code contracts - Page 601

Transactional Messaging in the Windows Azure Service Bus

- by Alan Smith

Introduction I’m currently working on broadening the content in the Windows Azure Service Bus Developer Guide. One of the features I have been looking at over the past week is the support for transactional messaging. When using the direct programming model and the WCF interface some, but not all, messaging operations can participate in transactions. This allows developers to improve the reliability of messaging systems. There are some limitations in the transactional model, transactions can only include one top level messaging entity (such as a queue or topic, subscriptions are no top level entities), and transactions cannot include other systems, such as databases. As the transaction model is currently not well documented I have had to figure out how things work through experimentation, with some help from the development team to confirm any questions I had. Hopefully I’ve got the content mostly correct, I will update the content in the e-book if I find any errors or improvements that can be made (any feedback would be very welcome). I’ve not had a chance to look into the code for transactions and asynchronous operations, maybe that would make a nice challenge lab for my Windows Azure Service Bus course. Transactional Messaging Messaging entities in the Windows Azure Service Bus provide support for participation in transactions. This allows developers to perform several messaging operations within a transactional scope, and ensure that all the actions are committed or, if there is a failure, none of the actions are committed. There are a number of scenarios where the use of transactions can increase the reliability of messaging systems. Using TransactionScope In .NET the TransactionScope class can be used to perform a series of actions in a transaction. The using declaration is typically used de define the scope of the transaction. Any transactional operations that are contained within the scope can be committed by calling the Complete method. If the Complete method is not called, any transactional methods in the scope will not commit. // Create a transactional scope. using (TransactionScope scope = new TransactionScope()) { // Do something. // Do something else. // Commit the transaction. scope.Complete(); } In order for methods to participate in the transaction, they must provide support for transactional operations. Database and message queue operations typically provide support for transactions. Transactions in Brokered Messaging Transaction support in Service Bus Brokered Messaging allows message operations to be performed within a transactional scope; however there are some limitations around what operations can be performed within the transaction. In the current release, only one top level messaging entity, such as a queue or topic can participate in a transaction, and the transaction cannot include any other transaction resource managers, making transactions spanning a messaging entity and a database not possible. When sending messages, the send operations can participate in a transaction allowing multiple messages to be sent within a transactional scope. This allows for “all or nothing” delivery of a series of messages to a single queue or topic. When receiving messages, messages that are received in the peek-lock receive mode can be completed, deadlettered or deferred within a transactional scope. In the current release the Abandon method will not participate in a transaction. The same restrictions of only one top level messaging entity applies here, so the Complete method can be called transitionally on messages received from the same queue, or messages received from one or more subscriptions in the same topic. Sending Multiple Messages in a Transaction A transactional scope can be used to send multiple messages to a queue or topic. This will ensure that all the messages will be enqueued or, if the transaction fails to commit, no messages will be enqueued. An example of the code used to send 10 messages to a queue as a single transaction from a console application is shown below. QueueClient queueClient = messagingFactory.CreateQueueClient(Queue1); Console.Write("Sending"); // Create a transaction scope. using (TransactionScope scope = new TransactionScope()) { for (int i = 0; i < 10; i++) { // Send a message BrokeredMessage msg = new BrokeredMessage("Message: " + i); queueClient.Send(msg); Console.Write("."); } Console.WriteLine("Done!"); Console.WriteLine(); // Should we commit the transaction? Console.WriteLine("Commit send 10 messages? (yes or no)"); string reply = Console.ReadLine(); if (reply.ToLower().Equals("yes")) { // Commit the transaction. scope.Complete(); } } Console.WriteLine(); messagingFactory.Close(); The transaction scope is used to wrap the sending of 10 messages. Once the messages have been sent the user has the option to either commit the transaction or abandon the transaction. If the user enters “yes”, the Complete method is called on the scope, which will commit the transaction and result in the messages being enqueued. If the user enters anything other than “yes”, the transaction will not commit, and the messages will not be enqueued. Receiving Multiple Messages in a Transaction The receiving of multiple messages is another scenario where the use of transactions can improve reliability. When receiving a group of messages that are related together, maybe in the same message session, it is possible to receive the messages in the peek-lock receive mode, and then complete, defer, or deadletter the messages in one transaction. (In the current version of Service Bus, abandon is not transactional.) The following code shows how this can be achieved. using (TransactionScope scope = new TransactionScope()) { while (true) { // Receive a message. BrokeredMessage msg = q1Client.Receive(TimeSpan.FromSeconds(1)); if (msg != null) { // Wrote message body and complete message. string text = msg.GetBody<string>(); Console.WriteLine("Received: " + text); msg.Complete(); } else { break; } } Console.WriteLine(); // Should we commit? Console.WriteLine("Commit receive? (yes or no)"); string reply = Console.ReadLine(); if (reply.ToLower().Equals("yes")) { // Commit the transaction. scope.Complete(); } Console.WriteLine(); } Note that if there are a large number of messages to be received, there will be a chance that the transaction may time out before it can be committed. It is possible to specify a longer timeout when the transaction is created, but It may be better to receive and commit smaller amounts of messages within the transaction. It is also possible to complete, defer, or deadletter messages received from more than one subscription, as long as all the subscriptions are contained in the same topic. As subscriptions are not top level messaging entities this scenarios will work. The following code shows how this can be achieved. try { using (TransactionScope scope = new TransactionScope()) { // Receive one message from each subscription. BrokeredMessage msg1 = subscriptionClient1.Receive(); BrokeredMessage msg2 = subscriptionClient2.Receive(); // Complete the message receives. msg1.Complete(); msg2.Complete(); Console.WriteLine("Msg1: " + msg1.GetBody<string>()); Console.WriteLine("Msg2: " + msg2.GetBody<string>()); // Commit the transaction. scope.Complete(); } } catch (Exception ex) { Console.WriteLine(ex.Message); } Unsupported Scenarios The restriction of only one top level messaging entity being able to participate in a transaction makes some useful scenarios unsupported. As the Windows Azure Service Bus is under continuous development and new releases are expected to be frequent it is possible that this restriction may not be present in future releases. The first is the scenario where messages are to be routed to two different systems. The following code attempts to do this. try { // Create a transaction scope. using (TransactionScope scope = new TransactionScope()) { BrokeredMessage msg1 = new BrokeredMessage("Message1"); BrokeredMessage msg2 = new BrokeredMessage("Message2"); // Send a message to Queue1 Console.WriteLine("Sending Message1"); queue1Client.Send(msg1); // Send a message to Queue2 Console.WriteLine("Sending Message2"); queue2Client.Send(msg2); // Commit the transaction. Console.WriteLine("Committing transaction..."); scope.Complete(); } } catch (Exception ex) { Console.WriteLine(ex.Message); } The results of running the code are shown below. When attempting to send a message to the second queue the following exception is thrown: No active Transaction was found for ID '35ad2495-ee8a-4956-bbad-eb4fedf4a96e:1'. The Transaction may have timed out or attempted to span multiple top-level entities such as Queue or Topic. The server Transaction timeout is: 00:01:00..TrackingId:947b8c4b-7754-4044-b91b-4a959c3f9192_3_3,TimeStamp:3/29/2012 7:47:32 AM. Another scenario where transactional support could be useful is when forwarding messages from one queue to another queue. This would also involve more than one top level messaging entity, and is therefore not supported. Another scenario that developers may wish to implement is performing transactions across messaging entities and other transactional systems, such as an on-premise database. In the current release this is not supported. Workarounds for Unsupported Scenarios There are some techniques that developers can use to work around the one top level entity limitation of transactions. When sending two messages to two systems, topics and subscriptions can be used. If the same message is to be sent to two destinations then the subscriptions would have the default subscriptions, and the client would only send one message. If two different messages are to be sent, then filters on the subscriptions can route the messages to the appropriate destination. The client can then send the two messages to the topic in the same transaction. In scenarios where a message needs to be received and then forwarded to another system within the same transaction topics and subscriptions can also be used. A message can be received from a subscription, and then sent to a topic within the same transaction. As a topic is a top level messaging entity, and a subscription is not, this scenario will work.

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Best Practices vs Reality

- by RonHill

On a scale depicting how closely best practices are followed, with "always" on one end and "never" on the other, my current company falls uncomfortably close to the latter. Just a couple trivial examples: We have no code review process There is very little documentation despite a very large code base (and some of it is blatantly incorrect/misleading) Untested/buggy/uncompilable code is frequently checked in to source control It is comically complicated to create a debuggable build for some of our components because of its underlying architecture. Unhandled exceptions are not uncommon in our releases Empty Catch{ } blocks are everywhere. Now, with the understanding that it's neither practical nor realistic to follow ALL best practices ALL the time, my question is this: How closely have commonly accepted best practices been followed at the companies you've worked for? I'm kind of a noob--this is only the second company I've worked for--so I'm not sure if I'm just more of an anal retentive coder or if I've just ended up at mediocre companies. My guess (hope?) is the latter, but a coworker with way more experience than me says every company he's ever worked for is like this. Given the obvious benefits of following most best practices most of the time, I find it hard to believe it's like this everywhere. Am I wrong?

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Good place to look for example Database Designs - Best practices

- by Younes

I have been given the task to design a database to store a lot of information for our company. Because the task is rather big and contains multiple modules where users should be able to do stuff, I'm worried about designing a good data model for this. I just don't want to end up with a badly designed database. I want to have some decent examples of database structures for contracts / billing / orders etc to combine those in one nice relational database. Are there any resources out there that can help me with some examples regarding this?

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Add Free Google Apps to Your Website or Blog

- by Matthew Guay

Would you like to have an email address from your own domain, but prefer Gmail’s interface and integration with Google Docs? Here’s how you can add the free Google Apps Standard to your site and get the best of both worlds. Note: To signup for Google Apps and get it setup on your domain, you will need to be able to add info to your WordPress blog or change Domain settings manually. Getting Started Head to the Google Apps signup page (link below), and click the Get Started button on the right. Note that we are signing up for the free Google Apps which allows a max of 50 users; if you need more than 50 email addresses for your domain, you can choose Premiere Edition instead for $50/year. Select that you are the Administrator of the domain, and enter the domain or subdomain you want to use with Google Apps. Here we’re adding Google Apps to the techinch.com site, but we could instead add Apps to mail.techinch.com if needed…click Get Started. Enter your name, phone number, an existing email address, and other Administrator information. The Apps signup page also includes some survey questions about your organization, but you only have to fill in the required fields. On the next page, enter a username and password for the administrator account. Note that the user name will also be the administrative email address as [email protected]. Now you’re ready to authenticate your Google Apps account with your domain. The steps are slightly different depending on whether your site is on WordPress.com or on your own hosting service or server, so we’ll show how to do it both ways. Authenticate and Integrate Google Apps with WordPress.com To add Google Apps to a domain you have linked to your WordPress.com blog, select Change yourdomain.com CNAME record and click Continue. Copy the code under #2, which should be something like googleabcdefg123456. Do not click the button at the bottom; wait until we’ve completed the next step. Now, in a separate browser window or tab, open your WordPress Dashboard. Click the arrow beside Upgrades, and select Domains from the menu. Click the Edit DNS link beside the domain name you’re adding to Google Apps. Scroll down to the Google Apps section, and paste your code from Google Apps into the verification code field. Click Generate DNS records when you’re done. This will add the needed DNS settings to your records in the box above the Google Apps section. Click Save DNS records. Now, go back to the Google Apps signup page, and click I’ve completed the steps above. Authenticate Google Apps on Your Own Server If your website is hosted on your own server or hosting account, you’ll need to take a few more steps to add Google Apps to your domain. You can add a CNAME record to your domain host using the same information that you would use with a WordPress account, or you can upload an HTML file to your site’s main directory. In this test we’re going to upload an HTML file to our site for verification. Copy the code under #1, which should be something like googleabcdefg123456. Do not click the button at the bottom; wait until we’ve completed the next step first. Create a new HTML file and paste the code in it. You can do this easily in Notepad: create a new document, paste the code, and then save as googlehostedservice.html. Make sure to select the type as All Files or otherwise the file will have a .txt extension. Upload this file to your web server via FTP or a web dashboard for your site. Make sure it is in the top level of your site’s directory structure, and try visiting it at yoursite.com/googlehostedservice.html. Now, go back to the Google Apps signup page, and click I’ve completed the steps above. Setup Your Email on Google Apps When this is done, your Google Apps account should be activated and ready to finish setting up. Google Apps will offer to launch a guide to step you through the rest of the process; you can click Launch guide if you want, or click Skip this guide to continue on your own and go directly to the Apps dashboard. If you choose to open the guide, you’ll be able to easily learn the ropes of Google Apps administration. Once you’ve completed the tutorial, you’ll be taken to the Google Apps dashboard. Most of the Google Apps will be available for immediate use, but Email may take a bit more setup. Click Activate email to get your Gmail-powered email running on your domain. Add Google MX Records to Your Server You will need to add Google MX records to your domain registrar in order to have your mail routed to Google. If your domain is hosted on WordPress.com, you’ve already made these changes so simply click I have completed these steps. Otherwise, you’ll need to manually add these records before clicking that button. Adding MX Entries is fairly easy, but the steps may depend on your hosting company or registrar. With some hosts, you may have to contact support to have them add the MX records for you. Our site’s host uses the popular cPanel for website administration, so here’s how we added the MX Entries through cPanel. Add MX Entries through cPanel Login to your site’s cPanel, and click the MX Entry link under Mail. Delete any existing MX Records for your domain or subdomain first to avoid any complications or interactions with Google Apps. If you think you may want to revert to your old email service in the future, save a copy of the records so you can switch back if you need. Now, enter the MX Records that Google listed. Here’s our account after we added all of the entries to our account. Finally, return to your Google Apps Dashboard and click the I have completed these steps button at the bottom of the page. Activating Service You’re now officially finished activating and setting up your Google Apps account. Google will first have to check the MX records for your domain; this only took around an hour in our test, but Google warns it can take up to 48 hours in some cases. You may then see that Google is updating its servers with your account information. Once again, this took much less time than Google’s estimate. When everything’s finished, you can click the link to access the inbox of your new Administrator email account in Google Apps. Welcome to Gmail … at your own domain! All of the Google Apps work just the same in this version as they do in the public @gmail.com version, so you should feel right at home. You can return to the Google Apps dashboard from the Administrative email account by clicking the Manage this domain at the top right. In the Dashboard, you can easily add new users and email accounts, as well as change settings in your Google Apps account and add your site’s branding to your Apps. Your Google Apps will work just like their standard @gmail.com counterparts. Here’s an example of an inbox customized with the techinch logo and a Gmail theme. Links to Remember Here are the common links to your Google Apps online. Substitute your domain or subdomain for yourdomain.com. Dashboard https://www.google.com/a/cpanel/yourdomain.com Email https://mail.google.com/a/yourdomain.com Calendar https://www.google.com/calendar/hosted/yourdomain.com Docs https://docs.google.com/a/yourdomain.com Sites https://sites.google.com/a/yourdomain.com Conclusion Google Apps offers you great webapps and webmail for your domain, and let’s you take advantage of Google’s services while still maintaining the professional look of your own domain. Setting up your account can be slightly complicated, but once it’s finished, it will run seamlessly and you’ll never have to worry about email or collaboration with your team again. Signup for the free Google Apps Standard Similar Articles Productive Geek Tips Mysticgeek Blog: Create Your Own Simple iGoogle GadgetAccess Your Favorite Google Services in Chrome the Easy WayRevo Uninstaller Pro [REVIEW]Mysticgeek Blog: A Look at Internet Explorer 8 Beta 1 on Windows XPFind Similar Websites in Google Chrome TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 Video preview of new Windows Live Essentials 21 Cursor Packs for XP, Vista & 7 Map the Stars with Stellarium Use ILovePDF To Split and Merge PDF Files TimeToMeet is a Simple Online Meeting Planning Tool Easily Create More Bookmark Toolbars in Firefox

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facebook connect for android returns a blank login screen?

- by jonney

Hi, i am trying to use the old facebook connect authentication to authenticate my android client to get the necessary session id's and other credentials thats needed to start using the web service of facebook. the issue i am having is that when my android application launces and tries to load the login page for facebook, that very same login page is blank and it only displays the the facebook logo as the title of the screen. No login fields or buttons are visible leaving me nowhere to login and authenticate a user. i have tried two API's one is facebook connect api for android http://code.google.com/p/fbconnect-android/ and the other one is the official android facebook sdk that is recommended to be used instead of the previous one i have just mentioned https://github.com/facebook/facebook-android-sdk/ . please see the image below of how it looks like on my app. Here is code that uses the latest android sdk facebook: /** * Authenticate facebook network */ private void authenticateFacebook() { // TODO: move this away from this activty class into some kind of // helper/wrapper class Log.d(TAG, "Clicked on the facebook"); Facebook facebook = new Facebook(OAUTH_KEY_FACEBOOK_API); facebook.authorize(this, new AuthorizeListener()); } class AuthorizeListener implements DialogListener{ @Override public void onComplete(Bundle values) { // TODO Auto-generated method stub Log.d(TAG, "finished authorizing facebook user"); } @Override public void onFacebookError(FacebookError e) { // TODO Auto-generated method stub } @Override public void onError(DialogError e) { // TODO Auto-generated method stub } @Override public void onCancel() { // TODO Auto-generated method stub } } And a simple example of how to use it: http://developers.facebook.com/docs/guides/mobile/ My code is more or less identical to the above example. edit: i did not catch what logcat was inputing in my first attempted at my code above but their was no exceptions or warnings thrown at the time. just a blank page. i then tried it again and diddnt touch my code and what happens now is that a loading dialogue view pops up and stays their for a few minutes until the facebook windows disapears and the logcat outputs the error below: 11-18 17:26:19.913: DEBUG/Facebook-WebView(783): Webview loading URL: https://www.facebook.com/dialog/oauth?type=user_agent&redirect_uri=fbconnect%3A%2F%2Fsuccess&display=touch&client_id=e??????????????????? 11-18 17:27:01.756: DEBUG/Facebook-authorize(783): Login failed: com.kc.unity.agent.util.oauth.facebook.DialogError: The connection to the server was unsuccessful. 11-18 17:27:01.783: DEBUG/Facebook-WebView(783): Webview loading URL: https://www.facebook.com/dialog/oauth?type=user_agent&redirect_uri=fbconnect%3A%2F%2Fsuccess&display=touch&client_id=??????????????? please note that the client id i have amended for obvious reasons but the rest of the logcat is untouched

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Are programmers bad testers?

- by jhsowter

I know this sounds a lot like other questions which have already being asked, but it is actually slightly different. It seems to be generally considered that programmers are not good at performing the role of testing an application. For example: Joel on Software - Top Five (Wrong) Reasons You Don't Have Testers (emphasis mine) Don't even think of trying to tell college CS graduates that they can come work for you, but "everyone has to do a stint in QA for a while before moving on to code". I've seen a lot of this. Programmers do not make good testers, and you'll lose a good programmer, who is a lot harder to replace. And in this question, one of the most popular answers says (again, my emphasis): Developers can be testers, but they shouldn't be testers. Developers tend to unintentionally/unconciously avoid to use the application in a way that might break it. That's because they wrote it and mostly test it in the way it should be used. So the question is are programmers bad at testing? What evidence or arguments are there to support this conclusion? Are programmers only bad at testing their own code? Is there any evidence to suggest that programmers are actually good at testing? What do I mean by "testing?" I do not mean unit testing or anything that is considered part of the methodology used by the software team to write software. I mean some kind of quality assurance method that is used after the code has been built and deployed to whatever that software team would call the "test environment."

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Thread Synchronization and Synchronization Primitives

When considering synchronization in an application, the decision truly depends on what the application and its worker threads are going to do. I would use synchronization if two or more threads could possibly manipulate the same instance of an object at the same time. An example of this in C# can be demonstrated through the use of storing data in a static object. A static object is initialized once per application and the data within the object can be accessed by all threads. I would use the synchronization primitives to prevent any data from being manipulated by multiple threads simultaneously. This would reduce any data corruption from occurring within the object. On the other hand if all the threads used non static objects and were independent of the other tasks there would be no need to use synchronization. Synchronization Primitives in C#: Basic Blocking Locking Signaling Non-Blocking Synchronization Constructs The Basic Blocking methods include Sleep, Join, and Task.Wait. These methods force threads to wait until other threads have completed. In addition, these methods can also force a thread to wait a set amount of time before continuing to work. The Locking primitive prevents a thread from entering a critical section of code while another thread is in the same critical section. If another thread attempts to enter a locked code, it will wait, until the code block is released. The Signaling primitive allows a thread to temporarily pause work until receiving a notification from another thread that it is ok to continue working. The Signaling primitive removes the need for polling.The Non-Blocking Synchronization Constructs protect access to a common field by calling upon processor primitives.

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Using RIA DomainServices with ASP.NET and MVC 2

- by Bobby Diaz

Recently, I started working on a new ASP.NET MVC 2 project and I wanted to reuse the data access (LINQ to SQL) and business logic methods (WCF RIA Services) that had been developed for a previous project that used Silverlight for the front-end. I figured that I would be able to instantiate the various DomainService classes from within my controller’s action methods, because after all, the code for those services didn’t look very complicated. WRONG! I didn’t realize at first that some of the functionality is handled automatically by the framework when the domain services are hosted as WCF services. After some initial searching, I came across an invaluable post by Joe McBride, which described how to get RIA Service .svc files to work in an MVC 2 Web Application, and another by Brad Abrams. Unfortunately, Brad’s solution was for an earlier preview release of RIA Services and no longer works with the version that I am running (PDC Preview). I have not tried the RC version of WCF RIA Services, so I am not sure if any of the issues I am having have been resolved, but I wanted to come up with a way to reuse the shared libraries so I wouldn’t have to write a non-RIA version that basically did the same thing. The classes I came up with work with the scenarios I have encountered so far, but I wanted to go ahead and post the code in case someone else is having the same trouble I had. Hopefully this will save you a few headaches! 1. Querying When I first tried to use a DomainService class to perform a query inside one of my controller’s action methods, I got an error stating that “This DomainService has not been initialized.” To solve this issue, I created an extension method for all DomainServices that creates the required DomainServiceContext and passes it to the service’s Initialize() method. Here is the code for the extension method; notice that I am creating a sort of mock HttpContext for those cases when the service is running outside of IIS, such as during unit testing! public static class ServiceExtensions { /// <summary> /// Initializes the domain service by creating a new <see cref="DomainServiceContext"/> /// and calling the base DomainService.Initialize(DomainServiceContext) method. /// </summary> /// <typeparam name="TService">The type of the service.</typeparam> /// <param name="service">The service.</param> /// <returns></returns> public static TService Initialize<TService>(this TService service) where TService : DomainService { var context = CreateDomainServiceContext(); service.Initialize(context); return service; } private static DomainServiceContext CreateDomainServiceContext() { var provider = new ServiceProvider(new HttpContextWrapper(GetHttpContext())); return new DomainServiceContext(provider, DomainOperationType.Query); } private static HttpContext GetHttpContext() { var context = HttpContext.Current; #if DEBUG // create a mock HttpContext to use during unit testing... if ( context == null ) { var writer = new StringWriter(); var request = new SimpleWorkerRequest("/", "/", String.Empty, String.Empty, writer); context = new HttpContext(request) { User = new GenericPrincipal(new GenericIdentity("debug"), null) }; } #endif return context; } } With that in place, I can use it almost as normally as my first attempt, except with a call to Initialize(): public ActionResult Index() { var service = new NorthwindService().Initialize(); var customers = service.GetCustomers(); return View(customers); } 2. Insert / Update / Delete Once I got the records showing up, I was trying to insert new records or update existing data when I ran into the next issue. I say issue because I wasn’t getting any kind of error, which made it a little difficult to track down. But once I realized that that the DataContext.SubmitChanges() method gets called automatically at the end of each domain service submit operation, I could start working on a way to mimic the behavior of a hosted domain service. What I came up with, was a base class called LinqToSqlRepository<T> that basically sits between your implementation and the default LinqToSqlDomainService<T> class. [EnableClientAccess()] public class NorthwindService : LinqToSqlRepository<NorthwindDataContext> { public IQueryable<Customer> GetCustomers() { return this.DataContext.Customers; } public void InsertCustomer(Customer customer) { this.DataContext.Customers.InsertOnSubmit(customer); } public void UpdateCustomer(Customer currentCustomer) { this.DataContext.Customers.TryAttach(currentCustomer, this.ChangeSet.GetOriginal(currentCustomer)); } public void DeleteCustomer(Customer customer) { this.DataContext.Customers.TryAttach(customer); this.DataContext.Customers.DeleteOnSubmit(customer); } } Notice the new base class name (just change LinqToSqlDomainService to LinqToSqlRepository). I also added a couple of DataContext (for Table<T>) extension methods called TryAttach that will check to see if the supplied entity is already attached before attempting to attach it, which would cause an error! 3. LinqToSqlRepository<T> Below is the code for the LinqToSqlRepository class. The comments are pretty self explanatory, but be aware of the [IgnoreOperation] attributes on the generic repository methods, which ensures that they will be ignored by the code generator and not available in the Silverlight client application. /// <summary> /// Provides generic repository methods on top of the standard /// <see cref="LinqToSqlDomainService<TContext>"/> functionality. /// </summary> /// <typeparam name="TContext">The type of the context.</typeparam> public abstract class LinqToSqlRepository<TContext> : LinqToSqlDomainService<TContext> where TContext : System.Data.Linq.DataContext, new() { /// <summary> /// Retrieves an instance of an entity using it's unique identifier. /// </summary> /// <typeparam name="TEntity">The type of the entity.</typeparam> /// <param name="keyValues">The key values.</param> /// <returns></returns> [IgnoreOperation] public virtual TEntity GetById<TEntity>(params object[] keyValues) where TEntity : class { var table = this.DataContext.GetTable<TEntity>(); var mapping = this.DataContext.Mapping.GetTable(typeof(TEntity)); var keys = mapping.RowType.IdentityMembers .Select((m, i) => m.Name + " = @" + i) .ToArray(); return table.Where(String.Join(" && ", keys), keyValues).FirstOrDefault(); } /// <summary> /// Creates a new query that can be executed to retrieve a collection /// of entities from the <see cref="DataContext"/>. /// </summary> /// <typeparam name="TEntity">The type of the entity.</typeparam> /// <returns></returns> [IgnoreOperation] public virtual IQueryable<TEntity> GetEntityQuery<TEntity>() where TEntity : class { return this.DataContext.GetTable<TEntity>(); } /// <summary> /// Inserts the specified entity. /// </summary> /// <typeparam name="TEntity">The type of the entity.</typeparam> /// <param name="entity">The entity.</param> /// <returns></returns> [IgnoreOperation] public virtual bool Insert<TEntity>(TEntity entity) where TEntity : class { //var table = this.DataContext.GetTable<TEntity>(); //table.InsertOnSubmit(entity); return this.Submit(entity, null, DomainOperation.Insert); } /// <summary> /// Updates the specified entity. /// </summary> /// <typeparam name="TEntity">The type of the entity.</typeparam> /// <param name="entity">The entity.</param> /// <returns></returns> [IgnoreOperation] public virtual bool Update<TEntity>(TEntity entity) where TEntity : class { return this.Update(entity, null); } /// <summary> /// Updates the specified entity. /// </summary> /// <typeparam name="TEntity">The type of the entity.</typeparam> /// <param name="entity">The entity.</param> /// <param name="original">The original.</param> /// <returns></returns> [IgnoreOperation] public virtual bool Update<TEntity>(TEntity entity, TEntity original) where TEntity : class { if ( original == null ) { original = GetOriginal(entity); } var table = this.DataContext.GetTable<TEntity>(); table.TryAttach(entity, original); return this.Submit(entity, original, DomainOperation.Update); } /// <summary> /// Deletes the specified entity. /// </summary> /// <typeparam name="TEntity">The type of the entity.</typeparam> /// <param name="entity">The entity.</param> /// <returns></returns> [IgnoreOperation] public virtual bool Delete<TEntity>(TEntity entity) where TEntity : class { //var table = this.DataContext.GetTable<TEntity>(); //table.TryAttach(entity); //table.DeleteOnSubmit(entity); return this.Submit(entity, null, DomainOperation.Delete); } protected virtual bool Submit(Object entity, Object original, DomainOperation operation) { var entry = new ChangeSetEntry(0, entity, original, operation); var changes = new ChangeSet(new ChangeSetEntry[] { entry }); return base.Submit(changes); } private TEntity GetOriginal<TEntity>(TEntity entity) where TEntity : class { var context = CreateDataContext(); var table = context.GetTable<TEntity>(); return table.FirstOrDefault(e => e == entity); } } 4. Conclusion So there you have it, a fully functional Repository implementation for your RIA Domain Services that can be consumed by your ASP.NET and MVC applications. I have uploaded the source code along with unit tests and a sample web application that queries the Customers table from inside a Controller, as well as a Silverlight usage example. As always, I welcome any comments or suggestions on the approach I have taken. If there is enough interest, I plan on contacting Colin Blair or maybe even the man himself, Brad Abrams, to see if this is something worthy of inclusion in the WCF RIA Services Contrib project. What do you think? Enjoy!

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Interfacing Android Nexus One with Arduino + BlueSmirf

- by efgomez

I'm a bit new to all of this, so bear with me - I'd really appreciate your help. I am trying to link the Android Nexus One with an arduino (Duemilanove) that is connected to a BlueSmirf. I have a program that is simply outputting the string "Hello Bluetooth" to whatever device the BlueSmirf is connected to. Here is the Arduino program: void setup(){ Serial.begin(115200); int i; } void loop(){Serial.print("Hello Bluetooth!"); delay(1000); } One my computer BT terminal I can see the message and connect no problem. The trouble is with my android code. I can connect to the device with android, but when I look at the log it is not displaying "Hello Bluetooth". Here is the debug log: 04-09 16:27:49.022: ERROR/BTArduino(17288): FireFly-2583 connected 04-09 16:27:49.022: ERROR/BTArduino(17288): STARTING TO CONNECT THE SOCKET 04-09 16:27:55.705: ERROR/BTArduino(17288): Received: 16 04-09 16:27:56.702: ERROR/BTArduino(17288): Received: 1 04-09 16:27:56.712: ERROR/BTArduino(17288): Received: 15 04-09 16:27:57.702: ERROR/BTArduino(17288): Received: 1 04-09 16:27:57.702: ERROR/BTArduino(17288): Received: 15 04-09 16:27:58.704: ERROR/BTArduino(17288): Received: 1 04-09 16:27:58.704: ERROR/BTArduino(17288): Received: 15 ect... Here is the code, I'm trying to put only the relative code but if you need more please let me know: private class ConnectThread extends Thread { private final BluetoothSocket mySocket; private final BluetoothDevice myDevice; public ConnectThread(BluetoothDevice device) { myDevice = device; BluetoothSocket tmp = null; try { tmp = device.createRfcommSocketToServiceRecord(MY_UUID); } catch (IOException e) { Log.e(TAG, "CONNECTION IN THREAD DIDNT WORK"); } mySocket = tmp; } public void run() { Log.e(TAG, "STARTING TO CONNECT THE SOCKET"); InputStream inStream = null; boolean run = false; //...More Connection code here... The more relative code is here: byte[] buffer = new byte[1024]; int bytes; // handle Connection try { inStream = mySocket.getInputStream(); while (run) { try { bytes = inStream.read(buffer); Log.e(TAG, "Received: " + bytes); } catch (IOException e3) { Log.e(TAG, "disconnected"); } } I am reading bytes = inStream.read(buffer). I know bytes is an integer, so I tried sending integers over bluetooth because "bytes" was an integer but it still didn't make sense. It almost appears that is sending incorrect baud rate. Could this be true? Any help would be appreciated. Thank you very much.

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Does software architect/designer require more skills and intellectual than software engineer (implementation)?

- by Amumu

So I heard the positions for designing software and writing spec for developers to implement are higher and getting paid more. I think many companies are using the Software Engineering title to depict the person to implement software, which means using tools and technologies to write the actual code. I know that in order to be a software architecture, one needs to be good at implementation in order to have an architectural overview of a system using a set of specific technologies. This is different than I thought of a Software Engineer. My thinking is similar to the standard of IEEE: A software engineer is an engineer who is capable of going from requirement analysis until the software is deployed, based on the SWEBOK (IEEE). Just look at the table of content. The IEEE even has the certificate for Software Engineering, since ABET (Accreditation Board for Engineering and Technology) seems to not have an official qualification test for Software Engineer (although IEEE is a member of ABET). The two certificates are CSDA and CSDP. I intend to take on these two examination in the future to be qualified as a software engineer, although I am already working as one (Junior position). On a side note on the issues of Software Engineer, you can read the dicussion here: Just a Programmer and Just a Software Engineer. The information of ABET does not accredit Software Engineer is in "Just a Software Engineer". On the other hand, why is Programmer/Softwar Engineer who writes code considered a low level position? Suppose if two people have equal skills after the same years of experience, one becomes a software architect and one keeps focus on implementation aspect of Software Engineering (of course he also has design skill to compose a system, since he's a software engineer as well, but maybe less than the specialized software architect), how comes work from Software Engineer is less complicated than the Software Architect? In order to write great code with turn design into reality, it requires far greater skill than just understanding a particular language and a framework. I don't think the ones who wrote and contributing Linux OS are lower level job and easier than conceptual design and writing spec. Can someone enlighten me?

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jQuery not loading on Master Page when the Content Page is in a child folder.

- by ProfK

I have a site where I am trying to implement a jQuery UI based MessageBox in my master page. Content pages are arranged accoring to business area folders, i.e. '~/Branding/Contracts.aspx'. I find that when I load such a content page, jQuery, which is referenced in the master page as below, does not load. I assume that this is because the browser is requesting 'Branding/Scripts/jQuery '. What can I do about this? I don't have the 'root' operator in a plain 'script' tag. <script src="/Scripts/jquery-1.3.2.js" type="text/javascript"></script> <script src="Scripts/jquery-1.3.2.js" type="text/javascript"></script> <script src="Scripts/jquery-ui-1.7.2.custom.min.js" type="text/javascript"></script>

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ANTLR: using stringTemplate

- by Kevin Won

(I'm a Noob with Antlr)... I'm having difficulties getting my grammar with StringTemplates. Basically I'm trying to write a little DSL. I can get my grammar the way I want (it parses correctly), but I can't get the generation of the target code to work with templates. So here's a snippet of my grammar: grammar Pfig; options { output=template; language=CSharp2; } conf : globalName ; globalName : 'GlobalName:' ID -> localConf(name ={$ID.text}) ; I simplified it quite a bit just to get the essence across. Basically, when the lex/parse comes across `GlobalName: Foo' I want it to spit out text based on the StringTemplate called 'localConf'. Super straightforward. So now, let's fire up the parser in a test app and have it process an input file. // C# processing a file with the lex/parser. // the 'app.pfig' file just has one line that reads 'GlobalName: Bla' using (FileStream fs = File.OpenRead("c:\\app.pfig")) { PfigParser parser = new PfigParser(new CommonTokenStream( new PfigLexer(new ANTLRInputStream(fs)))); using (TextReader tr = File.OpenText("./Pfig.stg")) { parser.TemplateLib = new StringTemplateGroup(tr); } var parseResult = parser.conf(); string code = parseResult.Template.ToString(); // Fail: template is null } I can step through the parser code and see that it correctly identifies my text and applies the stringTemplate correctly. The problem is that since this 'globalName' rule is a subrule of 'conf' it doesn't get executed directly--the method just finds it and returns. But the calling 'Conf' method does not keep the return value from the subrule--it goes to thin air. This means that my resultant template on the last line is null. If I get rid of the 'conf' rule in my grammar and call 'globalName' directly, it will work (since it's the only rule on the stack). But I obviously want more than one rule. I've generated the parser in Java and it does the same thing: // antlr generated parser code public PfigParser.conf_return conf() // throws RecognitionException [1] { PfigParser.conf_return retval = new PfigParser.conf_return(); try { { PushFollow(FOLLOW_globalName_in_conf30); globalName(); // <- it calls globalName() but doesn't keep the return. state.followingStackPointer--; } retval.Stop = input.LT(-1); } // snip It's simple to see I don't get some basic concept with how the Template approach is supposed to work with Antlr. I'm quite sure this is my problem but I'm a loggerheads to know what I'm doing wrong... the examples I've seen don't really show real-world template emission of code.

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gl_PointCoord always zero

- by Jonathan

I am trying to draw point sprites in OpenGL with a shader but gl_PointCoord is always zero. Here is my code Setup: //Shader creation..(includes glBindAttribLocation(program, ATTRIB_P, "p");) glEnableVertexAttribArray(ATTRIB_P); In the rendering loop: glUseProgram(shader_particles); float vertices[]={0.0f,0.0f,0.0f}; glEnable(GL_TEXTURE_2D); glEnable(GL_POINT_SPRITE); glEnable(GL_VERTEX_PROGRAM_POINT_SIZE); //glTexEnvi(GL_POINT_SPRITE, GL_COORD_REPLACE, GL_TRUE);(tried with this on/off, doesn't work) glVertexAttribPointer(ATTRIB_P, 3, GL_FLOAT, GL_FALSE, 0, vertices); glDrawArrays(GL_POINTS, 0, 1); Vertex Shader: attribute highp vec4 p; void main() { gl_PointSize = 40.0f; gl_Position = p; } Fragment Shader: void main() { gl_FragColor = vec4(gl_PointCoord.st, 0, 1);//if the coords range from 0-1, this should draw a square with black,red,green,yellow corners } But this only draws a black square with a size of 40. What am I doing wrong? Edit: Point sprites work when i use the fixed function, but I need to use shaders because in the end the code will be for opengl es 2.0 glUseProgram(0); glEnable(GL_TEXTURE_2D); glEnable(GL_POINT_SPRITE); glTexEnvi(GL_POINT_SPRITE, GL_COORD_REPLACE, GL_TRUE); glPointSize(40); glBegin(GL_POINTS); glVertex3f(0.0f,0.0f,0.0f); glEnd(); Is anyone able to get point sprites working with shader? If so, please share some code.

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ASP.NET Frameworks and Raw Throughput Performance

- by Rick Strahl

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

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DDD Melbourne -lessons leant

- by Michael Freidgeim

I've attended DDD Melbourne and want to list the interesting points, that I've leant and want to follow. To read more: * Moles-Mocking Isolation framework for .NET. Documentation is here. (See also Mocking frameworks comparison created October 4, 2009 ) * WebFormsMVP * PluralSight http://www.pluralsight-training.net/offers/default.aspx?cc=trial * ELMAH: Error Logging Modules and Handlers *Rhino.Mocks * VS UI Test Recorder -see posts Visual Studio 2010 Coded UI Test User Guide. Note that Microsoft Test Manager (MTM) toolis a separate application, that can be started from Program files/VS 2010 menu.It is not a menu inside Visual Studio. * CodeContract- seems great in Debug. Will be good if in production will be possible runtime configuration, ability to log instead of throw exception. Current recommendation to customize Debug.Assert is not trivial The programmer is free to use the customization provided by Debug.Assert using assert listeners to obtain whatever runtime behavior they desire (e.g., ignoring the error, logging it, or throwing an exception). // Clears the existing list of assert listener (the default pop-up box) System.Diagnostics.Debug.Listeners.Clear(); // Install your own listener System.Diagnostics.Debug.Listeners.Add(MyTraceListener); Note that you can't catch specific ContractException, but can catch generic Exception(see How come you cannot catch Code Contract exceptions?) Books recommended "Working effectively with legacy code" by Michael Feathers (corresponding article) Fowler, Martin Refactoring: Improving the Design of Existing Code, slides http://jaoo.dk/jaoo1999/schedule/MartinFowlerRefractoring.pdf

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Part 2: Career development as a Software Developer without becoming a manager.

- by albertpascual

Seems like my previous post inspired by the work of Michael “Doc” Norton was a great success for the amount of emails I have received. Yet amazed how many people didn’t want to discuss their questions in the comments sections. I would encourage people to be more public, still I would like to reply to all of you on this public media. I still welcome those emails. What I found out is that many people feels like me, they want to be developers and still be compensated for their experience without wanting to take a job as a manager. Their perfect day is a full day of coding and learning. Many believe their companies will never pay a manager’s salary to a developer no matter what. Most of you ask how to get the ball rolling. And is the later that I’m addressing here, the previous group, will never try. What companies understand developers value and where can I find them? This is a very difficult question to ask, I don’t have a list of those companies or departments, I have seen in my past signs in companies bending backwards to compensate, in more ways the monetary, a developer that is a good resource to them. Allowing the person to move out of the state and still let them work for the company from home is a sign that company goes by individual cases. Allowing them to go to conference that will not benefit the company is another big sign. Simple signs like flexible hours and letting some people work from home. To see those signs you need to be working in that company for awhile and look at the departments where the manager is taking care of their employees in individual cases. Look for the department where people get quiet extra perks, where some people in the department work from home or remotely. In my experience, but not always true, medium to big companies, are prompt to recognize good developers. Then again, some companies just don’t get it and is when you see many technical people managing developers. For all the people that email me stating that developers can also be very good managers, I do not disagree, I just think that a good developers loves writing code, when you remove that part the better salary isn’t enough to keep a developer happy. Burned out developers appreciate being promoted to managers. How do I know I work in a bad company? In my experience I have been a consultant and seen many companies, a few signs I have learned about companies that will not recognize good developers are: When the turn over is pretty high, when developers are moving out in a big rate, no rocket scientist needs to tap you in the shoulder. When the company is looking always to outsource their development resources. The product is not that interesting nor the company cares too much for their final result and support. Code sweat shops. You’ll know when you start working in one of those. Run for the hills! Where do I start? Disclaimer: I have only based this post on Michael “Doc” Norton, this is just my interpretation and ideas. First thing is to look at Michael “Doc” Norton presentation Take Control of Your Development Career http://docondev.blogspot.com/ That should be the first thing any developer should look and follow like it was a pattern. I would personally recommend to find some language or pattern you are interested with and learn it, learn something that will make you happy. Second, join a User Group and get involve in the community. There are hundreds of user groups, and I’m sure you’ll find one in your city or near you town. Code Camps are Developers Meet Ups are also good resources. Third, I would join a open source project you are interested or better yet, create a new open source project with the new technology that you have learn and get coding. Fourth, create a Twitter account and follow the people that talks about the technology you are interested on. If you follow this 4 steps above I think you’ll be on your way, after they are complete, when you release your Open Source project you can say that you accomplished the first steps. Now, do not expect anything to change in your career life, you are changing and should not expect anything in return, besides borrowing some time from sleeping and your family. Creating a good schedule may help you, I find wasted time in many places that I use. Flying for work is actually one of those that allows me to do my best work on a airplane, don’t need to borrow time from anywhere else. Making sure you always have a light, charged laptop is so important. Next steps following the Michael “Doc” Norton Pattern or my interpretation of. First, help run a user group or better yet, start a new user group. I’ll add, as well, go to one conference a year and free development events around your city; Code Camps, Geek Dinners, etc. There are many free events sponsored by different companies for developers to get to know their products, I highly recommend those as the way to get connected. Second, chose a mentor, this is a very hard thing to do I experienced, find an expert in the technology you are learning that has the time for you, it is difficult, I wish you best of luck. Third, learn another technology or pattern, open your horizons a little bit more. Why not, if you had fun previously, keep doing it. Fourth, get involved in forums to answer and ask questions, getting notice in public forums is rewarding for your ego after such a long journey. Final steps following the Michael “Doc” Norton Pattern Teach what you know, become humble on your knowledge, find as many opportunities to teach and to get involved with the community, bring all that to your day job. Mr. Norton talks about getting naked, expose yourself to others in your knowledge and what you do not know. You are never too important for small opportunities, yet don’t be afraid to take anything big and learn from the experience. Anytime you have the opportunity to talk to somebody that has reach the point the community knows his or her name, means that you should learn from it. Take opportunities that won’t make you money, yet will make you happy. Sometimes you need to spend money and time. Register talks in Code Camps and Dev Meet Ups, those are free, also go to Conference, Development Summits and Geek Diners for example. One day, people will pay you to attend. When will all these pay off? I don’t know. I’m still in the path, there are a few things that during your journey you may get little acknowledgements that you are in the correct path. In my case I think those are the little signs that tells you about your journey. I got awarded the Microsoft Most Valuable Professional for ASP.NET in 2007, 2008, 2009 and 2010. I got selected to speak at the DevConnections in Las Vegas in 2010 and Orlando 2011. I do believe that I do have a long way to go, yet what I do makes me happy and I hope I can keep doing for years to come. Every year I can see an improvement on my code, and more frameworks and languages are under my belt, I learn to embrace them all as well as in my daily job, I have been able to work in a few projects beyond my department. I’m a learner and believer of the Michael “Doc” Norton pattern. Looking forward to learn more about it to be able to apply it better. In my short journey I now see my mistakes, I did a few things right, I have been listening the intelligent people and not being afraid to move along the technology changes. In my professional life, I have tried to avoid being placed in only one technology and product. I have always share my code and never confused anybody that wanted to take over any of my projects, I didn’t think anything I created as my own nor care too much when politics didn’t see my vision. I stayed flexible, ready and visible, yet humble. I keep my head just below the clouds, and avoided managers meetings. I credit my manager for my success, and I faulted publicly only myself for the failures. Hope this helps. Cheers, Al Follow me in Twitter Read my previous post tweetmeme_url = 'http://weblogs.asp.net/albertpascual/archive/2010/12/09/part-2-career-development-as-a-software-developer-without-becoming-a-manager.aspx'; tweetmeme_source = 'alpascual';

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Create nice animation on your ASP.NET Menu control using jQuery

- by hajan

In this blog post, I will show how you can apply some nice animation effects on your ASP.NET Menu control. ASP.NET Menu control offers many possibilities, but together with jQuery, you can make very rich, interactive menu accompanied with animations and effects. Lets start with an example: - Create new ASP.NET Web Application and give it a name - Open your Default.aspx page (or any other .aspx page where you will create the menu) - Our page ASPX code is: <form id="form1" runat="server"> <div id="menu"> <asp:Menu ID="Menu1" runat="server" Orientation="Horizontal" RenderingMode="List"> <Items> <asp:MenuItem NavigateUrl="~/Default.aspx" ImageUrl="~/Images/Home.png" Text="Home" Value="Home" /> <asp:MenuItem NavigateUrl="~/About.aspx" ImageUrl="~/Images/Friends.png" Text="About Us" Value="AboutUs" /> <asp:MenuItem NavigateUrl="~/Products.aspx" ImageUrl="~/Images/Box.png" Text="Products" Value="Products" /> <asp:MenuItem NavigateUrl="~/Contact.aspx" ImageUrl="~/Images/Chat.png" Text="Contact Us" Value="ContactUs" /> </Items> </asp:Menu> </div> </form> As you can see, we have ASP.NET Menu with Horizontal orientation and RenderMode=”List”. It has four Menu Items where for each I have specified NavigateUrl, ImageUrl, Text and Value properties. All images are in Images folder in the root directory of this web application. The images I’m using for this demo are from Free Web Icons. - Next, lets create CSS for the LI and A tags (place this code inside head tag) <style type="text/css"> li { border:1px solid black; padding:20px 20px 20px 20px; width:110px; background-color:Gray; color:White; cursor:pointer; } a { color:White; font-family:Tahoma; } </style> This is nothing very important and you can change the style as you want. - Now, lets reference the jQuery core library directly from Microsoft CDN. <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.min.js"></script> - And we get to the most interesting part, applying the animations with jQuery Before we move on writing jQuery code, lets see what is the HTML code that our ASP.NET Menu control generates in the client browser. <ul class="level1"> <li><a class="level1" href="Default.aspx"><img src="Images/Home.png" alt="" title="" class="icon" />Home</a></li> <li><a class="level1" href="About.aspx"><img src="Images/Friends.png" alt="" title="" class="icon" />About Us</a></li> <li><a class="level1" href="Products.aspx"><img src="Images/Box.png" alt="" title="" class="icon" />Products</a></li> <li><a class="level1" href="Contact.aspx"><img src="Images/Chat.png" alt="" title="" class="icon" />Contact Us</a></li> </ul> So, it generates unordered list which has class level1 and for each item creates li element with an anchor with image + menu text inside it. If we want to access the list element only from our menu (not other list element sin the page), we need to use the following jQuery selector: “ul.level1 li”, which will find all li elements which have parent element ul with class level1. Hence, the jQuery code is: <script type="text/javascript"> $(function () { $("ul.level1 li").hover(function () { $(this).stop().animate({ opacity: 0.7, width: "170px" }, "slow"); }, function () { $(this).stop().animate({ opacity: 1, width: "110px" }, "slow"); }); }); </script> I’m using hover, so that the animation will occur once we go over the menu item. The two different functions are one for the over, the other for the out effect. The following line $(this).stop().animate({ opacity: 0.7, width: "170px" }, "slow"); does the real job. So, this will first stop any previous animations (if any) that are in progress and will animate the menu item by giving to it opacity of 0.7 and changing the width to 170px (the default width is 110px as in the defined CSS style for li tag). This happens on mouse over. The second function on mouse out reverts the opacity and width properties to the default ones. The last parameter “slow” is the speed of the animation. The end result is: The complete ASPX code: <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title>ASP.NET Menu + jQuery</title> <style type="text/css"> li { border:1px solid black; padding:20px 20px 20px 20px; width:110px; background-color:Gray; color:White; cursor:pointer; } a { color:White; font-family:Tahoma; } </style> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.min.js"></script> <script type="text/javascript"> $(function () { $("ul.level1 li").hover(function () { $(this).stop().animate({ opacity: 0.7, width: "170px" }, "slow"); }, function () { $(this).stop().animate({ opacity: 1, width: "110px" }, "slow"); }); }); </script> </head> <body> <form id="form1" runat="server"> <div id="menu"> <asp:Menu ID="Menu1" runat="server" Orientation="Horizontal" RenderingMode="List"> <Items> <asp:MenuItem NavigateUrl="~/Default.aspx" ImageUrl="~/Images/Home.png" Text="Home" Value="Home" /> <asp:MenuItem NavigateUrl="~/About.aspx" ImageUrl="~/Images/Friends.png" Text="About Us" Value="AboutUs" /> <asp:MenuItem NavigateUrl="~/Products.aspx" ImageUrl="~/Images/Box.png" Text="Products" Value="Products" /> <asp:MenuItem NavigateUrl="~/Contact.aspx" ImageUrl="~/Images/Chat.png" Text="Contact Us" Value="ContactUs" /> </Items> </asp:Menu> </div> </form> </body> </html> Hope this was useful. Regards, Hajan

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Developing Spring Portlet for use inside Weblogic Portal / Webcenter Portal

- by Murali Veligeti

We need to understand the main difference between portlet workflow and servlet workflow.The main difference between portlet workflow and servlet workflow is that, the request to the portlet can have two distinct phases: 1) Action phase 2) Render phase. The Action phase is executed only once and is where any 'backend' changes or actions occur, such as making changes in a database. The Render phase then produces what is displayed to the user each time the display is refreshed. The critical point here is that for a single overall request, the action phase is executed only once, but the render phase may be executed multiple times. This provides a clean separation between the activities that modify the persistent state of your system and the activities that generate what is displayed to the user.The dual phases of portlet requests are one of the real strengths of the JSR-168 specification. For example, dynamic search results can be updated routinely on the display without the user explicitly re-running the search. Most other portlet MVC frameworks attempt to completely hide the two phases from the developer and make it look as much like traditional servlet development as possible - we think this approach removes one of the main benefits of using portlets. So, the separation of the two phases is preserved throughout the Spring Portlet MVC framework. The primary manifestation of this approach is that where the servlet version of the MVC classes will have one method that deals with the request, the portlet version of the MVC classes will have two methods that deal with the request: one for the action phase and one for the render phase. For example, where the servlet version of AbstractController has the handleRequestInternal(..) method, the portlet version of AbstractController has handleActionRequestInternal(..) and handleRenderRequestInternal(..) methods.The Spring Portlet Framework is designed around a DispatcherPortlet that dispatches requests to handlers, with configurable handler mappings and view resolution, just as the DispatcherServlet in the Spring Web Framework does. Developing portlet.xml Let's start the sample development by creating the portlet.xml file in the /WebContent/WEB-INF/ folder as shown below: <?xml version="1.0" encoding="UTF-8"?> <portlet-app version="2.0" xmlns="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <portlet> <portlet-name>SpringPortletName</portlet-name> <portlet-class>org.springframework.web.portlet.DispatcherPortlet</portlet-class> <supports> <mime-type>text/html</mime-type> <portlet-mode>view</portlet-mode> </supports> <portlet-info> <title>SpringPortlet</title> </portlet-info> </portlet> </portlet-app> DispatcherPortlet is responsible for handling every client request. When it receives a request, it finds out which Controller class should be used for handling this request, and then it calls its handleActionRequest() or handleRenderRequest() method based on the request processing phase. The Controller class executes business logic and returns a View name that should be used for rendering markup to the user. The DispatcherPortlet then forwards control to that View for actual markup generation. As you can see, DispatcherPortlet is the central dispatcher for use within Spring Portlet MVC Framework. Note that your portlet application can define more than one DispatcherPortlet. If it does so, then each of these portlets operates its own namespace, loading its application context and handler mapping. The DispatcherPortlet is also responsible for loading application context (Spring configuration file) for this portlet. First, it tries to check the value of the configLocation portlet initialization parameter. If that parameter is not specified, it takes the portlet name (that is, the value of the <portlet-name> element), appends "-portlet.xml" to it, and tries to load that file from the /WEB-INF folder. In the portlet.xml file, we did not specify the configLocation initialization parameter, so let's create SpringPortletName-portlet.xml file in the next section. Developing SpringPortletName-portlet.xml Create the SpringPortletName-portlet.xml file in the /WebContent/WEB-INF folder of your application as shown below: <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd"> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> <property name="prefix" value="/jsp/"/> <property name="suffix" value=".jsp"/> </bean> <bean id="pointManager" class="com.wlp.spring.bo.internal.PointManagerImpl"> <property name="users"> <list> <ref bean="point1"/> <ref bean="point2"/> <ref bean="point3"/> <ref bean="point4"/> </list> </property> </bean> <bean id="point1" class="com.wlp.spring.bean.User"> <property name="name" value="Murali"/> <property name="points" value="6"/> </bean> <bean id="point2" class="com.wlp.spring.bean.User"> <property name="name" value="Sai"/> <property name="points" value="13"/> </bean> <bean id="point3" class="com.wlp.spring.bean.User"> <property name="name" value="Rama"/> <property name="points" value="43"/> </bean> <bean id="point4" class="com.wlp.spring.bean.User"> <property name="name" value="Krishna"/> <property name="points" value="23"/> </bean> <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource"> <property name="basename" value="messages"/> </bean> <bean name="/users.htm" id="userController" class="com.wlp.spring.controller.UserController"> <property name="pointManager" ref="pointManager"/> </bean> <bean name="/pointincrease.htm" id="pointIncreaseController" class="com.wlp.spring.controller.IncreasePointsFormController"> <property name="sessionForm" value="true"/> <property name="pointManager" ref="pointManager"/> <property name="commandName" value="pointIncrease"/> <property name="commandClass" value="com.wlp.spring.bean.PointIncrease"/> <property name="formView" value="pointincrease"/> <property name="successView" value="users"/> </bean> <bean id="parameterMappingInterceptor" class="org.springframework.web.portlet.handler.ParameterMappingInterceptor" /> <bean id="portletModeParameterHandlerMapping" class="org.springframework.web.portlet.handler.PortletModeParameterHandlerMapping"> <property name="order" value="1" /> <property name="interceptors"> <list> <ref bean="parameterMappingInterceptor" /> </list> </property> <property name="portletModeParameterMap"> <map> <entry key="view"> <map> <entry key="pointincrease"> <ref bean="pointIncreaseController" /> </entry> <entry key="users"> <ref bean="userController" /> </entry> </map> </entry> </map> </property> </bean> <bean id="portletModeHandlerMapping" class="org.springframework.web.portlet.handler.PortletModeHandlerMapping"> <property name="order" value="2" /> <property name="portletModeMap"> <map> <entry key="view"> <ref bean="userController" /> </entry> </map> </property> </bean> </beans> The SpringPortletName-portlet.xml file is an application context file for your MVC portlet. It has a couple of bean definitions: viewController. At this point, remember that the viewController bean definition points to the com.ibm.developerworks.springmvc.ViewController.java class. portletModeHandlerMapping. As we discussed in the last section, whenever DispatcherPortlet gets a client request, it tries to find a suitable Controller class for handling that request. That is where PortletModeHandlerMapping comes into the picture. The PortletModeHandlerMapping class is a simple implementation of the HandlerMapping interface and is used by DispatcherPortlet to find a suitable Controller for every request. The PortletModeHandlerMapping class uses Portlet mode for the current request to find a suitable Controller class to use for handling the request. The portletModeMap property of portletModeHandlerMapping bean is the place where we map the Portlet mode name against the Controller class. In the sample code, we show that viewController is responsible for handling View mode requests. Developing UserController.java In the preceding section, you learned that the viewController bean is responsible for handling all the View mode requests. Your next step is to create the UserController.java class as shown below: public class UserController extends AbstractController { private PointManager pointManager; public void handleActionRequest(ActionRequest request, ActionResponse response) throws Exception { } public ModelAndView handleRenderRequest(RenderRequest request, RenderResponse response) throws ServletException, IOException { String now = (new java.util.Date()).toString(); Map<String, Object> myModel = new HashMap<String, Object>(); myModel.put("now", now); myModel.put("users", this.pointManager.getUsers()); return new ModelAndView("users", "model", myModel); } public void setPointManager(PointManager pointManager) { this.pointManager = pointManager; } } Every controller class in Spring Portlet MVC Framework must implement the org.springframework.web. portlet.mvc.Controller interface directly or indirectly. To make things easier, Spring Framework provides AbstractController class, which is the default implementation of the Controller interface. As a developer, you should always extend your controller from either AbstractController or one of its more specific subclasses. Any implementation of the Controller class should be reusable, thread-safe, and capable of handling multiple requests throughout the lifecycle of the portlet. In the sample code, we create the ViewController class by extending it from AbstractController. Because we don't want to do any action processing in the HelloSpringPortletMVC portlet, we override only the handleRenderRequest() method of AbstractController. Now, the only thing that HelloWorldPortletMVC should do is render the markup of View.jsp to the user when it receives a user request to do so. To do that, return the object of ModelAndView with a value of view equal to View. Developing web.xml According to Portlet Specification 1.0, every portlet application is also a Servlet Specification 2.3-compliant Web application, and it needs a Web application deployment descriptor (that is, web.xml). Let’s create the web.xml file in the /WEB-INF/ folder as shown in listing 4. Follow these steps: Open the existing web.xml file located at /WebContent/WEB-INF/web.xml. Replace the contents of this file with the code as shown below: <servlet> <servlet-name>ViewRendererServlet</servlet-name> <servlet-class>org.springframework.web.servlet.ViewRendererServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ViewRendererServlet</servlet-name> <url-pattern>/WEB-INF/servlet/view</url-pattern> </servlet-mapping> <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/applicationContext.xml</param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> The web.xml file for the sample portlet declares two things: ViewRendererServlet. The ViewRendererServlet is the bridge servlet for portlet support. During the render phase, DispatcherPortlet wraps PortletRequest into ServletRequest and forwards control to ViewRendererServlet for actual rendering. This process allows Spring Portlet MVC Framework to use the same View infrastructure as that of its servlet version, that is, Spring Web MVC Framework. ContextLoaderListener. The ContextLoaderListener class takes care of loading Web application context at the time of the Web application startup. The Web application context is shared by all the portlets in the portlet application. In case of duplicate bean definition, the bean definition in the portlet application context takes precedence over the Web application context. The ContextLoader class tries to read the value of the contextConfigLocation Web context parameter to find out the location of the context file. If the contextConfigLocation parameter is not set, then it uses the default value, which is /WEB-INF/applicationContext.xml, to load the context file. The Portlet Controller interface requires two methods that handle the two phases of a portlet request: the action request and the render request. The action phase should be capable of handling an action request and the render phase should be capable of handling a render request and returning an appropriate model and view. While the Controller interface is quite abstract, Spring Portlet MVC offers a lot of controllers that already contain a lot of the functionality you might need – most of these are very similar to controllers from Spring Web MVC. The Controller interface just defines the most common functionality required of every controller - handling an action request, handling a render request, and returning a model and a view. How rendering works As you know, when the user tries to access a page with PointSystemPortletMVC portlet on it or when the user performs some action on any other portlet on that page or tries to refresh that page, a render request is sent to the PointSystemPortletMVC portlet. In the sample code, because DispatcherPortlet is the main portlet class, Weblogic Portal / Webcenter Portal calls its render() method and then the following sequence of events occurs: The render() method of DispatcherPortlet calls the doDispatch() method, which in turn calls the doRender() method. After the doRenderService() method gets control, first it tries to find out the locale of the request by calling the PortletRequest.getLocale() method. This locale is used while making all the locale-related decisions for choices such as which resource bundle should be loaded or which JSP should be displayed to the user based on the locale. After that, the doRenderService() method starts iterating through all the HandlerMapping classes configured for this portlet, calling their getHandler() method to identify the appropriate Controller for handling this request. In the sample code, we have configured only PortletModeHandlerMapping as a HandlerMapping class. The PortletModeHandlerMapping class reads the value of the current portlet mode, and based on that, it finds out, the Controller class that should be used to handle this request. In the sample code, ViewController is configured to handle the View mode request so that the PortletModeHandlerMapping class returns the object of ViewController. After the object of ViewController is returned, the doRenderService() method calls its handleRenderRequestInternal() method. Implementation of the handleRenderRequestInternal() method in ViewController.java is very simple. It logs a message saying that it got control, and then it creates an instance of ModelAndView with a value equal to View and returns it to DispatcherPortlet. After control returns to doRenderService(), the next task is to figure out how to render View. For that, DispatcherPortlet starts iterating through all the ViewResolvers configured in your portlet application, calling their resolveViewName() method. In the sample code we have configured only one ViewResolver, InternalResourceViewResolver. When its resolveViewName() method is called with viewName, it tries to add /WEB-INF/jsp as a prefix to the view name and to add JSP as a suffix. And it checks if /WEB-INF/jsp/View.jsp exists. If it does exist, it returns the object of JstlView wrapping View.jsp. After control is returned to the doRenderService() method, it creates the object PortletRequestDispatcher, which points to /WEB-INF/servlet/view – that is, ViewRendererServlet. Then it sets the object of JstlView in the request and dispatches the request to ViewRendererServlet. After ViewRendererServlet gets control, it reads the JstlView object from the request attribute and creates another RequestDispatcher pointing to the /WEB-INF/jsp/View.jsp URL and passes control to it for actual markup generation. The markup generated by View.jsp is returned to user. At this point, you may question the need for ViewRendererServlet. Why can't DispatcherPortlet directly forward control to View.jsp? Adding ViewRendererServlet in between allows Spring Portlet MVC Framework to reuse the existing View infrastructure. You may appreciate this more when we discuss how easy it is to integrate Apache Tiles Framework with your Spring Portlet MVC Framework. The attached project SpringPortlet.zip should be used to import the project in to your OEPE Workspace. SpringPortlet_Jars.zip contains jar files required for the application. Project is written on Spring 2.5. The same JSR 168 portlet should work on Webcenter Portal as well. Downloads: Download WeblogicPotal Project which consists of Spring Portlet. Download Spring Jars In-addition to above you need to download Spring.jar (Spring2.5)

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Syncing Data with a Server using Silverlight and HTTP Polling Duplex

- by dwahlin

Many applications have the need to stay in-sync with data provided by a service. Although web applications typically rely on standard polling techniques to check if data has changed, Silverlight provides several interesting options for keeping an application in-sync that rely on server “push” technologies. A few years back I wrote several blog posts covering different “push” technologies available in Silverlight that rely on sockets or HTTP Polling Duplex. We recently had a project that looked like it could benefit from pushing data from a server to one or more clients so I thought I’d revisit the subject and provide some updates to the original code posted. If you’ve worked with AJAX before in Web applications then you know that until browsers fully support web sockets or other duplex (bi-directional communication) technologies that it’s difficult to keep applications in-sync with a server without relying on polling. The problem with polling is that you have to check for changes on the server on a timed-basis which can often be wasteful and take up unnecessary resources. With server “push” technologies, data can be pushed from the server to the client as it changes. Once the data is received, the client can update the user interface as appropriate. Using “push” technologies allows the client to listen for changes from the data but stay 100% focused on client activities as opposed to worrying about polling and asking the server if anything has changed. Silverlight provides several options for pushing data from a server to a client including sockets, TCP bindings and HTTP Polling Duplex. Each has its own strengths and weaknesses as far as performance and setup work with HTTP Polling Duplex arguably being the easiest to setup and get going. In this article I’ll demonstrate how HTTP Polling Duplex can be used in Silverlight 4 applications to push data and show how you can create a WCF server that provides an HTTP Polling Duplex binding that a Silverlight client can consume. What is HTTP Polling Duplex? Technologies that allow data to be pushed from a server to a client rely on duplex functionality. Duplex (or bi-directional) communication allows data to be passed in both directions. A client can call a service and the server can call the client. HTTP Polling Duplex (as its name implies) allows a server to communicate with a client without forcing the client to constantly poll the server. It has the benefit of being able to run on port 80 making setup a breeze compared to the other options which require specific ports to be used and cross-domain policy files to be exposed on port 943 (as with sockets and TCP bindings). Having said that, if you’re looking for the best speed possible then sockets and TCP bindings are the way to go. But, they’re not the only game in town when it comes to duplex communication. The first time I heard about HTTP Polling Duplex (initially available in Silverlight 2) I wasn’t exactly sure how it was any better than standard polling used in AJAX applications. I read the Silverlight SDK, looked at various resources and generally found the following definition unhelpful as far as understanding the actual benefits that HTTP Polling Duplex provided: "The Silverlight client periodically polls the service on the network layer, and checks for any new messages that the service wants to send on the callback channel. The service queues all messages sent on the client callback channel and delivers them to the client when the client polls the service." Although the previous definition explained the overall process, it sounded as if standard polling was used. Fortunately, Microsoft’s Scott Guthrie provided me with a more clear definition several years back that explains the benefits provided by HTTP Polling Duplex quite well (used with his permission): "The [HTTP Polling Duplex] duplex support does use polling in the background to implement notifications – although the way it does it is different than manual polling. It initiates a network request, and then the request is effectively “put to sleep” waiting for the server to respond (it doesn’t come back immediately). The server then keeps the connection open but not active until it has something to send back (or the connection times out after 90 seconds – at which point the duplex client will connect again and wait). This way you are avoiding hitting the server repeatedly – but still get an immediate response when there is data to send." After hearing Scott’s definition the light bulb went on and it all made sense. A client makes a request to a server to check for changes, but instead of the request returning immediately, it parks itself on the server and waits for data. It’s kind of like waiting to pick up a pizza at the store. Instead of calling the store over and over to check the status, you sit in the store and wait until the pizza (the request data) is ready. Once it’s ready you take it back home (to the client). This technique provides a lot of efficiency gains over standard polling techniques even though it does use some polling of its own as a request is initially made from a client to a server. So how do you implement HTTP Polling Duplex in your Silverlight applications? Let’s take a look at the process by starting with the server. Creating an HTTP Polling Duplex WCF Service Creating a WCF service that exposes an HTTP Polling Duplex binding is straightforward as far as coding goes. Add some one way operations into an interface, create a client callback interface and you’re ready to go. The most challenging part comes into play when configuring the service to properly support the necessary binding and that’s more of a cut and paste operation once you know the configuration code to use. To create an HTTP Polling Duplex service you’ll need to expose server-side and client-side interfaces and reference the System.ServiceModel.PollingDuplex assembly (located at C:\Program Files (x86)\Microsoft SDKs\Silverlight\v4.0\Libraries\Server on my machine) in the server project. For the demo application I upgraded a basketball simulation service to support the latest polling duplex assemblies. The service simulates a simple basketball game using a Game class and pushes information about the game such as score, fouls, shots and more to the client as the game changes over time. Before jumping too far into the game push service, it’s important to discuss two interfaces used by the service to communicate in a bi-directional manner. The first is called IGameStreamService and defines the methods/operations that the client can call on the server (see Listing 1). The second is IGameStreamClient which defines the callback methods that a server can use to communicate with a client (see Listing 2). [ServiceContract(Namespace = "Silverlight", CallbackContract = typeof(IGameStreamClient))] public interface IGameStreamService { [OperationContract(IsOneWay = true)] void GetTeamData(); } Listing 1. The IGameStreamService interface defines server operations that can be called on the server. [ServiceContract] public interface IGameStreamClient { [OperationContract(IsOneWay = true)] void ReceiveTeamData(List<Team> teamData); [OperationContract(IsOneWay = true, AsyncPattern=true)] IAsyncResult BeginReceiveGameData(GameData gameData, AsyncCallback callback, object state); void EndReceiveGameData(IAsyncResult result); } Listing 2. The IGameStreamClient interfaces defines client operations that a server can call. The IGameStreamService interface is decorated with the standard ServiceContract attribute but also contains a value for the CallbackContract property. This property is used to define the interface that the client will expose (IGameStreamClient in this example) and use to receive data pushed from the service. Notice that each OperationContract attribute in both interfaces sets the IsOneWay property to true. This means that the operation can be called and passed data as appropriate, however, no data will be passed back. Instead, data will be pushed back to the client as it’s available. Looking through the IGameStreamService interface you can see that the client can request team data whereas the IGameStreamClient interface allows team and game data to be received by the client. One interesting point about the IGameStreamClient interface is the inclusion of the AsyncPattern property on the BeginReceiveGameData operation. I initially created this operation as a standard one way operation and it worked most of the time. However, as I disconnected clients and reconnected new ones game data wasn’t being passed properly. After researching the problem more I realized that because the service could take up to 7 seconds to return game data, things were getting hung up. By setting the AsyncPattern property to true on the BeginReceivedGameData operation and providing a corresponding EndReceiveGameData operation I was able to get around this problem and get everything running properly. I’ll provide more details on the implementation of these two methods later in this post. Once the interfaces were created I moved on to the game service class. The first order of business was to create a class that implemented the IGameStreamService interface. Since the service can be used by multiple clients wanting game data I added the ServiceBehavior attribute to the class definition so that I could set its InstanceContextMode to InstanceContextMode.Single (in effect creating a Singleton service object). Listing 3 shows the game service class as well as its fields and constructor. [ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, InstanceContextMode = InstanceContextMode.Single)] public class GameStreamService : IGameStreamService { object _Key = new object(); Game _Game = null; Timer _Timer = null; Random _Random = null; Dictionary<string, IGameStreamClient> _ClientCallbacks = new Dictionary<string, IGameStreamClient>(); static AsyncCallback _ReceiveGameDataCompleted = new AsyncCallback(ReceiveGameDataCompleted); public GameStreamService() { _Game = new Game(); _Timer = new Timer { Enabled = false, Interval = 2000, AutoReset = true }; _Timer.Elapsed += new ElapsedEventHandler(_Timer_Elapsed); _Timer.Start(); _Random = new Random(); }} Listing 3. The GameStreamService implements the IGameStreamService interface which defines a callback contract that allows the service class to push data back to the client. By implementing the IGameStreamService interface, GameStreamService must supply a GetTeamData() method which is responsible for supplying information about the teams that are playing as well as individual players. GetTeamData() also acts as a client subscription method that tracks clients wanting to receive game data. Listing 4 shows the GetTeamData() method. public void GetTeamData() { //Get client callback channel var context = OperationContext.Current; var sessionID = context.SessionId; var currClient = context.GetCallbackChannel<IGameStreamClient>(); context.Channel.Faulted += Disconnect; context.Channel.Closed += Disconnect; IGameStreamClient client; if (!_ClientCallbacks.TryGetValue(sessionID, out client)) { lock (_Key) { _ClientCallbacks[sessionID] = currClient; } } currClient.ReceiveTeamData(_Game.GetTeamData()); //Start timer which when fired sends updated score information to client if (!_Timer.Enabled) { _Timer.Enabled = true; } } Listing 4. The GetTeamData() method subscribes a given client to the game service and returns. The key the line of code in the GetTeamData() method is the call to GetCallbackChannel<IGameStreamClient>(). This method is responsible for accessing the calling client’s callback channel. The callback channel is defined by the IGameStreamClient interface shown earlier in Listing 2 and used by the server to communicate with the client. Before passing team data back to the client, GetTeamData() grabs the client’s session ID and checks if it already exists in the _ClientCallbacks dictionary object used to track clients wanting callbacks from the server. If the client doesn’t exist it adds it into the collection. It then pushes team data from the Game class back to the client by calling ReceiveTeamData(). Since the service simulates a basketball game, a timer is then started if it’s not already enabled which is then used to randomly send data to the client. When the timer fires, game data is pushed down to the client. Listing 5 shows the _Timer_Elapsed() method that is called when the timer fires as well as the SendGameData() method used to send data to the client. void _Timer_Elapsed(object sender, ElapsedEventArgs e) { int interval = _Random.Next(3000, 7000); lock (_Key) { _Timer.Interval = interval; _Timer.Enabled = false; } SendGameData(_Game.GetGameData()); } private void SendGameData(GameData gameData) { var cbs = _ClientCallbacks.Where(cb => ((IContextChannel)cb.Value).State == CommunicationState.Opened); for (int i = 0; i < cbs.Count(); i++) { var cb = cbs.ElementAt(i).Value; try { cb.BeginReceiveGameData(gameData, _ReceiveGameDataCompleted, cb); } catch (TimeoutException texp) { //Log timeout error } catch (CommunicationException cexp) { //Log communication error } } lock (_Key) _Timer.Enabled = true; } private static void ReceiveGameDataCompleted(IAsyncResult result) { try { ((IGameStreamClient)(result.AsyncState)).EndReceiveGameData(result); } catch (CommunicationException) { // empty } catch (TimeoutException) { // empty } } LIsting 5. _Timer_Elapsed is used to simulate time in a basketball game. When _Timer_Elapsed() fires the SendGameData() method is called which iterates through the clients wanting to be notified of changes. As each client is identified, their respective BeginReceiveGameData() method is called which ultimately pushes game data down to the client. Recall that this method was defined in the client callback interface named IGameStreamClient shown earlier in Listing 2. Notice that BeginReceiveGameData() accepts _ReceiveGameDataCompleted as its second parameter (an AsyncCallback delegate defined in the service class) and passes the client callback as the third parameter. The initial version of the sample application had a standard ReceiveGameData() method in the client callback interface. However, sometimes the client callbacks would work properly and sometimes they wouldn’t which was a little baffling at first glance. After some investigation I realized that I needed to implement an asynchronous pattern for client callbacks to work properly since 3 – 7 second delays are occurring as a result of the timer. Once I added the BeginReceiveGameData() and ReceiveGameDataCompleted() methods everything worked properly since each call was handled in an asynchronous manner. The final task that had to be completed to get the server working properly with HTTP Polling Duplex was adding configuration code into web.config. In the interest of brevity I won’t post all of the code here since the sample application includes everything you need. However, Listing 6 shows the key configuration code to handle creating a custom binding named pollingDuplexBinding and associate it with the service’s endpoint. <bindings> <customBinding> <binding name="pollingDuplexBinding"> <binaryMessageEncoding /> <pollingDuplex maxPendingSessions="2147483647" maxPendingMessagesPerSession="2147483647" inactivityTimeout="02:00:00" serverPollTimeout="00:05:00"/> <httpTransport /> </binding> </customBinding> </bindings> <services> <service name="GameService.GameStreamService" behaviorConfiguration="GameStreamServiceBehavior"> <endpoint address="" binding="customBinding" bindingConfiguration="pollingDuplexBinding" contract="GameService.IGameStreamService"/> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> </service> </services> Listing 6. Configuring an HTTP Polling Duplex binding in web.config and associating an endpoint with it. Calling the Service and Receiving “Pushed” Data Calling the service and handling data that is pushed from the server is a simple and straightforward process in Silverlight. Since the service is configured with a MEX endpoint and exposes a WSDL file, you can right-click on the Silverlight project and select the standard Add Service Reference item. After the web service proxy is created you may notice that the ServiceReferences.ClientConfig file only contains an empty configuration element instead of the normal configuration elements created when creating a standard WCF proxy. You can certainly update the file if you want to read from it at runtime but for the sample application I fed the service URI directly to the service proxy as shown next: var address = new EndpointAddress("http://localhost.:5661/GameStreamService.svc"); var binding = new PollingDuplexHttpBinding(); _Proxy = new GameStreamServiceClient(binding, address); _Proxy.ReceiveTeamDataReceived += _Proxy_ReceiveTeamDataReceived; _Proxy.ReceiveGameDataReceived += _Proxy_ReceiveGameDataReceived; _Proxy.GetTeamDataAsync(); This code creates the proxy and passes the endpoint address and binding to use to its constructor. It then wires the different receive events to callback methods and calls GetTeamDataAsync(). Calling GetTeamDataAsync() causes the server to store the client in the server-side dictionary collection mentioned earlier so that it can receive data that is pushed. As the server-side timer fires and game data is pushed to the client, the user interface is updated as shown in Listing 7. Listing 8 shows the _Proxy_ReceiveGameDataReceived() method responsible for handling the data and calling UpdateGameData() to process it. Listing 7. The Silverlight interface. Game data is pushed from the server to the client using HTTP Polling Duplex. void _Proxy_ReceiveGameDataReceived(object sender, ReceiveGameDataReceivedEventArgs e) { UpdateGameData(e.gameData); } private void UpdateGameData(GameData gameData) { //Update Score this.tbTeam1Score.Text = gameData.Team1Score.ToString(); this.tbTeam2Score.Text = gameData.Team2Score.ToString(); //Update ball visibility if (gameData.Action != ActionsEnum.Foul) { if (tbTeam1.Text == gameData.TeamOnOffense) { AnimateBall(this.BB1, this.BB2); } else //Team 2 { AnimateBall(this.BB2, this.BB1); } } if (this.lbActions.Items.Count > 9) this.lbActions.Items.Clear(); this.lbActions.Items.Add(gameData.LastAction); if (this.lbActions.Visibility == Visibility.Collapsed) this.lbActions.Visibility = Visibility.Visible; } private void AnimateBall(Image onBall, Image offBall) { this.FadeIn.Stop(); Storyboard.SetTarget(this.FadeInAnimation, onBall); Storyboard.SetTarget(this.FadeOutAnimation, offBall); this.FadeIn.Begin(); } Listing 8. As the server pushes game data, the client’s _Proxy_ReceiveGameDataReceived() method is called to process the data. In a real-life application I’d go with a ViewModel class to handle retrieving team data, setup data bindings and handle data that is pushed from the server. However, for the sample application I wanted to focus on HTTP Polling Duplex and keep things as simple as possible. Summary Silverlight supports three options when duplex communication is required in an application including TCP bindins, sockets and HTTP Polling Duplex. In this post you’ve seen how HTTP Polling Duplex interfaces can be created and implemented on the server as well as how they can be consumed by a Silverlight client. HTTP Polling Duplex provides a nice way to “push” data from a server while still allowing the data to flow over port 80 or another port of your choice. Sample Application Download

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C# 4.0: Alternative To Optional Arguments

- by Paulo Morgado

Like I mentioned in my last post, exposing publicly methods with optional arguments is a bad practice (that’s why C# has resisted to having it, until now). You might argument that your method or constructor has to many variants and having ten or more overloads is a maintenance nightmare, and you’re right. But the solution has been there for ages: have an arguments class. The arguments class pattern is used in the .NET Framework is used by several classes, like XmlReader and XmlWriter that use such pattern in their Create methods, since version 2.0: XmlReaderSettings settings = new XmlReaderSettings(); settings.ValidationType = ValidationType.Auto; XmlReader.Create("file.xml", settings); With this pattern, you don’t have to maintain a long list of overloads and any default values for properties of XmlReaderSettings (or XmlWriterSettings for XmlWriter.Create) can be changed or new properties added in future implementations that won’t break existing compiled code. You might now argue that it’s too much code to write, but, with object initializers added in C# 3.0, the same code can be written like this: XmlReader.Create("file.xml", new XmlReaderSettings { ValidationType = ValidationType.Auto }); Looks almost like named and optional arguments, doesn’t it? And, who knows, in a future version of C#, it might even look like this: XmlReader.Create("file.xml", new { ValidationType = ValidationType.Auto });

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Windows Workflow Foundation 4.0 and WCF web service faults (soap fault)

- by Lygpt

In my Workflow Foundation 4.0 RC app I have a 'Receive' and 'SendReplyToReceive' WCF messaging pair that work fine with a simple request/response operation, but I'm having trouble attempting to perform validation on the request and reply with a fault. In WCF I am able to create a throw custom fault contracts (which in turn sent out SOAP faults) but I just can't see how to achieve this with the built-in workflow messaging activities. I can only seem to response with a data transfer object (I'm not even able to respond with a choice of object). Any ideas? (Can you save my day yet again Maurice!?) Thanks!

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SQL SERVER – Attach or Detach Database – SQL in Sixty Seconds #068

- by Pinal Dave

When we have to move a database from one server to another server or when we have to move a database from one file to another file, we commonly use Database Attach or Detach process. I have been doing this for quite a while as well. Recently, when I was visiting an organization I found that in this organization lots of developers are still using an older version of the code to attach the database. I quickly pointed that out to them the new method to attach the database, however it was really interesting to find out that they really did not know that sp_attach_db is now a deprecated method to attach the database. This really made me to do today’s SQL in Sixty Seconds. I demonstrate in this SQL in Sixty Seconds how to attach or detach the database using a new method of attaching database. The code which I have used in this code is over here: -- Detach Database USE [master] GO EXEC MASTER.dbo.sp_detach_db @dbname = N'AdventureWorks2014_new' GO -- Deprecated Way to Attach Database USE [master] GO EXEC MASTER.dbo.sp_attach_db 'AdventureWorks2014_new', 'E:\AdventureWorks2012_Data_new.mdf', 'E:\AdventureWorks2012_log_new.ldf' GO -- Correct Way to Attach Database USE [master] GO CREATE DATABASE [AdventureWorks2014_new] ON ( FILENAME = 'E:\AdventureWorks2012_Data_new.mdf'), ( FILENAME = 'E:\AdventureWorks2012_log_new.ldf') FOR ATTACH GO Here is the question back to you – Do you still use old methods to attach database? If yes, I suggest that you start using the new method onwards. SQL in Sixty Seconds Video I have attempted to explain the same subject in simple words over in following video. Action Item Here are the blog posts I have previously written on the subject of SA password. You can read it over here: SQL SERVER – 2005 – T-SQL Script to Attach and Detach Database SQL SERVER – Move Database Files MDF and LDF to Another Location SQL SERVER – 2005 Take Off Line or Detach Database SQL SERVER – Attach mdf file without ldf file in Database SQL SERVER – Copy Database from Instance to Another Instance – Copy Paste in SQL Server You can subscribe to my YouTube Channel for frequent updates. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Book Review, SQLAuthority News, T SQL, Video

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How to push changes from Test server to Live server?

- by anonymous

As a beginner, I finally noticed the issue with making changes to the live server I've been working on, now that I have a couple users on it, since I bring it down so often. I created an EC2 image of my live server and set up a separate instance on EC2, so now I have 2 EC2 instances, Stage and Production. I set up GitHub and push changes to stage and test my code there, and when it's all done and working, I push it to the production branch, and everything is good. And there is a slight issue here since I name my files config_stage.js and config_production.js and set up .gitignore on each server, and in my code, I would have it read the ENV flags and set up the appropriate configs, is this the correct approach? And my main question is: how do you keep track of non-code changes to the server? For example, I installed HAProxy, Stunnel, Redis, MongoDB and several other things onto the Stage server for testing and now that it's all working and good, how do I deploy them to production? Right now, I'm just keeping track of everything I installed and copying configuration files over, which is very tedious and I'm afraid I may have missed a step somewhere. Is there a better way to port these changes over from my test server to my live server?

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Azure storage: Uploaded files with size zero bytes

- by Fabio Milheiro

When I upload an image file to a blob, the image is uploaded apparently successfully (no errors). When I go to cloud storage studio, the file is there, but with a size of 0 (zero) bytes. The following is the code that I am using: // These two methods belong to the ContentService class used to upload // files in the storage. public void SetContent(HttpPostedFileBase file, string filename, bool overwrite) { CloudBlobContainer blobContainer = GetContainer(); var blob = blobContainer.GetBlobReference(filename); if (file != null) { blob.Properties.ContentType = file.ContentType; blob.UploadFromStream(file.InputStream); } else { blob.Properties.ContentType = "application/octet-stream"; blob.UploadByteArray(new byte[1]); } } public string UploadFile(HttpPostedFileBase file, string uploadPath) { if (file.ContentLength == 0) { return null; } string filename; int indexBar = file.FileName.LastIndexOf('\\'); if (indexBar > -1) { filename = DateTime.UtcNow.Ticks + file.FileName.Substring(indexBar + 1); } else { filename = DateTime.UtcNow.Ticks + file.FileName; } ContentService.Instance.SetContent(file, Helper.CombinePath(uploadPath, filename), true); return filename; } // The above code is called by this code. HttpPostedFileBase newFile = Request.Files["newFile"] as HttpPostedFileBase; ContentService service = new ContentService(); blog.Image = service.UploadFile(newFile, string.Format("{0}{1}", Constants.Paths.BlogImages, blog.RowKey)); Before the image file is uploaded to the storage, the Property InputStream from the HttpPostedFileBase appears to be fine (the size of the of image corresponds to what is expected! And no exceptions are thrown). And the really strange thing is that this works perfectly in other cases (uploading Power Points or even other images from the Worker role). The code that calls the SetContent method seems to be exactly the same and file seems to be correct since a new file with zero bytes is created at the correct location. Does any one have any suggestion please? I debugged this code dozens of times and I cannot see the problem. Any suggestions are welcome! Thanks

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Professional Scrum Developer (.NET) Training in London

- by Martin Hinshelwood

On the 26th - 30th July in Microsoft’s offices in London Adam Cogan from SSW will be presenting the first Professional Scrum Developer course in the UK. I will be teaching this course along side Adam and it is a fantastic experience. You are split into teams and go head-to-head to deliver units of potentially shippable work in four two hour sprints. The Professional Scrum Developer course is the only course endorsed by both Microsoft and Ken Schwaber and they have worked together very effectively in brining this course to fruition. This course is the brain child of Richard Hundhausen, a Microsoft Regional Director, and both Adam and I attending the Trainer Prep in Sydney when he was there earlier this year. He is a fantastic trainer and no matter where you do this course you can be safe in the knowledge that he has trained and vetted all of the teachers. A tools version of Ken if you will Find a course and register Download this syllabus Download the Scrum Guide What is the Professional Scrum Developer course all about? Professional Scrum Developer course is a unique and intensive five-day experience for software developers. The course guides teams on how to turn product requirements into potentially shippable increments of software using the Scrum framework, Visual Studio 2010, and modern software engineering practices. Attendees will work in self-organizing, self-managing teams using a common instance of Team Foundation Server 2010. Who should attend this course? This course is suitable for any member of a software development team – architect, programmer, database developer, tester, etc. Entire teams are encouraged to attend and experience the course together, but individuals are welcome too. Attendees will self-organize to form cross-functional Scrum teams. These teams require an aggregate of skills specific to the selected case study. Please see the last page of this document for specific details. Product Owners, ScrumMasters, and other stakeholders are welcome too, but keep in mind that everyone who attends will be expected to commit to work and pull their weight on a Scrum team. What should you know by the end of the course? Scrum will be experienced through a combination of lecture, demonstration, discussion, and hands-on exercises. Attendees will learn how to do Scrum correctly while being coached and critiqued by the instructor, in the following topic areas: Form effective teams Explore and understand legacy “Brownfield” architecture Define quality attributes, acceptance criteria, and “done” Create automated builds How to handle software hotfixes Verify that bugs are identified and eliminated Plan releases and sprints Estimate product backlog items Create and manage a sprint backlog Hold an effective sprint review Improve your process by using retrospectives Use emergent architecture to avoid technical debt Use Test Driven Development as a design tool Setup and leverage continuous integration Use Test Impact Analysis to decrease testing times Manage SQL Server development in an Agile way Use .NET and T-SQL refactoring effectively Build, deploy, and test SQL Server databases Create and manage test plans and cases Create, run, record, and play back manual tests Setup a branching strategy and branch code Write more maintainable code Identify and eliminate people and process dysfunctions Inspect and improve your team’s software development process What does the week look like? This course is a mix of lecture, demonstration, group discussion, simulation, and hands-on software development. The bulk of the course will be spent working as a team on a case study application delivering increments of new functionality in mini-sprints. Here is the week at a glance: Monday morning and most of the day Friday will be spent with the computers powered off, so you can focus on sharpening your game of Scrum and avoiding the common pitfalls when implementing it. The Sprints Timeboxing is a critical concept in Scrum as well as in this course. We expect each team and student to understand and obey all of the timeboxes. The timebox duration will always be clearly displayed during each activity. Expect the instructor to enforce it. Each of the ½ day sprints will roughly follow this schedule: Component Description Minutes Instruction Presentation and demonstration of new and relevant tools & practices 60 Sprint planning meeting Product owner presents backlog; each team commits to delivering functionality 10 Sprint planning meeting Each team determines how to build the functionality 10 The Sprint The team self-organizes and self-manages to complete their tasks 120 Sprint Review meeting Each team will present their increment of functionality to the other teams = 30 Sprint Retrospective A group retrospective meeting will be held to inspect and adapt 10 Each team is expected to self-organize and manage their own work during the sprint. Pairing is highly encouraged. The instructor/product owner will be available if there are questions or impediments, but will be hands-off by default. You should be prepared to communicate and work with your team members in order to achieve your sprint goal. If you have development-related questions or get stuck, your partner or team should be your first level of support. Module 1: INTRODUCTION This module provides a chance for the attendees to get to know the instructors as well as each other. The Professional Scrum Developer program, as well as the day by day agenda, will be explained. Finally, the Scrum team will be selected and assembled so that the forming, storming, norming, and performing can begin. Trainer and student introductions Professional Scrum Developer program Agenda Logistics Team formation Retrospective Module 2: SCRUMDAMENTALS This module provides a level-setting understanding of the Scrum framework including the roles, timeboxes, and artifacts. The team will then experience Scrum firsthand by simulating a multi-day sprint of product development, including planning, review, and retrospective meetings. Scrum overview Scrum roles Scrum timeboxes (ceremonies) Scrum artifacts Simulation Retrospective It’s required that you read Ken Schwaber’s Scrum Guide in preparation for this module and course. MODULE 3: IMPLEMENTING SCRUM IN VISUAL STUDIO 2010 This module demonstrates how to implement Scrum in Visual Studio 2010 using a Scrum process template*. The team will learn the mapping between the Scrum concepts and how they are implemented in the tool. After connecting to the shared Team Foundation Server, the team members will then return to the simulation – this time using Visual Studio to manage their product development. Mapping Scrum to Visual Studio 2010 User Story work items Task work items Bug work items Demonstration Simulation Retrospective Module 4: THE CASE STUDY In this module the team is introduced to their problem domain for the week. A kickoff meeting by the Product Owner (the instructor) will set the stage for the why and what that will take during the upcoming sprints. The team will then define the quality attributes of the project and their definition of “done.” The legacy application code will be downloaded, built, and explored, so that any bugs can be discovered and reported. Introduction to the case study Download the source code, build, and explore the application Define the quality attributes for the project Define “done” How to file effective bugs in Visual Studio 2010 Retrospective Module 5: HOTFIX This module drops the team directly into a Brownfield (legacy) experience by forcing them to analyze the existing application’s architecture and code in order to locate and fix the Product Owner’s high-priority bug(s). The team will learn best practices around finding, testing, fixing, validating, and closing a bug. How to use Architecture Explorer to visualize and explore Create a unit test to validate the existence of a bug Find and fix the bug Validate and close the bug Retrospective Module 6: PLANNING This short module introduces the team to release and sprint planning within Visual Studio 2010. The team will define and capture their goals as well as other important planning information. Release vs. Sprint planning Release planning and the Product Backlog Product Backlog prioritization Acceptance criteria and tests Sprint planning and the Sprint Backlog Creating and linking Sprint tasks Retrospective At this point the team will have the knowledge of Scrum, Visual Studio 2010, and the case study application to begin developing increments of potentially shippable functionality that meet their definition of done. Module 7: EMERGENT ARCHITECTURE This module introduces the architectural practices and tools a team can use to develop a valid design on which to develop new functionality. The teams will learn how Scrum supports good architecture and design practices. After the discussion, the teams will be presented with the product owner’s prioritized backlog so that they may select and commit to the functionality they can deliver in this sprint. Architecture and Scrum Emergent architecture Principles, patterns, and practices Visual Studio 2010 modeling tools UML and layer diagrams SPRINT 1 Retrospective Module 8: TEST DRIVEN DEVELOPMENT This module introduces Test Driven Development as a design tool and how to implement it using Visual Studio 2010. To maximize productivity and quality, a Scrum team should setup Continuous Integration to regularly build every team member’s code changes and run regression tests. Refactoring will also be defined and demonstrated in combination with Visual Studio’s Test Impact Analysis to efficiently re-run just those tests which were impacted by refactoring. Continuous integration Team Foundation Build Test Driven Development (TDD) Refactoring Test Impact Analysis SPRINT 2 Retrospective Module 9: AGILE DATABASE DEVELOPMENT This module lets the SQL Server database developers in on a little secret – they can be agile too. By using the database projects in Visual Studio 2010, the database developers can join the rest of the team. The students will see how to apply Agile database techniques within Visual Studio to support the SQL Server 2005/2008/2008R2 development lifecycle. Agile database development Visual Studio database projects Importing schema and scripts Building and deploying Generating data Unit testing SPRINT 3 Retrospective Module 10: SHIP IT Teams need to know that just because they like the functionality doesn’t mean the Product Owner will. This module revisits acceptance criteria as it pertains to acceptance testing. By refining acceptance criteria into manual test steps, team members can execute the tests, recording the results and reporting bugs in a number of ways. Manual tests will be defined and executed using the Microsoft Test Manager tool. As the Sprint completes and an increment of functionality is delivered, the team will also learn why and when they should create a branch of the codeline. Acceptance criteria Testing in Visual Studio 2010 Microsoft Test Manager Writing and running manual tests Branching SPRINT 4 Retrospective Module 11: OVERCOMING DYSFUNCTION This module introduces the many types of people, process, and tool dysfunctions that teams face in the real world. Many dysfunctions and scenarios will be identified, along with ideas and discussion for how a team might mitigate them. This module will enable you and your team to move toward independence and improve your game of Scrum when you depart class. Scrum-butts and flaccid Scrum Best practices working as a team Team challenges ScrumMaster challenges Product Owner challenges Stakeholder challenges Course Retrospective What will be expected of you and you team? This is a unique course in that it’s technically-focused, team-based, and employs timeboxes. It demands that the members of the teams self-organize and self-manage their own work to collaboratively develop increments of software. All attendees must commit to: Pay attention to all lectures and demonstrations Participate in team and group discussions Work collaboratively with other team members Obey the timebox for each activity Commit to work and do your best to deliver All teams should have these skills: Understanding of Scrum Familiarity with Visual Studio 201 C#, .NET 4.0 & ASP.NET 4.0 experience* SQL Server 2008 development experience Software testing experience * Check with the instructor ahead of time for the exact technologies Self-organising teams Another unique attribute of this course is that it’s a technical training class being delivered to teams of developers, not pairs, and not individuals. Ideally, your actual software development team will attend the training to ensure that all necessary skills are covered. However, if you wish to attend an open enrolment course alone or with just a couple of colleagues, realize that you may be placed on a team with other attendees. The instructor will do his or her best to ensure that each team is cross-functional to tackle the case study, but there are no guarantees. You may be required to try a new role, learn a new skill, or pair with somebody unfamiliar to you. This is just good Scrum! Who should NOT take this course? Because of the nature of this course, as explained above, certain types of people should probably not attend this course: Students requiring command and control style instruction – there are no prescriptive/step-by-step (think traditional Microsoft Learning) labs in this course Students who are unwilling to work within a timebox Students who are unwilling to work collaboratively on a team Students who don’t have any skill in any of the software development disciplines Students who are unable to commit fully to their team – not only will this diminish the student’s learning experience, but it will also impact their team’s learning experience Find a course and register Download this syllabus Download the Scrum Guide Technorati Tags: Scrum,SSW,Pro Scrum Dev

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