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• Foreach is crashing script, but no errors reported.

  - by ILMV

  So I've created this smarty function to get images from my flickr photostream using SimplePie... simple really, or so it should be. The problem I'm having is the foreach will crash the script, this doesn't happen if I put an exit after the closing foreach, of course because of this the rest of my script doesn't execute. The problem also completely subsides if I remove the foreach, I've tested it and it's not the contents of the foreach, but the loop itself. Error reporting is turned on but I don't get any, I also tried messing with the memory_limit, with no luck. Anyone know why this foreach is killing my script? Thanks! function smarty_function_flickr ($params, &$smarty) { require_once('system/library/SimplePie/simplepie.inc'); require_once('system/library/SimplePie/idn/idna_convert.class.php'); $flickr=new flickr(); /** * Set up SimplePie with all default values using shorthand syntax. */ $feed = new SimplePie($params['feed'], 'system/library/SimplePie/cache', '600'); $feed->handle_content_type(); /** * What sizes should we use? * Choices: square, thumb, small, medium, large. */ $thumb = 'square'; $full = 'medium'; $output = array(); $counter=0; // If I comment this foreach out the problem subsides, I know it is not the code within the foreach foreach ($feed->get_items() as $item) { $url = $flickr->image_from_description($item->get_description()); $output[$counter]['title'] = $item->get_title(); $output[$counter]['image'] = $flickr->select_image($url, $full); $output[$counter]['thumb'] = $flickr->select_image($url, $thumb); $counter++; } // Set template variables and template $smarty->assign('flickr',$output); $smarty->display('forms/'.$params['template'].'.tpl'); }

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• Improve Application Performace

  - by Gtest

  Hello, Want To Improvide Performace Of C#.Net Applicaiton.. In My Application I am using Third Party Interop/Dll To Process .doc Files. It's a Simple Operation, Which Pass Input/Output FilePath to Interop dll ...& dll will execute text form input file. To Improve Performace I have Tried, Execute 2 therad to process 32 files.(each Thread process 16 files) Execute application code by creating 2 new AppDomains(each AppDomain Code process 16 files) Execute Code Using TPL(Task Parellel Library) But all options take around same time (32 sec) to process 32 files.Manually process tooks same 32 sec to process 32 files. Just tried one thing ..when i have created sample exe to process 16 files as input & output for refrence PAth given in TextBox. ..I open 2 exe instance to process. 1 exe has differnt 16 input files & output Created with input file path 2 exe has differnt 16 input files & output Created with input file path When i click on start button of both exe ..it use 100% cpu & Utilize both core significantly & Process Completed within 16 sec for 32 files. Can we provide this kind of explicit prallism to Improve my applicaiton Peformace? Thanks.

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• Smarty multiple random numbers list

  - by Heinrich

  Hey Stackoverflow-Folks, is there any smart way to post random numbers (e.g. 1-4) in a list by using the smarty tpl-engine? standart list sorted 1-5: <ul> <li>1</li> <li>2</li> <li>3</li> <li>4</li> <li>5</li> </ul> Here's my solution (PHP): <ul> {foreach from=randomNumbers} <li>{smarty.randomNumbers}</li> {/foreach} </ul> modified list sorted 1-5 (random): <ul> <li>3</li> <li>2</li> <li>5</li> <li>1</li> <li>4</li> </ul> I've really tested nearly everything, but I do only need a smart & small solution for this :-) Kind Regards, Heinrich

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• ExtJs Grid in TabPanel auto Fit issue.

  - by Jinah Adam

  Hi, I am having problems redering an grid in a a tab panel (Its made with Ext Designer.). the hierarchy is as follows , Viewport. - tabPanel - Panel - Container - Grid. This is how its displayed now Here is the code for viewport mainWindowUi = Ext.extend(Ext.Viewport, { layout: 'border', id: 'mainWindow', initComponent: function() { this.items = [ { xtype: 'panel', title: 'Navigation', region: 'west', width: 200, frame: true, split: true, titleCollapse: true, collapsible: true, id: 'navigation', items: [ { flex: 1, xtype: 'mytreepanel' } ] }, { xtype: 'tabpanel', layoutOnTabChange: true, resizeTabs: true, defaults: { layout: 'fit', autoScroll: true }, region: 'center', tpl: '', id: 'mainTabPanel', layoutConfig: { deferredRender: true } } ]; mainWindowUi.superclass.initComponent.call(this); } }); here is the code to create the tab.. (created from a nav panel programmatically) var currentTab = tabPanel.findById(node.id); // If not yet created, create the tab if (!currentTab){ currentTab = tabPanel.add({ title:node.id, id:node.id, closable:true, items:[{ xtype: 'phasePanel', layout: 'fit', autoscroll: true, }], autoScroll:true, }); } // Activate tab tabPanel.setActiveTab(currentTab); here is the code for the panel/container/grid PhasePanelUi = Ext.extend(Ext.Panel, { frame: true, layout: 'anchor', autoScroll: true, autoWidth: true, defaults: '', initComponent: function() { this.items = [ { xtype: 'container', autoScroll: true, layout: 'fit', defaults: { layout: 'fit', autoScroll: true }, id: 'gridHolder', items: [ { xtype: 'grid', title: 'Current Phases', store: 'PhaseStore', autoDestroy: false, viewConfig: '', deferRowRender: false, autoLoad: '', ref: '../phaseGrid', id: 'phaseGrid', columns: [ { xtype: 'gridcolumn', header: 'Name', dataIndex: 'name', sortable: true, width: 200 }, { xtype: 'gridcolumn', header: 'Estate', dataIndex: 'estate_name', sortable: true, width: 500 } ] } ] } ]; PhasePanelUi.superclass.initComponent.call(this); } }); i have tried all sorts of combinations. but just cant get the grid to render correctly any sort of assistance will be appreciated.

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• Drupal administration theme doesn't apply to Blocks pages (admin/build/block)

  - by hfidgen

  A site I'm creating for a customer in D6 has various images overlaying parts of the main content area. It looks very pretty and they have to be there for the general effect. The problem is, if you use this theme in the administration pages, the images get in the way of everything. My solution was to create a custom admin theme, based on the default one, which has these image areas disabled in the output template files - page.tpl.php The problem is that when you try and edit the blocks page, it uses the default theme and half the blocks admin settings are unclickable behind the images. I KNOW this is by design in Drupal, but it's annoying the hell out of me and is edging towards "bug" rather than "feature" in my mind. It also appears that there is no way of getting around it. You can edit /modules/blocks/block.admin.inc to force Drupal to show the blocks page in the chosen admin theme. BUT whichever changes you then make will not be transferred to the default theme, as Drupal treats each theme separately and each theme can have different block layouts. :x function block_admin_display($theme = NULL) { global $custom_theme; // If non-default theme configuration has been selected, set the custom theme. // $custom_theme = isset($theme) ? $theme : variable_get('theme_default', 'garland'); // Display admin theme $custom_theme = variable_get('admin_theme', '0'); // Fetch and sort blocks $blocks = _block_rehash(); usort($blocks, '_block_compare'); return drupal_get_form('block_admin_display_form', $blocks, $theme); } Can anyone help? the only thing I can think of is to push the $content area well below the areas where the image appear and use blocks only for content display. Thanks!

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• jQuery noobie can't make a checked checkbox show an alert.

  - by Kyle Sevenoaks

  I found this answer before, to fire an alert if the button is pressed but the checkbox isn't checked. Why won't this work? <input value="1" type="checkbox" name="salgsvilkar" ID="checkbox2" style="float:left;" onclick="document.getElementById('scrollwrap').style.cssText='border-color:#85c222; background-color:#E5F7C7;';" /><label for="checkbox2" class="akslabel">Salgs og leveringsvilkår er lest og akseptert</label> </span> {literal} <script type="text/javascript"> $(function() { //checkbox $("#checkbox2").click(function(){ //if this... //alert("this")... if($("#checkbox2").is(':checked')) { alert("im checked"); } }); //button $("#fullfor_btn").click(function(e){ if(!$("#checkbox2").is(':checked')) { alert("you did not check the agree to terms..."); e.preventDefault(); } }); } </script> {/literal} This on another .tpl: <label></label> <button type="submit" class="submit" name="{$method}" id="fullfor_btn" title="Fullfør bestillingen nå" value="">&nbsp;</button> What could be going wrong? The jQuery doesn't fire anything at all.

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• Drupal 6: getting particular fields from Node Reference types...

  - by artmania

  Hi friends, I'm a drupal newbie... <?php print $node->field_date[0]['view']; ?> I can get the custom created CCK fields' value and display in tpl.php files as above... that's fine. my question is how can I get the Node reference fields' in-fields? for example, I have an event content type, and I have defined Node Reference for Location (title, address, img, etc.). When I write the code below, it displays all location content; <?php print $node->field_location[0]['view']; ?> but I need to get only address field from this location content type. sth like below would be great :D but not working; <?php print $node->field_location[0]['field_address']['view']; ?> so how can get that? appreciate helps so much! thanks a lot!

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• How can I merge two Linq IEnumerable<T> queries without running them?

  - by makerofthings7

  How do I merge a List<T> of TPL-based tasks for later execution? public async IEnumerable<Task<string>> CreateTasks(){ /* stuff*/ } My assumption is .Concat() but that doesn't seem to work: void MainTestApp() // Full sample available upon request. { List<string> nothingList = new List<string>(); nothingList.Add("whatever"); cts = new CancellationTokenSource(); delayedExecution = from str in nothingList select AccessTheWebAsync("", cts.Token); delayedExecution2 = from str in nothingList select AccessTheWebAsync("1", cts.Token); delayedExecution = delayedExecution.Concat(delayedExecution2); } /// SNIP async Task AccessTheWebAsync(string nothing, CancellationToken ct) { // return a Task } I want to make sure that this won't spawn any task or evaluate anything. In fact, I suppose I'm asking "what logically executes an IQueryable to something that returns data"? Background Since I'm doing recursion and I don't want to execute this until the correct time, what is the correct way to merge the results if called multiple times? If it matters I'm thinking of running this command to launch all the tasks var AllRunningDataTasks = results.ToList(); followed by this code: while (AllRunningDataTasks.Count > 0) { // Identify the first task that completes. Task<TableResult> firstFinishedTask = await Task.WhenAny(AllRunningDataTasks); // ***Remove the selected task from the list so that you don't // process it more than once. AllRunningDataTasks.Remove(firstFinishedTask); // TODO: Await the completed task. var taskOfTableResult = await firstFinishedTask; // Todo: (doen't work) TrustState thisState = (TrustState)firstFinishedTask.AsyncState; // TODO: Update the concurrent dictionary with data // thisState.QueryStartPoint + thisState.ThingToSearchFor Interlocked.Decrement(ref thisState.RunningDirectQueries); Interlocked.Increment(ref thisState.CompletedDirectQueries); if (thisState.RunningDirectQueries == 0) { thisState.TimeCompleted = DateTime.UtcNow; } }

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• Nginx - Treats PHP as binary

  - by Think Floyd

  We are running Nginx+FastCgi as the backend for our Drupal site. Everything seems to work like fine, except for this one url. http:///sites/all/modules/tinymce/tinymce/jscripts/tiny_mce/plugins/smimage/index.php (We use TinyMCE module in Drupal, and the url above is invoked when user tries to upload an image) When we were using Apache, everything was working fine. However, nginx treats that above url Binary and tries to Download it. (We've verified that the file pointed out by the url is a valid PHP file) Any idea what could be wrong here? I think it's something to do with the NGINX configuration, but not entirely sure what that is. Any help is greatly appreciated. Config: Here's the snippet from the nginx configuration file: root /var/www/; index index.php; if (!-e $request_filename) { rewrite ^/(.*)$ /index.php?q=$1 last; } error_page 404 index.php; location ~* \.(engine|inc|info|install|module|profile|po|sh|.*sql|theme|tpl(\.php)?|xtmpl)$|^(code-style\.pl|Entries.*|Repository|Root|Tag|Template)$ { deny all; } location ~* ^.+\.(jpg|jpeg|gif|png|ico)$ { access_log off; expires 7d; } location ~* ^.+\.(css|js)$ { access_log off; expires 7d; } location ~ .php$ { include /etc/nginx/fcgi.conf; fastcgi_pass 127.0.0.1:8888; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; fastcgi_param QUERY_STRING $query_string; fastcgi_param REQUEST_METHOD $request_method; fastcgi_param CONTENT_TYPE $content_type; fastcgi_param CONTENT_LENGTH $content_length; } location ~ /\.ht { deny all; }

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• Task Parallel Library exception handling

  - by user1680766

  When handling exceptions in TPL tasks I have come across two ways to handle exceptions. The first catches the exception within the task and returns it within the result like so: var task = Task<Exception>.Factory.StartNew( () => { try { // Do Something return null; } catch (System.Exception e) { return e; } }); task.ContinueWith( r => { if (r.Result != null) { // Handle Exception } }); The second is the one shown within the documentation and I guess the proper way to do things: var task = Task.Factory.StartNew( () => { // Do Something }); task.ContinueWith( r => { if (r.Exception != null) { // Handle Aggregate Exception r.Exception.Handle(y => true); } }); I am wondering if there is anything wrong with the first approach? I have received 'unhandled aggregate exception' exceptions every now and again using this technique and was wondering how this can happen?

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• How to perform a Depth First Search iteratively using async/parallel processing?

  - by Prabhu

  Here is a method that does a DFS search and returns a list of all items given a top level item id. How could I modify this to take advantage of parallel processing? Currently, the call to get the sub items is made one by one for each item in the stack. It would be nice if I could get the sub items for multiple items in the stack at the same time, and populate my return list faster. How could I do this (either using async/await or TPL, or anything else) in a thread safe manner? private async Task<IList<Item>> GetItemsAsync(string topItemId) { var items = new List<Item>(); var topItem = await GetItemAsync(topItemId); Stack<Item> stack = new Stack<Item>(); stack.Push(topItem); while (stack.Count > 0) { var item = stack.Pop(); items.Add(item); var subItems = await GetSubItemsAsync(item.SubId); foreach (var subItem in subItems) { stack.Push(subItem); } } return items; } EDIT: I was thinking of something along these lines, but it's not coming together: var tasks = stack.Select(async item => { items.Add(item); var subItems = await GetSubItemsAsync(item.SubId); foreach (var subItem in subItems) { stack.Push(subItem); } }).ToList(); if (tasks.Any()) await Task.WhenAll(tasks); UPDATE: If I wanted to chunk the tasks, would something like this work? foreach (var batch in items.BatchesOf(100)) { var tasks = batch.Select(async item => { await DoSomething(item); }).ToList(); if (tasks.Any()) { await Task.WhenAll(tasks); } } The language I'm using is C#.

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• Mercurial: Class library that will exist for both .NET 3.5 and 4.0?

  - by Lasse V. Karlsen

  I have a rather big class library written in .NET 3.5 that I'd like to upgrade to make available for .NET 4.0 as well. In that process, I will rip out a lot of old junk, and rewrite some code to better take advantage of the new classes and support in .NET 4.0 (like TPL.) The class libraries will thus diverge, but still be similar enough that some bug-fixes can be done to both in the same manner. How should I best organize this class library in Mercurial? I'm using Kiln (fogbugz) if that matters. I'm thinking: Named branches in one repository, can then transplant any bugfixes from one to the other Unnamed branches in one repository, can also transplant, but I think this will look messy Separate repositories, will have to reimplement the bugfixes (or use a non-mercurial-integraded compare tool to help me) What would you do? (any other alternatives that I haven't though of is welcome as well.) Note that the class libraries will diverge pretty heavily in areas, I have some remnants of old collection-type code that does something similar to Linq that I will remove, and some code that uses it that I will rewrite to use the Linq-methods instead. As such, just copying the project files and using #if NET40..#endif sections is not going to work out. Also, the 3.5 version of the class library will not be getting many new features, mostly just critical bug-fixes, so keeping both versions equally "alive" isn't really necessary. Thus, separate copies of all the files are good enough.

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• how to unzip uploaded zip file?

  - by Jaydeepsinh Jadeja

  I am trying to upload a zipped file using codeigniter framework with following code function do_upload() { $name=time(); $config['upload_path'] = './uploadedModules/'; $config['allowed_types'] = 'zip|rar'; $this->load->library('upload', $config); if ( ! $this->upload->do_upload()) { $error = array('error' => $this->upload->display_errors()); $this->load->view('upload_view', $error); } else { $data = array('upload_data' => $this->upload->data()); $this->load->library('unzip'); // Optional: Only take out these files, anything else is ignored $this->unzip->allow(array('css', 'js', 'png', 'gif', 'jpeg', 'jpg', 'tpl', 'html', 'swf')); $this->unzip->extract('./uploadedModules/'.$data['upload_data']['file_name'], './application/modules/'); $pieces = explode(".", $data['upload_data']['file_name']); $title=$pieces[0]; $status=1; $core=0; $this->addons_model->insertNewModule($title,$status,$core); } } But the main problem is that when extract function is called, it extract the zip but the result is empty folder. Is there any way to overcome this problem?

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• nginx proxypass content 404s when adding caching location block

  - by Thermionix

  Below is my nginx conf - the location block for adding expires max to content is causing issues with content from the /internal proxied sites. nginx error log; 2011/11/22 15:51:23 [error] 22124#0: *2 open() "/var/www/internal/static/javascripts/lib.js" failed (2: No such file or directory), client: 127.0.0.1, server: example.com, request: "GET /internal/static/javascripts/lib.js?0.6.11RC1 HTTP/1.1", host: "example.com", referrer: "https://example.com/internal/" browser error; lib.js Failed to load resource: the server responded with a status of 404 (Not Found) commenting out the expires max location block allows the proxied sites to work as intended. Config files; proxy.conf location /internal { proxy_pass http://localhost:10001/internal/; include proxy.inc; } .... more entries .... sites-enabled/main server { listen 80; include www.conf; } server { listen 443; include proxy.conf; include www.conf; ssl on; } www.conf root /var/www; server_name example.com; location / { autoindex off; allow all; rewrite ^/$ /mainsite last; } location ~* \.(jpg|jpeg|gif|css|png|js|ico)$ { expires max; } # hide protected files location ~* \.(engine|inc|info|install|module|profile|po|sh|.*sql|theme|tpl(\.php)?|xtmpl)$|^(code-style\.pl|Entries.*|Repository|Root|Tag|Template)$ { deny all; } location ~ \.php$ { fastcgi_index index.php; include fastcgi_params; if (-f $request_filename) { fastcgi_pass 127.0.0.1:9000; } } proxy.inc proxy_connect_timeout 59s; proxy_send_timeout 600; proxy_read_timeout 600; proxy_buffer_size 64k; proxy_buffers 16 32k; proxy_pass_header Set-Cookie; proxy_redirect off; proxy_hide_header Vary; proxy_busy_buffers_size 64k; proxy_temp_file_write_size 64k; proxy_set_header Accept-Encoding ''; proxy_ignore_headers Cache-Control Expires; proxy_set_header Referer $http_referer; proxy_set_header Host $host; proxy_set_header Cookie $http_cookie; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-Host $host; proxy_set_header X-Forwarded-Server $host; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

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• Using LogParser - part 2

  - by fatherjack

  PersonAddress.csv SalesOrderDetail.tsv In part 1 of this series we downloaded and installed LogParser and used it to list data from a csv file. That was a good start and in this article we are going to see the different ways we can stream data and choose whether a whole file is selected. We are also going to take a brief look at what file types we can interrogate. If we take the query from part 1 and add a value for the output parameter as -o:datagrid so that the query becomes LOGPARSER "SELECT top 15 * FROM C:\LP\person_address.csv" -o:datagrid and run that we get a different result. A pop-up dialog that lets us view the results in a resizable grid. Notice that because we didn't specify the columns we wanted returned by LogParser (we used SELECT *) is has added two columns to the recordset - filename and rownumber. This behaviour can be very useful as we will see in future parts of this series. You can click Next 10 rows or All rows or close the datagrid once you are finished reviewing the data. You may have noticed that the files that I am working with are different file types - one is a csv (comma separated values) and the other is a tsv (tab separated values). If you want to convert a file from one to another then LogParser makes it incredibly simple. Rather than using 'datagrid' as the value for the output parameter, use 'csv': logparser "SELECT SalesOrderID, SalesOrderDetailID, CarrierTrackingNumber, OrderQty, ProductID, SpecialOfferID, UnitPrice, UnitPriceDiscount, LineTotal, rowguid, ModifiedDate into C:\Sales_SalesOrderDetail.csv FROM C:\Sales_SalesOrderDetail.tsv" -i:tsv -o:csv Those familiar with SQL will not have to make a very big leap of faith to making adjustments to the above query to filter in/out records from the source file. Lets get all the records from the same file where the Order Quantity (OrderQty) is more than 25: logparser "SELECT SalesOrderID, SalesOrderDetailID, CarrierTrackingNumber, OrderQty, ProductID, SpecialOfferID, UnitPrice, UnitPriceDiscount, LineTotal, rowguid, ModifiedDate into C:\LP\Sales_SalesOrderDetailOver25.csv FROM C:\LP\Sales_SalesOrderDetail.tsv WHERE orderqty > 25" -i:tsv -o:csv Or we could find all those records where the Order Quantity is equal to 25 and output it to an xml file: logparser "SELECT SalesOrderID, SalesOrderDetailID, CarrierTrackingNumber, OrderQty, ProductID, SpecialOfferID, UnitPrice, UnitPriceDiscount, LineTotal, rowguid, ModifiedDate into C:\LP\Sales_SalesOrderDetailEq25.xml FROM C:\LP\Sales_SalesOrderDetail.tsv WHERE orderqty = 25" -i:tsv -o:xml All the standard comparison operators are to be found in LogParser; >, <, =, LIKE, BETWEEN, OR, NOT, AND. Input and Output file formats. LogParser has a pretty impressive list of file formats that it can parse and a good selection of output formats that will let you generate output in a format that is useable for whatever process or application you may be using. From any of these To any of these IISW3C: parses IIS log files in the W3C Extended Log File Format.   NAT: formats output records as readable tabulated columns. IIS: parses IIS log files in the Microsoft IIS Log File Format. CSV: formats output records as comma-separated values text. BIN: parses IIS log files in the Centralized Binary Log File Format. TSV: formats output records as tab-separated or space-separated values text. IISODBC: returns database records from the tables logged to by IIS when configured to log in the ODBC Log Format. XML: formats output records as XML documents. HTTPERR: parses HTTP error log files generated by Http.sys. W3C: formats output records in the W3C Extended Log File Format. URLSCAN: parses log files generated by the URLScan IIS filter. TPL: formats output records following user-defined templates. CSV: parses comma-separated values text files. IIS: formats output records in the Microsoft IIS Log File Format. TSV: parses tab-separated and space-separated values text files. SQL: uploads output records to a table in a SQL database. XML: parses XML text files. SYSLOG: sends output records to a Syslog server. W3C: parses text files in the W3C Extended Log File Format. DATAGRID: displays output records in a graphical user interface. NCSA: parses web server log files in the NCSA Common, Combined, and Extended Log File Formats. CHART: creates image files containing charts. TEXTLINE: returns lines from generic text files. TEXTWORD: returns words from generic text files. EVT: returns events from the Windows Event Log and from Event Log backup files (.evt files). FS: returns information on files and directories. REG: returns information on registry values. ADS: returns information on Active Directory objects. NETMON: parses network capture files created by NetMon. ETW: parses Enterprise Tracing for Windows trace log files and live sessions. COM: provides an interface to Custom Input Format COM Plugins. So, you can query data from any of the types on the left and really easily get it into a format where it is ready for analysis by other tools. To a DBA or network Administrator with an enquiring mind this is a treasure trove. In part 3 we will look at working with multiple sources and specifically outputting to SQL format. See you there!

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• NET Math Libraries

  - by JoshReuben

  NET Mathematical Libraries   .NET Builder for Matlab The MathWorks Inc. - http://www.mathworks.com/products/netbuilder/ MATLAB Builder NE generates MATLAB based .NET and COM components royalty-free deployment creates the components by encrypting MATLAB functions and generating either a .NET or COM wrapper around them. .NET/Link for Mathematica www.wolfram.com a product that 2-way integrates Mathematica and Microsoft's .NET platform call .NET from Mathematica - use arbitrary .NET types directly from the Mathematica language. use and control the Mathematica kernel from a .NET program. turns Mathematica into a scripting shell to leverage the computational services of Mathematica. write custom front ends for Mathematica or use Mathematica as a computational engine for another program comes with full source code. Leverages MathLink - a Wolfram Research's protocol for sending data and commands back and forth between Mathematica and other programs. .NET/Link abstracts the low-level details of the MathLink C API. Extreme Optimization http://www.extremeoptimization.com/ a collection of general-purpose mathematical and statistical classes built for the.NET framework. It combines a math library, a vector and matrix library, and a statistics library in one package. download the trial of version 4.0 to try it out. Multi-core ready - Full support for Task Parallel Library features including cancellation. Broad base of algorithms covering a wide range of numerical techniques, including: linear algebra (BLAS and LAPACK routines), numerical analysis (integration and differentiation), equation solvers. Mathematics leverages parallelism using .NET 4.0's Task Parallel Library. Basic math: Complex numbers, 'special functions' like Gamma and Bessel functions, numerical differentiation. Solving equations: Solve equations in one variable, or solve systems of linear or nonlinear equations. Curve fitting: Linear and nonlinear curve fitting, cubic splines, polynomials, orthogonal polynomials. Optimization: find the minimum or maximum of a function in one or more variables, linear programming and mixed integer programming. Numerical integration: Compute integrals over finite or infinite intervals, over 2D and higher dimensional regions. Integrate systems of ordinary differential equations (ODE's). Fast Fourier Transforms: 1D and 2D FFT's using managed or fast native code (32 and 64 bit) BigInteger, BigRational, and BigFloat: Perform operations with arbitrary precision. Vector and Matrix Library Real and complex vectors and matrices. Single and double precision for elements. Structured matrix types: including triangular, symmetrical and band matrices. Sparse matrices. Matrix factorizations: LU decomposition, QR decomposition, singular value decomposition, Cholesky decomposition, eigenvalue decomposition. Portability and performance: Calculations can be done in 100% managed code, or in hand-optimized processor-specific native code (32 and 64 bit). Statistics Data manipulation: Sort and filter data, process missing values, remove outliers, etc. Supports .NET data binding. Statistical Models: Simple, multiple, nonlinear, logistic, Poisson regression. Generalized Linear Models. One and two-way ANOVA. Hypothesis Tests: 12 14 hypothesis tests, including the z-test, t-test, F-test, runs test, and more advanced tests, such as the Anderson-Darling test for normality, one and two-sample Kolmogorov-Smirnov test, and Levene's test for homogeneity of variances. Multivariate Statistics: K-means cluster analysis, hierarchical cluster analysis, principal component analysis (PCA), multivariate probability distributions. Statistical Distributions: 25 29 continuous and discrete statistical distributions, including uniform, Poisson, normal, lognormal, Weibull and Gumbel (extreme value) distributions. Random numbers: Random variates from any distribution, 4 high-quality random number generators, low discrepancy sequences, shufflers. New in version 4.0 (November, 2010) Support for .NET Framework Version 4.0 and Visual Studio 2010 TPL Parallellized – multicore ready sparse linear program solver - can solve problems with more than 1 million variables. Mixed integer linear programming using a branch and bound algorithm. special functions: hypergeometric, Riemann zeta, elliptic integrals, Frensel functions, Dawson's integral. Full set of window functions for FFT's. Product  Price Update subscription Single Developer License $999  $399  Team License (3 developers) $1999  $799  Department License (8 developers) $3999  $1599  Site License (Unlimited developers in one physical location) $7999  $3199    NMath http://www.centerspace.net .NET math and statistics libraries matrix and vector classes random number generators Fast Fourier Transforms (FFTs) numerical integration linear programming linear regression curve and surface fitting optimization hypothesis tests analysis of variance (ANOVA) probability distributions principal component analysis cluster analysis built on the Intel Math Kernel Library (MKL), which contains highly-optimized, extensively-threaded versions of BLAS (Basic Linear Algebra Subroutines) and LAPACK (Linear Algebra PACKage). Product  Price Update subscription Single Developer License $1295 $388 Team License (5 developers) $5180 $1554   DotNumerics http://www.dotnumerics.com/NumericalLibraries/Default.aspx free DotNumerics is a website dedicated to numerical computing for .NET that includes a C# Numerical Library for .NET containing algorithms for Linear Algebra, Differential Equations and Optimization problems. The Linear Algebra library includes CSLapack, CSBlas and CSEispack, ports from Fortran to C# of LAPACK, BLAS and EISPACK, respectively. Linear Algebra (CSLapack, CSBlas and CSEispack). Systems of linear equations, eigenvalue problems, least-squares solutions of linear systems and singular value problems. Differential Equations. Initial-value problem for nonstiff and stiff ordinary differential equations ODEs (explicit Runge-Kutta, implicit Runge-Kutta, Gear's BDF and Adams-Moulton). Optimization. Unconstrained and bounded constrained optimization of multivariate functions (L-BFGS-B, Truncated Newton and Simplex methods).   Math.NET Numerics http://numerics.mathdotnet.com/ free an open source numerical library - includes special functions, linear algebra, probability models, random numbers, interpolation, integral transforms. A merger of dnAnalytics with Math.NET Iridium in addition to a purely managed implementation will also support native hardware optimization. constants & special functions complex type support real and complex, dense and sparse linear algebra (with LU, QR, eigenvalues, ... decompositions) non-uniform probability distributions, multivariate distributions, sample generation alternative uniform random number generators descriptive statistics, including order statistics various interpolation methods, including barycentric approaches and splines numerical function integration (quadrature) routines integral transforms, like fourier transform (FFT) with arbitrary lengths support, and hartley spectral-space aware sequence manipulation (signal processing) combinatorics, polynomials, quaternions, basic number theory. parallelized where appropriate, to leverage multi-core and multi-processor systems fully managed or (if available) using native libraries (Intel MKL, ACMS, CUDA, FFTW) provides a native facade for F# developers

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• Implementing synchronous MediaTypeFormatters in ASP.NET Web API

  - by cibrax

  One of main characteristics of MediaTypeFormatter’s in ASP.NET Web API is that they leverage the Task Parallel Library (TPL) for reading or writing an model into an stream. When you derive your class from the base class MediaTypeFormatter, you have to either implement the WriteToStreamAsync or ReadFromStreamAsync methods for writing or reading a model from a stream respectively. These two methods return a Task, which internally does all the serialization work, as it is illustrated bellow. public abstract class MediaTypeFormatter { public virtual Task WriteToStreamAsync(Type type, object value, Stream writeStream, HttpContent content, TransportContext transportContext); public virtual Task<object> ReadFromStreamAsync(Type type, Stream readStream, HttpContent content, IFormatterLogger formatterLogger); }   .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } However, most of the times, serialization is a safe operation that can be done synchronously. In fact, many of the serializer classes you will find in the .NET framework only provide sync methods. So the question is, how you can transform that synchronous work into a Task ?. Creating a new task using the method Task.Factory.StartNew for doing all the serialization work would be probably the typical answer. That would work, as a new task is going to be scheduled. However, that might involve some unnecessary context switches, which are out of our control and might be affect performance on server code specially.   If you take a look at the source code of the MediaTypeFormatters shipped as part of the framework, you will notice that they actually using another pattern, which uses a TaskCompletionSource class. public Task WriteToStreamAsync(Type type, object value, Stream writeStream, HttpContent content, TransportContext transportContext) {   var tsc = new TaskCompletionSource<AsyncVoid>(); tsc.SetResult(default(AsyncVoid));   //Do all the serialization work here synchronously   return tsc.Task; }   /// <summary> /// Used as the T in a "conversion" of a Task into a Task{T} /// </summary> private struct AsyncVoid { } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } They are basically doing all the serialization work synchronously and using a TaskCompletionSource for returning a task already done. To conclude this post, this is another approach you might want to consider when using serializers that are not compatible with an async model. Update: Henrik Nielsen from the ASP.NET team pointed out the existence of a built-in media type formatter for writing sync formatters. BufferedMediaTypeFormatter http://t.co/FxOfeI5x

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• A Basic Thread

  - by Joe Mayo

  Most of the programs written are single-threaded, meaning that they run on the main execution thread. For various reasons such as performance, scalability, and/or responsiveness additional threads can be useful. .NET has extensive threading support, from the basic threads introduced in v1.0 to the Task Parallel Library (TPL) introduced in v4.0. To get started with threads, it's helpful to begin with the basics; starting a Thread. Why Do I Care? The scenario I'll use for needing to use a thread is writing to a file.  Sometimes, writing to a file takes a while and you don't want your user interface to lock up until the file write is done. In other words, you want the application to be responsive to the user. How Would I Go About It? The solution is to launch a new thread that performs the file write, allowing the main thread to return to the user right away.  Whenever the file writing thread completes, it will let the user know.  In the meantime, the user is free to interact with the program for other tasks. The following examples demonstrate how to do this. Show Me the Code? The code we'll use to work with threads is in the System.Threading namespace, so you'll need the following using directive at the top of the file: using System.Threading; When you run code on a thread, the code is specified via a method.  Here's the code that will execute on the thread: private static void WriteFile() { Thread.Sleep(1000); Console.WriteLine("File Written."); } The call to Thread.Sleep(1000) delays thread execution. The parameter is specified in milliseconds, and 1000 means that this will cause the program to sleep for approximately 1 second.  This method happens to be static, but that's just part of this example, which you'll see is launched from the static Main method.  A thread could be instance or static.  Notice that the method does not have parameters and does not have a return type. As you know, the way to refer to a method is via a delegate.  There is a delegate named ThreadStart in System.Threading that refers to a method without parameters or return type, shown below: ThreadStart fileWriterHandlerDelegate = new ThreadStart(WriteFile); I'll show you the whole program below, but the ThreadStart instance above goes in the Main method. The thread uses the ThreadStart instance, fileWriterHandlerDelegate, to specify the method to execute on the thread: Thread fileWriter = new Thread(fileWriterHandlerDelegate); As shown above, the argument type for the Thread constructor is the ThreadStart delegate type. The fileWriterHandlerDelegate argument is an instance of the ThreadStart delegate type. This creates an instance of a thread and what code will execute, but the new thread instance, fileWriter, isn't running yet. You have to explicitly start it, like this: fileWriter.Start(); Now, the code in the WriteFile method is executing on a separate thread. Meanwhile, the main thread that started the fileWriter thread continues on it's own.  You have two threads running at the same time. Okay, I'm Starting to Get Glassy Eyed. How Does it All Fit Together? The example below is the whole program, pulling all the previous bits together. It's followed by its output and an explanation. using System; using System.Threading; namespace BasicThread { class Program { static void Main() { ThreadStart fileWriterHandlerDelegate = new ThreadStart(WriteFile); Thread fileWriter = new Thread(fileWriterHandlerDelegate); Console.WriteLine("Starting FileWriter"); fileWriter.Start(); Console.WriteLine("Called FileWriter"); Console.ReadKey(); } private static void WriteFile() { Thread.Sleep(1000); Console.WriteLine("File Written"); } } } And here's the output: Starting FileWriter Called FileWriter File Written So, Why are the Printouts Backwards? The output above corresponds to Console.Writeline statements in the program, with the second and third seemingly reversed. In a single-threaded program, "File Written" would print before "Called FileWriter". However, this is a multi-threaded (2 or more threads) program.  In multi-threading, you can't make any assumptions about when a given thread will run.  In this case, I added the Sleep statement to the WriteFile method to greatly increase the chances that the message from the main thread will print first. Without the Thread.Sleep, you could run this on a system with multiple cores and/or multiple processors and potentially get different results each time. Interesting Tangent but What Should I Get Out of All This? Going back to the main point, launching the WriteFile method on a separate thread made the program more responsive.  The file writing logic ran for a while, but the main thread returned to the user, as demonstrated by the print out of "Called FileWriter".  When the file write finished, it let the user know via another print statement. This was a very efficient use of CPU resources that made for a more pleasant user experience. Joe

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• How can give validation on custom registration form in drupal?

  - by Nitz

  Hey Friends, I have created custom registration form in drupal 6. i have used changed the behavior of the drupal registration page by adding this code in themes. template file function earthen_theme($existing, $type, $theme, $path) { return array( // tell Drupal what template to use for the user register form 'user_register' => array( 'arguments' => array('form' => NULL), 'template' => 'user_register', // this is the name of the template ), ); } and my user_register.tpl.php file is looking like this... //php tag starts from here $forms['access'] = array( '#type' = 'fieldset', '#title' = t('Access log settings'), ); $form['my_text_field']=array( '#type' = 'textfield', '#default_value' = $node-title, '#size' = 30, '#maxlength' = 50, '#required' = TRUE ); <div id="registration_form"><br> <div class="field"> <?php print drupal_render($form['my_text_field']); // prints the username field ?> </div> <div class="field"> <?php print drupal_render($form['account']['name']); // prints the username field ?> </div> <div class="field"> <?php print drupal_render($form['account']['pass']); // print the password field ?> </div> <div class="field"> <?php print drupal_render($form['account']['email']); // print the password field ?> </div> <div class="field"> <?php print drupal_render($form['submit']); // print the submit button ?> </div> </div> How to make validation on "my_text_field" which is custmized. and exactly i want that as soon as user click on my_text_field then datetime picker should be open and whichever date user select, that date should be value in my_text_field. so guys help. Thanks in advance, nitish Panchjanya Corporation

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• Looping class, for template engine kind of thing

  - by tarnfeld

  Hey, I am updating my class Nesty so it's infinite but I'm having a little trouble.... Here is the class: <?php Class Nesty { // Class Variables private $text; private $data = array(); private $loops = 0; private $maxLoops = 0; public function __construct($text,$data = array(),$maxLoops = 5) { // Set the class vars $this->text = $text; $this->data = $data; $this->maxLoops = $maxLoops; } // Loop funtion private function loopThrough($data) { if( ($this->loops +1) > $this->maxLoops ) { die("ERROR: Too many loops!"); } else { $keys = array_keys($data); for($x = 0; $x < count($keys); $x++) { if(is_array($data[$keys[$x]])) { $this->loopThrough($data[$keys[$x]]); } else { return $data[$keys[$x]]; } } } } // Templater method public function template() { echo $this->loopThrough($this->data); } } ?> Here is the code you would use to create an instance of the class: <?php // The nested array $data = array( "person" => array( "name" => "Tom Arnfeld", "age" => 15 ), "product" => array ( "name" => "Cakes", "price" => array ( "single" => 59, "double" => 99 ) ), "other" => "string" ); // Retreive the template text $file = "TestData.tpl"; $fp = fopen($file,"r"); $text = fread($fp,filesize($file)); // Create the Nesty object require_once('Nesty.php'); $nesty = new Nesty($text,$data); // Save the newly templated text to a variable $message $message = $nesty->template(); // Print out $message on the page echo("<pre>".$message."</pre>"); ?> Any ideas?

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• Dealing with C++ web views

  - by Jeffrey

  I'm working, as an hobby (before any one rage out of their mind, I'm just trying to study C++ regarding something I love: web. I'm not trying to reinvent your precious wheel, and I'm not trying to create the new web technology. I just have the time to go for it.), creating a web CGI C++ library. I'm at a pretty good point, but in the future I see one big problem: views. I'm used to the great <body><?php echo "Hey!"; ?></body> embedded php, but there's no such thing in C++, so I'm wondering: How would you deal with views? Would you create a simple find-replace-variable templating system and deal with thousands of partial views? For example: View view; view.load("header.html"); view.load("nav.html"); view.load("post_start.html"); for (int i = 0; i < 10; i++) { std::map<std::string, std::string> post; Post p(i); post = p.get(); view.load(post_view.html, post); // p is passed as argument and every `{% varname %}` in the html will be replaced with its value inside the map } view.load(post_end.html); view.load(footer); Would you create a simple templating system? So that we can deal with this C++ code: std::vector<std::map<std::string, std::string>> posts; Posts p; posts = p.getAll(); view.load(posts.html, posts); and then this HTML/TPL: <html> ... <body> <h2> Posts </h2> {% for (i = 0; i < 10; i++): %} <div class="post">...</div> {% endfor %} </body> </html> Is there any other way? What is the best way to do this? (And no, I don't think this is subjective question)

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• Parallelism in .NET – Part 10, Cancellation in PLINQ and the Parallel class

  - by Reed

  Many routines are parallelized because they are long running processes.  When writing an algorithm that will run for a long period of time, its typically a good practice to allow that routine to be cancelled.  I previously discussed terminating a parallel loop from within, but have not demonstrated how a routine can be cancelled from the caller’s perspective.  Cancellation in PLINQ and the Task Parallel Library is handled through a new, unified cooperative cancellation model introduced with .NET 4.0. Cancellation in .NET 4 is based around a new, lightweight struct called CancellationToken.  A CancellationToken is a small, thread-safe value type which is generated via a CancellationTokenSource.  There are many goals which led to this design.  For our purposes, we will focus on a couple of specific design decisions: Cancellation is cooperative.  A calling method can request a cancellation, but it’s up to the processing routine to terminate – it is not forced. Cancellation is consistent.  A single method call requests a cancellation on every copied CancellationToken in the routine. Let’s begin by looking at how we can cancel a PLINQ query.  Supposed we wanted to provide the option to cancel our query from Part 6: double min = collection .AsParallel() .Min(item => item.PerformComputation()); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } We would rewrite this to allow for cancellation by adding a call to ParallelEnumerable.WithCancellation as follows: var cts = new CancellationTokenSource(); // Pass cts here to a routine that could, // in parallel, request a cancellation try { double min = collection .AsParallel() .WithCancellation(cts.Token) .Min(item => item.PerformComputation()); } catch (OperationCanceledException e) { // Query was cancelled before it finished } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, if the user calls cts.Cancel() before the PLINQ query completes, the query will stop processing, and an OperationCanceledException will be raised.  Be aware, however, that cancellation will not be instantaneous.  When cts.Cancel() is called, the query will only stop after the current item.PerformComputation() elements all finish processing.  cts.Cancel() will prevent PLINQ from scheduling a new task for a new element, but will not stop items which are currently being processed.  This goes back to the first goal I mentioned – Cancellation is cooperative.  Here, we’re requesting the cancellation, but it’s up to PLINQ to terminate. If we wanted to allow cancellation to occur within our routine, we would need to change our routine to accept a CancellationToken, and modify it to handle this specific case: public void PerformComputation(CancellationToken token) { for (int i=0; i<this.iterations; ++i) { // Add a check to see if we've been canceled // If a cancel was requested, we'll throw here token.ThrowIfCancellationRequested(); // Do our processing now this.RunIteration(i); } } With this overload of PerformComputation, each internal iteration checks to see if a cancellation request was made, and will throw an OperationCanceledException at that point, instead of waiting until the method returns.  This is good, since it allows us, as developers, to plan for cancellation, and terminate our routine in a clean, safe state. This is handled by changing our PLINQ query to: try { double min = collection .AsParallel() .WithCancellation(cts.Token) .Min(item => item.PerformComputation(cts.Token)); } catch (OperationCanceledException e) { // Query was cancelled before it finished } PLINQ is very good about handling this exception, as well.  There is a very good chance that multiple items will raise this exception, since the entire purpose of PLINQ is to have multiple items be processed concurrently.  PLINQ will take all of the OperationCanceledException instances raised within these methods, and merge them into a single OperationCanceledException in the call stack.  This is done internally because we added the call to ParallelEnumerable.WithCancellation. If, however, a different exception is raised by any of the elements, the OperationCanceledException as well as the other Exception will be merged into a single AggregateException. The Task Parallel Library uses the same cancellation model, as well.  Here, we supply our CancellationToken as part of the configuration.  The ParallelOptions class contains a property for the CancellationToken.  This allows us to cancel a Parallel.For or Parallel.ForEach routine in a very similar manner to our PLINQ query.  As an example, we could rewrite our Parallel.ForEach loop from Part 2 to support cancellation by changing it to: try { var cts = new CancellationTokenSource(); var options = new ParallelOptions() { CancellationToken = cts.Token }; Parallel.ForEach(customers, options, customer => { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // Check for cancellation here options.CancellationToken.ThrowIfCancellationRequested(); // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { theStore.EmailCustomer(customer); customer.LastEmailContact = DateTime.Now; } }); } catch (OperationCanceledException e) { // The loop was cancelled } Notice that here we use the same approach taken in PLINQ.  The Task Parallel Library will automatically handle our cancellation in the same manner as PLINQ, providing a clean, unified model for cancellation of any parallel routine.  The TPL performs the same aggregation of the cancellation exceptions as PLINQ, as well, which is why a single exception handler for OperationCanceledException will cleanly handle this scenario.  This works because we’re using the same CancellationToken provided in the ParallelOptions.  If a different exception was thrown by one thread, or a CancellationToken from a different CancellationTokenSource was used to raise our exception, we would instead receive all of our individual exceptions merged into one AggregateException.

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• C#/.NET Little Wonders: The Timeout static class

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. When I started the “Little Wonders” series, I really wanted to pay homage to parts of the .NET Framework that are often small but can help in big ways.  The item I have to discuss today really is a very small item in the .NET BCL, but once again I feel it can help make the intention of code much clearer and thus is worthy of note. The Problem - Magic numbers aren’t very readable or maintainable In my first Little Wonders Post (Five Little Wonders That Make Code Better) I mention the TimeSpan factory methods which, I feel, really help the readability of constructed TimeSpan instances. Just to quickly recap that discussion, ask yourself what the TimeSpan specified in each case below is 1: // Five minutes? Five Seconds? 2: var fiveWhat1 = new TimeSpan(0, 0, 5); 3: var fiveWhat2 = new TimeSpan(0, 0, 5, 0); 4: var fiveWhat3 = new TimeSpan(0, 0, 5, 0, 0); You’d think they’d all be the same unit of time, right?  After all, most overloads tend to tack additional arguments on the end.  But this is not the case with TimeSpan, where the constructor forms are:     TimeSpan(int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds, int milliseconds); Notice how in the 4 and 5 parameter version we suddenly have the parameter days slipping in front of hours?  This can make reading constructors like those above much harder.  Fortunately, there are TimeSpan factory methods to help make your intention crystal clear: 1: // Ah! Much clearer! 2: var fiveSeconds = TimeSpan.FromSeconds(5); These are great because they remove all ambiguity from the reader!  So in short, magic numbers in constructors and methods can be ambiguous, and anything we can do to clean up the intention of the developer will make the code much easier to read and maintain. Timeout – Readable identifiers for infinite timeout values In a similar way to TimeSpan, let’s consider specifying timeouts for some of .NET’s (or our own) many methods that allow you to specify timeout periods. For example, in the TPL Task class, there is a family of Wait() methods that can take TimeSpan or int for timeouts.  Typically, if you want to specify an infinite timeout, you’d just call the version that doesn’t take a timeout parameter at all: 1: myTask.Wait(); // infinite wait But there are versions that take the int or TimeSpan for timeout as well: 1: // Wait for 100 ms 2: myTask.Wait(100); 3:  4: // Wait for 5 seconds 5: myTask.Wait(TimeSpan.FromSeconds(5); Now, if we want to specify an infinite timeout to wait on the Task, we could pass –1 (or a TimeSpan set to –1 ms), which what the .NET BCL methods with timeouts use to represent an infinite timeout: 1: // Also infinite timeouts, but harder to read/maintain 2: myTask.Wait(-1); 3: myTask.Wait(TimeSpan.FromMilliseconds(-1)); However, these are not as readable or maintainable.  If you were writing this code, you might make the mistake of thinking 0 or int.MaxValue was an infinite timeout, and you’d be incorrect.  Also, reading the code above it isn’t as clear that –1 is infinite unless you happen to know that is the specified behavior. To make the code like this easier to read and maintain, there is a static class called Timeout in the System.Threading namespace which contains definition for infinite timeouts specified as both int and TimeSpan forms: Timeout.Infinite An integer constant with a value of –1 Timeout.InfiniteTimeSpan A static readonly TimeSpan which represents –1 ms (only available in .NET 4.5+) This makes our calls to Task.Wait() (or any other calls with timeouts) much more clear: 1: // intention to wait indefinitely is quite clear now 2: myTask.Wait(Timeout.Infinite); 3: myTask.Wait(Timeout.InfiniteTimeSpan); But wait, you may say, why would we care at all?  Why not use the version of Wait() that takes no arguments?  Good question!  When you’re directly calling the method with an infinite timeout that’s what you’d most likely do, but what if you are just passing along a timeout specified by a caller from higher up?  Or perhaps storing a timeout value from a configuration file, and want to default it to infinite? For example, perhaps you are designing a communications module and want to be able to shutdown gracefully, but if you can’t gracefully finish in a specified amount of time you want to force the connection closed.  You could create a Shutdown() method in your class, and take a TimeSpan or an int for the amount of time to wait for a clean shutdown – perhaps waiting for client to acknowledge – before terminating the connection.  So, assume we had a pub/sub system with a class to broadcast messages: 1: // Some class to broadcast messages to connected clients 2: public class Broadcaster 3: { 4: // ... 5:  6: // Shutdown connection to clients, wait for ack back from clients 7: // until all acks received or timeout, whichever happens first 8: public void Shutdown(int timeout) 9: { 10: // Kick off a task here to send shutdown request to clients and wait 11: // for the task to finish below for the specified time... 12:  13: if (!shutdownTask.Wait(timeout)) 14: { 15: // If Wait() returns false, we timed out and task 16: // did not join in time. 17: } 18: } 19: } We could even add an overload to allow us to use TimeSpan instead of int, to give our callers the flexibility to specify timeouts either way: 1: // overload to allow them to specify Timeout in TimeSpan, would 2: // just call the int version passing in the TotalMilliseconds... 3: public void Shutdown(TimeSpan timeout) 4: { 5: Shutdown(timeout.TotalMilliseconds); 6: } Notice in case of this class, we don’t assume the caller wants infinite timeouts, we choose to rely on them to tell us how long to wait.  So now, if they choose an infinite timeout, they could use the –1, which is more cryptic, or use Timeout class to make the intention clear: 1: // shutdown the broadcaster, waiting until all clients ack back 2: // without timing out. 3: myBroadcaster.Shutdown(Timeout.Infinite); We could even add a default argument using the int parameter version so that specifying no arguments to Shutdown() assumes an infinite timeout: 1: // Modified original Shutdown() method to add a default of 2: // Timeout.Infinite, works because Timeout.Infinite is a compile 3: // time constant. 4: public void Shutdown(int timeout = Timeout.Infinite) 5: { 6: // same code as before 7: } Note that you can’t default the ShutDown(TimeSpan) overload with Timeout.InfiniteTimeSpan since it is not a compile-time constant.  The only acceptable default for a TimeSpan parameter would be default(TimeSpan) which is zero milliseconds, which specified no wait, not infinite wait. Summary While Timeout.Infinite and Timeout.InfiniteTimeSpan are not earth-shattering classes in terms of functionality, they do give you very handy and readable constant values that you can use in your programs to help increase readability and maintainability when specifying infinite timeouts for various timeouts in the BCL and your own applications. Technorati Tags: C#,CSharp,.NET,Little Wonders,Timeout,Task

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• Why Is Faulty Behaviour In The .NET Framework Not Fixed?

  - by Alois Kraus

  Here is the scenario: You have a Windows Form Application that calls a method via Invoke or BeginInvoke which throws exceptions. Now you want to find out where the error did occur and how the method has been called. Here is the output we do get when we call Begin/EndInvoke or simply Invoke The actual code that was executed was like this:         private void cInvoke_Click(object sender, EventArgs e)         {             InvokingFunction(CallMode.Invoke);         }            [MethodImpl(MethodImplOptions.NoInlining)]         void InvokingFunction(CallMode mode)         {             switch (mode)             {                 case CallMode.Invoke:                     this.Invoke(new MethodInvoker(GenerateError));   The faulting method is called GenerateError which does throw a NotImplementedException exception and wraps it in a NotSupportedException.           [MethodImpl(MethodImplOptions.NoInlining)]         void GenerateError()         {             F1();         }           private void F1()         {             try             {                 F2();             }             catch (Exception ex)             {                 throw new NotSupportedException("Outer Exception", ex);             }         }           private void F2()         {            throw new NotImplementedException("Inner Exception");         } It is clear that the method F2 and F1 did actually throw these exceptions but we do not see them in the call stack. If we directly call the InvokingFunction and catch and print the exception we can find out very easily how we did get into this situation. We see methods F1,F2,GenerateError and InvokingFunction directly in the stack trace and we see that actually two exceptions did occur. Here is for comparison what we get from Invoke/EndInvoke System.NotImplementedException: Inner Exception     StackTrace:    at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous)     at System.Windows.Forms.Control.Invoke(Delegate method, Object[] args)     at WindowsFormsApplication1.AppForm.InvokingFunction(CallMode mode)     at WindowsFormsApplication1.AppForm.cInvoke_Click(Object sender, EventArgs e)     at System.Windows.Forms.Control.OnClick(EventArgs e)     at System.Windows.Forms.Button.OnClick(EventArgs e) The exception message is kept but the stack starts running from our Invoke call and not from the faulting method F2. We have therefore no clue where this exception did occur! The stack starts running at the method MarshaledInvoke because the exception is rethrown with the throw catchedException which resets the stack trace. That is bad but things are even worse because if previously lets say 5 exceptions did occur .NET will return only the first (innermost) exception. That does mean that we do not only loose the original call stack but all other exceptions and all data contained therein as well. It is a pity that MS does know about this and simply closes this issue as not important. Programmers will play a lot more around with threads than before thanks to TPL, PLINQ that do come with .NET 4. Multithreading is hyped quit a lot in the press and everybody wants to use threads. But if the .NET Framework makes it nearly impossible to track down the easiest UI multithreading issue I have a problem with that. The problem has been reported but obviously not been solved. .NET 4 Beta 2 did not have changed that dreaded GetBaseException call in MarshaledInvoke to return only the innermost exception of the complete exception stack. It is really time to fix this. WPF on the other hand does the right thing and wraps the exceptions inside a TargetInvocationException which makes much more sense. But Not everybody uses WPF for its daily work and Windows forms applications will still be used for a long time. Below is the code to repro the issues shown and how the exceptions can be rendered in a meaningful way. The default Exception.ToString implementation generates a hard to interpret stack if several nested exceptions did occur. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading; using System.Globalization; using System.Runtime.CompilerServices;   namespace WindowsFormsApplication1 {     public partial class AppForm : Form     {         enum CallMode         {             Direct = 0,             BeginInvoke = 1,             Invoke = 2         };           public AppForm()         {             InitializeComponent();             Thread.CurrentThread.CurrentUICulture = CultureInfo.InvariantCulture;             Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(Application_ThreadException);         }           void Application_ThreadException(object sender, System.Threading.ThreadExceptionEventArgs e)         {             cOutput.Text = PrintException(e.Exception, 0, null).ToString();         }           private void cDirectUnhandled_Click(object sender, EventArgs e)         {             InvokingFunction(CallMode.Direct);         }           private void cDirectCall_Click(object sender, EventArgs e)         {             try             {                 InvokingFunction(CallMode.Direct);             }             catch (Exception ex)             {                 cOutput.Text = PrintException(ex, 0, null).ToString();             }         }           private void cInvoke_Click(object sender, EventArgs e)         {             InvokingFunction(CallMode.Invoke);         }           private void cBeginInvokeCall_Click(object sender, EventArgs e)         {             InvokingFunction(CallMode.BeginInvoke);         }           [MethodImpl(MethodImplOptions.NoInlining)]         void InvokingFunction(CallMode mode)         {             switch (mode)             {                 case CallMode.Direct:                     GenerateError();                     break;                 case CallMode.Invoke:                     this.Invoke(new MethodInvoker(GenerateError));                     break;                 case CallMode.BeginInvoke:                     IAsyncResult res = this.BeginInvoke(new MethodInvoker(GenerateError));                     this.EndInvoke(res);                     break;             }         }           [MethodImpl(MethodImplOptions.NoInlining)]         void GenerateError()         {             F1();         }           private void F1()         {             try             {                 F2();             }             catch (Exception ex)             {                 throw new NotSupportedException("Outer Exception", ex);             }         }           private void F2()         {            throw new NotImplementedException("Inner Exception");         }           StringBuilder PrintException(Exception ex, int identLevel, StringBuilder sb)         {             StringBuilder builtStr = sb;             if( builtStr == null )                 builtStr = new StringBuilder();               if( ex == null )                 return builtStr;                 WriteLine(builtStr, String.Format("{0}: {1}", ex.GetType().FullName, ex.Message), identLevel);             WriteLine(builtStr, String.Format("StackTrace: {0}", ShortenStack(ex.StackTrace)), identLevel + 1);             builtStr.AppendLine();               return PrintException(ex.InnerException, ++identLevel, builtStr);         }               void WriteLine(StringBuilder sb, string msg, int identLevel)         {             foreach (string trimmedLine in SplitToLines(msg)                                            .Select( (line) => line.Trim()) )             {                 for (int i = 0; i < identLevel; i++)                     sb.Append('\t');                 sb.Append(trimmedLine);                 sb.AppendLine();             }         }           string ShortenStack(string stack)         {             int nonAppFrames = 0;             // Skip stack frames not part of our app but include two foreign frames and skip the rest             // If our stack frame is encountered reset counter to 0             return SplitToLines(stack)                               .Where((line) =>                               {                                   nonAppFrames = line.Contains("WindowsFormsApplication1") ? 0 : nonAppFrames + 1;                                   return nonAppFrames < 3;                               })                              .Select((line) => line)                              .Aggregate("", (current, line) => current + line + Environment.NewLine);         }           static char[] NewLines = Environment.NewLine.ToCharArray();         string[] SplitToLines(string str)         {             return str.Split(NewLines, StringSplitOptions.RemoveEmptyEntries);         }     } }

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• Consuming the Amazon S3 service from a Win8 Metro Application

  - by cibrax

  As many of the existing Http APIs for Cloud Services, AWS also provides a set of different platform SDKs for hiding many of complexities present in the APIs. While there is a platform SDK for .NET, which is open source and available in C#, that SDK does not work in Win8 Metro Applications for the changes introduced in WinRT. WinRT offers a complete different set of APIs for doing I/O operations such as doing http calls or using cryptography for signing or encrypting data, two aspects that are absolutely necessary for consuming AWS. All the I/O APIs available as part of WinRT are asynchronous, and uses the TPL model for .NET applications (HTML and JavaScript Metro applications use a model based in promises, which is similar concept).  In the case of S3, the http Authorization header is used for two purposes, authenticating clients and make sure the messages were not altered while they were in transit. For doing that, it uses a signature or hash of the message content and some of the headers using a symmetric key (That's just one of the available mechanisms). Windows Azure for example also uses the same mechanism in many of its APIs. There are three challenges that any developer working for first time in Metro will have to face to consume S3, the new WinRT APIs, the asynchronous nature of them and the complexity introduced for generating the Authorization header. Having said that, I decided to write this post with some of the gotchas I found myself trying to consume this Amazon service. 1. Generating the signature for the Authorization header All the cryptography APIs in WinRT are available under Windows.Security.Cryptography namespace. Many of operations available in these APIs uses the concept of buffers (IBuffer) for representing a chunk of binary data. As you will see in the example below, these buffers are mainly generated with the use of static methods in a WinRT class CryptographicBuffer available as part of the namespace previously mentioned. private string DeriveAuthToken(string resource, string httpMethod, string timestamp) { var stringToSign = string.Format("{0}\n" + "\n" + "\n" + "\n" + "x-amz-date:{1}\n" + "/{2}/", httpMethod, timestamp, resource); var algorithm = MacAlgorithmProvider.OpenAlgorithm("HMAC_SHA1"); var keyMaterial = CryptographicBuffer.CreateFromByteArray(Encoding.UTF8.GetBytes(this.secret)); var hmacKey = algorithm.CreateKey(keyMaterial); var signature = CryptographicEngine.Sign( hmacKey, CryptographicBuffer.CreateFromByteArray(Encoding.UTF8.GetBytes(stringToSign)) ); return CryptographicBuffer.EncodeToBase64String(signature); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The algorithm that determines the information or content you need to use for generating the signature is very well described as part of the AWS documentation. In this case, this method is generating a signature required for creating a new bucket. A HmacSha1 hash is computed using a secret or symetric key provided by AWS in the management console. 2. Sending an Http Request to the S3 service WinRT also ships with the System.Net.Http.HttpClient that was first introduced some months ago with ASP.NET Web API. This client provides a rich interface on top the traditional WebHttpRequest class, and also solves some of limitations found in this last one. There are a few things that don't work with a raw WebHttpRequest such as setting the Host header, which is something absolutely required for consuming S3. Also, HttpClient is more friendly for doing unit tests, as it receives a HttpMessageHandler as part of the constructor that can fake to emulate a real http call. This is how the code for consuming the service with HttpClient looks like, public async Task<S3Response> CreateBucket(string name, string region = null, params string[] acl) { var timestamp = string.Format("{0:r}", DateTime.UtcNow); var auth = DeriveAuthToken(name, "PUT", timestamp); var request = new HttpRequestMessage(HttpMethod.Put, "http://s3.amazonaws.com/"); request.Headers.Host = string.Format("{0}.s3.amazonaws.com", name); request.Headers.TryAddWithoutValidation("Authorization", "AWS " + this.key + ":" + auth); request.Headers.Add("x-amz-date", timestamp); var client = new HttpClient(); var response = await client.SendAsync(request); return new S3Response { Succeed = response.StatusCode == HttpStatusCode.OK, Message = (response.Content != null) ? await response.Content.ReadAsStringAsync() : null }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You will notice a few additional things in this code. By default, HttpClient validates the values for some well-know headers, and Authorization is one of them. It won't allow you to set a value with ":" on it, which is something that S3 expects. However, that's not a problem at all, as you can skip the validation by using the TryAddWithoutValidation method. Also, the code is heavily relying on the new async and await keywords to transform all the asynchronous calls into synchronous ones. In case you would want to unit test this code and faking the call to the real S3 service, you should have to modify it to inject a custom HttpMessageHandler into the HttpClient. The following implementation illustrates this concept, In case you would want to unit test this code and faking the call to the real S3 service, you should have to modify it to inject a custom HttpMessageHandler into the HttpClient. The following implementation illustrates this concept, public class FakeHttpMessageHandler : HttpMessageHandler { HttpResponseMessage response; public FakeHttpMessageHandler(HttpResponseMessage response) { this.response = response; } protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { var tcs = new TaskCompletionSource<HttpResponseMessage>(); tcs.SetResult(response); return tcs.Task; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You can use this handler for injecting any response while you are unit testing the code.

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