillary object named a.out.anc. $ cat hello.c #include <stdio.h> int main(int argc, char **argv) { (void) printf("hello, world\n"); return (0); } $ cc -g -zancillary hello.c $ file a.out a.out.anc a.out: ELF 32-bit LSB executable 80386 Version 1 [FPU], dynamically linked, not stripped, ancillary object a.out.anc a.out.anc: ELF 32-bit LSB ancillary 80386 Version 1, primary object a.out $ ./a.out hello worldThe resulting primary object is an ordinary executable that can be executed in the usual manner. It is no different at runtime than an executable built without the use of ancillary objects, and then stripped of non-allocable content using the strip or mcs commands. As previously described, the primary object and ancillary objects contain the same section headers. To see how this works, it is helpful to use the elfdump utility to display these section headers and compare them. The following table shows the section header information for a selection of headers from the previous link-edit example. Index Section Name Type Primary Flags Ancillary Flags Primary Size Ancillary Size 13 .text PROGBITS ALLOC EXECINSTR ALLOC EXECINSTR SUNW_ABSENT 0x131 0 20 .data PROGBITS WRITE ALLOC WRITE ALLOC SUNW_ABSENT 0x4c 0 21 .symtab SYMTAB 0 0 0x450 0x450 22 .strtab STRTAB STRINGS STRINGS 0x1ad 0x1ad 24 .debug_info PROGBITS SUNW_ABSENT 0 0 0x1a7 28 .shstrtab STRTAB STRINGS STRINGS 0x118 0x118 29 .SUNW_ancillary SUNW_ancillary 0 0 0x30 0x30 The data for most sections is only present in one of the two files, and absent from the other file. The SHF_SUNW_ABSENT section header flag is set when the data is absent. The data for allocable sections needed at runtime are found in the primary object. The data for non-allocable sections used for debugging but not needed at runtime are placed in the ancillary file. A small set of non-allocable sections are fully present in both files. These are the .SUNW_ancillary section used to relate the primary and ancillary objects together, the section name string table .shstrtab, as well as the symbol table.symtab, and its associated string table .strtab. It is possible to strip the symbol table from the primary object. A debugger that encounters an object without a symbol table can use the .SUNW_ancillary section to locate the ancillary object, and access the symbol contained within. The primary object, and all associated ancillary objects, contain a .SUNW_ancillary section that allows all the objects to be identified and related together. $ elfdump -T SUNW_ancillary a.out a.out.anc a.out: Ancillary Section: .SUNW_ancillary index tag value [0] ANC_SUNW_CHECKSUM 0x8724 [1] ANC_SUNW_MEMBER 0x1 a.out [2] ANC_SUNW_CHECKSUM 0x8724 [3] ANC_SUNW_MEMBER 0x1a3 a.out.anc [4] ANC_SUNW_CHECKSUM 0xfbe2 [5] ANC_SUNW_NULL 0 a.out.anc: Ancillary Section: .SUNW_ancillary index tag value [0] ANC_SUNW_CHECKSUM 0xfbe2 [1] ANC_SUNW_MEMBER 0x1 a.out [2] ANC_SUNW_CHECKSUM 0x8724 [3] ANC_SUNW_MEMBER 0x1a3 a.out.anc [4] ANC_SUNW_CHECKSUM 0xfbe2 [5] ANC_SUNW_NULL 0 The ancillary sections for both objects contain the same number of elements, and are identical except for the first element. Each object, starting with the primary object, is introduced with a MEMBER element that gives the file name, followed by a CHECKSUM that identifies the object. In this example, the primary object is a.out, and has a checksum of 0x8724. The ancillary object is a.out.anc, and has a checksum of 0xfbe2. The first element in a .SUNW_ancillary section, preceding the MEMBER element for the primary object, is always a CHECKSUM element, containing the checksum for the file being examined. The presence of a .SUNW_ancillary section in an object indicates that the object has associated ancillary objects. The names of the primary and all associated ancillary objects can be obtained from the ancillary section from any one of the files. It is possible to determine which file is being examined from the larger set of files by comparing the first checksum value to the checksum of each member that follows. Debugger Access and Use of Ancillary Objects Debuggers and other observability tools must merge the information found in the primary and ancillary object files in order to build a complete view of the object. This is equivalent to processing the information from a single file. This merging is simplified by the primary object and ancillary objects containing the same section headers, and a single symbol table. The following steps can be used by a debugger to assemble the information contained in these files. Starting with the primary object, or any of the ancillary objects, locate the .SUNW_ancillary section. The presence of this section identifies the object as part of an ancillary group, contains information that can be used to obtain a complete list of the files and determine which of those files is the one currently being examined. Create a section header array in memory, using the section header array from the object being examined as an initial template. Open and read each file identified by the .SUNW_ancillary section in turn. For each file, fill in the in-memory section header array with the information for each section that does not have the SHF_SUNW_ABSENT flag set. The result will be a complete in-memory copy of the section headers with pointers to the data for all sections. Once this information has been acquired, the debugger can proceed as it would in the single file case, to access and control the running program. Note - The ELF definition of ancillary objects provides for a single primary object, and an arbitrary number of ancillary objects. At this time, the Oracle Solaris link-editor only produces a single ancillary object containing all non-allocable sections. This may change in the future. Debuggers and other observability tools should be written to handle the general case of multiple ancillary objects. ELF Implementation Details (From the Solaris Linker and Libraries Guide) To implement ancillary objects, it was necessary to extend the ELF format to add a new object type (ET_SUNW_ANCILLARY), a new section type (SHT_SUNW_ANCILLARY), and 2 new section header flags (SHF_SUNW_ABSENT, SHF_SUNW_PRIMARY). In this section, I will detail these changes, in the form of diffs to the Solaris Linker and Libraries manual. Part IV ELF Application Binary Interface Chapter 13: Object File Format Object File Format Edit Note: This existing section at the beginning of the chapter describes the ELF header. There's a table of object file types, which now includes the new ET_SUNW_ANCILLARY type. e_type Identifies the object file type, as listed in the following table. NameValueMeaning ET_NONE0No file type ET_REL1Relocatable file ET_EXEC2Executable file ET_DYN3Shared object file ET_CORE4Core file ET_LOSUNW0xfefeStart operating system specific range ET_SUNW_ANCILLARY0xfefeAncillary object file ET_HISUNW0xfefdEnd operating system specific range ET_LOPROC0xff00Start processor-specific range ET_HIPROC0xffffEnd processor-specific range Sections Edit Note: This overview section defines the section header structure, and provides a high level description of known sections. It was updated to define the new SHF_SUNW_ABSENT and SHF_SUNW_PRIMARY flags and the new SHT_SUNW_ANCILLARY section. ... sh_type Categorizes the section's contents and semantics. Section types and their descriptions are listed in Table 13-5. sh_flags Sections support 1-bit flags that describe miscellaneous attributes. Flag definitions are listed in Table 13-8. ... Table 13-5 ELF Section Types, sh_type NameValue . . . SHT_LOSUNW0x6fffffee SHT_SUNW_ancillary0x6fffffee . . . ... SHT_LOSUNW - SHT_HISUNW Values in this inclusive range are reserved for Oracle Solaris OS semantics. SHT_SUNW_ANCILLARY Present when a given object is part of a group of ancillary objects. Contains information required to identify all the files that make up the group. See Ancillary Section. ... Table 13-8 ELF Section Attribute Flags NameValue . . . SHF_MASKOS0x0ff00000 SHF_SUNW_NODISCARD0x00100000 SHF_SUNW_ABSENT0x00200000 SHF_SUNW_PRIMARY0x00400000 SHF_MASKPROC0xf0000000 . . . ... SHF_SUNW_ABSENT Indicates that the data for this section is not present in this file. When ancillary objects are created, the primary object and any ancillary objects, will all have the same section header array, to facilitate merging them to form a complete view of the object, and to allow them to use the same symbol tables. Each file contains a subset of the section data. The data for allocable sections is written to the primary object while the data for non-allocable sections is written to an ancillary file. The SHF_SUNW_ABSENT flag is used to indicate that the data for the section is not present in the object being examined. When the SHF_SUNW_ABSENT flag is set, the sh_size field of the section header must be 0. An application encountering an SHF_SUNW_ABSENT section can choose to ignore the section, or to search for the section data within one of the related ancillary files. SHF_SUNW_PRIMARY The default behavior when ancillary objects are created is to write all allocable sections to the primary object and all non-allocable sections to the ancillary objects. The SHF_SUNW_PRIMARY flag overrides this behavior. Any output section containing one more input section with the SHF_SUNW_PRIMARY flag set is written to the primary object without regard for its allocable status. ... Two members in the section header, sh_link, and sh_info, hold special information, depending on section type. Table 13-9 ELF sh_link and sh_info Interpretation sh_typesh_linksh_info . . . SHT_SUNW_ANCILLARY The section header index of the associated string table. 0 . . . Special Sections Edit Note: This section describes the sections used in Solaris ELF objects, using the types defined in the previous description of section types. It was updated to define the new .SUNW_ancillary (SHT_SUNW_ANCILLARY) section. Various sections hold program and control information. Sections in the following table are used by the system and have the indicated types and attributes. Table 13-10 ELF Special Sections NameTypeAttribute . . . .SUNW_ancillarySHT_SUNW_ancillaryNone . . . ... .SUNW_ancillary Present when a given object is part of a group of ancillary objects. Contains information required to identify all the files that make up the group. See Ancillary Section for details. ... Ancillary Section Edit Note: This new section provides the format reference describing the layout of a .SUNW_ancillary section and the meaning of the various tags. Note that these sections use the same tag/value concept used for dynamic and capabilities sections, and will be familiar to anyone used to working with ELF. In addition to the primary output object, the Solaris link-editor can produce one or more ancillary objects. Ancillary objects contain non-allocable sections that would normally be written to the primary object. When ancillary objects are produced, the primary object and all of the associated ancillary objects contain a SHT_SUNW_ancillary section, containing information that identifies these related objects. Given any one object from such a group, the ancillary section provides the information needed to identify and interpret the others. This section contains an array of the following structures. See sys/elf.h. typedef struct { Elf32_Word a_tag; union { Elf32_Word a_val; Elf32_Addr a_ptr; } a_un; } Elf32_Ancillary; typedef struct { Elf64_Xword a_tag; union { Elf64_Xword a_val; Elf64_Addr a_ptr; } a_un; } Elf64_Ancillary; For each object with this type, a_tag controls the interpretation of a_un. a_val These objects represent integer values with various interpretations. a_ptr These objects represent file offsets or addresses. The following ancillary tags exist. Table 13-NEW1 ELF Ancillary Array Tags NameValuea_un ANC_SUNW_NULL0Ignored ANC_SUNW_CHECKSUM1a_val ANC_SUNW_MEMBER2a_ptr ANC_SUNW_NULL Marks the end of the ancillary section. ANC_SUNW_CHECKSUM Provides the checksum for a file in the c_val element. When ANC_SUNW_CHECKSUM precedes the first instance of ANC_SUNW_MEMBER, it provides the checksum for the object from which the ancillary section is being read. When it follows an ANC_SUNW_MEMBER tag, it provides the checksum for that member. ANC_SUNW_MEMBER Specifies an object name. The a_ptr element contains the string table offset of a null-terminated string, that provides the file name. An ancillary section must always contain an ANC_SUNW_CHECKSUM before the first instance of ANC_SUNW_MEMBER, identifying the current object. Following that, there should be an ANC_SUNW_MEMBER for each object that makes up the complete set of objects. Each ANC_SUNW_MEMBER should be followed by an ANC_SUNW_CHECKSUM for that object. A typical ancillary section will therefore be structured as: TagMeaning ANC_SUNW_CHECKSUMChecksum of this object ANC_SUNW_MEMBERName of object #1 ANC_SUNW_CHECKSUMChecksum for object #1 . . . ANC_SUNW_MEMBERName of object N ANC_SUNW_CHECKSUMChecksum for object N ANC_SUNW_NULL An object can therefore identify itself by comparing the initial ANC_SUNW_CHECKSUM to each of the ones that follow, until it finds a match. Related Other Work The GNU developers have also encountered the need/desire to support separate debug information files, and use the solution detailed at http://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html. At the current time, the separate debug file is constructed by building the standard object first, and then copying the debug data out of it in a separate post processing step, Hence, it is limited to a total of 4GB of code and debug data, just as a single object file would be. They are aware of this, and I have seen online comments indicating that they may add direct support for generating these separate files to their link-editor. It is worth noting that the GNU objcopy utility is available on Solaris, and that the Studio dbx debugger is able to use these GNU style separate debug files even on Solaris. Although this is interesting in terms giving Linux users a familiar environment on Solaris, the 4GB limit means it is not an answer to the problem of very large 32-bit objects. We have also encountered issues with objcopy not understanding Solaris-specific ELF sections, when using this approach. The GNU community also has a current effort to adapt their DWARF debug sections in order to move them to separate files before passing the relocatable objects to the linker. The details of Project Fission can be found at http://gcc.gnu.org/wiki/DebugFission. The goal of this project appears to be to reduce the amount of data seen by the link-editor. The primary effort revolves around moving DWARF data to separate .dwo files so that the link-editor never encounters them. The details of modifying the DWARF data to be usable in this form are involved — please see the above URL for details.

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  • Security Issues with Single Page Apps

    - by Stephen.Walther
    Last week, I was asked to do a code review of a Single Page App built using the ASP.NET Web API, Durandal, and Knockout (good stuff!). In particular, I was asked to investigate whether there any special security issues associated with building a Single Page App which are not present in the case of a traditional server-side ASP.NET application. In this blog entry, I discuss two areas in which you need to exercise extra caution when building a Single Page App. I discuss how Single Page Apps are extra vulnerable to both Cross-Site Scripting (XSS) attacks and Cross-Site Request Forgery (CSRF) attacks. This goal of this blog post is NOT to persuade you to avoid writing Single Page Apps. I’m a big fan of Single Page Apps. Instead, the goal is to ensure that you are fully aware of some of the security issues related to Single Page Apps and ensure that you know how to guard against them. Cross-Site Scripting (XSS) Attacks According to WhiteHat Security, over 65% of public websites are open to XSS attacks. That’s bad. By taking advantage of XSS holes in a website, a hacker can steal your credit cards, passwords, or bank account information. Any website that redisplays untrusted information is open to XSS attacks. Let me give you a simple example. Imagine that you want to display the name of the current user on a page. To do this, you create the following server-side ASP.NET page located at http://MajorBank.com/SomePage.aspx: <%@Page Language="C#" %> <html> <head> <title>Some Page</title> </head> <body> Welcome <%= Request["username"] %> </body> </html> Nothing fancy here. Notice that the page displays the current username by using Request[“username”]. Using Request[“username”] displays the username regardless of whether the username is present in a cookie, a form field, or a query string variable. Unfortunately, by using Request[“username”] to redisplay untrusted information, you have now opened your website to XSS attacks. Here’s how. Imagine that an evil hacker creates the following link on another website (hackers.com): <a href="/SomePage.aspx?username=<script src=Evil.js></script>">Visit MajorBank</a> Notice that the link includes a query string variable named username and the value of the username variable is an HTML <SCRIPT> tag which points to a JavaScript file named Evil.js. When anyone clicks on the link, the <SCRIPT> tag will be injected into SomePage.aspx and the Evil.js script will be loaded and executed. What can a hacker do in the Evil.js script? Anything the hacker wants. For example, the hacker could display a popup dialog on the MajorBank.com site which asks the user to enter their password. The script could then post the password back to hackers.com and now the evil hacker has your secret password. ASP.NET Web Forms and ASP.NET MVC have two automatic safeguards against this type of attack: Request Validation and Automatic HTML Encoding. Protecting Coming In (Request Validation) In a server-side ASP.NET app, you are protected against the XSS attack described above by a feature named Request Validation. If you attempt to submit “potentially dangerous” content — such as a JavaScript <SCRIPT> tag — in a form field or query string variable then you get an exception. Unfortunately, Request Validation only applies to server-side apps. Request Validation does not help in the case of a Single Page App. In particular, the ASP.NET Web API does not pay attention to Request Validation. You can post any content you want – including <SCRIPT> tags – to an ASP.NET Web API action. For example, the following HTML page contains a form. When you submit the form, the form data is submitted to an ASP.NET Web API controller on the server using an Ajax request: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title></title> </head> <body> <form data-bind="submit:submit"> <div> <label> User Name: <input data-bind="value:user.userName" /> </label> </div> <div> <label> Email: <input data-bind="value:user.email" /> </label> </div> <div> <input type="submit" value="Submit" /> </div> </form> <script src="Scripts/jquery-1.7.1.js"></script> <script src="Scripts/knockout-2.1.0.js"></script> <script> var viewModel = { user: { userName: ko.observable(), email: ko.observable() }, submit: function () { $.post("/api/users", ko.toJS(this.user)); } }; ko.applyBindings(viewModel); </script> </body> </html> The form above is using Knockout to bind the form fields to a view model. When you submit the form, the view model is submitted to an ASP.NET Web API action on the server. Here’s the server-side ASP.NET Web API controller and model class: public class UsersController : ApiController { public HttpResponseMessage Post(UserViewModel user) { var userName = user.UserName; return Request.CreateResponse(HttpStatusCode.OK); } } public class UserViewModel { public string UserName { get; set; } public string Email { get; set; } } If you submit the HTML form, you don’t get an error. The “potentially dangerous” content is passed to the server without any exception being thrown. In the screenshot below, you can see that I was able to post a username form field with the value “<script>alert(‘boo’)</script”. So what this means is that you do not get automatic Request Validation in the case of a Single Page App. You need to be extra careful in a Single Page App about ensuring that you do not display untrusted content because you don’t have the Request Validation safety net which you have in a traditional server-side ASP.NET app. Protecting Going Out (Automatic HTML Encoding) Server-side ASP.NET also protects you from XSS attacks when you render content. By default, all content rendered by the razor view engine is HTML encoded. For example, the following razor view displays the text “<b>Hello!</b>” instead of the text “Hello!” in bold: @{ var message = "<b>Hello!</b>"; } @message   If you don’t want to render content as HTML encoded in razor then you need to take the extra step of using the @Html.Raw() helper. In a Web Form page, if you use <%: %> instead of <%= %> then you get automatic HTML Encoding: <%@ Page Language="C#" %> <% var message = "<b>Hello!</b>"; %> <%: message %> This automatic HTML Encoding will prevent many types of XSS attacks. It prevents <script> tags from being rendered and only allows &lt;script&gt; tags to be rendered which are useless for executing JavaScript. (This automatic HTML encoding does not protect you from all forms of XSS attacks. For example, you can assign the value “javascript:alert(‘evil’)” to the Hyperlink control’s NavigateUrl property and execute the JavaScript). The situation with Knockout is more complicated. If you use the Knockout TEXT binding then you get HTML encoded content. On the other hand, if you use the HTML binding then you do not: <!-- This JavaScript DOES NOT execute --> <div data-bind="text:someProp"></div> <!-- This Javacript DOES execute --> <div data-bind="html:someProp"></div> <script src="Scripts/jquery-1.7.1.js"></script> <script src="Scripts/knockout-2.1.0.js"></script> <script> var viewModel = { someProp : "<script>alert('Evil!')<" + "/script>" }; ko.applyBindings(viewModel); </script>   So, in the page above, the DIV element which uses the TEXT binding is safe from XSS attacks. According to the Knockout documentation: “Since this binding sets your text value using a text node, it’s safe to set any string value without risking HTML or script injection.” Just like server-side HTML encoding, Knockout does not protect you from all types of XSS attacks. For example, there is nothing in Knockout which prevents you from binding JavaScript to a hyperlink like this: <a data-bind="attr:{href:homePageUrl}">Go</a> <script src="Scripts/jquery-1.7.1.min.js"></script> <script src="Scripts/knockout-2.1.0.js"></script> <script> var viewModel = { homePageUrl: "javascript:alert('evil!')" }; ko.applyBindings(viewModel); </script> In the page above, the value “javascript:alert(‘evil’)” is bound to the HREF attribute using Knockout. When you click the link, the JavaScript executes. Cross-Site Request Forgery (CSRF) Attacks Cross-Site Request Forgery (CSRF) attacks rely on the fact that a session cookie does not expire until you close your browser. In particular, if you visit and login to MajorBank.com and then you navigate to Hackers.com then you will still be authenticated against MajorBank.com even after you navigate to Hackers.com. Because MajorBank.com cannot tell whether a request is coming from MajorBank.com or Hackers.com, Hackers.com can submit requests to MajorBank.com pretending to be you. For example, Hackers.com can post an HTML form from Hackers.com to MajorBank.com and change your email address at MajorBank.com. Hackers.com can post a form to MajorBank.com using your authentication cookie. After your email address has been changed, by using a password reset page at MajorBank.com, a hacker can access your bank account. To prevent CSRF attacks, you need some mechanism for detecting whether a request is coming from a page loaded from your website or whether the request is coming from some other website. The recommended way of preventing Cross-Site Request Forgery attacks is to use the “Synchronizer Token Pattern” as described here: https://www.owasp.org/index.php/Cross-Site_Request_Forgery_%28CSRF%29_Prevention_Cheat_Sheet When using the Synchronizer Token Pattern, you include a hidden input field which contains a random token whenever you display an HTML form. When the user opens the form, you add a cookie to the user’s browser with the same random token. When the user posts the form, you verify that the hidden form token and the cookie token match. Preventing Cross-Site Request Forgery Attacks with ASP.NET MVC ASP.NET gives you a helper and an action filter which you can use to thwart Cross-Site Request Forgery attacks. For example, the following razor form for creating a product shows how you use the @Html.AntiForgeryToken() helper: @model MvcApplication2.Models.Product <h2>Create Product</h2> @using (Html.BeginForm()) { @Html.AntiForgeryToken(); <div> @Html.LabelFor( p => p.Name, "Product Name:") @Html.TextBoxFor( p => p.Name) </div> <div> @Html.LabelFor( p => p.Price, "Product Price:") @Html.TextBoxFor( p => p.Price) </div> <input type="submit" /> } The @Html.AntiForgeryToken() helper generates a random token and assigns a serialized version of the same random token to both a cookie and a hidden form field. (Actually, if you dive into the source code, the AntiForgeryToken() does something a little more complex because it takes advantage of a user’s identity when generating the token). Here’s what the hidden form field looks like: <input name=”__RequestVerificationToken” type=”hidden” value=”NqqZGAmlDHh6fPTNR_mti3nYGUDgpIkCiJHnEEL59S7FNToyyeSo7v4AfzF2i67Cv0qTB1TgmZcqiVtgdkW2NnXgEcBc-iBts0x6WAIShtM1″ /> And here’s what the cookie looks like using the Google Chrome developer toolbar: You use the [ValidateAntiForgeryToken] action filter on the controller action which is the recipient of the form post to validate that the token in the hidden form field matches the token in the cookie. If the tokens don’t match then validation fails and you can’t post the form: public ActionResult Create() { return View(); } [ValidateAntiForgeryToken] [HttpPost] public ActionResult Create(Product productToCreate) { if (ModelState.IsValid) { // save product to db return RedirectToAction("Index"); } return View(); } How does this all work? Let’s imagine that a hacker has copied the Create Product page from MajorBank.com to Hackers.com – the hacker grabs the HTML source and places it at Hackers.com. Now, imagine that the hacker trick you into submitting the Create Product form from Hackers.com to MajorBank.com. You’ll get the following exception: The Cross-Site Request Forgery attack is blocked because the anti-forgery token included in the Create Product form at Hackers.com won’t match the anti-forgery token stored in the cookie in your browser. The tokens were generated at different times for different users so the attack fails. Preventing Cross-Site Request Forgery Attacks with a Single Page App In a Single Page App, you can’t prevent Cross-Site Request Forgery attacks using the same method as a server-side ASP.NET MVC app. In a Single Page App, HTML forms are not generated on the server. Instead, in a Single Page App, forms are loaded dynamically in the browser. Phil Haack has a blog post on this topic where he discusses passing the anti-forgery token in an Ajax header instead of a hidden form field. He also describes how you can create a custom anti-forgery token attribute to compare the token in the Ajax header and the token in the cookie. See: http://haacked.com/archive/2011/10/10/preventing-csrf-with-ajax.aspx Also, take a look at Johan’s update to Phil Haack’s original post: http://johan.driessen.se/posts/Updated-Anti-XSRF-Validation-for-ASP.NET-MVC-4-RC (Other server frameworks such as Rails and Django do something similar. For example, Rails uses an X-CSRF-Token to prevent CSRF attacks which you generate on the server – see http://excid3.com/blog/rails-tip-2-include-csrf-token-with-every-ajax-request/#.UTFtgDDkvL8 ). For example, if you are creating a Durandal app, then you can use the following razor view for your one and only server-side page: @{ Layout = null; } <!DOCTYPE html> <html> <head> <title>Index</title> </head> <body> @Html.AntiForgeryToken() <div id="applicationHost"> Loading app.... </div> @Scripts.Render("~/scripts/vendor") <script type="text/javascript" src="~/App/durandal/amd/require.js" data-main="/App/main"></script> </body> </html> Notice that this page includes a call to @Html.AntiForgeryToken() to generate the anti-forgery token. Then, whenever you make an Ajax request in the Durandal app, you can retrieve the anti-forgery token from the razor view and pass the token as a header: var csrfToken = $("input[name='__RequestVerificationToken']").val(); $.ajax({ headers: { __RequestVerificationToken: csrfToken }, type: "POST", dataType: "json", contentType: 'application/json; charset=utf-8', url: "/api/products", data: JSON.stringify({ name: "Milk", price: 2.33 }), statusCode: { 200: function () { alert("Success!"); } } }); Use the following code to create an action filter which you can use to match the header and cookie tokens: using System.Linq; using System.Net.Http; using System.Web.Helpers; using System.Web.Http.Controllers; namespace MvcApplication2.Infrastructure { public class ValidateAjaxAntiForgeryToken : System.Web.Http.AuthorizeAttribute { protected override bool IsAuthorized(HttpActionContext actionContext) { var headerToken = actionContext .Request .Headers .GetValues("__RequestVerificationToken") .FirstOrDefault(); ; var cookieToken = actionContext .Request .Headers .GetCookies() .Select(c => c[AntiForgeryConfig.CookieName]) .FirstOrDefault(); // check for missing cookie or header if (cookieToken == null || headerToken == null) { return false; } // ensure that the cookie matches the header try { AntiForgery.Validate(cookieToken.Value, headerToken); } catch { return false; } return base.IsAuthorized(actionContext); } } } Notice that the action filter derives from the base AuthorizeAttribute. The ValidateAjaxAntiForgeryToken only works when the user is authenticated and it will not work for anonymous requests. Add the action filter to your ASP.NET Web API controller actions like this: [ValidateAjaxAntiForgeryToken] public HttpResponseMessage PostProduct(Product productToCreate) { // add product to db return Request.CreateResponse(HttpStatusCode.OK); } After you complete these steps, it won’t be possible for a hacker to pretend to be you at Hackers.com and submit a form to MajorBank.com. The header token used in the Ajax request won’t travel to Hackers.com. This approach works, but I am not entirely happy with it. The one thing that I don’t like about this approach is that it creates a hard dependency on using razor. Your single page in your Single Page App must be generated from a server-side razor view. A better solution would be to generate the anti-forgery token in JavaScript. Unfortunately, until all browsers support a way to generate cryptographically strong random numbers – for example, by supporting the window.crypto.getRandomValues() method — there is no good way to generate anti-forgery tokens in JavaScript. So, at least right now, the best solution for generating the tokens is the server-side solution with the (regrettable) dependency on razor. Conclusion The goal of this blog entry was to explore some ways in which you need to handle security differently in the case of a Single Page App than in the case of a traditional server app. In particular, I focused on how to prevent Cross-Site Scripting and Cross-Site Request Forgery attacks in the case of a Single Page App. I want to emphasize that I am not suggesting that Single Page Apps are inherently less secure than server-side apps. Whatever type of web application you build – regardless of whether it is a Single Page App, an ASP.NET MVC app, an ASP.NET Web Forms app, or a Rails app – you must constantly guard against security vulnerabilities.

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  • Much Ado About Nothing: Stub Objects

    - by user9154181
    The Solaris 11 link-editor (ld) contains support for a new type of object that we call a stub object. A stub object is a shared object, built entirely from mapfiles, that supplies the same linking interface as the real object, while containing no code or data. Stub objects cannot be executed — the runtime linker will kill any process that attempts to load one. However, you can link to a stub object as a dependency, allowing the stub to act as a proxy for the real version of the object. You may well wonder if there is a point to producing an object that contains nothing but linking interface. As it turns out, stub objects are very useful for building large bodies of code such as Solaris. In the last year, we've had considerable success in applying them to one of our oldest and thorniest build problems. In this discussion, I will describe how we came to invent these objects, and how we apply them to building Solaris. This posting explains where the idea for stub objects came from, and details our long and twisty journey from hallway idea to standard link-editor feature. I expect that these details are mainly of interest to those who work on Solaris and its makefiles, those who have done so in the past, and those who work with other similar bodies of code. A subsequent posting will omit the history and background details, and instead discuss how to build and use stub objects. If you are mainly interested in what stub objects are, and don't care about the underlying software war stories, I encourage you to skip ahead. The Long Road To Stubs This all started for me with an email discussion in May of 2008, regarding a change request that was filed in 2002, entitled: 4631488 lib/Makefile is too patient: .WAITs should be reduced This CR encapsulates a number of cronic issues with Solaris builds: We build Solaris with a parallel make (dmake) that tries to build as much of the code base in parallel as possible. There is a lot of code to build, and we've long made use of parallelized builds to get the job done quicker. This is even more important in today's world of massively multicore hardware. Solaris contains a large number of executables and shared objects. Executables depend on shared objects, and shared objects can depend on each other. Before you can build an object, you need to ensure that the objects it needs have been built. This implies a need for serialization, which is in direct opposition to the desire to build everying in parallel. To accurately build objects in the right order requires an accurate set of make rules defining the things that depend on each other. This sounds simple, but the reality is quite complex. In practice, having programmers explicitly specify these dependencies is a losing strategy: It's really hard to get right. It's really easy to get it wrong and never know it because things build anyway. Even if you get it right, it won't stay that way, because dependencies between objects can change over time, and make cannot help you detect such drifing. You won't know that you got it wrong until the builds break. That can be a long time after the change that triggered the breakage happened, making it hard to connect the cause and the effect. Usually this happens just before a release, when the pressure is on, its hard to think calmly, and there is no time for deep fixes. As a poor compromise, the libraries in core Solaris were built using a set of grossly incomplete hand written rules, supplemented with a number of dmake .WAIT directives used to group the libraries into sets of non-interacting groups that can be built in parallel because we think they don't depend on each other. From time to time, someone will suggest that we could analyze the built objects themselves to determine their dependencies and then generate make rules based on those relationships. This is possible, but but there are complications that limit the usefulness of that approach: To analyze an object, you have to build it first. This is a classic chicken and egg scenario. You could analyze the results of a previous build, but then you're not necessarily going to get accurate rules for the current code. It should be possible to build the code without having a built workspace available. The analysis will take time, and remember that we're constantly trying to make builds faster, not slower. By definition, such an approach will always be approximate, and therefore only incremantally more accurate than the hand written rules described above. The hand written rules are fast and cheap, while this idea is slow and complex, so we stayed with the hand written approach. Solaris was built that way, essentially forever, because these are genuinely difficult problems that had no easy answer. The makefiles were full of build races in which the right outcomes happened reliably for years until a new machine or a change in build server workload upset the accidental balance of things. After figuring out what had happened, you'd mutter "How did that ever work?", add another incomplete and soon to be inaccurate make dependency rule to the system, and move on. This was not a satisfying solution, as we tend to be perfectionists in the Solaris group, but we didn't have a better answer. It worked well enough, approximately. And so it went for years. We needed a different approach — a new idea to cut the Gordian Knot. In that discussion from May 2008, my fellow linker-alien Rod Evans had the initial spark that lead us to a game changing series of realizations: The link-editor is used to link objects together, but it only uses the ELF metadata in the object, consisting of symbol tables, ELF versioning sections, and similar data. Notably, it does not look at, or understand, the machine code that makes an object useful at runtime. If you had an object that only contained the ELF metadata for a dependency, but not the code or data, the link-editor would find it equally useful for linking, and would never know the difference. Call it a stub object. In the core Solaris OS, we require all objects to be built with a link-editor mapfile that describes all of its publically available functions and data. Could we build a stub object using the mapfile for the real object? It ought to be very fast to build stub objects, as there are no input objects to process. Unlike the real object, stub objects would not actually require any dependencies, and so, all of the stubs for the entire system could be built in parallel. When building the real objects, one could link against the stub objects instead of the real dependencies. This means that all the real objects can be built built in parallel too, without any serialization. We could replace a system that requires perfect makefile rules with a system that requires no ordering rules whatsoever. The results would be considerably more robust. We immediately realized that this idea had potential, but also that there were many details to sort out, lots of work to do, and that perhaps it wouldn't really pan out. As is often the case, it would be necessary to do the work and see how it turned out. Following that conversation, I set about trying to build a stub object. We determined that a faithful stub has to do the following: Present the same set of global symbols, with the same ELF versioning, as the real object. Functions are simple — it suffices to have a symbol of the right type, possibly, but not necessarily, referencing a null function in its text segment. Copy relocations make data more complicated to stub. The possibility of a copy relocation means that when you create a stub, the data symbols must have the actual size of the real data. Any error in this will go uncaught at link time, and will cause tragic failures at runtime that are very hard to diagnose. For reasons too obscure to go into here, involving tentative symbols, it is also important that the data reside in bss, or not, matching its placement in the real object. If the real object has more than one symbol pointing at the same data item, we call these aliased symbols. All data symbols in the stub object must exhibit the same aliasing as the real object. We imagined the stub library feature working as follows: A command line option to ld tells it to produce a stub rather than a real object. In this mode, only mapfiles are examined, and any object or shared libraries on the command line are are ignored. The extra information needed (function or data, size, and bss details) would be added to the mapfile. When building the real object instead of the stub, the extra information for building stubs would be validated against the resulting object to ensure that they match. In exploring these ideas, I immediately run headfirst into the reality of the original mapfile syntax, a subject that I would later write about as The Problem(s) With Solaris SVR4 Link-Editor Mapfiles. The idea of extending that poor language was a non-starter. Until a better mapfile syntax became available, which seemed unlikely in 2008, the solution could not involve extentions to the mapfile syntax. Instead, we cooked up the idea (hack) of augmenting mapfiles with stylized comments that would carry the necessary information. A typical definition might look like: # DATA(i386) __iob 0x3c0 # DATA(amd64,sparcv9) __iob 0xa00 # DATA(sparc) __iob 0x140 iob; A further problem then became clear: If we can't extend the mapfile syntax, then there's no good way to extend ld with an option to produce stub objects, and to validate them against the real objects. The idea of having ld read comments in a mapfile and parse them for content is an unacceptable hack. The entire point of comments is that they are strictly for the human reader, and explicitly ignored by the tool. Taking all of these speed bumps into account, I made a new plan: A perl script reads the mapfiles, generates some small C glue code to produce empty functions and data definitions, compiles and links the stub object from the generated glue code, and then deletes the generated glue code. Another perl script used after both objects have been built, to compare the real and stub objects, using data from elfdump, and validate that they present the same linking interface. By June 2008, I had written the above, and generated a stub object for libc. It was a useful prototype process to go through, and it allowed me to explore the ideas at a deep level. Ultimately though, the result was unsatisfactory as a basis for real product. There were so many issues: The use of stylized comments were fine for a prototype, but not close to professional enough for shipping product. The idea of having to document and support it was a large concern. The ideal solution for stub objects really does involve having the link-editor accept the same arguments used to build the real object, augmented with a single extra command line option. Any other solution, such as our prototype script, will require makefiles to be modified in deeper ways to support building stubs, and so, will raise barriers to converting existing code. A validation script that rederives what the linker knew when it built an object will always be at a disadvantage relative to the actual linker that did the work. A stub object should be identifyable as such. In the prototype, there was no tag or other metadata that would let you know that they weren't real objects. Being able to identify a stub object in this way means that the file command can tell you what it is, and that the runtime linker can refuse to try and run a program that loads one. At that point, we needed to apply this prototype to building Solaris. As you might imagine, the task of modifying all the makefiles in the core Solaris code base in order to do this is a massive task, and not something you'd enter into lightly. The quality of the prototype just wasn't good enough to justify that sort of time commitment, so I tabled the project, putting it on my list of long term things to think about, and moved on to other work. It would sit there for a couple of years. Semi-coincidentally, one of the projects I tacked after that was to create a new mapfile syntax for the Solaris link-editor. We had wanted to do something about the old mapfile syntax for many years. Others before me had done some paper designs, and a great deal of thought had already gone into the features it should, and should not have, but for various reasons things had never moved beyond the idea stage. When I joined Sun in late 2005, I got involved in reviewing those things and thinking about the problem. Now in 2008, fresh from relearning for the Nth time why the old mapfile syntax was a huge impediment to linker progress, it seemed like the right time to tackle the mapfile issue. Paving the way for proper stub object support was not the driving force behind that effort, but I certainly had them in mind as I moved forward. The new mapfile syntax, which we call version 2, integrated into Nevada build snv_135 in in February 2010: 6916788 ld version 2 mapfile syntax PSARC/2009/688 Human readable and extensible ld mapfile syntax In order to prove that the new mapfile syntax was adequate for general purpose use, I had also done an overhaul of the ON consolidation to convert all mapfiles to use the new syntax, and put checks in place that would ensure that no use of the old syntax would creep back in. That work went back into snv_144 in June 2010: 6916796 OSnet mapfiles should use version 2 link-editor syntax That was a big putback, modifying 517 files, adding 18 new files, and removing 110 old ones. I would have done this putback anyway, as the work was already done, and the benefits of human readable syntax are obvious. However, among the justifications listed in CR 6916796 was this We anticipate adding additional features to the new mapfile language that will be applicable to ON, and which will require all sharable object mapfiles to use the new syntax. I never explained what those additional features were, and no one asked. It was premature to say so, but this was a reference to stub objects. By that point, I had already put together a working prototype link-editor with the necessary support for stub objects. I was pleased to find that building stubs was indeed very fast. On my desktop system (Ultra 24), an amd64 stub for libc can can be built in a fraction of a second: % ptime ld -64 -z stub -o stubs/libc.so.1 -G -hlibc.so.1 \ -ztext -zdefs -Bdirect ... real 0.019708910 user 0.010101680 sys 0.008528431 In order to go from prototype to integrated link-editor feature, I knew that I would need to prove that stub objects were valuable. And to do that, I knew that I'd have to switch the Solaris ON consolidation to use stub objects and evaluate the outcome. And in order to do that experiment, ON would first need to be converted to version 2 mapfiles. Sub-mission accomplished. Normally when you design a new feature, you can devise reasonably small tests to show it works, and then deploy it incrementally, letting it prove its value as it goes. The entire point of stub objects however was to demonstrate that they could be successfully applied to an extremely large and complex code base, and specifically to solve the Solaris build issues detailed above. There was no way to finesse the matter — in order to move ahead, I would have to successfully use stub objects to build the entire ON consolidation and demonstrate their value. In software, the need to boil the ocean can often be a warning sign that things are trending in the wrong direction. Conversely, sometimes progress demands that you build something large and new all at once. A big win, or a big loss — sometimes all you can do is try it and see what happens. And so, I spent some time staring at ON makefiles trying to get a handle on how things work, and how they'd have to change. It's a big and messy world, full of complex interactions, unspecified dependencies, special cases, and knowledge of arcane makefile features... ...and so, I backed away, put it down for a few months and did other work... ...until the fall, when I felt like it was time to stop thinking and pondering (some would say stalling) and get on with it. Without stubs, the following gives a simplified high level view of how Solaris is built: An initially empty directory known as the proto, and referenced via the ROOT makefile macro is established to receive the files that make up the Solaris distribution. A top level setup rule creates the proto area, and performs operations needed to initialize the workspace so that the main build operations can be launched, such as copying needed header files into the proto area. Parallel builds are launched to build the kernel (usr/src/uts), libraries (usr/src/lib), and commands. The install makefile target builds each item and delivers a copy to the proto area. All libraries and executables link against the objects previously installed in the proto, implying the need to synchronize the order in which things are built. Subsequent passes run lint, and do packaging. Given this structure, the additions to use stub objects are: A new second proto area is established, known as the stub proto and referenced via the STUBROOT makefile macro. The stub proto has the same structure as the real proto, but is used to hold stub objects. All files in the real proto are delivered as part of the Solaris product. In contrast, the stub proto is used to build the product, and then thrown away. A new target is added to library Makefiles called stub. This rule builds the stub objects. The ld command is designed so that you can build a stub object using the same ld command line you'd use to build the real object, with the addition of a single -z stub option. This means that the makefile rules for building the stub objects are very similar to those used to build the real objects, and many existing makefile definitions can be shared between them. A new target is added to the Makefiles called stubinstall which delivers the stub objects built by the stub rule into the stub proto. These rules reuse much of existing plumbing used by the existing install rule. The setup rule runs stubinstall over the entire lib subtree as part of its initialization. All libraries and executables link against the objects in the stub proto rather than the main proto, and can therefore be built in parallel without any synchronization. There was no small way to try this that would yield meaningful results. I would have to take a leap of faith and edit approximately 1850 makefiles and 300 mapfiles first, trusting that it would all work out. Once the editing was done, I'd type make and see what happened. This took about 6 weeks to do, and there were many dark days when I'd question the entire project, or struggle to understand some of the many twisted and complex situations I'd uncover in the makefiles. I even found a couple of new issues that required changes to the new stub object related code I'd added to ld. With a substantial amount of encouragement and help from some key people in the Solaris group, I eventually got the editing done and stub objects for the entire workspace built. I found that my desktop system could build all the stub objects in the workspace in roughly a minute. This was great news, as it meant that use of the feature is effectively free — no one was likely to notice or care about the cost of building them. After another week of typing make, fixing whatever failed, and doing it again, I succeeded in getting a complete build! The next step was to remove all of the make rules and .WAIT statements dedicated to controlling the order in which libraries under usr/src/lib are built. This came together pretty quickly, and after a few more speed bumps, I had a workspace that built cleanly and looked like something you might actually be able to integrate someday. This was a significant milestone, but there was still much left to do. I turned to doing full nightly builds. Every type of build (open, closed, OpenSolaris, export, domestic) had to be tried. Each type failed in a new and unique way, requiring some thinking and rework. As things came together, I became aware of things that could have been done better, simpler, or cleaner, and those things also required some rethinking, the seeking of wisdom from others, and some rework. After another couple of weeks, it was in close to final form. My focus turned towards the end game and integration. This was a huge workspace, and needed to go back soon, before changes in the gate would made merging increasingly difficult. At this point, I knew that the stub objects had greatly simplified the makefile logic and uncovered a number of race conditions, some of which had been there for years. I assumed that the builds were faster too, so I did some builds intended to quantify the speedup in build time that resulted from this approach. It had never occurred to me that there might not be one. And so, I was very surprised to find that the wall clock build times for a stock ON workspace were essentially identical to the times for my stub library enabled version! This is why it is important to always measure, and not just to assume. One can tell from first principles, based on all those removed dependency rules in the library makefile, that the stub object version of ON gives dmake considerably more opportunities to overlap library construction. Some hypothesis were proposed, and shot down: Could we have disabled dmakes parallel feature? No, a quick check showed things being build in parallel. It was suggested that we might be I/O bound, and so, the threads would be mostly idle. That's a plausible explanation, but system stats didn't really support it. Plus, the timing between the stub and non-stub cases were just too suspiciously identical. Are our machines already handling as much parallelism as they are capable of, and unable to exploit these additional opportunities? Once again, we didn't see the evidence to back this up. Eventually, a more plausible and obvious reason emerged: We build the libraries and commands (usr/src/lib, usr/src/cmd) in parallel with the kernel (usr/src/uts). The kernel is the long leg in that race, and so, wall clock measurements of build time are essentially showing how long it takes to build uts. Although it would have been nice to post a huge speedup immediately, we can take solace in knowing that stub objects simplify the makefiles and reduce the possibility of race conditions. The next step in reducing build time should be to find ways to reduce or overlap the uts part of the builds. When that leg of the build becomes shorter, then the increased parallelism in the libs and commands will pay additional dividends. Until then, we'll just have to settle for simpler and more robust. And so, I integrated the link-editor support for creating stub objects into snv_153 (November 2010) with 6993877 ld should produce stub objects PSARC/2010/397 ELF Stub Objects followed by the work to convert the ON consolidation in snv_161 (February 2011) with 7009826 OSnet should use stub objects 4631488 lib/Makefile is too patient: .WAITs should be reduced This was a huge putback, with 2108 modified files, 8 new files, and 2 removed files. Due to the size, I was allowed a window after snv_160 closed in which to do the putback. It went pretty smoothly for something this big, a few more preexisting race conditions would be discovered and addressed over the next few weeks, and things have been quiet since then. Conclusions and Looking Forward Solaris has been built with stub objects since February. The fact that developers no longer specify the order in which libraries are built has been a big success, and we've eliminated an entire class of build error. That's not to say that there are no build races left in the ON makefiles, but we've taken a substantial bite out of the problem while generally simplifying and improving things. The introduction of a stub proto area has also opened some interesting new possibilities for other build improvements. As this article has become quite long, and as those uses do not involve stub objects, I will defer that discussion to a future article.

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  • Using the ASP.NET Cache to cache data in a Model or Business Object layer, without a dependency on System.Web in the layer - Part One.

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

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  • Nagging As A Strategy For Better Linking: -z guidance

    - by user9154181
    The link-editor (ld) in Solaris 11 has a new feature that we call guidance that is intended to help you build better objects. The basic idea behind guidance is that if (and only if) you request it, the link-editor will issue messages suggesting better options and other changes you might make to your ld command to get better results. You can choose to take the advice, or you can disable specific types of guidance while acting on others. In some ways, this works like an experienced friend leaning over your shoulder and giving you advice — you're free to take it or leave it as you see fit, but you get nudged to do a better job than you might have otherwise. We use guidance to build the core Solaris OS, and it has proven to be useful, both in improving our objects, and in making sure that regressions don't creep back in later. In this article, I'm going to describe the evolution in thinking and design that led to the implementation of the -z guidance option, as well as give a brief description of how it works. The guidance feature issues non-fatal warnings. However, experience shows that once developers get used to ignoring warnings, it is inevitable that real problems will be lost in the noise and ignored or missed. This is why we have a zero tolerance policy against build noise in the core Solaris OS. In order to get maximum benefit from -z guidance while maintaining this policy, I added the -z fatal-warnings option at the same time. Much of the material presented here is adapted from the arc case: PSARC 2010/312 Link-editor guidance The History Of Unfortunate Link-Editor Defaults The Solaris link-editor is one of the oldest Unix commands. It stands to reason that this would be true — in order to write an operating system, you need the ability to compile and link code. The original link-editor (ld) had defaults that made sense at the time. As new features were needed, command line option switches were added to let the user use them, while maintaining backward compatibility for those who didn't. Backward compatibility is always a concern in system design, but is particularly important in the case of the tool chain (compilers, linker, and related tools), since it is a basic building block for the entire system. Over the years, applications have grown in size and complexity. Important concepts like dynamic linking that didn't exist in the original Unix system were invented. Object file formats changed. In the case of System V Release 4 Unix derivatives like Solaris, the ELF (Extensible Linking Format) was adopted. Since then, the ELF system has evolved to provide tools needed to manage today's larger and more complex environments. Features such as lazy loading, and direct bindings have been added. In an ideal world, many of these options would be defaults, with rarely used options that allow the user to turn them off. However, the reality is exactly the reverse: For backward compatibility, these features are all options that must be explicitly turned on by the user. This has led to a situation in which most applications do not take advantage of the many improvements that have been made in linking over the last 20 years. If their code seems to link and run without issue, what motivation does a developer have to read a complex manpage, absorb the information provided, choose the features that matter for their application, and apply them? Experience shows that only the most motivated and diligent programmers will make that effort. We know that most programs would be improved if we could just get you to use the various whizzy features that we provide, but the defaults conspire against us. We have long wanted to do something to make it easier for our users to use the linkers more effectively. There have been many conversations over the years regarding this issue, and how to address it. They always break down along the following lines: Change ld Defaults Since the world would be a better place the newer ld features were the defaults, why not change things to make it so? This idea is simple, elegant, and impossible. Doing so would break a large number of existing applications, including those of ISVs, big customers, and a plethora of existing open source packages. In each case, the owner of that code may choose to follow our lead and fix their code, or they may view it as an invitation to reconsider their commitment to our platform. Backward compatibility, and our installed base of working software, is one of our greatest assets, and not something to be lightly put at risk. Breaking backward compatibility at this level of the system is likely to do more harm than good. But, it sure is tempting. New Link-Editor One might create a new linker command, not called 'ld', leaving the old command as it is. The new one could use the same code as ld, but would offer only modern options, with the proper defaults for features such as direct binding. The resulting link-editor would be a pleasure to use. However, the approach is doomed to niche status. There is a vast pile of exiting code in the world built around the existing ld command, that reaches back to the 1970's. ld use is embedded in large and unknown numbers of makefiles, and is used by name by compilers that execute it. A Unix link-editor that is not named ld will not find a majority audience no matter how good it might be. Finally, a new linker command will eventually cease to be new, and will accumulate its own burden of backward compatibility issues. An Option To Make ld Do The Right Things Automatically This line of reasoning is best summarized by a CR filed in 2005, entitled 6239804 make it easier for ld(1) to do what's best The idea is to have a '-z best' option that unchains ld from its backward compatibility commitment, and allows it to turn on the "best" set of features, as determined by the authors of ld. The specific set of features enabled by -z best would be subject to change over time, as requirements change. This idea is more realistic than the other two, but was never implemented because it has some important issues that we could never answer to our satisfaction: The -z best proposal assumes that the user can turn it on, and trust it to select good options without the user needing to be aware of the options being applied. This is a fallacy. Features such as direct bindings require the user to do some analysis to ensure that the resulting program will still operate properly. A user who is willing to do the work to verify that what -z best does will be OK for their application is capable of turning on those features directly, and therefore gains little added benefit from -z best. The intent is that when a user opts into -z best, that they understand that z best is subject to sometimes incompatible evolution. Experience teaches us that this won't work. People will use this feature, the meaning of -z best will change, code that used to build will fail, and then there will be complaints and demands to retract the change. When (not if) this occurs, we will of course defend our actions, and point at the disclaimer. We'll win some of those debates, and lose others. Ultimately, we'll end up with -z best2 (-z better), or other compromises, and our goal of simplifying the world will have failed. The -z best idea rolls up a set of features that may or may not be related to each other into a unit that must be taken wholesale, or not at all. It could be that only a subset of what it does is compatible with a given application, in which case the user is expected to abandon -z best and instead set the options that apply to their application directly. In doing so, they lose one of the benefits of -z best, that if you use it, future versions of ld may choose a different set of options, and automatically improve the object through the act of rebuilding it. I drew two conclusions from the above history: For a link-editor, backward compatibility is vital. If a given command line linked your application 10 years ago, you have every reason to expect that it will link today, assuming that the libraries you're linking against are still available and compatible with their previous interfaces. For an application of any size or complexity, there is no substitute for the work involved in examining the code and determining which linker options apply and which do not. These options are largely orthogonal to each other, and it can be reasonable not to use any or all of them, depending on the situation, even in modern applications. It is a mistake to tie them together. The idea for -z guidance came from consideration of these points. By decoupling the advice from the act of taking the advice, we can retain the good aspects of -z best while avoiding its pitfalls: -z guidance gives advice, but the decision to take that advice remains with the user who must evaluate its merit and make a decision to take it or not. As such, we are free to change the specific guidance given in future releases of ld, without breaking existing applications. The only fallout from this will be some new warnings in the build output, which can be ignored or dealt with at the user's convenience. It does not couple the various features given into a single "take it or leave it" option, meaning that there will never be a need to offer "-zguidance2", or other such variants as things change over time. Guidance has the potential to be our final word on this subject. The user is given the flexibility to disable specific categories of guidance without losing the benefit of others, including those that might be added to future versions of the system. Although -z fatal-warnings stands on its own as a useful feature, it is of particular interest in combination with -z guidance. Used together, the guidance turns from advice to hard requirement: The user must either make the suggested change, or explicitly reject the advice by specifying a guidance exception token, in order to get a build. This is valuable in environments with high coding standards. ld Command Line Options The guidance effort resulted in new link-editor options for guidance and for turning warnings into fatal errors. Before I reproduce that text here, I'd like to highlight the strategic decisions embedded in the guidance feature: In order to get guidance, you have to opt in. We hope you will opt in, and believe you'll get better objects if you do, but our default mode of operation will continue as it always has, with full backward compatibility, and without judgement. Guidance suggestions always offers specific advice, and not vague generalizations. You can disable some guidance without turning off the entire feature. When you get guidance warnings, you can choose to take the advice, or you can specify a keyword to disable guidance for just that category. This allows you to get guidance for things that are useful to you, without being bothered about things that you've already considered and dismissed. As the world changes, we will add new guidance to steer you in the right direction. All such new guidance will come with a keyword that let's you turn it off. In order to facilitate building your code on different versions of Solaris, we quietly ignore any guidance keywords we don't recognize, assuming that they are intended for newer versions of the link-editor. If you want to see what guidance tokens ld does and does not recognize on your system, you can use the ld debugging feature as follows: % ld -Dargs -z guidance=foo,nodefs debug: debug: Solaris Linkers: 5.11-1.2275 debug: debug: arg[1] option=-D: option-argument: args debug: arg[2] option=-z: option-argument: guidance=foo,nodefs debug: warning: unrecognized -z guidance item: foo The -z fatal-warning option is straightforward, and generally useful in environments with strict coding standards. Note that the GNU ld already had this feature, and we accept their option names as synonyms: -z fatal-warnings | nofatal-warnings --fatal-warnings | --no-fatal-warnings The -z fatal-warnings and the --fatal-warnings option cause the link-editor to treat warnings as fatal errors. The -z nofatal-warnings and the --no-fatal-warnings option cause the link-editor to treat warnings as non-fatal. This is the default behavior. The -z guidance option is defined as follows: -z guidance[=item1,item2,...] Provide guidance messages to suggest ld options that can improve the quality of the resulting object, or which are otherwise considered to be beneficial. The specific guidance offered is subject to change over time as the system evolves. Obsolete guidance offered by older versions of ld may be dropped in new versions. Similarly, new guidance may be added to new versions of ld. Guidance therefore always represents current best practices. It is possible to enable guidance, while preventing specific guidance messages, by providing a list of item tokens, representing the class of guidance to be suppressed. In this way, unwanted advice can be suppressed without losing the benefit of other guidance. Unrecognized item tokens are quietly ignored by ld, allowing a given ld command line to be executed on a variety of older or newer versions of Solaris. The guidance offered by the current version of ld, and the item tokens used to disable these messages, are as follows. Specify Required Dependencies Dynamic executables and shared objects should explicitly define all of the dependencies they require. Guidance recommends the use of the -z defs option, should any symbol references remain unsatisfied when building dynamic objects. This guidance can be disabled with -z guidance=nodefs. Do Not Specify Non-Required Dependencies Dynamic executables and shared objects should not define any dependencies that do not satisfy the symbol references made by the dynamic object. Guidance recommends that unused dependencies be removed. This guidance can be disabled with -z guidance=nounused. Lazy Loading Dependencies should be identified for lazy loading. Guidance recommends the use of the -z lazyload option should any dependency be processed before either a -z lazyload or -z nolazyload option is encountered. This guidance can be disabled with -z guidance=nolazyload. Direct Bindings Dependencies should be referenced with direct bindings. Guidance recommends the use of the -B direct, or -z direct options should any dependency be processed before either of these options, or the -z nodirect option is encountered. This guidance can be disabled with -z guidance=nodirect. Pure Text Segment Dynamic objects should not contain relocations to non-writable, allocable sections. Guidance recommends compiling objects with Position Independent Code (PIC) should any relocations against the text segment remain, and neither the -z textwarn or -z textoff options are encountered. This guidance can be disabled with -z guidance=notext. Mapfile Syntax All mapfiles should use the version 2 mapfile syntax. Guidance recommends the use of the version 2 syntax should any mapfiles be encountered that use the version 1 syntax. This guidance can be disabled with -z guidance=nomapfile. Library Search Path Inappropriate dependencies that are encountered by ld are quietly ignored. For example, a 32-bit dependency that is encountered when generating a 64-bit object is ignored. These dependencies can result from incorrect search path settings, such as supplying an incorrect -L option. Although benign, this dependency processing is wasteful, and might hide a build problem that should be solved. Guidance recommends the removal of any inappropriate dependencies. This guidance can be disabled with -z guidance=nolibpath. In addition, -z guidance=noall can be used to entirely disable the guidance feature. See Chapter 7, Link-Editor Quick Reference, in the Linker and Libraries Guide for more information on guidance and advice for building better objects. Example The following example demonstrates how the guidance feature is intended to work. We will build a shared object that has a variety of shortcomings: Does not specify all it's dependencies Specifies dependencies it does not use Does not use direct bindings Uses a version 1 mapfile Contains relocations to the readonly allocable text (not PIC) This scenario is sadly very common — many shared objects have one or more of these issues. % cat hello.c #include <stdio.h> #include <unistd.h> void hello(void) { printf("hello user %d\n", getpid()); } % cat mapfile.v1 # This version 1 mapfile will trigger a guidance message % cc hello.c -o hello.so -G -M mapfile.v1 -lelf As you can see, the operation completes without error, resulting in a usable object. However, turning on guidance reveals a number of things that could be better: % cc hello.c -o hello.so -G -M mapfile.v1 -lelf -zguidance ld: guidance: version 2 mapfile syntax recommended: mapfile.v1 ld: guidance: -z lazyload option recommended before first dependency ld: guidance: -B direct or -z direct option recommended before first dependency Undefined first referenced symbol in file getpid hello.o (symbol belongs to implicit dependency /lib/libc.so.1) printf hello.o (symbol belongs to implicit dependency /lib/libc.so.1) ld: warning: symbol referencing errors ld: guidance: -z defs option recommended for shared objects ld: guidance: removal of unused dependency recommended: libelf.so.1 warning: Text relocation remains referenced against symbol offset in file .rodata1 (section) 0xa hello.o getpid 0x4 hello.o printf 0xf hello.o ld: guidance: position independent (PIC) code recommended for shared objects ld: guidance: see ld(1) -z guidance for more information Given the explicit advice in the above guidance messages, it is relatively easy to modify the example to do the right things: % cat mapfile.v2 # This version 2 mapfile will not trigger a guidance message $mapfile_version 2 % cc hello.c -o hello.so -Kpic -G -Bdirect -M mapfile.v2 -lc -zguidance There are situations in which the guidance does not fit the object being built. For instance, you want to build an object without direct bindings: % cc -Kpic hello.c -o hello.so -G -M mapfile.v2 -lc -zguidance ld: guidance: -B direct or -z direct option recommended before first dependency ld: guidance: see ld(1) -z guidance for more information It is easy to disable that specific guidance warning without losing the overall benefit from allowing the remainder of the guidance feature to operate: % cc -Kpic hello.c -o hello.so -G -M mapfile.v2 -lc -zguidance=nodirect Conclusions The linking guidelines enforced by the ld guidance feature correspond rather directly to our standards for building the core Solaris OS. I'm sure that comes as no surprise. It only makes sense that we would want to build our own product as well as we know how. Solaris is usually the first significant test for any new linker feature. We now enable guidance by default for all builds, and the effect has been very positive. Guidance helps us find suboptimal objects more quickly. Programmers get concrete advice for what to change instead of vague generalities. Even in the cases where we override the guidance, the makefile rules to do so serve as documentation of the fact. Deciding to use guidance is likely to cause some up front work for most code, as it forces you to consider using new features such as direct bindings. Such investigation is worthwhile, but does not come for free. However, the guidance suggestions offer a structured and straightforward way to tackle modernizing your objects, and once that work is done, for keeping them that way. The investment is often worth it, and will replay you in terms of better performance and fewer problems. I hope that you find guidance to be as useful as we have.

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  • How to shoot yourself in the foot (DO NOT Read in the office)

    - by TATWORTH
    Originally posted on: http://geekswithblogs.net/TATWORTH/archive/2013/06/21/how-to-shoot-yourself-in-the-foot-do-not-read.aspxLet me make it absolutely clear - the following is:merely collated by your Geek from http://www.codeproject.com/Lounge.aspx?msg=3917012#xx3917012xxvery, very very funny so you read it in the presence of others at your own riskso here is the list - you have been warned!C You shoot yourself in the foot.   C++ You accidently create a dozen instances of yourself and shoot them all in the foot. Providing emergency medical assistance is impossible since you can't tell which are bitwise copies and which are just pointing at others and saying "That's me, over there."   FORTRAN You shoot yourself in each toe, iteratively, until you run out of toes, then you read in the next foot and repeat. If you run out of bullets, you continue anyway because you have no exception-handling facility.   Modula-2 After realizing that you can't actually accomplish anything in this language, you shoot yourself in the head.   COBOL USEing a COLT 45 HANDGUN, AIM gun at LEG.FOOT, THEN place ARM.HAND.FINGER on HANDGUN.TRIGGER and SQUEEZE. THEN return HANDGUN to HOLSTER. CHECK whether shoelace needs to be retied.   Lisp You shoot yourself in the appendage which holds the gun with which you shoot yourself in the appendage which holds the gun with which you shoot yourself in the appendage which holds...   BASIC Shoot yourself in the foot with a water pistol. On big systems, continue until entire lower body is waterlogged.   Forth Foot yourself in the shoot.   APL You shoot yourself in the foot; then spend all day figuring out how to do it in fewer characters.   Pascal The compiler won't let you shoot yourself in the foot.   Snobol If you succeed, shoot yourself in the left foot. If you fail, shoot yourself in the right foot.   HyperTalk Put the first bullet of the gun into foot left of leg of you. Answer the result.   Prolog You tell your program you want to be shot in the foot. The program figures out how to do it, but the syntax doesn't allow it to explain.   370 JCL You send your foot down to MIS with a 4000-page document explaining how you want it to be shot. Three years later, your foot comes back deep-fried.   FORTRAN-77 You shoot yourself in each toe, iteratively, until you run out of toes, then you read in the next foot and repeat. If you run out of bullets, you continue anyway because you still can't do exception-processing.   Modula-2 (alternative) You perform a shooting on what might be currently a foot with what might be currently a bullet shot by what might currently be a gun.   BASIC (compiled) You shoot yourself in the foot with a BB using a SCUD missile launcher.   Visual Basic You'll really only appear to have shot yourself in the foot, but you'll have so much fun doing it that you won't care.   Forth (alternative) BULLET DUP3 * GUN LOAD FOOT AIM TRIGGER PULL BANG! EMIT DEAD IF DROP ROT THEN (This takes about five bytes of memory, executes in two to ten clock cycles on any processor and can be used to replace any existing function of the language as well as in any future words). (Welcome to bottom up programming - where you, too, can perform compiler pre-processing instead of writing code)   APL (alternative) You hear a gunshot and there's a hole in your foot, but you don't remember enough linear algebra to understand what happened. or @#&^$%&%^ foot   Pascal (alternative) Same as Modula-2 except that the bullet is not the right type for the gun and your hand is blown off.   Snobol (alternative) You grab your foot with your hand, then rewrite your hand to be a bullet. The act of shooting the original foot then changes your hand/bullet into yet another foot (a left foot).   Prolog (alternative) You attempt to shoot yourself in the foot, but the bullet, failing to find its mark, backtracks to the gun, which then explodes in your face.   COMAL You attempt to shoot yourself in the foot with a water pistol, but the bore is clogged, and the pressure build-up blows apart both the pistol and your hand. or draw_pistol aim_at_foot(left) pull_trigger hop(swearing)   Scheme As Lisp, but none of the other appendages are aware of this happening.   Algol You shoot yourself in the foot with a musket. The musket is aesthetically fascinating and the wound baffles the adolescent medic in the emergency room.   Ada If you are dumb enough to actually use this language, the United States Department of Defense will kidnap you, stand you up in front of a firing squad and tell the soldiers, "Shoot at the feet." or The Department of Defense shoots you in the foot after offering you a blindfold and a last cigarette. or After correctly packaging your foot, you attempt to concurrently load the gun, pull the trigger, scream and shoot yourself in the foot. When you try, however, you discover that your foot is of the wrong type. or After correctly packing your foot, you attempt to concurrently load the gun, pull the trigger, scream, and confidently aim at your foot knowing it is safe. However the cordite in the round does an Unchecked Conversion, fires and shoots you in the foot anyway.   Eiffel   You create a GUN object, two FOOT objects and a BULLET object. The GUN passes both the FOOT objects a reference to the BULLET. The FOOT objects increment their hole counts and forget about the BULLET. A little demon then drives a garbage truck over your feet and grabs the bullet (both of it) on the way. Smalltalk You spend so much time playing with the graphics and windowing system that your boss shoots you in the foot, takes away your workstation and makes you develop in COBOL on a character terminal. or You send the message shoot to gun, with selectors bullet and myFoot. A window pops up saying Gunpowder doesNotUnderstand: spark. After several fruitless hours spent browsing the methods for Trigger, FiringPin and IdealGas, you take the easy way out and create ShotFoot, a subclass of Foot with an additional instance variable bulletHole. Object Oriented Pascal You perform a shooting on what might currently be a foot with what might currently be a bullet fired from what might currently be a gun.   PL/I You consume all available system resources, including all the offline bullets. The Data Processing & Payroll Department doubles its size, triples its budget, acquires four new mainframes and drops the original one on your foot. Postscript foot bullets 6 locate loadgun aim gun shoot showpage or It takes the bullet ten minutes to travel from the gun to your foot, by which time you're long since gone out to lunch. The text comes out great, though.   PERL You stab yourself in the foot repeatedly with an incredibly large and very heavy Swiss Army knife. or You pick up the gun and begin to load it. The gun and your foot begin to grow to huge proportions and the world around you slows down, until the gun fires. It makes a tiny hole, which you don't feel. Assembly Language You crash the OS and overwrite the root disk. The system administrator arrives and shoots you in the foot. After a moment of contemplation, the administrator shoots himself in the foot and then hops around the room rabidly shooting at everyone in sight. or You try to shoot yourself in the foot only to discover you must first reinvent the gun, the bullet, and your foot.or The bullet travels to your foot instantly, but it took you three weeks to load the round and aim the gun.   BCPL You shoot yourself somewhere in the leg -- you can't get any finer resolution than that. Concurrent Euclid You shoot yourself in somebody else's foot.   Motif You spend days writing a UIL description of your foot, the trajectory, the bullet and the intricate scrollwork on the ivory handles of the gun. When you finally get around to pulling the trigger, the gun jams.   Powerbuilder While attempting to load the gun you discover that the LoadGun system function is buggy; as a work around you tape the bullet to the outside of the gun and unsuccessfully attempt to fire it with a nail. In frustration you club your foot with the butt of the gun and explain to your client that this approximates the functionality of shooting yourself in the foot and that the next version of Powerbuilder will fix it.   Standard ML By the time you get your code to typecheck, you're using a shoot to foot yourself in the gun.   MUMPS You shoot 583149 AK-47 teflon-tipped, hollow-point, armour-piercing bullets into even-numbered toes on odd-numbered feet of everyone in the building -- with one line of code. Three weeks later you shoot yourself in the head rather than try to modify that line.   Java You locate the Gun class, but discover that the Bullet class is abstract, so you extend it and write the missing part of the implementation. Then you implement the ShootAble interface for your foot, and recompile the Foot class. The interface lets the bullet call the doDamage method on the Foot, so the Foot can damage itself in the most effective way. Now you run the program, and call the doShoot method on the instance of the Gun class. First the Gun creates an instance of Bullet, which calls the doFire method on the Gun. The Gun calls the hit(Bullet) method on the Foot, and the instance of Bullet is passed to the Foot. But this causes an IllegalHitByBullet exception to be thrown, and you die.   Unix You shoot yourself in the foot or % ls foot.c foot.h foot.o toe.c toe.o % rm * .o rm: .o: No such file or directory % ls %   370 JCL (alternative) You shoot yourself in the head just thinking about it.   DOS JCL You first find the building you're in in the phone book, then find your office number in the corporate phone book. Then you have to write this down, then describe, in cubits, your exact location, in relation to the door (right hand side thereof). Then you need to write down the location of the gun (loading it is a proprietary utility), then you load it, and the COBOL program, and run them, and, with luck, it may be run tonight.   VMS   $ MOUNT/DENSITY=.45/LABEL=BULLET/MESSAGE="BYE" BULLET::BULLET$GUN SYS$BULLET $ SET GUN/LOAD/SAFETY=OFF/SIGHT=NONE/HAND=LEFT/CHAMBER=1/ACTION=AUTOMATIC/ LOG/ALL/FULL SYS$GUN_3$DUA3:[000000]GUN.GNU $ SHOOT/LOG/AUTO SYS$GUN SYS$SYSTEM:[FOOT]FOOT.FOOT   %DCL-W-ACTIMAGE, error activating image GUN -CLI-E-IMGNAME, image file $3$DUA240:[GUN]GUN.EXE;1 -IMGACT-F-NOTNATIVE, image is not an OpenVMS Alpha AXP image or %SYS-F-FTSHT, foot shot (fifty lines of traceback omitted) sh,csh, etc You can't remember the syntax for anything, so you spend five hours reading manual pages, then your foot falls asleep. You shoot the computer and switch to C.   Apple System 7 Double click the gun icon and a window giving a selection for guns, target areas, plus balloon help with medical remedies, and assorted sound effects. Click "shoot" button and a small bomb appears with note "Error of Type 1 has occurred."   Windows 3.1 Double click the gun icon and wait. Eventually a window opens giving a selection for guns, target areas, plus balloon help with medical remedies, and assorted sound effects. Click "shoot" button and a small box appears with note "Unable to open Shoot.dll, check that path is correct."   Windows 95 Your gun is not compatible with this OS and you must buy an upgrade and install it before you can continue. Then you will be informed that you don't have enough memory.   CP/M I remember when shooting yourself in the foot with a BB gun was a big deal.   DOS You finally found the gun, but can't locate the file with the foot for the life of you.   MSDOS You shoot yourself in the foot, but can unshoot yourself with add-on software.   Access You try to point the gun at your foot, but it shoots holes in all your Borland distribution diskettes instead.   Paradox Not only can you shoot yourself in the foot, your users can too.   dBase You squeeze the trigger, but the bullet moves so slowly that by the time your foot feels the pain, you've forgotten why you shot yourself anyway. or You buy a gun. Bullets are only available from another company and are promised to work so you buy them. Then you find out that the next version of the gun is the one scheduled to actually shoot bullets.   DBase IV, V1.0 You pull the trigger, but it turns out that the gun was a poorly designed hand grenade and the whole building blows up.   SQL You cut your foot off, send it out to a service bureau and when it returns, it has a hole in it but will no longer fit the attachment at the end of your leg. or Insert into Foot Select Bullet >From Gun.Hand Where Chamber = 'LOADED' And Trigger = 'PULLED'   Clipper You grab a bullet, get ready to insert it in the gun so that you can shoot yourself in the foot and discover that the gun that the bullets fits has not yet been built, but should be arriving in the mail _REAL_SOON_NOW_. Oracle The menus for coding foot_shooting have not been implemented yet and you can't do foot shooting in SQL.   English You put your foot in your mouth, then bite it off. (For those who don't know, English is a McDonnell Douglas/PICK query language which allegedly requires 110% of system resources to run happily.) Revelation [an implementation of the PICK Operating System] You'll be able to shoot yourself in the foot just as soon as you figure out what all these bullets are for.   FlagShip Starting at the top of your head, you aim the gun at yourself repeatedly until, half an hour later, the gun is finally pointing at your foot and you pull the trigger. A new foot with a hole in it appears but you can't work out how to get rid of the old one and your gun doesn't work anymore.   FidoNet You put your foot in your mouth, then echo it internationally.   PicoSpan [a UNIX-based computer conferencing system] You can't shoot yourself in the foot because you're not a host. or (host variation) Whenever you shoot yourself in the foot, someone opens a topic in policy about it.   Internet You put your foot in your mouth, shoot it, then spam the bullet so that everybody gets shot in the foot.   troff rmtroff -ms -Hdrwp | lpr -Pwp2 & .*place bullet in footer .B .NR FT +3i .in 4 .bu Shoot! .br .sp .in -4 .br .bp NR HD -2i .*   Genetic Algorithms You create 10,000 strings describing the best way to shoot yourself in the foot. By the time the program produces the optimal solution, humans have evolved wings and the problem is moot.   CSP (Communicating Sequential Processes) You only fail to shoot everything that isn't your foot.   MS-SQL Server MS-SQL Server’s gun comes pre-loaded with an unlimited supply of Teflon coated bullets, and it only has two discernible features: the muzzle and the trigger. If that wasn't enough, MS-SQL Server also puts the gun in your hand, applies local anesthetic to the skin of your forefinger and stitches it to the gun's trigger. Meanwhile, another process has set up a spinal block to numb your lower body. It will then proceeded to surgically remove your foot, cryogenically freeze it for preservation, and attach it to the muzzle of the gun so that no matter where you aim, you will shoot your foot. In order to avoid shooting yourself in the foot, you need to unstitch your trigger finger, remove your foot from the muzzle of the gun, and have it surgically reattached. Then you probably want to get some crutches and go out to buy a book on SQL Server Performance Tuning.   Sybase Sybase's gun requires assembly, and you need to go out and purchase your own clip and bullets to load the gun. Assembly is complicated by the fact that Sybase has hidden the gun behind a big stack of reference manuals, but it hasn't told you where that stack is. While you were off finding the gun, assembling it, buying bullets, etc., Sybase was also busy surgically removing your foot and cryogenically freezing it for preservation. Instead of attaching it to the muzzle of the gun, though, it packed your foot on dry ice and sent it UPS-Ground to an unnamed hookah bar somewhere in the middle east. In order to shoot your foot, you must modify your gun with a GPS system for targeting and hire some guy named "Indy" to find the hookah bar and wire the coordinates back to you. By this time, you've probably become so daunted at the tasks stand between you and shooting your foot that you hire a guy who's read all the books on Sybase to help you shoot your foot. If you're lucky, he'll be smart enough both to find your foot and to stop you from shooting it.   Magic software You spend 1 week looking up the correct syntax for GUN. When you find it, you realise that GUN will not let you shoot in your own foot. It will allow you to shoot almost anything but your foot. You then decide to build your own gun. You can't use the standard barrel since this will only allow for standard bullets, which will not fire if the barrel is pointed at your foot. After four weeks, you have created your own custom gun. It blows up in your hand without warning, because you failed to initialise the safety catch and it doesn't know whether the initial state is "0", 0, NULL, "ZERO", 0.0, 0,0, "0.0", or "0,00". You fix the problem with your remaining hand by nesting 12 safety catches, and then decide to build the gun without safety catch. You then shoot the management and retire to a happy life where you code in languages that will allow you to shoot your foot in under 10 days.FirefoxLets you shoot yourself in as many feet as you'd like, while using multiple great addons! IEA moving target in terms of standard ammunition size and doesn't always work properly with non-Microsoft ammunition, so sometimes you shoot something other than your foot. However, it's the corporate world's standard foot-shooting apparatus. Hackers seem to enjoy rigging websites up to trigger cascading foot-shooting failures. Windows 98 About the same as Windows 95 in terms of overall bullet capacity and triggering mechanisms. Includes updated DirectShot API. A new version was released later on to support USB guns, Windows 98 SE.WPF:You get your baseball glove and a ball and you head out to your backyard, where you throw balls to your pitchback. Then your unkempt-haired-cargo-shorts-and-sandals-with-white-socks-wearing neighbor uses XAML to sculpt your arm into a gun, the ball into a bullet and the pitchback into your foot. By now, however, only the neighbor can get it to work and he's only around from 6:30 PM - 3:30 AM. LOGO: You very carefully lay out the trajectory of the bullet. Then you start the gun, which fires very slowly. You walk precisely to the point where the bullet will travel and wait, but just before it gets to you, your class time is up and one of the other kids has already used the system to hack into Sony's PS3 network. Flash: Someone has designed a beautiful-looking gun that anyone can shoot their feet with for free. It weighs six hundred pounds. All kinds of people are shooting themselves in the feet, and sending the link to everyone else so that they can too. That is, except for the criminals, who are all stealing iOS devices that the gun won't work with.APL: Its (mostly) all greek to me. Lisp: Place ((gun in ((hand sight (foot then shoot))))) (Lots of Insipid Stupid Parentheses)Apple OS/X and iOS Once a year, Steve Jobs returns from sick leave to tell millions of unwavering fans how they will be able to shoot themselves in the foot differently this year. They retweet and blog about it ad nauseam, and wait in line to be the first to experience "shoot different".Windows ME Usually fails, even at shooting you in the foot. Yo dawg, I heard you like shooting yourself in the foot. So I put a gun in your gun, so you can shoot yourself in the foot while you shoot yourself in the foot. (Okay, I'm not especially proud of this joke.) Windows 2000 Now you really do have to log in, before you are allowed to shoot yourself in the foot.Windows XPYou thought you learned your lesson: Don't use Windows ME. Then, along came this new creature, built on top of Windows NT! So you spend the next couple days installing antivirus software, patches and service packs, just so you can get that driver to install, and then proceed to shoot yourself in the foot. Windows Vista Newer! Glossier! Shootier! Windows 7 The bullets come out a lot smoother. Active Directory Each bullet now has an attached Bullet Identifier, and can be uniquely identified. Policies can be applied to dictate fragmentation, and the gun will occasionally have a confusing delay after the trigger has been pulled. PythonYou try to use import foot; foot.shoot() only to realize that's only available in 3.0, to which you can't yet upgrade from 2.7 because of all those extension libs lacking support. Solaris Shoots best when used on SPARC hardware, but still runs the trigger GUI under Java. After weeks of learning the appropriate STOP command to prevent the trigger from automatically being pressed on boot, you think you've got it under control. Then the one time you ever use dtrace, it hits a bug that fires the gun. MySQL The feature that allows you to shoot yourself in the foot has been in development for about 6 years, and they are adding it into the next version, which is coming out REAL SOON NOW, promise! But you can always check it out of source control and try it yourself (just not in any environment where data integrity is important because it will probably explode.) PostgreSQLAllows you to have a smug look on your face while you shoot yourself in the foot, because those MySQL guys STILL don't have that feature. NoSQL Barrel? Who needs a barrel? Just put the bullet on your foot, and strike it with a hammer. See? It's so much simpler and more efficient that way. You can even strike multiple bullets in one swing if you swing with a good enough arc, because hammers are easy to use. Getting them to synchronize is a little difficult, though.Eclipse There are about a dozen different packages for shooting yourself in the foot, with weird interdependencies on outdated components. Once you finally navigate the morass and get one installed, you then have something to look at while you shoot yourself in the foot with that package: You can watch the screen redraw.Outlook Makes it really easy to let everyone know you shot yourself in the foot!Shooting yourself in the foot using delegates.You really need to shoot yourself in the foot but you hate firearms (you don't want any dependency on the specifics of shooting) so you delegate it to somebody else. You don't care how it is done as long is shooting your foot. You can do it asynchronously in case you know you may faint so you are called back/slapped in the face by your shooter/friend (or background worker) when everything is done.C#You prepare the gun and the bullet, carefully modeling all of the physics of a bullet traveling through a foot. Just before you're about to pull the trigger, you stumble on System.Windows.BodyParts.Foot.ShootAt(System.Windows.Firearms.IGun gun) in the extended framework, realize you just wasted the entire afternoon, and shoot yourself in the head.PHP<?phprequire("foot_safety_check.php");?><!DOCTYPE HTML><html><head> <!--Lower!--><title>Shooting me in the foot</title></head> <body> <!--LOWER!!!--><leg> <!--OK, I made this one up...--><footer><?php echo (dungSift($_SERVER['HTTP_USER_AGENT'], "ie"))?("Your foot is safe, but you might want to wear a hard hat!"):("<div class=\"shot\">BANG!</div>"); ?></footer></leg> </body> </html>

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  • yum update works but yum --security update fails to work in Fedora 12

    - by bobo
    I had already installed the yum-security before. And I was going to do an update by entering the following command: [root@localhost /]# yum update Loaded plugins: presto, priorities, refresh-packagekit, security Skipping security plugin, no data Setting up Update Process Resolving Dependencies Skipping security plugin, no data --> Running transaction check ---> Package eject.i686 0:2.1.5-17.fc12 set to be updated ---> Package glibc.i686 0:2.11.1-4 set to be updated ---> Package glibc-common.i686 0:2.11.1-4 set to be updated ---> Package glibc-devel.i686 0:2.11.1-4 set to be updated ---> Package glibc-headers.i686 0:2.11.1-4 set to be updated ---> Package gnome-themes.noarch 0:2.28.1-3.fc12 set to be updated ---> Package gtk2.i686 0:2.18.9-3.fc12 set to be updated ---> Package gtk2-immodule-xim.i686 0:2.18.9-3.fc12 set to be updated ---> Package kernel-PAE.i686 0:2.6.32.11-99.fc12 set to be installed ---> Package kernel-PAE-devel.i686 0:2.6.32.11-99.fc12 set to be installed ---> Package kernel-PAEdebug-devel.i686 0:2.6.32.11-99.fc12 set to be installed ---> Package kernel-debug-devel.i686 0:2.6.32.11-99.fc12 set to be installed ---> Package kernel-devel.i686 0:2.6.32.11-99.fc12 set to be installed ---> Package kernel-firmware.noarch 0:2.6.32.11-99.fc12 set to be updated ---> Package kernel-headers.i686 0:2.6.32.11-99.fc12 set to be updated ---> Package libnetfilter_conntrack.i686 0:0.0.101-1.fc12 set to be updated ---> Package media-player-info.noarch 0:5-1.fc12 set to be updated ---> Package nscd.i686 0:2.11.1-4 set to be updated ---> Package perf.noarch 0:2.6.32.11-99.fc12 set to be updated ---> Package rhythmbox.i686 0:0.12.6-5.fc12 set to be updated ---> Package sysvinit-tools.i686 0:2.87-3.dsf.fc12 set to be updated --> Finished Dependency Resolution --> Running transaction check ---> Package kernel-PAE.i686 0:2.6.31.12-174.2.3.fc12 set to be erased --> Finished Dependency Resolution Dependencies Resolved ================================================================================ Package Arch Version Repository Size ================================================================================ Installing: kernel-PAE i686 2.6.32.11-99.fc12 updates 20 M kernel-PAE-devel i686 2.6.32.11-99.fc12 updates 6.2 M kernel-PAEdebug-devel i686 2.6.32.11-99.fc12 updates 6.2 M kernel-debug-devel i686 2.6.32.11-99.fc12 updates 6.2 M kernel-devel i686 2.6.32.11-99.fc12 updates 6.1 M Updating: eject i686 2.1.5-17.fc12 updates 49 k glibc i686 2.11.1-4 updates 4.2 M glibc-common i686 2.11.1-4 updates 14 M glibc-devel i686 2.11.1-4 updates 953 k glibc-headers i686 2.11.1-4 updates 590 k gnome-themes noarch 2.28.1-3.fc12 updates 1.5 M gtk2 i686 2.18.9-3.fc12 updates 3.2 M gtk2-immodule-xim i686 2.18.9-3.fc12 updates 60 k kernel-firmware noarch 2.6.32.11-99.fc12 updates 968 k kernel-headers i686 2.6.32.11-99.fc12 updates 749 k libnetfilter_conntrack i686 0.0.101-1.fc12 updates 37 k media-player-info noarch 5-1.fc12 updates 32 k nscd i686 2.11.1-4 updates 189 k perf noarch 2.6.32.11-99.fc12 updates 79 k rhythmbox i686 0.12.6-5.fc12 updates 4.0 M sysvinit-tools i686 2.87-3.dsf.fc12 updates 58 k Removing: kernel-PAE i686 2.6.31.12-174.2.3.fc12 @updates 72 M Transaction Summary ================================================================================ Install 5 Package(s) Upgrade 16 Package(s) Remove 1 Package(s) Reinstall 0 Package(s) Downgrade 0 Package(s) Total download size: 75 M Is this ok [y/N]: But then I changed my mind, I decided to do a security-only update instead of a full update, so I entered the following command: [root@localhost /]# yum --security update Loaded plugins: presto, priorities, refresh-packagekit, security Setting up Update Process Resolving Dependencies Limiting packages to security relevant ones http://download.fedoraproject.org/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.cuhk.edu.hk/pub/linux/fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ftp.cuhk.edu.hk/pub/linux/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.cuhk.edu.hk/pub/linux/fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ftp.riken.jp/Linux/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.riken.jp/Linux/fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://mirror.cse.iitk.ac.in/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirror.cse.iitk.ac.in/fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://mirrors.isu.net.sa/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirrors.isu.net.sa/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. ftp://ftp.chu.edu.tw/linux/Fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno -1] Metadata file does not match checksum Trying other mirror. http://mirror.yandex.ru/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirror.yandex.ru/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://linus.iyte.edu.tr/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://linus.iyte.edu.tr/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ftp.jaist.ac.jp/pub/Linux/Fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.jaist.ac.jp/pub/Linux/Fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ftp.kddilabs.jp/Linux/packages/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://srv2.ftp.ne.jp/Linux/packages/fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://www.ftp.ne.jp/Linux/distributions/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://srv2.ftp.ne.jp/Linux/distributions/fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ftp.rhd.ru/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.rhd.ru/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://mirrors.163.com/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirrors.163.com/fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://mirror.nus.edu.sg/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirror.nus.edu.sg/fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ftp.yz.yamagata-u.ac.jp/pub/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.yz.yamagata-u.ac.jp/pub/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ftp.linux.org.tr/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.linux.org.tr/fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://mirrors.cytanet.com.cy/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirrors.cytanet.com.cy/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://fedoramirror.hnsdc.com/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://fedoramirror.hnsdc.com/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ftp.twaren.net/Linux/Fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://c147.twaren.net/pub/Linux/Fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ftp.mirror.tw/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.mirror.tw/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ftp.cs.pu.edu.tw/Linux/Fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.cs.pu.edu.tw/Linux/Fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. http://ubuntu.cn99.com/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ubuntu.cn99.com/fedora/updates/12/i386/repodata/updateinfo.xml.gz Trying other mirror. Error: failure: repodata/updateinfo.xml.gz from updates: [Errno 256] No more mirrors to try. You could try using --skip-broken to work around the problem ^C[root@localhost /]# As it can be seen in the output, when I run the yum --security update command, it did show the Limiting packages to security relevant ones message so it's aware of the option. But I don't know why it keeps reporting the http error 416. I searched in google and found the following description of the error but it doesn't seem to help much. HTTP ERROR 416 - Requested Range Not Satisfiable A 416 status code indicates that the server was unable to fulfill the request. This may be, for example, because the client asked for the 800th-900th bytes of a document, but the document was only 200 bytes long. It suggests me to use the --skip-broken option, I tried and the output is the same. I already tested many times, it just doesn't work when the --security option is used. What could be the possible cause for this problem?

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