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• Deploy ASP.NET Web Applications with Web Deployment Projects

  - by Ben Griswold

  One may quickly build and deploy an ASP.NET web application via the Publish option in Visual Studio.  This option works great for most simple deployment scenarios but it won’t always cut it.  Let’s say you need to automate your deployments. Or you have environment-specific configuration settings. Or you need to execute pre/post build operations when you do your builds.  If so, you should consider using Web Deployment Projects. The Web Deployment Project type doesn’t come out-of-the-box with Visual Studio 2008.  You’ll need to Download Visual Studio® 2008 Web Deployment Projects – RTW and install if you want to follow along with this tutorial. I’ve created a shiny new ASP.NET MVC project.  Web Deployment Projects work with websites, web applications and MVC projects so feel free to go with any web project type you’d like.  Once your web application is in place, it’s time to add the Web Deployment project.  You can hunt and peck around the File > New > New Project… dialogue as long as you’d like, but you aren’t going to find what you need.  Instead, select the web project and then choose the “Add Web Deployment Project…” hiding behind the Build menu option. I prefer to name my projects based on the environment in which I plan to deploy.  In this case, I’ll be rolling to the QA machine. Don’t expect too much to happen at this point.  A seemingly empty project with a funny icon will be added to your solution.  That’s it. I want to take a minute and talk about configuration settings before we continue.  Some of the common settings which might change from environment to environment are appSettings, connectionStrings and mailSettings.  Here’s a look at my updated web.config: <appSettings>   <add key="MvcApplication293.Url" value="http://localhost:50596/" />     </appSettings> <connectionStrings>   <add name="ApplicationServices"        connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true"        providerName="System.Data.SqlClient"/> </connectionStrings>   <system.net>   <mailSettings>     <smtp from="[email protected]">         <network host="server.com" userName="username" password="password" port="587" defaultCredentials="false"/>     </smtp>   </mailSettings> </system.net> I want to update these values prior to deploying to the QA environment.  There are variations to this approach, but I like to maintain environment-specific settings for each of the web.config sections in the Config/[Environment] project folders.  I’ve provided a screenshot of the QA environment settings below. It may be obvious what one should include in each of the three files.  Basically, it is a copy of the associated web.config section with updated setting values.  For example, the AppSettings.config file may include a reference to the QA web url, the DB.config would include the QA database server and login information and the StmpSettings.config would include a QA Stmp server and user information. <?xml version="1.0" encoding="utf-8" ?> <appSettings>   <add key="MvcApplication293.Url" value="http://qa.MvcApplicatinon293.com/" /> </appSettings> AppSettings.config  <?xml version="1.0" encoding="utf-8" ?> <connectionStrings>   <add name="ApplicationServices"        connectionString="server=QAServer;integrated security=SSPI;database=MvcApplication293"        providerName="System.Data.SqlClient"/>   </connectionStrings> Db.config  <?xml version="1.0" encoding="utf-8" ?> <smtp from="[email protected]">     <network host="qaserver.com" userName="qausername" password="qapassword" port="587" defaultCredentials="false"/> </smtp> SmtpSettings.config  I think our web project is ready to deploy.  Now, it’s time to concentrate on the Web Deployment Project itself.  Right-click on the project file and open the Property Pages. The first thing to call out is the Configuration dropdown.  I only deploy a project which is built in Release Mode so I only setup the Web Deployment Project for this mode.  (This is when you change the Configuration selection to “Release.”)  I typically keep the Output Folder default value – .\Release\.  When the application is built, all artifacts will be dropped in the .\Release\ folder relative to the Web Deployment Project root.  The final option may be up for some debate.  I like to roll out updatable websites so I select the “Allow this precompiled site to be updatable” option.  I really do like to follow standard SDLC processes when I release my software but there are those times when you just have to make a hotfix to production and I like to keep this option open if need be.  If you are strongly opposed to this idea, please, by all means, don’t check the box. The next tab is boring.  I don’t like to deploy a crazy number of DLLs so I merge all outputs to a single assembly.  Again, you may have another option and feel free to change this selection if you so wish. If you follow my lead, take care when choosing a single assembly name.  The Assembly Name can not be the same as the website or any other project in your solution otherwise you’ll receive a circular reference build error.  In other words, I can’t name the assembly MvcApplication293 or my output window would start yelling at me. Remember when we called out our QA configuration files?  Click on the Deployment tab and you’ll see how where going to use them.  Notice the Web.config file section replacements value.  All this does is swap called out web.config sections with the content of the Config\QA\* files.  You can reduce or extend this list as you deem fit.  Did you see the “Use external configuration source file” option?  You know how you can point any of your web.config sections to an external file via the configSource attribute?  This option allows you to leverage that technique and instead of replacing the content of the sections, you will replace the configSource attribute value instead. <appSettings configSource="Config\QA\AppSettings.config" /> Go ahead and Apply your changes.  I’d like to take a look at the project file we just updated.  Right-click on the Web Deployment Project and select “Open Project File.” One of the first configuration blocks reflects core Release build settings.  There are a couple of points I’d like to call out here: DebugSymbols=false ensures the compilation debug attribute in your web.config is flipped to false as part of build process.  There’s some crumby (more likely old) documentation which implies you need a ToggleDebugCompilation task to make this happen.  Nope. Just make sure the DebugSymbols is set to false.  EnableUpdateable implies a single dll for the web application rather than a dll for each object and and empty view file. I think updatable applications are cleaner and include the benefit (or risk based on your perspective) that portions of the application can be updated directly on the server.  I called this out earlier but I wanted to reiterate. <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">     <DebugSymbols>false</DebugSymbols>     <OutputPath>.\Release</OutputPath>     <EnableUpdateable>true</EnableUpdateable>     <UseMerge>true</UseMerge>     <SingleAssemblyName>MvcApplication293</SingleAssemblyName>     <DeleteAppCodeCompiledFiles>true</DeleteAppCodeCompiledFiles>     <UseWebConfigReplacement>true</UseWebConfigReplacement>     <ValidateWebConfigReplacement>true</ValidateWebConfigReplacement>     <DeleteAppDataFolder>true</DeleteAppDataFolder>   </PropertyGroup> The next section is self-explanatory.  The content merely reflects the replacement value you provided via the Property Pages. <ItemGroup Condition="'$(Configuration)|$(Platform)' == 'Release|AnyCPU'">     <WebConfigReplacementFiles Include="Config\QA\AppSettings.config">       <Section>appSettings</Section>     </WebConfigReplacementFiles>     <WebConfigReplacementFiles Include="Config\QA\Db.config">       <Section>connectionStrings</Section>     </WebConfigReplacementFiles>     <WebConfigReplacementFiles Include="Config\QA\SmtpSettings.config">       <Section>system.net/mailSettings/smtp</Section>     </WebConfigReplacementFiles>   </ItemGroup> You’ll want to extend the ItemGroup section to include the files you wish to exclude from the build.  The sample ExcludeFromBuild nodes exclude all obj, svn, csproj, user, pdb artifacts from the build. Enough though they files aren’t included in your web project, you’ll need to exclude them or they’ll show up along with required deployment artifacts.  <ItemGroup Condition="'$(Configuration)|$(Platform)' == 'Release|AnyCPU'">     <WebConfigReplacementFiles Include="Config\QA\AppSettings.config">       <Section>appSettings</Section>     </WebConfigReplacementFiles>     <WebConfigReplacementFiles Include="Config\QA\Db.config">       <Section>connectionStrings</Section>     </WebConfigReplacementFiles>     <WebConfigReplacementFiles Include="Config\QA\SmtpSettings.config">       <Section>system.net/mailSettings/smtp</Section>     </WebConfigReplacementFiles>     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\obj\**\*.*" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\**\.svn\**\*.*" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\**\.svn\**\*" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\**\*.csproj" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\**\*.user" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\bin\*.pdb" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\Notes.txt" />   </ItemGroup> Pre/post build and Pre/post merge tasks are added to the final code block.  By default, your project file should look like the following – a completely commented out section. <!– To modify your build process, add your task inside one of        the targets below and uncomment it. Other similar extension        points exist, see Microsoft.WebDeployment.targets.   <Target Name="BeforeBuild">   </Target>   <Target Name="BeforeMerge">   </Target>   <Target Name="AfterMerge">   </Target>   <Target Name="AfterBuild">   </Target>   –> Update the section to remove all temporary Config folders and files after the build.  <!– To modify your build process, add your task inside one of        the targets below and uncomment it. Other similar extension        points exist, see Microsoft.WebDeployment.targets.     <Target Name="BeforeMerge">   </Target>   <Target Name="AfterMerge">   </Target>     <Target Name="BeforeBuild">      </Target>       –>   <Target Name="AfterBuild">     <!– WebConfigReplacement requires the Config files. Remove after build. –>     <RemoveDir Directories="$(OutputPath)\Config" />   </Target> That’s it for setup.  Save the project file, flip the solution to Release Mode and build.  If there’s an issue, consult the Output window for details.  If all went well, you will find your deployment artifacts in your Web Deployment Project folder like so. Both the code source and published application will be there. Inside the Release folder you will find your “published files” and you’ll notice the Config folder is no where to be found.  In the Source folder, all project files are found with the exception of the items which were excluded from the build. I’ll wrap up this tutorial by calling out a little Web Deployment pet peeve of mine: there doesn’t appear to be a way to add an existing web deployment project to a solution.  The best I can come up with is create a new web deployment project and then copy and paste the contents of the existing project file into the new project file.  It’s not a big deal but it bugs me. Download the Solution

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

  - by James Michael Hare

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

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• An Honest look at SharePoint Web Services

  - by juanlarios

  INTRODUCTION If you are a SharePoint developer you know that there are two basic ways to develop against SharePoint. 1) The object Model 2) Web services. SharePoint object model has the advantage of being quite rich. Anything you can do through the SharePoint UI as an administrator or end user, you can do through the object model. In fact everything that is done through the UI is done through the object model behind the scenes. The major disadvantage to getting at SharePoint this way is that the code needs to run on the server. This means that all web parts, event receivers, features, etc… all of this is code that is deployed to the server. The second way to get to SharePoint is through the built in web services. There are many articles on how to manipulate web services, how to authenticate to them and interact with them. The basic idea is that a remote application or process can contact SharePoint through a web service. Lots has been written about how great these web services are. This article is written to document the limitations, some of the issues and frustrations with working with SharePoint built in web services. Ultimately, for the tasks I was given to , SharePoint built in web services did not suffice. My evaluation of SharePoint built in services was compared against creating my own WCF Services to do what I needed. The current project I'm working on right now involved several "integration points". A remote application, installed on a separate server was to contact SharePoint and perform an task or operation. So I decided to start up Visual Studio and built a DLL and basically have 2 layers of logic. An integration layer and a data layer. A good friend of mine pointed me to SOLID principles and referred me to some videos and tutorials about it. I decided to implement the methodology (although a lot of the principles are common sense and I already incorporated in my coding practices). I was to deliver this dll to the application team and they would simply call the methods exposed by this dll and voila! it would do some task or operation in SharePoint. SOLUTION My integration layer implemented an interface that defined some of the basic integration tasks that I was to put together. My data layer was about the same, it implemented an interface with some of the tasks that I was going to develop. This gave me the opportunity to develop different data layers, ultimately different ways to get at SharePoint if I needed to. This is a classic SOLID principle. In this case it proved to be quite helpful because I wrote one data layer completely implementing SharePoint built in Web Services and another implementing my own WCF Service that I wrote. I should mention there is another layer underneath the data layer. In referencing SharePoint or WCF services in my visual studio project I created a class for every web service call. So for example, if I used List.asx. I created a class called "DocumentRetreival" this class would do the grunt work to connect to the correct URL, It would perform the basic operation of contacting the service and so on. If I used a view.asmx, I implemented a class called "ViewRetrieval" with the same idea as the last class but it would now interact with all he operations in view.asmx. This gave my data layer the ability to perform multiple calls without really worrying about some of the grunt work each class performs. This again, is a classic SOLID principle. So, in order to compare them side by side we can look at both data layers and with is involved in each. Lets take a look at the "Create Project" task or operation. The integration point is described as , "dll is to provide a way to create a project in SharePoint". Projects , in this case are basically document libraries. I am to implement a way in which a remote application can create a document library in SharePoint. Easy enough right? Use the list.asmx Web service in SharePoint. So here we go! Lets take a look at the code. I added the List.asmx web service reference to my project and this is the class that contacts it:  class DocumentRetrieval     {         private ListsSoapClient _service;      d   private bool _impersonation;         public DocumentRetrieval(bool impersonation, string endpt)         {             _service = new ListsSoapClient();             this.SetEndPoint(string.Format("{0}/{1}", endpt, ConfigurationManager.AppSettings["List"]));             _impersonation = impersonation;             if (_impersonation)             {                 _service.ClientCredentials.Windows.ClientCredential.Password = ConfigurationManager.AppSettings["password"];                 _service.ClientCredentials.Windows.ClientCredential.UserName = ConfigurationManager.AppSettings["username"];                 _service.ClientCredentials.Windows.AllowedImpersonationLevel =                     System.Security.Principal.TokenImpersonationLevel.Impersonation;             }     private void SetEndPoint(string p)          {             _service.Endpoint.Address = new EndpointAddress(p);          }          /// <summary>         /// Creates a document library with specific name and templateID         /// </summary>         /// <param name="listName">New list name</param>         /// <param name="templateID">Template ID</param>         /// <returns></returns>         public XmlElement CreateLibrary(string listName, int templateID, ref ExceptionContract exContract)         {             XmlDocument sample = new XmlDocument();             XmlElement viewCol = sample.CreateElement("Empty");             try             {                 _service.Open();                 viewCol = _service.AddList(listName, "", templateID);             }             catch (Exception ex)             {                 exContract = new ExceptionContract("DocumentRetrieval/CreateLibrary", ex.GetType(), "Connection Error", ex.StackTrace, ExceptionContract.ExceptionCode.error);                             }finally             {                 _service.Close();             }                                      return viewCol;         } } There was a lot more in this class (that I am not including) because i was reusing the grunt work and making other operations with LIst.asmx, For example, updating content types, changing or configuring lists or document libraries. One of the first things I noticed about working with the built in services is that you are really at the mercy of what is available to you. Before creating a document library (Project) I wanted to expose a IsProjectExisting method. This way the integration or data layer could recognize if a library already exists. Well there is no service call or method available to do that check. So this is what I wrote:   public bool DocLibExists(string listName, ref ExceptionContract exContract)         {             try             {                 var allLists = _service.GetListCollection();                                return allLists.ChildNodes.OfType<XmlElement>().ToList().Exists(x => x.Attributes["Title"].Value ==listName);             }             catch (Exception ex)             {                 exContract = new ExceptionContract("DocumentRetrieval/GetList/GetListWSCall", ex.GetType(), "Unable to Retrieve List Collection", ex.StackTrace, ExceptionContract.ExceptionCode.error);             }             return false;         } This really just gets an XMLElement with all the lists. It was then up to me to sift through the clutter and noise and see if Document library already existed. This took a little bit of getting used to. Now instead of working with code, you are working with XMLElement response format from web service. I wrote a LINQ query to go through and find if the attribute "Title" existed and had a value of the listname then it would return True, if not False. I didn't particularly like working this way. Dealing with XMLElement responses and then having to manipulate it to get at the exact data I was looking for. Once the check for the DocLibExists, was done, I would either create the document library or send back an error indicating the document library already existed. Now lets examine the code that actually creates the document library. It does what you are really after, it creates a document library. Notice how the template ID is really an integer. Every document library template in SharePoint has an ID associated with it. Document libraries, Image Library, Custom List, Project Tasks, etc… they all he a unique integer associated with it. Well, that's great but the client came back to me and gave me some specifics that each "project" or document library, should have. They specified they had 3 types of projects. Each project would have unique views, about 10 views for each project. Each Project specified unique configurations (auditing, versioning, content types, etc…) So what turned out to be a simple implementation of creating a document library as a repository for a project, turned out to be quite involved.  The first thing I thought of was to create a template for document library. There are other ways you can do this too. Using the web Service call, you could configure views, versioning, even content types, etc… the only catch is, you have to be working quite extensively with CAML. I am not fond of CAML. I can do it and work with it, I just don't like doing it. It is quite touchy and at times it is quite tough to understand where errors were made with CAML statements. Working with Web Services and CAML proved to be quite annoying. The service call would return a generic error message that did not particularly point me to a CAML statement syntax error, or even a CAML error. I was not sure if it was a security , performance or code based issue. It was quite tough to work with. At times it was difficult to work with because of the way SharePoint handles metadata. There are "Names", "Display Name", and "StaticName" fields. It was quite tough to understand at times, which one to use. So it took a lot of trial and error. There are tools that can help with CAML generation. There is also now intellisense for CAML statements in Visual Studio that might help but ultimately I'm not fond of CAML with Web Services.   So I decided on the template. So my plan was to create create a document library, configure it accordingly and then use The Template Builder that comes with the SharePoint SDK. This tool allows you to create site templates, list template etc… It is quite interesting because it does not generate an STP file, it actually generates an xml definition and a feature you can activate and make that template available on a site or site collection. The first issue I experienced with this is that one of the specifications to this template was that the "All Documents" view was to have 2 web parts on it. Well, it turns out that using the template builder , it did not include the web parts as part of the list template definition it generated. It backed up the settings, the views, the content types but not the custom web parts. I still decided to try this even without the web parts on the page. This new template defined a new Document library definition with a unique ID. The problem was that the service call accepts an int but it only has access to the built in library int definitions. Any new ones added or created will not be available to create. So this made it impossible for me to approach the problem this way.     I should also mention that one of the nice features about SharePoint is the ability to create list templates, back them up and then create lists based on that template. It can all be done by end user administrators. These templates are quite unique because they are saved as an STP file and not an xml definition. I also went this route and tried to see if there was another service call where I could create a document library based no given template name. Nope! none.      After some thinking I decide to implement a WCF service to do this creation for me. I was quite certain that the object model would allow me to create document libraries base on a template in which an ID was required and also templates saved as STP files. Now I don't want to bother with posting the code to contact WCF service because it's self explanatory, but I will post the code that I used to create a list with custom template. public ServiceResult CreateProject(string name, string templateName, string projectId)         {             string siteurl = SPContext.Current.Site.Url;             Guid webguid = SPContext.Current.Web.ID;                        using (SPSite site = new SPSite(siteurl))             {                 using (SPWeb rootweb = site.RootWeb)                 {                     SPListTemplateCollection temps = site.GetCustomListTemplates(rootweb);                     ProcessWeb(siteurl, webguid, web => Act_CreateProject(web, name, templateName, projectId, temps));                 }//SpWeb             }//SPSite              return _globalResult;                   }         private void Act_CreateProject(SPWeb targetsite, string name, string templateName, string projectId, SPListTemplateCollection temps) {                         var temp = temps.Cast<SPListTemplate>().FirstOrDefault(x => x.Name.Equals(templateName));             if (temp != null)             {                             try                 {                                         Guid listGuid = targetsite.Lists.Add(name, "", temp);                     SPList newList = targetsite.Lists[listGuid];                     _globalResult = new ServiceResult(true, "Success", "Success");                 }                 catch (Exception ex)                 {                     _globalResult = new ServiceResult(false, (string.IsNullOrEmpty(ex.Message) ? "None" : ex.Message + " " + templateName), ex.StackTrace.ToString());                 }                                       }        private void ProcessWeb(string siteurl, Guid webguid, Action<SPWeb> action) {                        using (SPSite sitecollection = new SPSite(siteurl)) {                 using (SPWeb web = sitecollection.AllWebs[webguid]) {                     action(web);                 }                     }                  } This code is actually some of the code I implemented for the service. there was a lot more I did on Project Creation which I will cover in my next blog post. I implemented an ACTION method to process the web. This allowed me to properly dispose the SPWEb and SPSite objects and not rewrite this code over and over again. So I implemented a WCF service to create projects for me, this allowed me to do a lot more than just create a document library with a template, it now gave me the flexibility to do just about anything the client wanted at project creation. Once this was implemented , the client came back to me and said, "we reference all our projects with ID's in our application. we want SharePoint to do the same". This has been something I have been doing for a little while now but I do hope that SharePoint 2010 can have more of an answer to this and address it properly. I have been adding metadata to SPWebs through property bag. I believe I have blogged about it before. This time it required metadata added to a document library. No problem!!! I also mentioned these web parts that were to go on the "All Documents" View. I took the opportunity to configure them to the appropriate settings. There were two settings that needed to be set on these web parts. One of them was a Project ID configured in the webpart properties. The following code enhances and replaces the "Act_CreateProject " method above:  private void Act_CreateProject(SPWeb targetsite, string name, string templateName, string projectId, SPListTemplateCollection temps) {                         var temp = temps.Cast<SPListTemplate>().FirstOrDefault(x => x.Name.Equals(templateName));             if (temp != null)             {                 SPLimitedWebPartManager wpmgr = null;                               try                 {                                         Guid listGuid = targetsite.Lists.Add(name, "", temp);                     SPList newList = targetsite.Lists[listGuid];                     SPFolder rootFolder = newList.RootFolder;                     rootFolder.Properties.Add(KEY, projectId);                     rootFolder.Update();                     if (rootFolder.ParentWeb != targetsite)                         rootFolder.ParentWeb.Dispose();                     if (!templateName.Contains("Natural"))                     {                         SPView alldocumentsview = newList.Views.Cast<SPView>().FirstOrDefault(x => x.Title.Equals(ALLDOCUMENTS));                         SPFile alldocfile = targetsite.GetFile(alldocumentsview.ServerRelativeUrl);                         wpmgr = alldocfile.GetLimitedWebPartManager(PersonalizationScope.Shared);                         ConfigureWebPart(wpmgr, projectId, CUSTOMWPNAME);                                              alldocfile.Update();                     }                                        if (newList.ParentWeb != targetsite)                         newList.ParentWeb.Dispose();                     _globalResult = new ServiceResult(true, "Success", "Success");                 }                 catch (Exception ex)                 {                     _globalResult = new ServiceResult(false, (string.IsNullOrEmpty(ex.Message) ? "None" : ex.Message + " " + templateName), ex.StackTrace.ToString());                 }                 finally                 {                     if (wpmgr != null)                     {                         wpmgr.Web.Dispose();                         wpmgr.Dispose();                     }                 }             }                         }       private void ConfigureWebPart(SPLimitedWebPartManager mgr, string prjId, string webpartname)         {             var wp = mgr.WebParts.Cast<System.Web.UI.WebControls.WebParts.WebPart>().FirstOrDefault(x => x.DisplayTitle.Equals(webpartname));             if (wp != null)             {                           (wp as ListRelationshipWebPart.ListRelationshipWebPart).ProjectID = prjId;                 mgr.SaveChanges(wp);             }         }   This Shows you how I was able to set metadata on the document library. It has to be added to the RootFolder of the document library, Unfortunately, the SPList does not have a Property bag that I can add a key\value pair to. It has to be done on the root folder. Now everything in the integration will reference projects by ID's and will not care about names. My, "DocLibExists" will now need to be changed because a web service is not set up to look at property bags.  I had to write another method on the Service to do the equivalent but with ID's instead of names.  The second thing you will notice about the code is the use of the Webpartmanager. I have seen several examples online, and also read a lot about memory leaks, The above code does not produce memory leaks. The web part manager creates an SPWeb, so just dispose it like I did. CONCLUSION This is a long long post so I will stop here for now, I will continue with more comparisons and limitations in my next post. My conclusion for this example is that Web Services will do the trick if you can suffer through CAML and if you are doing some simple operations. For Everything else, there's WCF! **** fireI apologize for the disorganization of this post, I was on a bus on a 12 hour trip to IOWA while I wrote it, I was half asleep and half awake, hopefully it makes enough sense to someone.

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

  - by Rhames

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

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• Asterisk SIP digest authentication username mismatch

  - by Matt

  I have an asterisk system that I'm attempting to get to work as a backup for our 3com system. We already use it for a conference bridge. Our phones are the 3com 3C10402B, so I don't have the issue of older 3com phones that come without a SIP image. The 3com phones are communicating SIP with the Asterisk, but are unable to register because they present a digest username value that doesn't match what Asterisk thinks it should. As an example, here are the relevant lines from a successful registration from a soft phone: Server sends: WWW-Authenticate: Digest algorithm=MD5, realm="asterisk", nonce="1cac3853" Phone responds: Authorization: Digest username="2321", realm="asterisk", nonce="1cac3853", uri="sip:192.168.254.12", algorithm=md5, response="d32df9ec719817282460e7c2625b6120" For the 3com phone, those same lines look like this (and fails): Server sends: WWW-Authenticate: Digest algorithm=MD5, realm="asterisk", nonce="6c915c33" Phone responds: Authorization: Digest username="sip:[email protected]", realm="asterisk", nonce="6c915c33", uri="sip:192.168.254.12", opaque="", algorithm=MD5, response="a89df25f19e4b4598595f919dac9db81" Basically, Asterisk wants to see a username in the Digest username field of 2321, but the 3com phone is sending sip:[email protected]. Anyone know how to tell asterisk to accept this format of username in the digest authentication? Here is the sip.conf info for that extension: [2321] deny=0.0.0.0/0.0.0.0 disallow=all type=friend secret=1234 qualify=yes port=5060 permit=0.0.0.0/0.0.0.0 nat=yes mailbox=2321@device host=dynamic dtmfmode=rfc2833 dial=SIP/2321 context=from-internal canreinvite=no callerid=device <2321 allow=ulaw, alaw call-limit=50 ... and for those interested in the grit, here is the debug output of the registration attempt: REGISTER sip:192.168.254.12 SIP/2.0 v: SIP/2.0/UDP 192.168.254.157:5060 t: f: i: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18580 REGISTER Max-Forwards: 70 m: ;dt=544 Expires: 3600 User-Agent: 3Com-SIP-Phone/V8.0.1.3 X-3Com-PhoneInfo: firstRegistration=no; primaryCallP=192.168.254.12; secondaryCallP=0.0.0.0; --- (11 headers 0 lines) --- Using latest REGISTER request as basis request Sending to 192.168.254.157 : 5060 (no NAT) SIP/2.0 100 Trying Via: SIP/2.0/UDP 192.168.254.157:5060;received=192.168.254.157 From: To: Call-ID: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18580 REGISTER User-Agent: Asterisk PBX Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Supported: replaces Contact: Content-Length: 0 SIP/2.0 401 Unauthorized Via: SIP/2.0/UDP 192.168.254.157:5060;received=192.168.254.157 From: To: ;tag=as3fb867e2 Call-ID: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18580 REGISTER User-Agent: Asterisk PBX Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Supported: replaces WWW-Authenticate: Digest algorithm=MD5, realm="asterisk", nonce="6c915c33" Content-Length: 0 Scheduling destruction of SIP dialog 'fa4451d8-01d6-1cc2-13e4-00e0bb33beb9' in 32000 ms (Method: REGISTER) confbridge*CLI REGISTER sip:192.168.254.12 SIP/2.0 v: SIP/2.0/UDP 192.168.254.157:5060 t: f: i: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18581 REGISTER Max-Forwards: 70 m: ;dt=544 Expires: 3600 User-Agent: 3Com-SIP-Phone/V8.0.1.3 Authorization: Digest username="sip:[email protected]", realm="asterisk", nonce="6c915c33", uri="sip:192.168.254.12", opaque="", algorithm=MD5, response="a89df25f19e4b4598595f919dac9db81" X-3Com-PhoneInfo: firstRegistration=no; primaryCallP=192.168.254.12; secondaryCallP=0.0.0.0; --- (12 headers 0 lines) --- Using latest REGISTER request as basis request Sending to 192.168.254.157 : 5060 (NAT) SIP/2.0 100 Trying Via: SIP/2.0/UDP 192.168.254.157:5060;received=192.168.254.157 From: To: Call-ID: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18581 REGISTER User-Agent: Asterisk PBX Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Supported: replaces Contact: Content-Length: 0 SIP/2.0 403 Authentication user name does not match account name Via: SIP/2.0/UDP 192.168.254.157:5060;received=192.168.254.157 From: To: ;tag=as3fb867e2 Call-ID: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18581 REGISTER User-Agent: Asterisk PBX Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Supported: replaces Content-Length: 0 Scheduling destruction of SIP dialog 'fa4451d8-01d6-1cc2-13e4-00e0bb33beb9' in 32000 ms (Method: REGISTER) Thanks for your input!

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• Ubuntu: Failure to login with multiple video adapters

  - by tsilb

  Forgive my ignorance, for I am a complete linux noob. I have a computer with three video cards and six monitors. Works great on Windows. Trying to get it to run Ubuntu as well. It loads fine when I have it configured to run on one adapter; detects both screens, runs ok. But I want to turn the other 4 monitors on and run the whole thing as one extended desktop (one session, etc). So I downloaded and installed the newest ATI driver for Linux, which seems to work, kinda. I ran this to set up the screens: aticonfig --adapter=all --initial -f Now when I boot, Ubuntu seems to turn on all the screens (3 viewports, each with two cloned displays from what I can tell). When I enter my login info OR move the mouse off the main screen, the screens freeze and the kbd/ms become unresponsive. aticonfig generated xorg.conf included below. Have tried the following: aticonfig -initial -f - works, but only detects the primary adapter and 2 screens aticccle - Tells me I have to reboot after enabling the other cards. Then goes into above described freezing state. aticonfig --adapter=all --initial -f - see above Manually editing xorg.conf file with my limited knowledge - Was able to get two adapters running, but only the second adapter initialized while the primary stopped at the Ubuntu boot screen. Was unable to see the login prompt. Froze after I logged in blindly (was able to hear the login sound). Using generic "radeon" driver instead of ATI Proprietary driver with the above init attempts Toggling xinerama Various combinations of the above Hardware: Intel Core 2 Quad q6600 8GB DDR2 (3x) ATI Radeon HD 4680 5 monitors (21W, 21W, 22W Portrait, 22W Portrait, 19")and an HDTV (26"W, HDMI) in a horizontal arrangement I know next to nothing about Linux/Ubuntu aside from basic filesystem navigation, editing text files, and accessing my local and networked Windows stores and shares. Basically this is the most advanced thing I've had to do. I installed today. Please advise how to make this configuration work. my xorg.conf: Section "ServerLayout" Identifier "Layout0" Screen 0 "aticonfig-Screen[0]-0" 0 0 Screen "aticonfig-Screen[1]-0" RightOf "aticonfig-Screen[0]-0" Screen "aticonfig-Screen[2]-0" RightOf "aticonfig-Screen[1]-0" Option "RenderAccel" "true" Option "AllowGLXWithComposite" "true" EndSection Section "Files" EndSection Section "Module" EndSection Section "ServerFlags" Option "Xinerama" "0" EndSection Section "Monitor" Identifier "aticonfig-Monitor[0]-0" Option "VendorName" "ATI Proprietary Driver" Option "ModelName" "Generic Autodetecting Monitor" Option "DPMS" "true" EndSection Section "Monitor" Identifier "aticonfig-Monitor[1]-0" Option "VendorName" "ATI Proprietary Driver" Option "ModelName" "Generic Autodetecting Monitor" Option "DPMS" "true" EndSection Section "Monitor" Identifier "aticonfig-Monitor[2]-0" Option "VendorName" "ATI Proprietary Driver" Option "ModelName" "Generic Autodetecting Monitor" Option "DPMS" "true" EndSection Section "Device" Identifier "aticonfig-Device[0]-0" Driver "fglrx" BusID "PCI:1:0:0" EndSection Section "Device" Identifier "aticonfig-Device[1]-0" Driver "fglrx" BusID "PCI:3:0:0" EndSection Section "Device" Identifier "aticonfig-Device[2]-0" Driver "fglrx" BusID "PCI:4:0:0" EndSection Section "Screen" Identifier "aticonfig-Screen[0]-0" Device "aticonfig-Device[0]-0" Monitor "aticonfig-Monitor[0]-0" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 EndSubSection EndSection Section "Screen" Identifier "aticonfig-Screen[1]-0" Device "aticonfig-Device[1]-0" Monitor "aticonfig-Monitor[1]-0" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 EndSubSection EndSection Section "Screen" Identifier "aticonfig-Screen[2]-0" Device "aticonfig-Device[2]-0" Monitor "aticonfig-Monitor[2]-0" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 EndSubSection EndSection

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• vim-powerline colors are out of whack in urxvt

  - by komidore64

  I have attached two images showing what my vim-powerline looks like. As you can see, something has happened to the colors and I cannot figure out how to fix it. I'm running Fedora 17 on a clean install with i3 (default config) and urxvt. Here is my bashrc: # .bashrc if [[ "$(uname)" != "Darwin" ]]; then # non mac os x # source global bashrc if [[ -f "/etc/bashrc" ]]; then . /etc/bashrc fi export TERM='xterm-256color' # probably shouldn't do this fi # bash prompt with colors # [ <user>@<hostname> <working directory> {current git branch (if you're in a repo)} ] # ==> PS1="\[\e[1;33m\][ \u\[\e[1;37m\]@\[\e[1;32m\]\h\[\e[1;33m\] \W\$(git branch 2> /dev/null | grep -e '\* ' | sed 's/^..\(.*\)/ {\[\e[1;36m\]\1\[\e[1;33m\]}/') ]\[\e[0m\]\n==> " # execute only in Mac OS X if [[ "$(uname)" == 'Darwin' ]]; then # if OS X has a $HOME/bin folder, then add it to PATH if [[ -d "$HOME/bin" ]]; then export PATH="$PATH:$HOME/bin" fi alias ls='ls -G' # ls with colors fi alias ll='ls -lah' # long listing of all files with human readable file sizes alias tree='tree -C' # turns on coloring for tree command alias mkdir='mkdir -p' # create parent directories as needed alias vim='vim -p' # if more than one file, open files in tabs export EDITOR='vim' # super-secret work stuff if [[ -f "$HOME/.workbashrc" ]]; then . $HOME/.workbashrc fi # Add RVM to PATH for scripting if [[ -d "$HOME/.rvm/bin" ]]; then # if installed PATH=$PATH:$HOME/.rvm/bin fi and my Xdefaults: ! URxvt config ! colors! URxvt.background: #101010 URxvt.foreground: #ededed URxvt.cursorColor: #666666 URxvt.color0: #2E3436 URxvt.color8: #555753 URxvt.color1: #993C3C URxvt.color9: #BF4141 URxvt.color2: #3C993C URxvt.color10: #41BF41 URxvt.color3: #99993C URxvt.color11: #BFBF41 URxvt.color4: #3C6199 URxvt.color12: #4174FB URxvt.color5: #993C99 URxvt.color13: #BF41BF URxvt.color6: #3C9999 URxvt.color14: #41BFBF URxvt.color7: #D3D7CF URxvt.color15: #E3E3E3 ! options URxvt*loginShell: true URxvt*font: xft:DejaVu Sans Mono for Powerline:antialias=true:size=12 URxvt*saveLines: 8192 URxvt*scrollstyle: plain URxvt*scrollBar_right: true URxvt*scrollTtyOutput: true URxvt*scrollTtyKeypress: true URxvt*urlLauncher: google-chrome and finally my vimrc set nocompatible set dir=~/.vim/ " set one place for vim swap files " vundler for vim plugins ---- filetype off set rtp+=~/.vim/bundle/vundle call vundle#rc() Bundle 'gmarik/vundle' Bundle 'tpope/vim-surround' Bundle 'greyblake/vim-preview' Bundle 'Lokaltog/vim-powerline' Bundle 'tpope/vim-endwise' Bundle 'kien/ctrlp.vim' " ---------------------------- syntax enable filetype plugin indent on " Powerline ------------------ set noshowmode set laststatus=2 let g:Powerline_symbols = 'fancy' " show fancy symbols (requires patched font) set encoding=utf-8 " ---------------------------- " ctrlp ---------------------- let g:ctrlp_open_multiple_files = 'tj' " open multiple files in additional tabs let g:ctrlp_show_hidden = 1 " include dotfiles and dotdirs in ctrlp indexing let g:ctrlp_prompt_mappings = { \ 'AcceptSelection("e")': ['<c-t>'], \ 'AcceptSelection("t")': ['<cr>', '<2-LeftMouse>'], \ } " remap <cr> to open file in a new tab " ---------------------------- set showcmd set tabpagemax=100 set hlsearch set incsearch set nowrapscan set ignorecase set smartcase set ruler set tabstop=4 set shiftwidth=4 set expandtab set wildmode=list:longest autocmd BufWritePre * :%s/\s\+$//e "remove trailing whitespace " :REV to "revert" file to state of the most recent save command REV earlier 1f " disable netrw -------------- let g:loaded_netrw = 1 let g:loaded_netrwPlugin = 1 " ---------------------------- Any guidance as to fixing the statusline would be fantastic. I've found a github issue outlining almost the exact same problem, but the solution was never posted. Thank you.

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• Asterisk SIP digest authentication username mismatch

  - by Matt

  I have an asterisk system that I'm attempting to get to work as a backup for our 3com system. We already use it for a conference bridge. Our phones are the 3com 3C10402B, so I don't have the issue of older 3com phones that come without a SIP image. The 3com phones are communicating SIP with the Asterisk, but are unable to register because they present a digest username value that doesn't match what Asterisk thinks it should. As an example, here are the relevant lines from a successful registration from a soft phone: Server sends: WWW-Authenticate: Digest algorithm=MD5, realm="asterisk", nonce="1cac3853" Phone responds: Authorization: Digest username="2321", realm="asterisk", nonce="1cac3853", uri="sip:192.168.254.12", algorithm=md5, response="d32df9ec719817282460e7c2625b6120" For the 3com phone, those same lines look like this (and fails): Server sends: WWW-Authenticate: Digest algorithm=MD5, realm="asterisk", nonce="6c915c33" Phone responds: Authorization: Digest username="sip:[email protected]", realm="asterisk", nonce="6c915c33", uri="sip:192.168.254.12", opaque="", algorithm=MD5, response="a89df25f19e4b4598595f919dac9db81" Basically, Asterisk wants to see a username in the Digest username field of 2321, but the 3com phone is sending sip:[email protected]. Anyone know how to tell asterisk to accept this format of username in the digest authentication? Here is the sip.conf info for that extension: [2321] deny=0.0.0.0/0.0.0.0 disallow=all type=friend secret=1234 qualify=yes port=5060 permit=0.0.0.0/0.0.0.0 nat=yes mailbox=2321@device host=dynamic dtmfmode=rfc2833 dial=SIP/2321 context=from-internal canreinvite=no callerid=device <2321 allow=ulaw, alaw call-limit=50 ... and for those interested in the grit, here is the debug output of the registration attempt: REGISTER sip:192.168.254.12 SIP/2.0 v: SIP/2.0/UDP 192.168.254.157:5060 t: f: i: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18580 REGISTER Max-Forwards: 70 m: ;dt=544 Expires: 3600 User-Agent: 3Com-SIP-Phone/V8.0.1.3 X-3Com-PhoneInfo: firstRegistration=no; primaryCallP=192.168.254.12; secondaryCallP=0.0.0.0; --- (11 headers 0 lines) --- Using latest REGISTER request as basis request Sending to 192.168.254.157 : 5060 (no NAT) SIP/2.0 100 Trying Via: SIP/2.0/UDP 192.168.254.157:5060;received=192.168.254.157 From: To: Call-ID: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18580 REGISTER User-Agent: Asterisk PBX Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Supported: replaces Contact: Content-Length: 0 SIP/2.0 401 Unauthorized Via: SIP/2.0/UDP 192.168.254.157:5060;received=192.168.254.157 From: To: ;tag=as3fb867e2 Call-ID: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18580 REGISTER User-Agent: Asterisk PBX Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Supported: replaces WWW-Authenticate: Digest algorithm=MD5, realm="asterisk", nonce="6c915c33" Content-Length: 0 Scheduling destruction of SIP dialog 'fa4451d8-01d6-1cc2-13e4-00e0bb33beb9' in 32000 ms (Method: REGISTER) confbridge*CLI REGISTER sip:192.168.254.12 SIP/2.0 v: SIP/2.0/UDP 192.168.254.157:5060 t: f: i: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18581 REGISTER Max-Forwards: 70 m: ;dt=544 Expires: 3600 User-Agent: 3Com-SIP-Phone/V8.0.1.3 Authorization: Digest username="sip:[email protected]", realm="asterisk", nonce="6c915c33", uri="sip:192.168.254.12", opaque="", algorithm=MD5, response="a89df25f19e4b4598595f919dac9db81" X-3Com-PhoneInfo: firstRegistration=no; primaryCallP=192.168.254.12; secondaryCallP=0.0.0.0; --- (12 headers 0 lines) --- Using latest REGISTER request as basis request Sending to 192.168.254.157 : 5060 (NAT) SIP/2.0 100 Trying Via: SIP/2.0/UDP 192.168.254.157:5060;received=192.168.254.157 From: To: Call-ID: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18581 REGISTER User-Agent: Asterisk PBX Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Supported: replaces Contact: Content-Length: 0 SIP/2.0 403 Authentication user name does not match account name Via: SIP/2.0/UDP 192.168.254.157:5060;received=192.168.254.157 From: To: ;tag=as3fb867e2 Call-ID: fa4451d8-01d6-1cc2-13e4-00e0bb33beb9 CSeq: 18581 REGISTER User-Agent: Asterisk PBX Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Supported: replaces Content-Length: 0 Scheduling destruction of SIP dialog 'fa4451d8-01d6-1cc2-13e4-00e0bb33beb9' in 32000 ms (Method: REGISTER) Thanks for your input!

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• Can't launch glassfish on ec2 - can't open port

  - by orange80

  I'm trying to start glassfish on an EBS-based AMI of Ubuntu 10.04 64-bit. I have used glassfish on non-ec2 servers with no problems, but on ec2 I get this message: $ sudo -u glassfish bin/asadmin start-domain domain1 There is a process already using the admin port 4848 -- it probably is another instance of a GlassFish server. Command start-domain failed. I know that ec2 has requires that firewall rules be modified using ec2-authorize to let outside traffic thru the firewall, as I had to do to make ssh work. This still doesn't explain the port error when all I'm trying to do is start glassfish so I can try $ wget localhost:8080and make sure it's working. This is very frustrating and I'd really appreciate any help. Thanks. FINAL UPDATE: Sorry if you came here looking for answers. I never figured out what was causing the problem. I created another fresh instance, installed the same stuff, and Glassfish worked perfectly. Something obviously got boned during installation, but I have no idea what. I guess it will remain a mystery. UPDATE: Here's what I get from netstat: # netstat -nuptl Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 462/sshd tcp6 0 0 :::22 :::* LISTEN 462/sshd udp 0 0 0.0.0.0:5353 0.0.0.0:* 483/avahi-daemon: r udp 0 0 0.0.0.0:1194 0.0.0.0:* 589/openvpn udp 0 0 0.0.0.0:37940 0.0.0.0:* 483/avahi-daemon: r udp 0 0 0.0.0.0:68 0.0.0.0:* 377/dhclient3 UPDATE: One more thing... I know that the "net.ipv6.bindv6only" kernel option can cause problems with java networking, so I did set this: # sysctl -w net.ipv6.bindv6only=0 UPDATE: I also verified that it has nothing at all to do with the port number (4848). As you can see here, when I changed the admin-listener port in domain.xml to 4949, I get a similar message: # sudo -u glassfish bin/asadmin start-domain domain1 There is a process already using the admin port 4949 -- it probably is another instance of a GlassFish server. Command start-domain failed. UPDATE: Here are the contents of /etc/hosts: 127.0.0.1 localhost # The following lines are desirable for IPv6 capable hosts ::1 ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters ff02::3 ip6-allhosts I should mention that I have another Ubuntu Lucid 10.04 64-bit slice that is NOT hosted on ec2, and set it up the exact same way with no problems whatsoever. Also server.log doesn't offer much insight either: # cat ./server.log Nov 20, 2010 8:46:49 AM com.sun.enterprise.admin.launcher.GFLauncherLogger info INFO: JVM invocation command line: /usr/lib/jvm/java-6-sun-1.6.0.22/bin/java -cp /opt/glassfishv3/glassfish/modules/glassfish.jar -XX:+UnlockDiagnosticVMOptions -XX:MaxPermSize=192m -XX:NewRatio=2 -XX:+LogVMOutput -XX:LogFile=/opt/glassfishv3/glassfish/domains/domain1/logs/jvm.log -Xmx512m -client -javaagent:/opt/glassfishv3/glassfish/lib/monitor/btrace-agent.jar=unsafe=true,noServer=true -Dosgi.shell.telnet.maxconn=1 -Djdbc.drivers=org.apache.derby.jdbc.ClientDriver -Dfelix.fileinstall.dir=/opt/glassfishv3/glassfish/modules/autostart/ -Djavax.net.ssl.keyStore=/opt/glassfishv3/glassfish/domains/domain1/config/keystore.jks -Dosgi.shell.telnet.port=6666 -Djava.security.policy=/opt/glassfishv3/glassfish/domains/domain1/config/server.policy -Dfelix.fileinstall.poll=5000 -Dcom.sun.aas.instanceRoot=/opt/glassfishv3/glassfish/domains/domain1 -Dcom.sun.enterprise.config.config_environment_factory_class=com.sun.enterprise.config.serverbeans.AppserverConfigEnvironmentFactory -Dosgi.shell.telnet.ip=127.0.0.1 -Djava.endorsed.dirs=/opt/glassfishv3/glassfish/modules/endorsed:/opt/glassfishv3/glassfish/lib/endorsed -Dcom.sun.aas.installRoot=/opt/glassfishv3/glassfish -Djava.ext.dirs=/usr/lib/jvm/java-6-sun-1.6.0.22/lib/ext:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/ext:/opt/glassfishv3/glassfish/domains/domain1/lib/ext -Dfelix.fileinstall.bundles.new.start=true -Djavax.net.ssl.trustStore=/opt/glassfishv3/glassfish/domains/domain1/config/cacerts.jks -Dcom.sun.enterprise.security.httpsOutboundKeyAlias=s1as -Djava.security.auth.login.config=/opt/glassfishv3/glassfish/domains/domain1/config/login.conf -DANTLR_USE_DIRECT_CLASS_LOADING=true -Dfelix.fileinstall.debug=1 -Dorg.glassfish.web.rfc2109_cookie_names_enforced=false -Djava.library.path=/opt/glassfishv3/glassfish/lib:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/amd64/server:/usr/lib/jvm/java-6-sun-1.6.0.22/jre/lib/amd64:/usr/lib/jvm/java-6-sun-1.6.0.22/lib/amd64:/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib com.sun.enterprise.glassfish.bootstrap.ASMain -domainname domain1 -asadmin-args start-domain,,,domain1 -instancename server -verbose false -debug false -asadmin-classpath /opt/glassfishv3/glassfish/modules/admin-cli.jar -asadmin-classname com.sun.enterprise.admin.cli.AsadminMain -upgrade false -domaindir /opt/glassfishv3/glassfish/domains/domain1 -read-stdin true

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• CPU/JVM/JBoss 7 slows down over time

  - by lukas

  I'm experiencing performance slow down on JBoss 7.1.1 Final. I wrote simple program that demostrates this behavior. I generate an array of 100,000 of random integers and run bubble sort on it. @Model public class PerformanceTest { public void proceed() { long now = System.currentTimeMillis(); int[] arr = new int[100000]; for(int i = 0; i < arr.length; i++) { arr[i] = (int) (Math.random() * 200000); } long now2 = System.currentTimeMillis(); System.out.println((now2 - now) + "ms took to generate array"); now = System.currentTimeMillis(); bubbleSort(arr); now2 = System.currentTimeMillis(); System.out.println((now2 - now) + "ms took to bubblesort array"); } public void bubbleSort(int[] arr) { boolean swapped = true; int j = 0; int tmp; while (swapped) { swapped = false; j++; for (int i = 0; i < arr.length - j; i++) { if (arr[i] > arr[i + 1]) { tmp = arr[i]; arr[i] = arr[i + 1]; arr[i + 1] = tmp; swapped = true; } } } } } Just after I start the server, it takes approximately 22 seconds to run this code. After few days of JBoss 7.1.1. running, it takes 330 sec to run this code. In both cases, I launch the code when the CPU utilization is very low (say, 1%). Any ideas why? I run the server with following arguments: -Xms1280m -Xmx2048m -XX:MaxPermSize=2048m -Djava.net.preferIPv4Stack=true -Dorg.jboss.resolver.warning=true -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000 -Djboss.modules.system.pkgs=org.jboss.byteman -Djava.awt.headless=true -Duser.timezone=UTC -Djboss.server.default.config=standalone-full.xml -Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=n I'm running it on Linux 2.6.32-279.11.1.el6.x86_64 with java version "1.7.0_07". It's within J2EE applicaiton. I use CDI so I have a button on JSF page that will call method "proceed" on @RequestScoped component PerformanceTest. I deploy this as separate war file and even if I undeploy other applications, it doesn't change the performance. It's a virtual machine that is sharing CPUs with another machine but that one doesn't consume anything. Here's yet another observation: when the server is after fresh start and I run the bubble sort, It utilizes 100% of one processor core. It never switches to another core or drops utilization below 95%. However after some time the server is running and I'm experiencing the performance problems, the method above is utilizing CPU core usually 100%, however I just found out from htop that this task is being switched very often to other cores. That is, at the beginning it's running on core #1, after say 2 seconds it's running on #5 then after say 2 seconds #8 etc. Furthermore, the utilization is not kept at 100% at the core but sometimes drops to 80% or even lower. For the server after fresh start, even though If I simulate a load, it never switches the task to another core.

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• JBoss https on port other than 8080 not working

  - by MilindaD

  We have a server with two JBoss instances where one runs on 8080, the other on 8081. We need to have HTTPS enabled for the 8081 server, firstly we tried enabling https on the 8080 port instance by generating the keystore and editing the server.xml and it successfully worked. However when we tried the same thing for 8081 it did not, note that we removed https for the 8080 server first before enabling it for 8081. This is what was used for both server.xml for 8080 and 8081. The only difference was that the port was changed from 8080 to 8081 when trying to enable https for 8081 port instance. What am I doing wrong and what needs to be changed? NOTE : When I meant enabled for 8080 I meant when you visit https:// URL:8484 you will actually be visiting the 8080 port instance. However when ssl is enabled for 8081 and I visit https:// URL:8484 I get that the web page is unavailable. COMMENTLESS VERSION <Server> <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" /> <Listener className="org.apache.catalina.core.JasperListener" /> <Service name="jboss.web"> <!-- https --> <Connector port="8080" address="${jboss.bind.address}" maxThreads="350" maxHttpHeaderSize="8192" emptySessionPath="true" protocol="HTTP/1.1" enableLookups="false" redirectPort="8443" acceptCount="100" connectionTimeout="20000" disableUploadTimeout="true" compression="on" ompressableMimeType="text/html,text/css,text/javascript,application/json,text/xml,text/plain,application/x-javascript,application/javascript"/> <Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" clientAuth="false" sslProtocol="TLS" address="${jboss.bind.address}" keystoreFile="${jboss.server.home.dir}/conf/supun1.keystore" keystorePass="aaaaaa" truststoreFile="${jboss.server.home.dir}/conf/supun1.keystore" truststorePass="aaaaaa" /> <!-- https1 --> <Connector port="8009" address="${jboss.bind.address}" protocol="AJP/1.3" emptySessionPath="true" enableLookups="false" redirectPort="8443" /> <Engine name="jboss.web" defaultHost="localhost" jvmRoute="khms1"> <Realm className="org.jboss.web.tomcat.security.JBossSecurityMgrRealm" certificatePrincipal="org.jboss.security.auth.certs.SubjectDNMapping" allRolesMode="authOnly" /> <Host name="localhost" autoDeploy="false" deployOnStartup="false" deployXML="false" configClass="org.jboss.web.tomcat.security.config.JBossContextConfig" > <Valve className="org.jboss.web.tomcat.service.sso.ClusteredSingleSignOn" /> <Valve className="org.jboss.web.tomcat.service.jca.CachedConnectionValve" cachedConnectionManagerObjectName="jboss.jca:service=CachedConnectionManager" transactionManagerObjectName="jboss:service=TransactionManager" /> </Host> </Engine> </Service> </Server> WITH COMMENTS VERSION <Server> <!--APR library loader. Documentation at /docs/apr.html --> <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" /> <!--Initialize Jasper prior to webapps are loaded. Documentation at /docs/jasper-howto.html --> <Listener className="org.apache.catalina.core.JasperListener" /> <!-- Use a custom version of StandardService that allows the connectors to be started independent of the normal lifecycle start to allow web apps to be deployed before starting the connectors. --> <Service name="jboss.web"> <!-- A "Connector" represents an endpoint by which requests are received and responses are returned. Documentation at : Java HTTP Connector: /docs/config/http.html (blocking & non-blocking) Java AJP Connector: /docs/config/ajp.html APR (HTTP/AJP) Connector: /docs/apr.html Define a non-SSL HTTP/1.1 Connector on port 8080 --> <Connector port="8080" address="${jboss.bind.address}" maxThreads="350" maxHttpHeaderSize="8192" emptySessionPath="true" protocol="HTTP/1.1" enableLookups="false" redirectPort="8443" acceptCount="100" connectionTimeout="20000" disableUploadTimeout="true" compression="on" ompressableMimeType="text/html,text/css,text/javascript,application/json,text/xml,text/plain,application/x-javascript,application/javascript"/> <!-- Define a SSL HTTP/1.1 Connector on port 8443 This connector uses the JSSE configuration, when using APR, the connector should be using the OpenSSL style configuration described in the APR documentation --> <!-- <Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" keystoreFile="${jboss.server.home.dir}/conf/zara.keystore" keystorePass="zara2010" clientAuth="false" sslProtocol="TLS" compression="on" /> --> <Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" clientAuth="false" sslProtocol="TLS" address="${jboss.bind.address}" keystoreFile="${jboss.server.home.dir}/conf/supun1.keystore" keystorePass="aaaaaa" truststoreFile="${jboss.server.home.dir}/conf/supun1.keystore" truststorePass="aaaaaa" /> <!-- Define an AJP 1.3 Connector on port 8009 --> <Connector port="8009" address="${jboss.bind.address}" protocol="AJP/1.3" emptySessionPath="true" enableLookups="false" redirectPort="8443" /> <Engine name="jboss.web" defaultHost="localhost" jvmRoute="khms1"> <!-- The JAAS based authentication and authorization realm implementation that is compatible with the jboss 3.2.x realm implementation. - certificatePrincipal : the class name of the org.jboss.security.auth.certs.CertificatePrincipal impl used for mapping X509[] cert chains to a Princpal. - allRolesMode : how to handle an auth-constraint with a role-name=*, one of strict, authOnly, strictAuthOnly + strict = Use the strict servlet spec interpretation which requires that the user have one of the web-app/security-role/role-name + authOnly = Allow any authenticated user + strictAuthOnly = Allow any authenticated user only if there are no web-app/security-roles --> <Realm className="org.jboss.web.tomcat.security.JBossSecurityMgrRealm" certificatePrincipal="org.jboss.security.auth.certs.SubjectDNMapping" allRolesMode="authOnly" /> <!-- A subclass of JBossSecurityMgrRealm that uses the authentication behavior of JBossSecurityMgrRealm, but overrides the authorization checks to use JACC permissions with the current java.security.Policy to determine authorized access. - allRolesMode : how to handle an auth-constraint with a role-name=*, one of strict, authOnly, strictAuthOnly + strict = Use the strict servlet spec interpretation which requires that the user have one of the web-app/security-role/role-name + authOnly = Allow any authenticated user + strictAuthOnly = Allow any authenticated user only if there are no web-app/security-roles <Realm className="org.jboss.web.tomcat.security.JaccAuthorizationRealm" certificatePrincipal="org.jboss.security.auth.certs.SubjectDNMapping" allRolesMode="authOnly" /> --> <Host name="localhost" autoDeploy="false" deployOnStartup="false" deployXML="false" configClass="org.jboss.web.tomcat.security.config.JBossContextConfig" > <!-- Uncomment to enable request dumper. This Valve "logs interesting contents from the specified Request (before processing) and the corresponding Response (after processing). It is especially useful in debugging problems related to headers and cookies." --> <!-- <Valve className="org.apache.catalina.valves.RequestDumperValve" /> --> <!-- Access logger --> <!-- <Valve className="org.apache.catalina.valves.AccessLogValve" prefix="localhost_access_log." suffix=".log" pattern="common" directory="${jboss.server.log.dir}" resolveHosts="false" /> --> <!-- Uncomment to enable single sign-on across web apps deployed to this host. Does not provide SSO across a cluster. If this valve is used, do not use the JBoss ClusteredSingleSignOn valve shown below. A new configuration attribute is available beginning with release 4.0.4: cookieDomain configures the domain to which the SSO cookie will be scoped (i.e. the set of hosts to which the cookie will be presented). By default the cookie is scoped to "/", meaning the host that presented it. Set cookieDomain to a wider domain (e.g. "xyz.com") to allow an SSO to span more than one hostname. --> <!-- <Valve className="org.apache.catalina.authenticator.SingleSignOn" /> --> <!-- Uncomment to enable single sign-on across web apps deployed to this host AND to all other hosts in the cluster. If this valve is used, do not use the standard Tomcat SingleSignOn valve shown above. Valve uses a JBossCache instance to support SSO credential caching and replication across the cluster. The JBossCache instance must be configured separately. By default, the valve shares a JBossCache with the service that supports HttpSession replication. See the "jboss-web-cluster-service.xml" file in the server/all/deploy directory for cache configuration details. Besides the attributes supported by the standard Tomcat SingleSignOn valve (see the Tomcat docs), this version also supports the following attributes: cookieDomain see above treeCacheName JMX ObjectName of the JBossCache MBean used to support credential caching and replication across the cluster. If not set, the default value is "jboss.cache:service=TomcatClusteringCache", the standard ObjectName of the JBossCache MBean used to support session replication. --> <Valve className="org.jboss.web.tomcat.service.sso.ClusteredSingleSignOn" /> <!-- Check for unclosed connections and transaction terminated checks in servlets/jsps. Important: The dependency on the CachedConnectionManager in META-INF/jboss-service.xml must be uncommented, too --> <Valve className="org.jboss.web.tomcat.service.jca.CachedConnectionValve" cachedConnectionManagerObjectName="jboss.jca:service=CachedConnectionManager" transactionManagerObjectName="jboss:service=TransactionManager" /> </Host> </Engine> </Service> </Server>

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• JSF index out of bounds exception when submiting a form

  - by selvin

  When I click submit button in a JSF form the following exception occurs. It says an Indexout of bounds exception, but I did not use any ArrayList associated with the code. Is this a bug? what should i do to get rid of this error.. Mojarra: 2.0.2 FCS with primefaces 2.2 JSF: 2.0 NetBeans IDE 6.8 Glassfish Domain V3 Form Code: <p:panel id="jobres" style="min-width: 200px" header="Reservation" widgetVar="jres" closable="true" toggleable="true" > <h:form id="arj" prependId="false" style="width:550px;max-height:400px;overflow:auto;"> <p:tooltip global="true"/> <h:panelGrid columns="2" > <p:panel style="min-width: 220px"> <h:outputLabel value="1.Job type:"/> </p:panel> <h:panelGroup> <h:messages id="aerr"/> <h:selectOneMenu title="Choose a Jobtype" value="#{arjob.jobtype}"> <f:selectItem itemLabel="Sequential" itemValue="sequential"/> <f:selectItem itemLabel="Parallel" itemValue="parallel"/> </h:selectOneMenu> </h:panelGroup> <p:panel> <h:outputLabel value="2.Executable: *"/> </p:panel> <h:panelGroup> <p:fileUpload id="aexeupload" fileUploadListener="#{arjob.chooseListener}" auto="true" update="adlist :erdialog" description="Resource Files"> </p:fileUpload> <br/> <h:panelGroup id="aexelistwrapper"> <p:dataList var="fileList" type="ordered" id="adlist" value="#{arjob.fexelist}"> <p:column> #{fileList}&nbsp; <p:commandLink ajax="true" update="aexelistwrapper" actionListener="#{arjob.removeExe(fileList)}"> <p:graphicImage value="images/closebar.png"/> </p:commandLink> </p:column> </p:dataList> </h:panelGroup> </h:panelGroup> <p:panel> <h:outputLabel value="3.Argument(s):"/> </p:panel> <h:panelGroup> <u style="color:orange"> <i> <p:inplace emptyLabel="Add Arguments" onEditUpdate="aarglist"> <h:inputText title="Enter the arguments" id="aiparg" value="#{arjob.args}"> <f:ajax event="valueChange"/> </h:inputText> <p:commandButton update="aarglistwrapper erdialog" value="add" actionListener="#{arjob.addArg}"/> </p:inplace> </i> </u> </h:panelGroup> <h:panelGroup> </h:panelGroup> <h:panelGroup> <h:panelGrid id="aarglistwrapper"> <p:dataList id="aarglist" type="ordered" var="args" value="#{arjob.arglist}"> <p:column id="col2"> #{args}&nbsp; <p:commandLink ajax="true" update="arj:arglistwrapper" actionListener="#{arjob.removeArgs(args)}"> <p:graphicImage title="remove" value="images/closebar.png"/> </p:commandLink> </p:column> </p:dataList> </h:panelGrid> </h:panelGroup> <p:panel> <h:outputLabel value="4.InputFile(s): *"/> </p:panel> <h:panelGroup> <p:fileUpload id="ainpupload" fileUploadListener="#{arjob.inputChooseListener}" auto="true" update="aipfilelistwrapper :erdialog" description="Resource Files"> </p:fileUpload> <br/> <h:panelGroup id="aipfilelistwrapper"> <p:dataList var="ipfile" type="ordered" id="aipflist" value="#{arjob.finlist}"> <p:column> #{ipfile}&nbsp; <p:commandLink ajax="true" update="aipfilelistwrapper" actionListener="#{arjob.removeInfile(ipfile)}"> <p:graphicImage value="images/closebar.png"/> </p:commandLink> </p:column> </p:dataList> </h:panelGroup> </h:panelGroup> <h:panelGroup> <p:panel > 5)Output File(s): </p:panel> </h:panelGroup> <h:panelGroup> <u style="color:orange"> <i> <p:inplace emptyLabel="Add file name" id="aipexe"> <h:inputText title="Enter the output filenames" id="aexe" value="#{arjob.ofilename}"> <f:ajax event="valueChange"/> </h:inputText> <p:commandButton update="adoutlist :erdialog" value="add" actionListener="#{arjob.addOutfile}"/> </p:inplace> </i> </u> </h:panelGroup> <h:panelGroup> </h:panelGroup> <h:panelGroup> <h:panelGrid id="afilelistwrapper"> <p:dataList id="adoutlist" type="ordered" var="ofile" value="#{arjob.foutlist}"> <p:column id="acol"> #{ofile}&nbsp; <p:commandLink ajax="true" update="afilelistwrapper" actionListener="#{arjob.removeOutfile(ofile)}"> <p:graphicImage value="images/closebar.png"/> </p:commandLink> </p:column> </p:dataList> </h:panelGrid> </h:panelGroup> <p:panel> <h:outputLabel value="6) Operating System"/> </p:panel> <h:panelGroup> <h:selectOneMenu title="Select an OperatingSystem" value="#{arjob.os}"> <f:selectItem itemLabel="CentOS Release 5.2" itemValue="Cent OS 5.2"/> <f:selectItem itemLabel="RHEL Server Release 5" itemValue="RHEL server 5"/> <f:selectItem itemLabel="RHEL Server Release 5.2" itemValue="RHEL server 5.2"/> </h:selectOneMenu> </h:panelGroup> <h:panelGroup> <p:panel> <h:outputLabel value="7) Physical Memory:"/> </p:panel> </h:panelGroup> <h:panelGroup> <p:spinner min="0" style="width: 100px" stepFactor="10" value="#{arjob.mem}"> </p:spinner>(MB) </h:panelGroup> <h:panelGroup> <p:panel> <h:outputLabel value="8) Disk Space:"/> </p:panel> </h:panelGroup> <h:panelGroup> <p:spinner min="0" style="width: 100px" stepFactor="10" value="#{arjob.diskspace}"> </p:spinner>(MB) </h:panelGroup> <h:panelGroup> <p:panel> <h:outputLabel value="9) CPU Mhz:"/> </p:panel> </h:panelGroup> <h:panelGroup> <p:spinner min="0" style="width: 100px" stepFactor="10" value="#{arjob.cpumhz}"> </p:spinner>(Mhz) </h:panelGroup> <p:panel> <h:outputLabel value="10) Start Time:"/> </p:panel> <h:panelGroup> <p:inputMask title="(YYYY-MM-DD HH:MM:SS)" mask="9999-99-99 99:99:99" value="#{arjob.startt}"> </p:inputMask> </h:panelGroup> <p:panel> <h:outputLabel value="11) End Time:"/> </p:panel> <h:panelGroup> <p:inputMask title="(YYYY-MM-DD HH:MM:SS)" mask="9999-99-99 99:99:99" value="#{arjob.endt}"> <p:ajax event="valueChange"/> </p:inputMask> </h:panelGroup> <p:panel> <h:outputLabel value="12) LRMS type"/> </p:panel> <h:panelGroup> <h:selectOneMenu value="#{arjob.lrms}"> <f:selectItem itemLabel="PBS" itemValue="PBS"/> <f:selectItem itemLabel="SGE" itemValue="SGE"/> </h:selectOneMenu> </h:panelGroup> <h:panelGroup> <p:panel> <h:outputLabel value="13)Number of Nodes: *"/> </p:panel> </h:panelGroup> <h:panelGroup> <h:panelGroup> <p:spinner style="width: 100px" min="1" max="100" value="#{arjob.numnodes}"> </p:spinner> </h:panelGroup> </h:panelGroup> <h:panelGroup> </h:panelGroup> <h:panelGroup> <p:commandButton ajax="false" value="Submit" action="#{arjob.jobSubmitAction}"/> </h:panelGroup> </h:panelGrid> </h:form> <p:draggable for="jobres" handle=".ui-panel-titlebar"/> </p:panel> Exception: SEVERE: javax.faces.FacesException: Unexpected error restoring state for component with id j_idt7. Cause: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0. at com.sun.faces.application.view.StateManagementStrategyImpl$2.visit(StateManagementStrategyImpl.java:239) at com.sun.faces.component.visit.FullVisitContext.invokeVisitCallback(FullVisitContext.java:147) at javax.faces.component.UIComponent.visitTree(UIComponent.java:1446) at javax.faces.component.UIComponent.visitTree(UIComponent.java:1457) at javax.faces.component.UIComponent.visitTree(UIComponent.java:1457) at javax.faces.component.UIComponent.visitTree(UIComponent.java:1457) at com.sun.faces.application.view.StateManagementStrategyImpl.restoreView(StateManagementStrategyImpl.java:223) at com.sun.faces.application.StateManagerImpl.restoreView(StateManagerImpl.java:177) at com.sun.faces.application.view.ViewHandlingStrategy.restoreView(ViewHandlingStrategy.java:131) at com.sun.faces.application.view.FaceletViewHandlingStrategy.restoreView(FaceletViewHandlingStrategy.java:430) at com.sun.faces.application.view.MultiViewHandler.restoreView(MultiViewHandler.java:143) at javax.faces.application.ViewHandlerWrapper.restoreView(ViewHandlerWrapper.java:288) at com.sun.faces.lifecycle.RestoreViewPhase.execute(RestoreViewPhase.java:199) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) at com.sun.faces.lifecycle.RestoreViewPhase.doPhase(RestoreViewPhase.java:110) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:312) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215) at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:277) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97) at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:332) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:233) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57) at com.sun.grizzly.ContextTask.run(ContextTask.java:69) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309) at java.lang.Thread.run(Thread.java:619) Caused by: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 at java.util.ArrayList.RangeCheck(ArrayList.java:547) at java.util.ArrayList.get(ArrayList.java:322) at javax.faces.component.AttachedObjectListHolder.restoreState(AttachedObjectListHolder.java:161) at javax.faces.component.UIComponentBase.restoreState(UIComponentBase.java:1427) at com.sun.faces.application.view.StateManagementStrategyImpl$2.visit(StateManagementStrategyImpl.java:231) ... 45 more

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• Executing legacy MSBuild scripts in TFS 2010 Build

  - by Jakob Ehn

  When upgrading from TFS 2008 to TFS 2010, all builds are “upgraded” in the sense that a build definition with the same name is created, and it uses the UpgradeTemplate  build process template to execute the build. This template basically just runs MSBuild on the existing TFSBuild.proj file. The build definition contains a property called ConfigurationFolderPath that points to the TFSBuild.proj file. So, existing builds will run just fine after upgrade. But what if you want to use the new workflow functionality in TFS 2010 Build, but still have a lot of MSBuild scripts that maybe call custom MSBuild tasks that you don’t have the time to rewrite? Then one option is to keep these MSBuild scrips and call them from a TFS 2010 Build workflow. This can be done using the MSBuild workflow activity that is avaiable in the toolbox in the Team Foundation Build Activities section: This activity wraps the call to MSBuild.exe and has the following parameters: Most of these properties are only relevant when actually compiling projects, for example C# project files. When calling custom MSBuild project files, you should focus on these properties: Property Meaning Example CommandLineArguments Use this to send in/override MSBuild properties in your project “/p:MyProperty=SomeValue” or MSBuildArguments (this will let you define the arguments in the build definition or when queuing the build) LogFile Name of the log file where MSbuild will log the output “MyBuild.log” LogFileDropLocation Location of the log file BuildDetail.DropLocation + “\log” Project The project to execute SourcesDirectory + “\BuildExtensions.targets” ResponseFile The name of the MSBuild response file SourcesDirectory + “\BuildExtensions.rsp” Targets The target(s) to execute New String() {“Target1”, “Target2”} Verbosity Logging verbosity Microsoft.TeamFoundation.Build.Workflow.BuildVerbosity.Normal Integrating with Team Build   If your MSBuild scripts tries to use Team Build tasks, they will most likely fail with the above approach. For example, the following MSBuild project file tries to add a build step using the BuildStep task:   <?xml version="1.0" encoding="utf-8"?> <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <Import Project="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\TeamBuild\Microsoft.TeamFoundation.Build.targets" /> <Target Name="MyTarget"> <BuildStep TeamFoundationServerUrl="$(TeamFoundationServerUrl)" BuildUri="$(BuildUri)" Name="MyBuildStep" Message="My build step executed" Status="Succeeded"></BuildStep> </Target> </Project> When executing this file using the MSBuild activity, calling the MyTarget, it will fail with the following message: The "Microsoft.TeamFoundation.Build.Tasks.BuildStep" task could not be loaded from the assembly \PrivateAssemblies\Microsoft.TeamFoundation.Build.ProcessComponents.dll. Could not load file or assembly 'file:///D:\PrivateAssemblies\Microsoft.TeamFoundation.Build.ProcessComponents.dll' or one of its dependencies. The system cannot find the file specified. Confirm that the <UsingTask> declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask. You can see that the path to the ProcessComponents.dll is incomplete. This is because in the Microsoft.TeamFoundation.Build.targets file the task is referenced using the $(TeamBuildRegPath) property. Also note that the task needs the TeamFounationServerUrl and BuildUri properties. One solution here is to pass these properties in using the Command Line Arguments parameter:   Here we pass in the parameters with the corresponding values from the curent build. The build log shows that the build step has in fact been inserted:   The problem as you probably spted is that the build step is insert at the top of the build log, instead of next to the MSBuild activity call. This is because we are using a legacy team build task (BuildStep), and that is how these are handled in TFS 2010. You can see the same behaviour when running builds that are using the UpgradeTemplate, that cutom build steps shows up at the top of the build log.

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• An Introduction to ASP.NET Web API

  - by Rick Strahl

  Microsoft recently released ASP.NET MVC 4.0 and .NET 4.5 and along with it, the brand spanking new ASP.NET Web API. Web API is an exciting new addition to the ASP.NET stack that provides a new, well-designed HTTP framework for creating REST and AJAX APIs (API is Microsoft’s new jargon for a service, in case you’re wondering). Although Web API ships and installs with ASP.NET MVC 4, you can use Web API functionality in any ASP.NET project, including WebForms, WebPages and MVC or just a Web API by itself. And you can also self-host Web API in your own applications from Console, Desktop or Service applications. If you're interested in a high level overview on what ASP.NET Web API is and how it fits into the ASP.NET stack you can check out my previous post: Where does ASP.NET Web API fit? In the following article, I'll focus on a practical, by example introduction to ASP.NET Web API. All the code discussed in this article is available in GitHub: https://github.com/RickStrahl/AspNetWebApiArticle [republished from my Code Magazine Article and updated for RTM release of ASP.NET Web API] Getting Started To start I’ll create a new empty ASP.NET application to demonstrate that Web API can work with any kind of ASP.NET project. Although you can create a new project based on the ASP.NET MVC/Web API template to quickly get up and running, I’ll take you through the manual setup process, because one common use case is to add Web API functionality to an existing ASP.NET application. This process describes the steps needed to hook up Web API to any ASP.NET 4.0 application. Start by creating an ASP.NET Empty Project. Then create a new folder in the project called Controllers. Add a Web API Controller Class Once you have any kind of ASP.NET project open, you can add a Web API Controller class to it. Web API Controllers are very similar to MVC Controller classes, but they work in any kind of project. Add a new item to this folder by using the Add New Item option in Visual Studio and choose Web API Controller Class, as shown in Figure 1. Figure 1: This is how you create a new Controller Class in Visual Studio   Make sure that the name of the controller class includes Controller at the end of it, which is required in order for Web API routing to find it. Here, the name for the class is AlbumApiController. For this example, I’ll use a Music Album model to demonstrate basic behavior of Web API. The model consists of albums and related songs where an album has properties like Name, Artist and YearReleased and a list of songs with a SongName and SongLength as well as an AlbumId that links it to the album. You can find the code for the model (and the rest of these samples) on Github. To add the file manually, create a new folder called Model, and add a new class Album.cs and copy the code into it. There’s a static AlbumData class with a static CreateSampleAlbumData() method that creates a short list of albums on a static .Current that I’ll use for the examples. Before we look at what goes into the controller class though, let’s hook up routing so we can access this new controller. Hooking up Routing in Global.asax To start, I need to perform the one required configuration task in order for Web API to work: I need to configure routing to the controller. Like MVC, Web API uses routing to provide clean, extension-less URLs to controller methods. Using an extension method to ASP.NET’s static RouteTable class, you can use the MapHttpRoute() (in the System.Web.Http namespace) method to hook-up the routing during Application_Start in global.asax.cs shown in Listing 1.using System; using System.Web.Routing; using System.Web.Http; namespace AspNetWebApi { public class Global : System.Web.HttpApplication { protected void Application_Start(object sender, EventArgs e) { RouteTable.Routes.MapHttpRoute( name: "AlbumVerbs", routeTemplate: "albums/{title}", defaults: new { symbol = RouteParameter.Optional, controller="AlbumApi" } ); } } } This route configures Web API to direct URLs that start with an albums folder to the AlbumApiController class. Routing in ASP.NET is used to create extensionless URLs and allows you to map segments of the URL to specific Route Value parameters. A route parameter, with a name inside curly brackets like {name}, is mapped to parameters on the controller methods. Route parameters can be optional, and there are two special route parameters – controller and action – that determine the controller to call and the method to activate respectively. HTTP Verb Routing Routing in Web API can route requests by HTTP Verb in addition to standard {controller},{action} routing. For the first examples, I use HTTP Verb routing, as shown Listing 1. Notice that the route I’ve defined does not include an {action} route value or action value in the defaults. Rather, Web API can use the HTTP Verb in this route to determine the method to call the controller, and a GET request maps to any method that starts with Get. So methods called Get() or GetAlbums() are matched by a GET request and a POST request maps to a Post() or PostAlbum(). Web API matches a method by name and parameter signature to match a route, query string or POST values. In lieu of the method name, the [HttpGet,HttpPost,HttpPut,HttpDelete, etc] attributes can also be used to designate the accepted verbs explicitly if you don’t want to follow the verb naming conventions. Although HTTP Verb routing is a good practice for REST style resource APIs, it’s not required and you can still use more traditional routes with an explicit {action} route parameter. When {action} is supplied, the HTTP verb routing is ignored. I’ll talk more about alternate routes later. When you’re finished with initial creation of files, your project should look like Figure 2.   Figure 2: The initial project has the new API Controller Album model   Creating a small Album Model Now it’s time to create some controller methods to serve data. For these examples, I’ll use a very simple Album and Songs model to play with, as shown in Listing 2. public class Song { public string AlbumId { get; set; } [Required, StringLength(80)] public string SongName { get; set; } [StringLength(5)] public string SongLength { get; set; } } public class Album { public string Id { get; set; } [Required, StringLength(80)] public string AlbumName { get; set; } [StringLength(80)] public string Artist { get; set; } public int YearReleased { get; set; } public DateTime Entered { get; set; } [StringLength(150)] public string AlbumImageUrl { get; set; } [StringLength(200)] public string AmazonUrl { get; set; } public virtual List<Song> Songs { get; set; } public Album() { Songs = new List<Song>(); Entered = DateTime.Now; // Poor man's unique Id off GUID hash Id = Guid.NewGuid().GetHashCode().ToString("x"); } public void AddSong(string songName, string songLength = null) { this.Songs.Add(new Song() { AlbumId = this.Id, SongName = songName, SongLength = songLength }); } } Once the model has been created, I also added an AlbumData class that generates some static data in memory that is loaded onto a static .Current member. The signature of this class looks like this and that's what I'll access to retrieve the base data:public static class AlbumData { // sample data - static list public static List<Album> Current = CreateSampleAlbumData(); /// <summary> /// Create some sample data /// </summary> /// <returns></returns> public static List<Album> CreateSampleAlbumData() { … }} You can check out the full code for the data generation online. Creating an AlbumApiController Web API shares many concepts of ASP.NET MVC, and the implementation of your API logic is done by implementing a subclass of the System.Web.Http.ApiController class. Each public method in the implemented controller is a potential endpoint for the HTTP API, as long as a matching route can be found to invoke it. The class name you create should end in Controller, which is how Web API matches the controller route value to figure out which class to invoke. Inside the controller you can implement methods that take standard .NET input parameters and return .NET values as results. Web API’s binding tries to match POST data, route values, form values or query string values to your parameters. Because the controller is configured for HTTP Verb based routing (no {action} parameter in the route), any methods that start with Getxxxx() are called by an HTTP GET operation. You can have multiple methods that match each HTTP Verb as long as the parameter signatures are different and can be matched by Web API. In Listing 3, I create an AlbumApiController with two methods to retrieve a list of albums and a single album by its title .public class AlbumApiController : ApiController { public IEnumerable<Album> GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); return albums; } public Album GetAlbum(string title) { var album = AlbumData.Current .SingleOrDefault(alb => alb.AlbumName.Contains(title)); return album; }} To access the first two requests, you can use the following URLs in your browser: http://localhost/aspnetWebApi/albumshttp://localhost/aspnetWebApi/albums/Dirty%20Deeds Note that you’re not specifying the actions of GetAlbum or GetAlbums in these URLs. Instead Web API’s routing uses HTTP GET verb to route to these methods that start with Getxxx() with the first mapping to the parameterless GetAlbums() method and the latter to the GetAlbum(title) method that receives the title parameter mapped as optional in the route. Content Negotiation When you access any of the URLs above from a browser, you get either an XML or JSON result returned back. The album list result for Chrome 17 and Internet Explorer 9 is shown Figure 3. Figure 3: Web API responses can vary depending on the browser used, demonstrating Content Negotiation in action as these two browsers send different HTTP Accept headers.   Notice that the results are not the same: Chrome returns an XML response and IE9 returns a JSON response. Whoa, what’s going on here? Shouldn’t we see the same result in both browsers? Actually, no. Web API determines what type of content to return based on Accept headers. HTTP clients, like browsers, use Accept headers to specify what kind of content they’d like to see returned. Browsers generally ask for HTML first, followed by a few additional content types. Chrome (and most other major browsers) ask for: Accept: text/html, application/xhtml+xml,application/xml; q=0.9,*/*;q=0.8 IE9 asks for: Accept: text/html, application/xhtml+xml, */* Note that Chrome’s Accept header includes application/xml, which Web API finds in its list of supported media types and returns an XML response. IE9 does not include an Accept header type that works on Web API by default, and so it returns the default format, which is JSON. This is an important and very useful feature that was missing from any previous Microsoft REST tools: Web API automatically switches output formats based on HTTP Accept headers. Nowhere in the server code above do you have to explicitly specify the output format. Rather, Web API determines what format the client is requesting based on the Accept headers and automatically returns the result based on the available formatters. This means that a single method can handle both XML and JSON results.. Using this simple approach makes it very easy to create a single controller method that can return JSON, XML, ATOM or even OData feeds by providing the appropriate Accept header from the client. By default you don’t have to worry about the output format in your code. Note that you can still specify an explicit output format if you choose, either globally by overriding the installed formatters, or individually by returning a lower level HttpResponseMessage instance and setting the formatter explicitly. More on that in a minute. Along the same lines, any content sent to the server via POST/PUT is parsed by Web API based on the HTTP Content-type of the data sent. The same formats allowed for output are also allowed on input. Again, you don’t have to do anything in your code – Web API automatically performs the deserialization from the content. Accessing Web API JSON Data with jQuery A very common scenario for Web API endpoints is to retrieve data for AJAX calls from the Web browser. Because JSON is the default format for Web API, it’s easy to access data from the server using jQuery and its getJSON() method. This example receives the albums array from GetAlbums() and databinds it into the page using knockout.js.$.getJSON("albums/", function (albums) { // make knockout template visible $(".album").show(); // create view object and attach array var view = { albums: albums }; ko.applyBindings(view); }); Figure 4 shows this and the next example’s HTML output. You can check out the complete HTML and script code at http://goo.gl/Ix33C (.html) and http://goo.gl/tETlg (.js). Figu Figure 4: The Album Display sample uses JSON data loaded from Web API.   The result from the getJSON() call is a JavaScript object of the server result, which comes back as a JavaScript array. In the code, I use knockout.js to bind this array into the UI, which as you can see, requires very little code, instead using knockout’s data-bind attributes to bind server data to the UI. Of course, this is just one way to use the data – it’s entirely up to you to decide what to do with the data in your client code. Along the same lines, I can retrieve a single album to display when the user clicks on an album. The response returns the album information and a child array with all the songs. The code to do this is very similar to the last example where we pulled the albums array:$(".albumlink").live("click", function () { var id = $(this).data("id"); // title $.getJSON("albums/" + id, function (album) { ko.applyBindings(album, $("#divAlbumDialog")[0]); $("#divAlbumDialog").show(); }); }); Here the URL looks like this: /albums/Dirty%20Deeds, where the title is the ID captured from the clicked element’s data ID attribute. Explicitly Overriding Output Format When Web API automatically converts output using content negotiation, it does so by matching Accept header media types to the GlobalConfiguration.Configuration.Formatters and the SupportedMediaTypes of each individual formatter. You can add and remove formatters to globally affect what formats are available and it’s easy to create and plug in custom formatters.The example project includes a JSONP formatter that can be plugged in to provide JSONP support for requests that have a callback= querystring parameter. Adding, removing or replacing formatters is a global option you can use to manipulate content. It’s beyond the scope of this introduction to show how it works, but you can review the sample code or check out my blog entry on the subject (http://goo.gl/UAzaR). If automatic processing is not desirable in a particular Controller method, you can override the response output explicitly by returning an HttpResponseMessage instance. HttpResponseMessage is similar to ActionResult in ASP.NET MVC in that it’s a common way to return an abstract result message that contains content. HttpResponseMessage s parsed by the Web API framework using standard interfaces to retrieve the response data, status code, headers and so on[MS2] . Web API turns every response – including those Controller methods that return static results – into HttpResponseMessage instances. Explicitly returning an HttpResponseMessage instance gives you full control over the output and lets you mostly bypass WebAPI’s post-processing of the HTTP response on your behalf. HttpResponseMessage allows you to customize the response in great detail. Web API’s attention to detail in the HTTP spec really shows; many HTTP options are exposed as properties and enumerations with detailed IntelliSense comments. Even if you’re new to building REST-based interfaces, the API guides you in the right direction for returning valid responses and response codes. For example, assume that I always want to return JSON from the GetAlbums() controller method and ignore the default media type content negotiation. To do this, I can adjust the output format and headers as shown in Listing 4.public HttpResponseMessage GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); // Create a new HttpResponse with Json Formatter explicitly var resp = new HttpResponseMessage(HttpStatusCode.OK); resp.Content = new ObjectContent<IEnumerable<Album>>( albums, new JsonMediaTypeFormatter()); // Get Default Formatter based on Content Negotiation //var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); resp.Headers.ConnectionClose = true; resp.Headers.CacheControl = new CacheControlHeaderValue(); resp.Headers.CacheControl.Public = true; return resp; } This example returns the same IEnumerable<Album> value, but it wraps the response into an HttpResponseMessage so you can control the entire HTTP message result including the headers, formatter and status code. In Listing 4, I explicitly specify the formatter using the JsonMediaTypeFormatter to always force the content to JSON.  If you prefer to use the default content negotiation with HttpResponseMessage results, you can create the Response instance using the Request.CreateResponse method:var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); This provides you an HttpResponse object that's pre-configured with the default formatter based on Content Negotiation. Once you have an HttpResponse object you can easily control most HTTP aspects on this object. What's sweet here is that there are many more detailed properties on HttpResponse than the core ASP.NET Response object, with most options being explicitly configurable with enumerations that make it easy to pick the right headers and response codes from a list of valid codes. It makes HTTP features available much more discoverable even for non-hardcore REST/HTTP geeks. Non-Serialized Results The output returned doesn’t have to be a serialized value but can also be raw data, like strings, binary data or streams. You can use the HttpResponseMessage.Content object to set a number of common Content classes. Listing 5 shows how to return a binary image using the ByteArrayContent class from a Controller method. [HttpGet] public HttpResponseMessage AlbumArt(string title) { var album = AlbumData.Current.FirstOrDefault(abl => abl.AlbumName.StartsWith(title)); if (album == null) { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found")); return resp; } // kinda silly - we would normally serve this directly // but hey - it's a demo. var http = new WebClient(); var imageData = http.DownloadData(album.AlbumImageUrl); // create response and return var result = new HttpResponseMessage(HttpStatusCode.OK); result.Content = new ByteArrayContent(imageData); result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg"); return result; } The image retrieval from Amazon is contrived, but it shows how to return binary data using ByteArrayContent. It also demonstrates that you can easily return multiple types of content from a single controller method, which is actually quite common. If an error occurs - such as a resource can’t be found or a validation error – you can return an error response to the client that’s very specific to the error. In GetAlbumArt(), if the album can’t be found, we want to return a 404 Not Found status (and realistically no error, as it’s an image). Note that if you are not using HTTP Verb-based routing or not accessing a method that starts with Get/Post etc., you have to specify one or more HTTP Verb attributes on the method explicitly. Here, I used the [HttpGet] attribute to serve the image. Another option to handle the error could be to return a fixed placeholder image if no album could be matched or the album doesn’t have an image. When returning an error code, you can also return a strongly typed response to the client. For example, you can set the 404 status code and also return a custom error object (ApiMessageError is a class I defined) like this:return Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found") );   If the album can be found, the image will be returned. The image is downloaded into a byte[] array, and then assigned to the result’s Content property. I created a new ByteArrayContent instance and assigned the image’s bytes and the content type so that it displays properly in the browser. There are other content classes available: StringContent, StreamContent, ByteArrayContent, MultipartContent, and ObjectContent are at your disposal to return just about any kind of content. You can create your own Content classes if you frequently return custom types and handle the default formatter assignments that should be used to send the data out . Although HttpResponseMessage results require more code than returning a plain .NET value from a method, it allows much more control over the actual HTTP processing than automatic processing. It also makes it much easier to test your controller methods as you get a response object that you can check for specific status codes and output messages rather than just a result value. Routing Again Ok, let’s get back to the image example. Using the original routing we have setup using HTTP Verb routing there's no good way to serve the image. In order to return my album art image I’d like to use a URL like this: http://localhost/aspnetWebApi/albums/Dirty%20Deeds/image In order to create a URL like this, I have to create a new Controller because my earlier routes pointed to the AlbumApiController using HTTP Verb routing. HTTP Verb based routing is great for representing a single set of resources such as albums. You can map operations like add, delete, update and read easily using HTTP Verbs. But you cannot mix action based routing into a an HTTP Verb routing controller - you can only map HTTP Verbs and each method has to be unique based on parameter signature. You can't have multiple GET operations to methods with the same signature. So GetImage(string id) and GetAlbum(string title) are in conflict in an HTTP GET routing scenario. In fact, I was unable to make the above Image URL work with any combination of HTTP Verb plus Custom routing using the single Albums controller. There are number of ways around this, but all involve additional controllers.  Personally, I think it’s easier to use explicit Action routing and then add custom routes if you need to simplify your URLs further. So in order to accommodate some of the other examples, I created another controller – AlbumRpcApiController – to handle all requests that are explicitly routed via actions (/albums/rpc/AlbumArt) or are custom routed with explicit routes defined in the HttpConfiguration. I added the AlbumArt() method to this new AlbumRpcApiController class. For the image URL to work with the new AlbumRpcApiController, you need a custom route placed before the default route from Listing 1.RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); Now I can use either of the following URLs to access the image: Custom route: (/albums/rpc/{title}/image)http://localhost/aspnetWebApi/albums/PowerAge/image Action route: (/albums/rpc/action/{title})http://localhost/aspnetWebAPI/albums/rpc/albumart/PowerAge Sending Data to the Server To send data to the server and add a new album, you can use an HTTP POST operation. Since I’m using HTTP Verb-based routing in the original AlbumApiController, I can implement a method called PostAlbum()to accept a new album from the client. Listing 6 shows the Web API code to add a new album.public HttpResponseMessage PostAlbum(Album album) { if (!this.ModelState.IsValid) { // my custom error class var error = new ApiMessageError() { message = "Model is invalid" }; // add errors into our client error model for client foreach (var prop in ModelState.Values) { var modelError = prop.Errors.FirstOrDefault(); if (!string.IsNullOrEmpty(modelError.ErrorMessage)) error.errors.Add(modelError.ErrorMessage); else error.errors.Add(modelError.Exception.Message); } return Request.CreateResponse<ApiMessageError>(HttpStatusCode.Conflict, error); } // update song id which isn't provided foreach (var song in album.Songs) song.AlbumId = album.Id; // see if album exists already var matchedAlbum = AlbumData.Current .SingleOrDefault(alb => alb.Id == album.Id || alb.AlbumName == album.AlbumName); if (matchedAlbum == null) AlbumData.Current.Add(album); else matchedAlbum = album; // return a string to show that the value got here var resp = Request.CreateResponse(HttpStatusCode.OK, string.Empty); resp.Content = new StringContent(album.AlbumName + " " + album.Entered.ToString(), Encoding.UTF8, "text/plain"); return resp; } The PostAlbum() method receives an album parameter, which is automatically deserialized from the POST buffer the client sent. The data passed from the client can be either XML or JSON. Web API automatically figures out what format it needs to deserialize based on the content type and binds the content to the album object. Web API uses model binding to bind the request content to the parameter(s) of controller methods. Like MVC you can check the model by looking at ModelState.IsValid. If it’s not valid, you can run through the ModelState.Values collection and check each binding for errors. Here I collect the error messages into a string array that gets passed back to the client via the result ApiErrorMessage object. When a binding error occurs, you’ll want to return an HTTP error response and it’s best to do that with an HttpResponseMessage result. In Listing 6, I used a custom error class that holds a message and an array of detailed error messages for each binding error. I used this object as the content to return to the client along with my Conflict HTTP Status Code response. If binding succeeds, the example returns a string with the name and date entered to demonstrate that you captured the data. Normally, a method like this should return a Boolean or no response at all (HttpStatusCode.NoConent). The sample uses a simple static list to hold albums, so once you’ve added the album using the Post operation, you can hit the /albums/ URL to see that the new album was added. The client jQuery code to call the POST operation from the client with jQuery is shown in Listing 7. var id = new Date().getTime().toString(); var album = { "Id": id, "AlbumName": "Power Age", "Artist": "AC/DC", "YearReleased": 1977, "Entered": "2002-03-11T18:24:43.5580794-10:00", "AlbumImageUrl": http://ecx.images-amazon.com/images/…, "AmazonUrl": http://www.amazon.com/…, "Songs": [ { "SongName": "Rock 'n Roll Damnation", "SongLength": 3.12}, { "SongName": "Downpayment Blues", "SongLength": 4.22 }, { "SongName": "Riff Raff", "SongLength": 2.42 } ] } $.ajax( { url: "albums/", type: "POST", contentType: "application/json", data: JSON.stringify(album), processData: false, beforeSend: function (xhr) { // not required since JSON is default output xhr.setRequestHeader("Accept", "application/json"); }, success: function (result) { // reload list of albums page.loadAlbums(); }, error: function (xhr, status, p3, p4) { var err = "Error"; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); The code in Listing 7 creates an album object in JavaScript to match the structure of the .NET Album class. This object is passed to the $.ajax() function to send to the server as POST. The data is turned into JSON and the content type set to application/json so that the server knows what to convert when deserializing in the Album instance. The jQuery code hooks up success and failure events. Success returns the result data, which is a string that’s echoed back with an alert box. If an error occurs, jQuery returns the XHR instance and status code. You can check the XHR to see if a JSON object is embedded and if it is, you can extract it by de-serializing it and accessing the .message property. REST standards suggest that updates to existing resources should use PUT operations. REST standards aside, I’m not a big fan of separating out inserts and updates so I tend to have a single method that handles both. But if you want to follow REST suggestions, you can create a PUT method that handles updates by forwarding the PUT operation to the POST method:public HttpResponseMessage PutAlbum(Album album) { return PostAlbum(album); } To make the corresponding $.ajax() call, all you have to change from Listing 7 is the type: from POST to PUT. Model Binding with UrlEncoded POST Variables In the example in Listing 7 I used JSON objects to post a serialized object to a server method that accepted an strongly typed object with the same structure, which is a common way to send data to the server. However, Web API supports a number of different ways that data can be received by server methods. For example, another common way is to use plain UrlEncoded POST  values to send to the server. Web API supports Model Binding that works similar (but not the same) as MVC's model binding where POST variables are mapped to properties of object parameters of the target method. This is actually quite common for AJAX calls that want to avoid serialization and the potential requirement of a JSON parser on older browsers. For example, using jQUery you might use the $.post() method to send a new album to the server (albeit one without songs) using code like the following:$.post("albums/",{AlbumName: "Dirty Deeds", YearReleased: 1976 … },albumPostCallback); Although the code looks very similar to the client code we used before passing JSON, here the data passed is URL encoded values (AlbumName=Dirty+Deeds&YearReleased=1976 etc.). Web API then takes this POST data and maps each of the POST values to the properties of the Album object in the method's parameter. Although the client code is different the server can both handle the JSON object, or the UrlEncoded POST values. Dynamic Access to POST Data There are also a few options available to dynamically access POST data, if you know what type of data you're dealing with. If you have POST UrlEncoded values, you can dynamically using a FormsDataCollection:[HttpPost] public string PostAlbum(FormDataCollection form) { return string.Format("{0} - released {1}", form.Get("AlbumName"),form.Get("RearReleased")); } The FormDataCollection is a very simple object, that essentially provides the same functionality as Request.Form[] in ASP.NET. Request.Form[] still works if you're running hosted in an ASP.NET application. However as a general rule, while ASP.NET's functionality is always available when running Web API hosted inside of an  ASP.NET application, using the built in classes specific to Web API makes it possible to run Web API applications in a self hosted environment outside of ASP.NET. If your client is sending JSON to your server, and you don't want to map the JSON to a strongly typed object because you only want to retrieve a few simple values, you can also accept a JObject parameter in your API methods:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } There quite a few options available to you to receive data with Web API, which gives you more choices for the right tool for the job. Unfortunately one shortcoming of Web API is that POST data is always mapped to a single parameter. This means you can't pass multiple POST parameters to methods that receive POST data. It's possible to accept multiple parameters, but only one can map to the POST content - the others have to come from the query string or route values. I have a couple of Blog POSTs that explain what works and what doesn't here: Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API   Handling Delete Operations Finally, to round out the server API code of the album example we've been discussin, here’s the DELETE verb controller method that allows removal of an album by its title:public HttpResponseMessage DeleteAlbum(string title) { var matchedAlbum = AlbumData.Current.Where(alb => alb.AlbumName == title) .SingleOrDefault(); if (matchedAlbum == null) return new HttpResponseMessage(HttpStatusCode.NotFound); AlbumData.Current.Remove(matchedAlbum); return new HttpResponseMessage(HttpStatusCode.NoContent); } To call this action method using jQuery, you can use:$(".removeimage").live("click", function () { var $el = $(this).parent(".album"); var txt = $el.find("a").text(); $.ajax({ url: "albums/" + encodeURIComponent(txt), type: "Delete", success: function (result) { $el.fadeOut().remove(); }, error: jqError }); }   Note the use of the DELETE verb in the $.ajax() call, which routes to DeleteAlbum on the server. DELETE is a non-content operation, so you supply a resource ID (the title) via route value or the querystring. Routing Conflicts In all requests with the exception of the AlbumArt image example shown so far, I used HTTP Verb routing that I set up in Listing 1. HTTP Verb Routing is a recommendation that is in line with typical REST access to HTTP resources. However, it takes quite a bit of effort to create REST-compliant API implementations based only on HTTP Verb routing only. You saw one example that didn’t really fit – the return of an image where I created a custom route albums/{title}/image that required creation of a second controller and a custom route to work. HTTP Verb routing to a controller does not mix with custom or action routing to the same controller because of the limited mapping of HTTP verbs imposed by HTTP Verb routing. To understand some of the problems with verb routing, let’s look at another example. Let’s say you create a GetSortableAlbums() method like this and add it to the original AlbumApiController accessed via HTTP Verb routing:[HttpGet] public IQueryable<Album> SortableAlbums() { var albums = AlbumData.Current; // generally should be done only on actual queryable results (EF etc.) // Done here because we're running with a static list but otherwise might be slow return albums.AsQueryable(); } If you compile this code and try to now access the /albums/ link, you get an error: Multiple Actions were found that match the request. HTTP Verb routing only allows access to one GET operation per parameter/route value match. If more than one method exists with the same parameter signature, it doesn’t work. As I mentioned earlier for the image display, the only solution to get this method to work is to throw it into another controller. Because I already set up the AlbumRpcApiController I can add the method there. First, I should rename the method to SortableAlbums() so I’m not using a Get prefix for the method. This also makes the action parameter look cleaner in the URL - it looks less like a method and more like a noun. I can then create a new route that handles direct-action mapping:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); As I am explicitly adding a route segment – rpc – into the route template, I can now reference explicit methods in the Web API controller using URLs like this: http://localhost/AspNetWebApi/rpc/SortableAlbums Error Handling I’ve already done some minimal error handling in the examples. For example in Listing 6, I detected some known-error scenarios like model validation failing or a resource not being found and returning an appropriate HttpResponseMessage result. But what happens if your code just blows up or causes an exception? If you have a controller method, like this:[HttpGet] public void ThrowException() { throw new UnauthorizedAccessException("Unauthorized Access Sucka"); } You can call it with this: http://localhost/AspNetWebApi/albums/rpc/ThrowException The default exception handling displays a 500-status response with the serialized exception on the local computer only. When you connect from a remote computer, Web API throws back a 500  HTTP Error with no data returned (IIS then adds its HTML error page). The behavior is configurable in the GlobalConfiguration:GlobalConfiguration .Configuration .IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Never; If you want more control over your error responses sent from code, you can throw explicit error responses yourself using HttpResponseException. When you throw an HttpResponseException the response parameter is used to generate the output for the Controller action. [HttpGet] public void ThrowError() { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.BadRequest, new ApiMessageError("Your code stinks!")); throw new HttpResponseException(resp); } Throwing an HttpResponseException stops the processing of the controller method and immediately returns the response you passed to the exception. Unlike other Exceptions fired inside of WebAPI, HttpResponseException bypasses the Exception Filters installed and instead just outputs the response you provide. In this case, the serialized ApiMessageError result string is returned in the default serialization format – XML or JSON. You can pass any content to HttpResponseMessage, which includes creating your own exception objects and consistently returning error messages to the client. Here’s a small helper method on the controller that you might use to send exception info back to the client consistently:private void ThrowSafeException(string message, HttpStatusCode statusCode = HttpStatusCode.BadRequest) { var errResponse = Request.CreateResponse<ApiMessageError>(statusCode, new ApiMessageError() { message = message }); throw new HttpResponseException(errResponse); } You can then use it to output any captured errors from code:[HttpGet] public void ThrowErrorSafe() { try { List<string> list = null; list.Add("Rick"); } catch (Exception ex) { ThrowSafeException(ex.Message); } }   Exception Filters Another more global solution is to create an Exception Filter. Filters in Web API provide the ability to pre- and post-process controller method operations. An exception filter looks at all exceptions fired and then optionally creates an HttpResponseMessage result. Listing 8 shows an example of a basic Exception filter implementation.public class UnhandledExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { HttpStatusCode status = HttpStatusCode.InternalServerError; var exType = context.Exception.GetType(); if (exType == typeof(UnauthorizedAccessException)) status = HttpStatusCode.Unauthorized; else if (exType == typeof(ArgumentException)) status = HttpStatusCode.NotFound; var apiError = new ApiMessageError() { message = context.Exception.Message }; // create a new response and attach our ApiError object // which now gets returned on ANY exception result var errorResponse = context.Request.CreateResponse<ApiMessageError>(status, apiError); context.Response = errorResponse; base.OnException(context); } } Exception Filter Attributes can be assigned to an ApiController class like this:[UnhandledExceptionFilter] public class AlbumRpcApiController : ApiController or you can globally assign it to all controllers by adding it to the HTTP Configuration's Filters collection:GlobalConfiguration.Configuration.Filters.Add(new UnhandledExceptionFilter()); The latter is a great way to get global error trapping so that all errors (short of hard IIS errors and explicit HttpResponseException errors) return a valid error response that includes error information in the form of a known-error object. Using a filter like this allows you to throw an exception as you normally would and have your filter create a response in the appropriate output format that the client expects. For example, an AJAX application can on failure expect to see a JSON error result that corresponds to the real error that occurred rather than a 500 error along with HTML error page that IIS throws up. You can even create some custom exceptions so you can differentiate your own exceptions from unhandled system exceptions - you often don't want to display error information from 'unknown' exceptions as they may contain sensitive system information or info that's not generally useful to users of your application/site. This is just one example of how ASP.NET Web API is configurable and extensible. Exception filters are just one example of how you can plug-in into the Web API request flow to modify output. Many more hooks exist and I’ll take a closer look at extensibility in Part 2 of this article in the future. Summary Web API is a big improvement over previous Microsoft REST and AJAX toolkits. The key features to its usefulness are its ease of use with simple controller based logic, familiar MVC-style routing, low configuration impact, extensibility at all levels and tight attention to exposing and making HTTP semantics easily discoverable and easy to use. Although none of the concepts used in Web API are new or radical, Web API combines the best of previous platforms into a single framework that’s highly functional, easy to work with, and extensible to boot. I think that Microsoft has hit a home run with Web API. Related Resources Where does ASP.NET Web API fit? Sample Source Code on GitHub Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API Creating a JSONP Formatter for ASP.NET Web API Removing the XML Formatter from ASP.NET Web API Applications© Rick Strahl, West Wind Technologies, 2005-2012Posted in 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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• Handling WCF Service Paths in Silverlight 4 – Relative Path Support

  - by dwahlin

  If you’re building Silverlight applications that consume data then you’re probably making calls to Web Services. We’ve been successfully using WCF along with Silverlight for several client Line of Business (LOB) applications and passing a lot of data back and forth. Due to the pain involved with updating the ServiceReferences.ClientConfig file generated by a Silverlight service proxy (see Tim Heuer’s post on that subject to see different ways to deal with it) we’ve been using our own technique to figure out the service URL. Going that route makes it a peace of cake to switch between development, staging and production environments. To start, we have a ServiceProxyBase class that handles identifying the URL to use based on the XAP file’s location (this assumes that the service is in the same Web project that serves up the XAP file). The GetServiceUrlBase() method handles this work: public class ServiceProxyBase { public ServiceProxyBase() { if (!IsDesignTime) { ServiceUrlBase = GetServiceUrlBase(); } } public string ServiceUrlBase { get; set; } public static bool IsDesignTime { get { return (Application.Current == null) || (Application.Current.GetType() == typeof (Application)); } } public static string GetServiceUrlBase() { if (!IsDesignTime) { string url = Application.Current.Host.Source.OriginalString; return url.Substring(0, url.IndexOf("/ClientBin", StringComparison.InvariantCultureIgnoreCase)); } return null; } } Silverlight 4 now supports relative paths to services which greatly simplifies things.  We changed the code above to the following: public class ServiceProxyBase { private const string ServiceUrlPath = "../Services/JobPlanService.svc"; public ServiceProxyBase() { if (!IsDesignTime) { ServiceUrl = ServiceUrlPath; } } public string ServiceUrl { get; set; } public static bool IsDesignTime { get { return (Application.Current == null) || (Application.Current.GetType() == typeof (Application)); } } public static string GetServiceUrl() { if (!IsDesignTime) { return ServiceUrlPath; } return null; } } Our ServiceProxy class derives from ServiceProxyBase and handles creating the ABC’s (Address, Binding, Contract) needed for a WCF service call. Looking through the code (mainly the constructor) you’ll notice that the service URI is created by supplying the base path to the XAP file along with the relative path defined in ServiceProxyBase:   public class ServiceProxy : ServiceProxyBase, IServiceProxy { private const string CompletedEventargs = "CompletedEventArgs"; private const string Completed = "Completed"; private const string Async = "Async"; private readonly CustomBinding _Binding; private readonly EndpointAddress _EndPointAddress; private readonly Uri _ServiceUri; private readonly Type _ProxyType = typeof(JobPlanServiceClient); public ServiceProxy() { _ServiceUri = new Uri(Application.Current.Host.Source, ServiceUrl); var elements = new BindingElementCollection { new BinaryMessageEncodingBindingElement(), new HttpTransportBindingElement { MaxBufferSize = 2147483647, MaxReceivedMessageSize = 2147483647 } }; // order of entries in collection is significant: dumb _Binding = new CustomBinding(elements); _EndPointAddress = new EndpointAddress(_ServiceUri); } #region IServiceProxy Members /// <summary> /// Used to call a WCF service operation. /// </summary> /// <typeparam name="T">The type of EventArgs that will be returned by the service operation.</typeparam> /// <param name="callback">The method to call once the WCF call returns (the callback).</param> /// <param name="parameters">Any parameters that the service operation expects.</param> public void CallService<T>(EventHandler<T> callback, params object[] parameters) where T : EventArgs { try { var proxy = new JobPlanServiceClient(_Binding, _EndPointAddress); string action = typeof (T).Name.Replace(CompletedEventargs, String.Empty); _ProxyType.GetEvent(action + Completed).AddEventHandler(proxy, callback); _ProxyType.InvokeMember(action + Async, BindingFlags.InvokeMethod, null, proxy, parameters); } catch (Exception exp) { MessageBox.Show("Unable to use ServiceProxy.CallService to retrieve data: " + exp.Message); } } #endregion } The relative path support for calling services in Silverlight 4 definitely simplifies code and is yet another good reason to move from Silverlight 3 to Silverlight 4.   For more information about onsite, online and video training, mentoring and consulting solutions for .NET, SharePoint or Silverlight please visit http://www.thewahlingroup.com.

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• Oracle Support Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1)

  - by faye.todd(at)oracle.com

  Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1) Copyright (c) 2010, Oracle Corporation. All Rights Reserved. In this Document  Purpose  Last Review Date  Instructions for the Reader  Troubleshooting Details     1. Scope and Application      2. Definitions and Classifications     3. How to Use This Guide     4. Basic AQ Propagation Troubleshooting     5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages     6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment     7. Performance Issues  References Applies to: Oracle Server - Enterprise Edition - Version: 8.1.7.0 to 11.2.0.2 - Release: 8.1.7 to 11.2Information in this document applies to any platform. Purpose This document presents a step-by-step methodology for troubleshooting and resolving problems with Advanced Queuing Propagation in both Streams and basic Advanced Queuing environments. It also serves as a master reference for other more specific notes on Oracle Streams Propagation and Advanced Queuing Propagation issues. Last Review Date December 20, 2010 Instructions for the Reader A Troubleshooting Guide is provided to assist in debugging a specific issue. When possible, diagnostic tools are included in the document to assist in troubleshooting. Troubleshooting Details 1. Scope and Application This note is intended for Database Administrators of Oracle databases where issues are being encountered with propagating messages between advanced queues, whether the queues are used for user-created messaging systems or for Oracle Streams. It contains troubleshooting steps and links to notes for further problem resolution.It can also be used a template to document a problem when it is necessary to engage Oracle Support Services. Knowing what is NOT happening can frequently speed up the resolution process by focusing solely on the pertinent problem area. This guide is divided into five parts: Section 2: Definitions and Classifications (discusses the different types and features of propagations possible - helpful for understanding the rest of the guide) Section 3: How to Use this Guide (to be used as a start part for determining the scope of the problem and what sections to consult) Section 4. Basic AQ propagation troubleshooting (applies to both AQ propagation of user enqueued and dequeued messages as well as Oracle Streams propagations) Section 5. Additional troubleshooting steps for AQ propagation of user enqueued and dequeued messages Section 6. Additional troubleshooting steps for Oracle Streams propagation Section 7. Performance issues 2. Definitions and Classifications Given the potential scope of issues that can be encountered with AQ propagation, the first recommended step is to do some basic diagnosis to determine the type of problem that is being encountered. 2.1. What Type of Propagation is Being Used? 2.1.1. Buffered Messaging For an advanced queue, messages can be maintained on disk (persistent messaging) or in memory (buffered messaging). To determine if a queue is buffered or not, reference the GV_$BUFFERED_QUEUES view. If the queue does not appear in this view, it is persistent. 2.1.2. Propagation mode - queue-to-dblink vs queue-to-queue As of 10.2, an AQ propagation can also be defined as queue-to-dblink, or queue-to-queue: queue-to-dblink: The propagation delivers messages or events from the source queue to all subscribing queues at the destination database identified by the dblink. A single propagation schedule is used to propagate messages to all subscribing queues. Hence any changes made to this schedule will affect message delivery to all the subscribing queues. This mode does not support multiple propagations from the same source queue to the same target database. queue-to-queue: Added in 10.2, this propagation mode delivers messages or events from the source queue to a specific destination queue identified on the database link. This allows the user to have fine-grained control on the propagation schedule for message delivery. This new propagation mode also supports transparent failover when propagating to a destination Oracle RAC system. With queue-to-queue propagation, you are no longer required to re-point a database link if the owner instance of the queue fails on Oracle RAC. This mode supports multiple propagations to the same target database if the target queues are different. The default is queue-to-dblink. To verify if queue-to-queue propagation is being used, in non-Streams environments query DBA_QUEUE_SCHEDULES.DESTINATION - if a remote queue is listed along with the remote database link, then queue-to-queue propagation is being used. For Streams environments, the DBA_PROPAGATION.QUEUE_TO_QUEUE column can be checked.See the following note for a method to switch between the two modes:Document 827473.1 How to alter propagation from queue-to-queue to queue-to-dblink 2.1.3. Combined Capture and Apply (CCA) for Streams In 11g Oracle Streams environments, an optimization called Combined Capture and Apply (CCA) is implemented by default when possible. Although a propagation is configured in this case, Streams does not use it; instead it passes information directly from capture to an apply receiver. To see if CCA is in use: COLUMN CAPTURE_NAME HEADING 'Capture Name' FORMAT A30COLUMN OPTIMIZATION HEADING 'CCA Mode?' FORMAT A10SELECT CAPTURE_NAME, DECODE(OPTIMIZATION,0, 'No','Yes') OPTIMIZATIONFROM V$STREAMS_CAPTURE; Also, see the following note:Document 463820.1 Streams Combined Capture and Apply in 11g 2.2. Queue Table Compatibility There are three types of queue table compatibility. In more recent databases, queue tables may be present in all three modes of compatibility: 8.0 - earliest version, deprecated in 10.2 onwards 8.1 - support added for RAC, asynchronous notification, secure queues, queue level access control, rule-based subscribers, separate storage of history information 10.0 - if the database is in 10.1-compatible mode, then the default value for queue table compatibility is 10.0 2.3. Single vs Multiple Consumer Queue Tables If more than one recipient can dequeue a message from a queue, then its queue table is multiple consumer. You can propagate messages from a multiple-consumer queue to a single-consumer queue. Propagation from a single-consumer queue to a multiple-consumer queue is not possible. 3. How to Use This Guide 3.1. Are Messages Being Propagated at All, or is the Propagation Just Slow? Run the following query on the source database for the propagation (assuming that it is running): select TOTAL_NUMBER from DBA_QUEUE_SCHEDULES where QNAME='<source_queue_name>'; If TOTAL_NUMBER is increasing, then propagation is most likely functioning, although it may be slow. For performance issues, see Section 7. 3.2. Propagation Between Persistent User-Created Queues See Sections 4 and 5 (and optionally Section 6 if performance is an issue). 3.3. Propagation Between Buffered User-Created Queues See Sections 4, 5, and 6 (and optionally Section 7 if performance is an issue). 3.4. Propagation between Oracle Streams Queues (without Combined Capture and Apply (CCA) Optimization) See Sections 4 and 6 (and optionally Section 7 if performance is an issue). 3.5. Propagation between Oracle Streams Queues (with Combined Capture and Apply (CCA) Optimization) Although an AQ propagation is not used directly in this case, some characteristics of the message transfer are inferred from the propagation parameters used. Some parts of Sections 4 and 6 still apply. 3.6. Messaging Gateway Propagations This note does not apply to Messaging Gateway propagations. 4. Basic AQ Propagation Troubleshooting 4.1. Double-check Your Code Make sure that you are consistent in your usage of the database link(s) names, queue names, etc. It may be useful to plot a diagram of which queues are connected via which database links to make sure that the logical structure is correct. 4.2. Verify that Job Queue Processes are Running 4.2.1. Versions 10.2 and Lower - DBA_JOBS Package For versions 10.2 and lower, a scheduled propagation is managed by DBMS_JOB package. The propagation is performed by job queue process background processes. Therefore we need to verify that there are sufficient processes available for the propagation process. We should have at least 4 job queue processes running and preferably more depending on the number of other jobs running in the database. It should be noted that for AQ specific work, AQ will only ever use half of the job queue processes available.An issue caused by an inadequate job queue processes parameter setting is described in the following note:Document 298015.1 Kwqjswproc:Excep After Loop: Assigning To Self 4.2.1.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; 4.2.1.2. Job Queue Processes in Memory The following command will show how many job queue processes are currentlyin use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.1.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (spids) of job queue processes involved in propagation via select p.SPID, p.PROGRAM from V$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOBand j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%'; and these SPIDs can be used to check at the operating system level that they exist.In 8i a job queue process will have a name similar to: ora_snp1_<instance_name>.In 9i onwards you will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.2.2. Version 11.1 and Above - Oracle Scheduler In version 11.1 and above, Oracle Scheduler is used to perform AQ and Streams propagations. Oracle Scheduler automatically tunes the number of slave processes for these jobs based on the load on the computer system, and the JOB_QUEUE_PROCESSES initialization parameter is only used to specify the maximum number of slave processes. Therefore, the JOB_QUEUE_PROCESSES initialization parameter does not need to be set (it defaults to a very high number), unless you want to limit the number of slaves that can be created. If JOB_QUEUE_PROCESSES = 0, no propagation jobs will run.See the following note for a discussion of Oracle Streams 11g and Oracle Scheduler:Document 1083608.1 11g Streams and Oracle Scheduler 4.2.2.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0, and preferably be left at its default value. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; To set the JOB_QUEUE_PROCESSES parameter to its default value, run: connect / as sysdbaalter system reset JOB_QUEUE_PROCESSES; and then bounce the instance. 4.2.2.2. Job Queue Processes in Memory The following command will show how many job queue processes are currently in use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.2.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (SPIDs) of job queue processes involved in propagation via col PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_namefrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDRand jr.JOB_name=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%'; and these SPIDs can be used to check at the operating system level that they exist.You will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.3. Check the Alert Log and Any Associated Trace Files The first place to check for propagation failures is the alert logs at all sites (local and if relevant all remote sites). When a job queue process attempts to execute a schedule and fails it will always write an error stack to the alert log. This error stack will also be written in a job queue process trace file, which will be written to the BACKGROUND_DUMP_DEST location for 10.2 and below, and in the DIAGNOSTIC_DEST location for 11g. The fact that errors are written to the alert log demonstrates that the schedule is executing. This means that the problem could be with the set up of the schedule. In this example the ORA-02068 demonstrates that the failure was at the remote site. Further investigation revealed that the remote database was not open, hence the ORA-03114 error. Starting the database resolved the problem. Thu Feb 14 10:40:05 2002 Propagation Schedule for (AQADM.MULTIPLEQ, SHANE816.WORLD) encountered following error:ORA-04052: error occurred when looking up Remote object [email protected]: error occurred at recursive SQL level 4ORA-02068: following severe error from SHANE816ORA-03114: not connected to ORACLEORA-06512: at "SYS.DBMS_AQADM_SYS", line 4770ORA-06512: at "SYS.DBMS_AQADM", line 548ORA-06512: at line 1 Other potential errors that may be written to the alert log can be found in the following notes:Document 827184.1 AQ Propagation with CLOB data types Fails with ORA-22990 (11.1)Document 846297.1 AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn] (10.2, 11.1)Document 731292.1 ORA-25215 Reported on Local Propagation When Using Transformation with ANYDATA queue tables (10.2, 11.1, 11.2)Document 365093.1 ORA-07445 [kwqppay2aqe()+7360] Reported on Propagation of a Transformed Message (10.1, 10.2)Document 219416.1 Advanced Queuing Propagation Fails with ORA-22922 (9.0)Document 1203544.1 AQ Propagation Aborted with ORA-600 [ociksin: invalid status] on SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE After Upgrade (11.1, 11.2)Document 1087324.1 ORA-01405 ORA-01422 reported by Advanced Queuing Propagation schedules after RAC reconfiguration (10.2)Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370 incorrect usage of method" (9.2, 10.2, 11.1, 11.2)Document 332792.1 ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up Statspack (8.1, 9.0, 9.2, 10.1)Document 353325.1 ORA-24056: Internal inconsistency for QUEUE <queue_name> and destination <dblink> (8.1, 9.0, 9.2, 10.1, 10.2, 11.1, 11.2)Document 787367.1 ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2 (10.1, 10.2)Document 566622.1 ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1 (9.2, 10.1)Document 731539.1 ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTP (9.0, 9.2, 10.1, 10.2, 11.1)Document 253131.1 Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555) (9.2)Document 118884.1 How to unschedule a propagation schedule stuck in pending stateDocument 222992.1 DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 1204080.1 AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.Document 1233675.1 AQ Propagation stops after upgrade to 11.2.0.1 ORA-30757 4.3.1. Errors Related to Incorrect Network Configuration The most common propagation errors result from an incorrect network configuration. The list below contains common errors caused by tnsnames.ora file or database links being configured incorrectly: - ORA-12154: TNS:could not resolve service name- ORA-12505: TNS:listener does not currently know of SID given in connect descriptor- ORA-12514: TNS:listener could not resolve SERVICE_NAME - ORA-12541: TNS-12541 TNS:no listener 4.4. Check the Database Links Exist and are Functioning Correctly For schedules to remote databases confirm the database link exists via. SQL> col DBLINK for a45SQL> select QNAME, NVL(REGEXP_SUBSTR(DESTINATION, '[^@]+', 1, 2), DESTINATION) dblink2 from DBA_QUEUE_SCHEDULES3 where MESSAGE_DELIVERY_MODE = 'PERSISTENT';QNAME DBLINK------------------------------ ---------------------------------------------MY_QUEUE ORCL102B.WORLD Connect as the owner of the link and select across it to verify it works and connects to the database we expect. i.e. select * from ALL_QUEUES@ ORCL102B.WORLD; You need to ensure that the userid that scheduled the propagation (using DBMS_AQADM.SCHEDULE_PROPAGATION or DBMS_PROPAGATION_ADM.CREATE_PROPAGATION if using Streams) has access to the database link for the destination. 4.5. Has Propagation Been Correctly Scheduled? Check that the propagation schedule has been created and that a job queue process has been assigned. Look for the entry in DBA_QUEUE_SCHEDULES and SYS.AQ$_SCHEDULES for your schedule. For 10g and below, check that it has a JOBNO entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_JOBS with that JOBNO. For 11g and above, check that the schedule has a JOB_NAME entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_SCHEDULER_JOBS with that JOB_NAME. Check the destination is as intended and spelled correctly. SQL> select SCHEMA, QNAME, DESTINATION, SCHEDULE_DISABLED, PROCESS_NAME from DBA_QUEUE_SCHEDULES;SCHEMA QNAME DESTINATION S PROCESS------- ---------- ------------------ - -----------AQADM MULTIPLEQ AQ$_LOCAL N J000 AQ$_LOCAL in the destination column shows that the queue to which we are propagating to is in the same database as the source queue. If the propagation was to a remote (different) database, a database link will be in the DESTINATION column. The entry in the SCHEDULE_DISABLED column, N, means that the schedule is NOT disabled. If Y (yes) appears in this column, propagation is disabled and the schedule will not be executed. If not using Oracle Streams, propagation should resume once you have enabled the schedule by invoking DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE (for 10.2 Oracle Streams and above, the DBMS_PROPAGATION_ADM.START_PROPAGATION procedure should be used). The PROCESS_NAME is the name of the job queue process currently allocated to execute the schedule. This process is allocated dynamically at execution time. If the PROCESS_NAME column is null (empty) the schedule is not currently executing. You may need to execute this statement a number of times to verify if a process is being allocated. If a process is at some time allocated to the schedule, it is attempting to execute. SQL> select SCHEMA, QNAME, LAST_RUN_DATE, NEXT_RUN_DATE from DBA_QUEUE_SCHEDULES;SCHEMA QNAME LAST_RUN_DATE NEXT_RUN_DATE------ ----- ----------------------- ----------------------- AQADM MULTIPLEQ 13-FEB-2002 13:18:57 13-FEB-2002 13:20:30 In 11g, these dates are expressed in TIMESTAMP WITH TIME ZONE datatypes. If the NEXT_RUN_DATE and NEXT_RUN_TIME columns are null when this statement is executed, the scheduled propagation is currently in progress. If they never change it would suggest that the schedule itself is never executing. If the next scheduled execution is too far away, change the NEXT_TIME parameter of the schedule so that schedules are executed more frequently (assuming that the window is not set to be infinite). Parameters of a schedule can be changed using the DBMS_AQADM.ALTER_PROPAGATION_SCHEDULE call. In 10g and below, scheduling propagation posts a job in the DBA_JOBS view. The columns are more or less the same as DBA_QUEUE_SCHEDULES so you just need to recognize the job and verify that it exists. SQL> select JOB, WHAT from DBA_JOBS where WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';JOB WHAT---- ----------------- 720 next_date := sys.dbms_aqadm.aq$_propaq(job); For 11g, scheduling propagation posts a job in DBA_SCHEDULER_JOBS instead: SQL> select JOB_NAME from DBA_SCHEDULER_JOBS where JOB_NAME like 'AQ_JOB$_%';JOB_NAME------------------------------AQ_JOB$_41 If no job exists, check DBA_QUEUE_SCHEDULES to make sure that the schedule has not been disabled. For 10g and below, the job number is dynamic for AQ propagation schedules. The procedure that is executed to expedite a propagation schedule runs, removes itself from DBA_JOBS, and then reposts a new job for the next scheduled propagation. The job number should therefore always increment unless the schedule has been set up to run indefinitely. 4.6. Is the Schedule Executing but Failing to Complete? Run the following query: SQL> select FAILURES, LAST_ERROR_MSG from DBA_QUEUE_SCHEDULES;FAILURES LAST_ERROR_MSG------------ -----------------------1 ORA-25207: enqueue failed, queue AQADM.INQ is disabled from enqueueingORA-02063: preceding line from SHANE816 The failures column shows how many times we have attempted to execute the schedule and failed. Oracle will attempt to execute the schedule 16 times after which it will be removed from the DBA_JOBS or DBA_SCHEDULER_JOBS view and the schedule will become disabled. The column DBA_QUEUE_SCHEDULES.SCHEDULE_DISABLED will show 'Y'. For 11g and above, the DBA_SCHEDULER_JOBS.STATE column will show 'BROKEN' for the job corresponding to DBA_QUEUE_SCHEDULES.JOB_NAME. Prior to 10g the back off algorithm for failures was exponential, whereas from 10g onwards it is linear. The propagation will become disabled on the 17th attempt. Only the last execution failure will be reflected in the LAST_ERROR_MSG column. That is, if the schedule fails 5 times for 5 different reasons, only the last set of errors will be recorded in DBA_QUEUE_SCHEDULES. Any errors need to be resolved to allow propagation to continue. If propagation has also become disabled due to 17 failures, first resolve the reason for the error and then re-enable the schedule using the DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE procedure, or DBMS_PROPAGATION_ADM.START_PROPAGATION if using 10.2 or above Oracle Streams. As soon as the schedule executes successfully the error message entries will be deleted. Oracle does not keep a history of past failures. However, when using Oracle Streams, the errors will be retained in the DBA_PROPAGATION view even after the schedule resumes successfully. See the following note for instructions on how to clear out the errors from the DBA_PROPAGATION view:Document 808136.1 How to clear the old errors from DBA_PROPAGATION view?If a schedule is active and no errors are being reported then the source queue may not have any messages to be propagated. 4.7. Do the Propagation Notification Queue Table and Queue Exist? Check to see that the propagation notification queue table and queue exist and are enabled for enqueue and dequeue. Propagation makes use of the propagation notification queue for handling propagation run-time events, and the messages in this queue are stored in a SYS-owned queue table. This queue should never be stopped or dropped and the corresponding queue table never be dropped. 10g and belowThe propagation notification queue table is of the format SYS.AQ$_PROP_TABLE_n, where 'n' is the RAC instance number, i.e. '1' for a non-RAC environment. This queue and queue table are created implicitly when propagation is first scheduled. If propagation has been scheduled and these objects do not exist, try unscheduling and rescheduling propagation. If they still do not exist contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ$_PROP_TABLE_1SQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ$_PROP_NOTIFY_1 YES YESAQ$_AQ$_PROP_TABLE_1_E NO NO If the AQ$_PROP_NOTIFY_1 queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_1_E should not be enabled for enqueue or dequeue.11g and aboveThe propagation notification queue table is of the format SYS.AQ_PROP_TABLE, and is created when the database is created. If they do not exist, contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ_PROP_TABLESQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ_PROP_NOTIFY YES YESAQ$_AQ_PROP_TABLE_E NO NO If the AQ_PROP_NOTIFY queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_E should not be enabled for enqueue or dequeue. 4.8. Does the Remote Queue Exist and is it Enabled for Enqueueing? Check that the remote queue the propagation is transferring messages to exists and is enabled for enqueue: SQL> select DESTINATION from USER_QUEUE_SCHEDULES where QNAME = 'OUTQ';DESTINATION-----------------------------------------------------------------------------"AQADM"."INQ"@M2V102.ESSQL> select OWNER, NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED from [email protected];OWNER NAME ENQUEUE DEQUEUE-------- ------ ----------- -----------AQADM INQ YES YES 4.9. Do the Target and Source Database Charactersets Differ? If a message fails to propagate, check the database charactersets of the source and target databases. Investigate whether the same message can propagate between the databases with the same characterset or it is only a particular combination of charactersets which causes a problem. 4.10. Check the Queue Table Type Agreement Propagation is not possible between queue tables which have types that differ in some respect. One way to determine if this is the case is to run the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure for the two queues that the propagation operates on. If the types do not agree, DBMS_AQADM.VERIFY_QUEUE_TYPES will return '0'.For AQ propagation between databases which have different NLS_LENGTH_SEMANTICS settings, propagation will not work, unless the queues are Oracle Streams ANYDATA queues.See the following notes for issues caused by lack of type agreement:Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 353754.1 Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT 4.11. Enable Propagation Tracing 4.11.1. System Level This is set it in the init.ora/spfile as follows: event="24040 trace name context forever, level 10" and restart the instanceThis event cannot be set dynamically with an alter system command until version 10.2: SQL> alter system set events '24040 trace name context forever, level 10'; To unset the event: SQL> alter system set events '24040 trace name context off'; Debugging information will be logged to job queue trace file(s) (jnnn) as propagation takes place. You can check the trace file for errors, and for statements indicating that messages have been sent. For the most part the trace information is understandable. This trace should also be uploaded to Oracle Support if a service request is created. 4.11.2. Attaching to a Specific Process We can also attach to an existing job queue processes that is running a propagation schedule and trace it individually using the oradebug utility, as follows:10.2 and below connect / as sysdbaselect p.SPID, p.PROGRAM from v$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 11g connect / as sysdbacol PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_NAMEfrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 4.11.3. Further Tracing The previous tracing steps only trace the job queue process executing the propagation on the source. At times it is useful to trace the propagation receiver process (the session which is enqueueing the messages into the target queue) on the target database which is associated with the job queue process on the source database.These following queries provide ways of identifying the processes involved in propagation so that you can attach to them via oradebug to generate trace information.In order to identify the propagation receiver process you need to execute the query as a user with privileges to access the v$ views in both the local and remote databases so the database link must connect as a user with those privileges in the remote database. The <DBLINK> in the queries should be replaced by the appropriate database link.The queries have two forms due to the differences between operating systems. The value returned by 'Rem Process' is the operating system identifier of the propagation receiver on the remote database. Once identified, this process can be attached to and traced on the remote database using the commands given in Section 4.11.2.10.2 and below - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from v$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 10.2 and below - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=sr.PROCESS; 11g - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 11g - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=sr.PROCESS;   5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages 5.1. Check the Privileges of All Users Involved Ensure that the owner of the database link has the necessary privileges on the aq packages. SQL> select TABLE_NAME, PRIVILEGE from USER_TAB_PRIVS;TABLE_NAME PRIVILEGE------------------------------ ----------------------------------------DBMS_LOCK EXECUTEDBMS_AQ EXECUTEDBMS_AQADM EXECUTEDBMS_AQ_BQVIEW EXECUTEQT52814_BUFFER SELECT Note that when queue table is created, a view called QT<nnn>_BUFFER is created in the SYS schema, and the queue table owner is given SELECT privileges on it. The <nnn> corresponds to the object_id of the associated queue table. SQL> select * from USER_ROLE_PRIVS;USERNAME GRANTED_ROLE ADM DEF OS_------------------------------ ------------------------------ ---- ---- ---AQ_USER1 AQ_ADMINISTRATOR_ROLE NO YES NOAQ_USER1 CONNECT NO YES NOAQ_USER1 RESOURCE NO YES NO It is good practice to configure central AQ administrative user. All admin and processing jobs are created, executed and administered as this user. This configuration is not mandatory however, and the database link can be owned by any existing queue user. If this latter configuration is used, ensure that the connecting user has the necessary privileges on the AQ packages and objects involved. Privileges for an AQ Administrative user Execute on DBMS_AQADM Execute on DBMS_AQ Granted the AQ_ADMINISTRATOR_ROLE Privileges for an AQ user Execute on DBMS_AQ Execute on the message payload Enqueue privileges on the remote queue Dequeue privileges on the originating queue Privileges need to be confirmed on both sites when propagation is scheduled to remote destinations. Verify that the user ID used to login to the destination through the database link has been granted privileges to use AQ. 5.2. Verify Queue Payload Types AQ will not propagate messages from one queue to another if the payload types of the two queues are not verified to be equivalent. An AQ administrator can verify if the source and destination's payload types match by executing the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure. The results of the type checking will be stored in the SYS.AQ$_MESSAGE_TYPES table. This table can be accessed using the object identifier OID of the source queue and the address database link of the destination queue, i.e. [schema.]queue_name[@destination]. Prior to Oracle 9i the payload (message type) had to be the same for all the queue tables involved in propagation. From Oracle9i onwards a transformation can be used so that payloads can be converted from one type to another. The following procedural call made on the source database can verify whether we can propagate between the source and the destination queue tables. connect aq_user1/[email protected] serverout onDECLARErc_value number;BEGINDBMS_AQADM.VERIFY_QUEUE_TYPES(src_queue_name => 'AQ_USER1.Q_1', dest_queue_name => 'AQ_USER2.Q_2',destination => 'dbl_aq_user2.es',rc => rc_value);dbms_output.put_line('rc_value code is '||rc_value);END;/ If propagation is possible then the return code value will be 1. If it is 0 then propagation is not possible and further investigation of the types and transformations used by and in conjunction with the queue tables is required. With regard to comparison of the types the following sql can be used to extract the DDL for a specific type with' %' changed appropriately on the source and target. This can then be compared for the source and target. SET LONG 20000 set pagesize 50 EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'STORAGE',false); SELECT DBMS_METADATA.GET_DDL('TYPE',t.type_name) from user_types t WHERE t.type_name like '%'; EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'DEFAULT'); 5.3. Check Message State and Destination The first step in this process is to identify the queue table associated with the problem source queue. Although you schedule propagation for a specific queue, most of the meta-data associated with that queue is stored in the underlying queue table. The following statement finds the queue table for a given queue (note that this is a multiple-consumer queue table). SQL> select QUEUE_TABLE from DBA_QUEUES where NAME = 'MULTIPLEQ';QUEUE_TABLE --------------------MULTIPLEQTABLE For a small amount of messages in a multiple-consumer queue table, the following query can be run: SQL> select MSG_STATE, CONSUMER_NAME, ADDRESS from AQ$MULTIPLEQTABLE where QUEUE = 'MULTIPLEQ';MSG_STATE CONSUMER_NAME ADDRESS-------------- ----------------------- -------------READY AQUSER2 [email protected] AQUSER1READY AQUSER3 AQADM.INQ In this example we see 2 messages ready to be propagated to remote queues and 1 that is not. If the address column is blank, the message is not scheduled for propagation and can only be dequeued from the queue upon which it was enqueued. The MSG_STATE column values are discussed in Document 102330.1 Advanced Queueing MSG_STATE Values and their Interpretation. If the address column has a value, the message has been enqueued for propagation to another queue. The first row in the example includes a database link (@M2V102.ES). This demonstrates that the message should be propagated to a queue at a remote database. The third row does not include a database link so will be propagated to a queue that resides on the same database as the source queue. The consumer name is the intended recipient at the target queue. Note that we are not querying the base queue table directly; rather, we are querying a view that is available on top of every queue table, AQ$<queue_table_name>.A more realistic query in an environment where the queue table contains thousands of messages is8.0.3-compatible multiple-consumer queue table and all compatibility single-consumer queue tables select count(*), MSG_STATE, QUEUE from AQ$<queue_table_name>  group by MSG_STATE, QUEUE; 8.1.3 and 10.0-compatible queue tables select count(*), MSG_STATE, QUEUE, CONSUMER_NAME from AQ$<queue_table_name>group by MSG_STATE, QUEUE, CONSUMER_NAME; For multiple-consumer queue tables, if you did not see the expected CONSUMER_NAME , check the syntax of the enqueue code and verify the recipients are declared correctly. If a recipients list is not used on enqueue, check the subscriber list in the AQ$_<queue_table_name>_S view (note that a single-consumer queue table does not have a subscriber view. This view records all members of the default subscription list which were added using the DBMS_AQADM.ADD_SUBSCRIBER procedure and also those enqueued using a recipient list. SQL> select QUEUE, NAME, ADDRESS from AQ$MULTIPLEQTABLE_S;QUEUE NAME ADDRESS---------- ----------- -------------MULTIPLEQ AQUSER2 [email protected] AQUSER1 In this example we have 2 subscribers registered with the queue. We have a local subscriber AQUSER1, and a remote subscriber AQUSER2, on the queue INQ, owned by AQADM, at M2V102.ES. Unless overridden with a recipient list during enqueue every message enqueued to this queue will be propagated to INQ at M2V102.ES.For 8.1 style and above multiple consumer queue tables, you can also check the following information at the target: select CONSUMER_NAME, DEQ_TXN_ID, DEQ_TIME, DEQ_USER_ID, PROPAGATED_MSGID from AQ$<queue_table_name> where QUEUE = '<QUEUE_NAME>'; For 8.0 style queues, if the queue table supports multiple consumers you can obtain the same information from the history column of the queue table: select h.CONSUMER, h.TRANSACTION_ID, h.DEQ_TIME, h.DEQ_USER, h.PROPAGATED_MSGIDfrom AQ$<queue_table_name> t, table(t.history) h where t.Q_NAME = '<QUEUE_NAME>'; A non-NULL TRANSACTION_ID indicates that the message was successfully propagated. Further, the DEQ_TIME indicates the time of propagation, the DEQ_USER indicates the userid used for propagation, and the PROPAGATED_MSGID indicates the message ID of the message that was enqueued at the destination. 6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment 6.1. Is the Propagation Enabled? For a propagation job to propagate messages, the propagation must be enabled. For Streams, a special view called DBA_PROPAGATION exists to convey information about Streams propagations. If messages are not being propagated by a propagation as expected, then the propagation might not be enabled. To query for this: SELECT p.PROPAGATION_NAME, DECODE(s.SCHEDULE_DISABLED, 'Y', 'Disabled','N', 'Enabled') SCHEDULE_DISABLED, s.PROCESS_NAME, s.FAILURES, s.LAST_ERROR_MSGFROM DBA_QUEUE_SCHEDULES s, DBA_PROPAGATION pWHERE p.DESTINATION_DBLINK = NVL(REGEXP_SUBSTR(s.DESTINATION, '[^@]+', 1, 2), s.DESTINATION) AND s.SCHEMA = p.SOURCE_QUEUE_OWNER AND s.QNAME = p.SOURCE_QUEUE_NAME AND MESSAGE_DELIVERY_MODE = 'PERSISTENT' order by PROPAGATION_NAME; At times, the propagation job may become "broken" or fail to start after an error has been encountered or after a database restart. If an error is indicated by the above query, an attempt to disable the propagation and then re-enable it can be made. In the examples below, for the propagation named STRMADMIN_PROPAGATE where the queue name is STREAMS_QUEUE owned by STRMADMIN and the destination database link is ORCL2.WORLD, the commands would be:10.2 and above exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE'); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); If the above does not fix the problem, stop the propagation specifying the force parameter (2nd parameter on stop_propagation) as TRUE: exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE',true); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); The statistics for the propagation as well as any old error messages are cleared when the force parameter is set to TRUE. Therefore if the propagation schedule is stopped with FORCE set to TRUE, and upon restart there is still an error message in DBA_PROPAGATION, then the error message is current.9.2 or 10.1 exec dbms_aqadm.disable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms.aqadm.enable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); If the above does not fix the problem, perform an unschedule of propagation and then schedule_propagation: exec dbms_aqadm.unschedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms_aqadm.schedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); Typically if the error from the first query in Section 6.1 recurs after restarting the propagation as shown above, further troubleshooting of the error is needed. 6.2. Check Propagation Rule Sets and Transformations Inspect the configuration of the rules in the rule set that is associated with the propagation process to make sure that they evaluate to TRUE as expected. If not, then the object or schema will not be propagated. Remember that when a negative rule evaluates to TRUE, the specified object or schema will not be propagated. Finally inspect any rule-based transformations that are implemented with propagation to make sure they are changing the data in the intended way.The following query shows what rule sets are assigned to a propagation: select PROPAGATION_NAME, RULE_SET_OWNER||'.'||RULE_SET_NAME "Positive Rule Set",NEGATIVE_RULE_SET_OWNER||'.'||NEGATIVE_RULE_SET_NAME "Negative Rule Set"from DBA_PROPAGATION; The next two queries list the propagation rules and their conditions. The first is for the positive rule set, the second is for the negative rule set: set long 4000select rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES rwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER and RULE_SET_NAME in(select RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME;   set long 4000select c.PROPAGATION_NAME, rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES r ,DBA_PROPAGATION cwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER andrsr.RULE_SET_OWNER=c.NEGATIVE_RULE_SET_OWNER and rsr.RULE_SET_NAME=c.NEGATIVE_RULE_SET_NAMEand rsr.RULE_SET_NAME in(select NEGATIVE_RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME; 6.3. Determining the Total Number of Messages and Bytes Propagated As in Section 3.1, determining if messages are flowing can be instructive to see whether the propagation is entirely hung or just slow. If the propagation is not in flow control (see Section 6.5.2), but the statistics are incrementing slowly, there may be a performance issue. For Streams implementations two views are available that can assist with this that can show the number of messages sent by a propagation, as well as the number of acknowledgements being returned from the target site: the V$PROPAGATION_SENDER view at the Source site and the V$PROPAGATION_RECEIVER view at the destination site. It is helpful to query both to determine if messages are being delivered to the target. Look for the statistics to increase.Source: select QUEUE_SCHEMA, QUEUE_NAME, DBLINK,HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS, TOTAL_BYTESfrom V$PROPAGATION_SENDER; Target: select SRC_QUEUE_SCHEMA, SRC_QUEUE_NAME, SRC_DBNAME, DST_QUEUE_SCHEMA, DST_QUEUE_NAME, HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS from V$PROPAGATION_RECEIVER; 6.4. Check Buffered Subscribers The V$BUFFERED_SUBSCRIBERS view displays information about subscribers for all buffered queues in the instance. This view can be queried to make sure that the site that the propagation is propagating to is listed as a subscriber address for the site being propagated from: select QUEUE_SCHEMA, QUEUE_NAME, SUBSCRIBER_ADDRESS from V$BUFFERED_SUBSCRIBERS; The SUBSCRIBER_ADDRESS column will not be populated when the propagation is local (between queues on the same database). 6.5. Common Streams Propagation Errors 6.5.1. ORA-02082: A loopback database link must have a connection qualifier. This error can occur if you use the Streams Setup Wizard in Oracle Enterprise Manager without first configuring the GLOBAL_NAME for your database. 6.5.2. ORA-25307: Enqueue rate too high. Enable flow control DBA_QUEUE_SCHEDULES will display this informational message for propagation when the automatic flow control (10g feature of Streams) has been invoked.Similar to Streams capture processes, a Streams propagation process can also go into a state of 'flow control. This is an informative message that indicates flow control has been automatically enabled to reduce the rate at which messages are being enqueued into at target queue.This typically occurs when the target site is unable to keep up with the rate of messages flowing from the source site. Other than checking that the apply process is running normally on the target site, usually no action is required by the DBA. Propagation and the capture process will be resumed automatically when the target site is able to accept more messages.The following document contains more information:Document 302109.1 Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlSee the following document for one potential cause of this situation:Document 1097115.1 Oracle Streams Apply Reader is in 'Paused' State 6.5.3. ORA-25315 unsupported configuration for propagation of buffered messages This error typically occurs when the target database is RAC and usually indicates that an attempt was made to propagate buffered messages with the database link pointing to an instance in the destination database which is not the owner instance of the destination queue. To resolve the problem, use queue-to-queue propagation for buffered messages. 6.5.4. ORA-600 [KWQBMCRCPTS101] after dropping / recreating propagation For cause/fixes refer to:Document 421237.1 ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams Propagation 6.5.5. Stopping or Dropping a Streams Propagation Hangs See the following note:Document 1159787.1 Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It Hang 6.6. Streams Propagation-Related Notes for Common Issues Document 437838.1 Streams Specific PatchesDocument 749181.1 How to Recover Streams After Dropping PropagationDocument 368912.1 Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentDocument 564649.1 ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveDocument 553017.1 Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201Document 944846.1 Streams Propagation Fails Ora-7445 [kohrsmc]Document 745601.1 ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'Document 333068.1 ORA-23603: Streams Enqueue Aborted Eue To Low SGADocument 363496.1 Ora-25315 Propagating on RAC StreamsDocument 368237.1 Unable to Unschedule Propagation. Streams Queue is InvalidDocument 436332.1 dbms_propagation_adm.stop_propagation hangsDocument 727389.1 Propagation Fails With ORA-12528Document 730911.1 ORA-4063 Is Reported After Dropping Negative Prop.RulesetDocument 460471.1 Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsDocument 1165583.1 ORA-600 [kwqpuspse0-ack] In Streams EnvironmentDocument 1059029.1 Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationDocument 556309.1 Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedDocument 839568.1 Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''Document 311021.1 Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredDocument 359971.1 STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068Document 1101616.1 DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747 7. Performance Issues A propagation may seem to be slow if the queries from Sections 3.1 and 6.3 show that the message statistics are not changing quickly. In Oracle Streams, this more usually is due to a slow apply process at the target rather than a slow propagation. Propagation could be inferred to be slow if the message statistics are changing, and the state of a capture process according to V$STREAMS_CAPTURE.STATE is PAUSED FOR FLOW CONTROL, but an ORA-25307 'Enqueue rate too high. Enable flow control' warning is NOT observed in DBA_QUEUE_SCHEDULES per Section 6.5.2. If this is the case, see the following notes / white papers for suggestions to increase performance:Document 335516.1 Master Note for Streams Performance RecommendationsDocument 730036.1 Overview for Troubleshooting Streams Performance IssuesDocument 780733.1 Streams Propagation Tuning with Network ParametersWhite Paper: http://www.oracle.com/technetwork/database/features/availability/maa-wp-10gr2-streams-performance-130059.pdfWhite Paper: Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2, http://www.oracle.com/technetwork/database/features/availability/maa-10gr2-streams-configuration-132039.pdf, See APPENDIX A: USING STREAMS CONFIGURATIONS OVER A NETWORKFor basic AQ propagation, the network tuning in the aforementioned Appendix A of the white paper 'Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2' is applicable. References NOTE:102330.1 - Advanced Queueing MSG_STATE Values and their InterpretationNOTE:102771.1 - Advanced Queueing Propagation using PL/SQLNOTE:1059029.1 - Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationNOTE:1079577.1 - Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"NOTE:1083608.1 - 11g Streams and Oracle SchedulerNOTE:1087324.1 - ORA-01405 ORA-01422 reported by Adavanced Queueing Propagation schedules after RAC reconfigurationNOTE:1097115.1 - Oracle Streams Apply Reader is in 'Paused' StateNOTE:1101616.1 - DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747NOTE:1159787.1 - Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It HangNOTE:1165583.1 - ORA-600 [kwqpuspse0-ack] In Streams EnvironmentNOTE:118884.1 - How to unschedule a propagation schedule stuck in pending stateNOTE:1203544.1 - AQ PROPAGATION ABORTED WITH ORA-600[OCIKSIN: INVALID STATUS] ON SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE AFTER UPGRADENOTE:1204080.1 - AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.NOTE:219416.1 - Advanced Queuing Propagation fails with ORA-22922NOTE:222992.1 - DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082NOTE:253131.1 - Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555)NOTE:282987.1 - Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueNOTE:298015.1 - Kwqjswproc:Excep After Loop: Assigning To SelfNOTE:302109.1 - Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlNOTE:311021.1 - Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredNOTE:332792.1 - ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up StatspackNOTE:333068.1 - ORA-23603: Streams Enqueue Aborted Eue To Low SGANOTE:335516.1 - Master Note for Streams Performance RecommendationsNOTE:353325.1 - ORA-24056: Internal inconsistency for QUEUE and destination NOTE:353754.1 - Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT.NOTE:359971.1 - STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068NOTE:363496.1 - Ora-25315 Propagating on RAC StreamsNOTE:365093.1 - ORA-07445 [kwqppay2aqe()+7360] reported on Propagation of a Transformed MessageNOTE:368237.1 - Unable to Unschedule Propagation. Streams Queue is InvalidNOTE:368912.1 - Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentNOTE:421237.1 - ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams PropagationNOTE:436332.1 - dbms_propagation_adm.stop_propagation hangsNOTE:437838.1 - Streams Specific PatchesNOTE:460471.1 - Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsNOTE:463820.1 - Streams Combined Capture and Apply in 11gNOTE:553017.1 - Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201NOTE:556309.1 - Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedNOTE:564649.1 - ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveNOTE:566622.1 - ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1NOTE:727389.1 - Propagation Fails With ORA-12528NOTE:730036.1 - Overview for Troubleshooting Streams Performance IssuesNOTE:730911.1 - ORA-4063 Is Reported After Dropping Negative Prop.RulesetNOTE:731292.1 - ORA-25215 Reported On Local Propagation When Using Transformation with ANYDATA queue tablesNOTE:731539.1 - ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTPNOTE:745601.1 - ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'NOTE:749181.1 - How to Recover Streams After Dropping PropagationNOTE:780733.1 - Streams Propagation Tuning with Network ParametersNOTE:787367.1 - ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2NOTE:808136.1 - How to clear the old errors from DBA_PROPAGATION view ?NOTE:827184.1 - AQ Propagation with CLOB data types Fails with ORA-22990NOTE:827473.1 - How to alter propagation from queue_to_queue to queue_to_dblinkNOTE:839568.1 - Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''NOTE:846297.1 - AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn]NOTE:944846.1 - Streams Propagation Fails Ora-7445 [kohrsmc]

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• Subterranean IL: Pseudo custom attributes

  - by Simon Cooper

  Custom attributes were designed to make the .NET framework extensible; if a .NET language needs to store additional metadata on an item that isn't expressible in IL, then an attribute could be applied to the IL item to represent this metadata. For instance, the C# compiler uses DecimalConstantAttribute and DateTimeConstantAttribute to represent compile-time decimal or datetime constants, which aren't allowed in pure IL, and FixedBufferAttribute to represent fixed struct fields. How attributes are compiled Within a .NET assembly are a series of tables containing all the metadata for items within the assembly; for instance, the TypeDef table stores metadata on all the types in the assembly, and MethodDef does the same for all the methods and constructors. Custom attribute information is stored in the CustomAttribute table, which has references to the IL item the attribute is applied to, the constructor used (which implies the type of attribute applied), and a binary blob representing the arguments and name/value pairs used in the attribute application. For example, the following C# class: [Obsolete("Please use MyClass2", true)] public class MyClass { // ... } corresponds to the following IL class definition: .class public MyClass { .custom instance void [mscorlib]System.ObsoleteAttribute::.ctor(string, bool) = { string('Please use MyClass2' bool(true) } // ... } and results in the following entry in the CustomAttribute table: TypeDef(MyClass) MemberRef(ObsoleteAttribute::.ctor(string, bool)) blob -> {string('Please use MyClass2' bool(true)} However, there are some attributes that don't compile in this way. Pseudo custom attributes Just like there are some concepts in a language that can't be represented in IL, there are some concepts in IL that can't be represented in a language. This is where pseudo custom attributes come into play. The most obvious of these is SerializableAttribute. Although it looks like an attribute, it doesn't compile to a CustomAttribute table entry; it instead sets the serializable bit directly within the TypeDef entry for the type. This flag is fully expressible within IL; this C#: [Serializable] public class MySerializableClass {} compiles to this IL: .class public serializable MySerializableClass {} For those interested, a full list of pseudo custom attributes is available here. For the rest of this post, I'll be concentrating on the ones that deal with P/Invoke. P/Invoke attributes P/Invoke is built right into the CLR at quite a deep level; there are 2 metadata tables within an assembly dedicated solely to p/invoke interop, and many more that affect it. Furthermore, all the attributes used to specify p/invoke methods in C# or VB have their own keywords and syntax within IL. For example, the following C# method declaration: [DllImport("mscorsn.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.U1)] private static extern bool StrongNameSignatureVerificationEx( [MarshalAs(UnmanagedType.LPWStr)] string wszFilePath, [MarshalAs(UnmanagedType.U1)] bool fForceVerification, [MarshalAs(UnmanagedType.U1)] ref bool pfWasVerified); compiles to the following IL definition: .method private static pinvokeimpl("mscorsn.dll" lasterr winapi) bool marshal(unsigned int8) StrongNameSignatureVerificationEx( string marshal(lpwstr) wszFilePath, bool marshal(unsigned int8) fForceVerification, bool& marshal(unsigned int8) pfWasVerified) cil managed preservesig {} As you can see, all the p/invoke and marshal properties are specified directly in IL, rather than using attributes. And, rather than creating entries in CustomAttribute, a whole bunch of metadata is emitted to represent this information. This single method declaration results in the following metadata being output to the assembly: A MethodDef entry containing basic information on the method Four ParamDef entries for the 3 method parameters and return type An entry in ModuleRef to mscorsn.dll An entry in ImplMap linking ModuleRef and MethodDef, along with the name of the function to import and the pinvoke options (lasterr winapi) Four FieldMarshal entries containing the marshal information for each parameter. Phew! Applying attributes Most of the time, when you apply an attribute to an element, an entry in the CustomAttribute table will be created to represent that application. However, some attributes represent concepts in IL that aren't expressible in the language you're coding in, and can instead result in a single bit change (SerializableAttribute and NonSerializedAttribute), or many extra metadata table entries (the p/invoke attributes) being emitted to the output assembly.

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• Great Customer Service Example

  - by MightyZot

  A few days ago I wrote about what I consider a poor customer service interaction with TiVo, a company that I have been faithful to for the past 12 years or so. In that post I talked about how they helped me, but I felt like I was doing something wrong at the end of the call – when in reality I was just following through with an offer that TiVo made possible through my cable company. Today I had a wonderful customer service interaction with American Express, another company that I have been loyal to for many years.(I am a Gold Card member.) I like my Amex card because I can use it for big purchases and it forces me to pay them off at the end of the month. Well, the reality is that I’m not always so good at doing that, so sometimes my payments are over a couple of months.  :) A few days ago I received an email from “American Express” fraud detection. The email stated that I should call a toll free number and have the last four digits of my card handy. I grew up during the BBS era with some creative and somewhat mischievous friends. I’ve learned to be extremely cautious with regard to my online life! So, I did what you would expect…I sent them a nice reply that said “Go screw yourself.” For the past couple of days someone has been trying to call me and I assumed it was the same prankster trying to get the last four digits of my card. The last caller left a message indicating that they were from American Express and they wanted to talk to me about my card. After looking up their customer service numbers on the www.americanexpress.com web site, I called and was put through to the fraud detection group. The rep explained that there were some charges on my wife’s card that did not fit our purchase profile. She went through each charge and, for the most part, they looked like charges my wife may have made. My wife had asked to use the card for some Christmas shopping during the same timeframe as the charges. The American Express rep very politely explained that these looked out of character to her. She continued through the charges. She listed a charge for $160 – at this point my adrenaline started kicking in. My wife said she was going to charge about $25 or $30 dollars, not $160. Next, the rep listed a charge for over $1200. Uh oh!! Now I know that my account has been compromised. I informed the rep that we definitely did not make those charges. She replied with, “that’s ok Mr Pope, we declined those charges as well as some others.” We went through the pending charges and there were a couple more that were questionable. The rep very patiently waited while I called my wife on my office phone to verify the charges. Sure enough, my wife had not ordered anything from Netflix or purchased anything with Yahoo Wallet! “No problem Mr Pope, we will remove those charges as well.” “We are going to cancel your wife’s card and send her a new one. She will receive it by 7pm tomorrow via Federal Express. Please watch your statements over the next couple of months. If you notice anything fishy, give us a call and we will take care of it for you.” (Wow, I’m thinking to myself!) “Is there anything else I can help you with Mr Pope?” “Nope, thank you very much for catching this so early and declining those charges!”, I said smiling. Apparently she could hear me smiling on the other end of the phone line because she replied with “keep smiling Mr Pope and have a good rest of your week.” Now THAT’s customer service!  Thank you American Express!!! I shall remain an ever faithful customer. Interesting…

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• A Closer Look at the HiddenInput Attribute in MVC 2

  - by Steve Michelotti

  MVC 2 includes an attribute for model metadata called the HiddenInput attribute. The typical usage of the attribute looks like this (line #3 below): 1: public class PersonViewModel 2: { 3: [HiddenInput(DisplayValue = false)] 4: public int? Id { get; set; } 5: public string FirstName { get; set; } 6: public string LastName { get; set; } 7: } So if you displayed your PersonViewModel with Html.EditorForModel() or Html.EditorFor(m => m.Id), the framework would detect the [HiddenInput] attribute metadata and produce HTML like this: 1: <input id="Id" name="Id" type="hidden" value="21" /> This is pretty straight forward and allows an elegant way to keep the technical key for your model (e.g., a Primary Key from the database) in the HTML so that everything will be wired up correctly when the form is posted to the server and of course not displaying this value visually to the end user. However, when I was giving a recent presentation, a member of the audience asked me (quite reasonably), “When would you ever set DisplayValue equal to true when using a HiddenInput?” To which I responded, “Well, it’s an edge case. There are sometimes when…er…um…people might want to…um…display this value to the user.” It was quickly apparent to me (and I’m sure everyone else in the room) what a terrible answer this was. I realized I needed to have a much better answer here. First off, let’s look at what is produced if we change our view model to use “true” (which is equivalent to use specifying [HiddenInput] since “true” is the default) on line #3: 1: public class PersonViewModel 2: { 3: [HiddenInput(DisplayValue = true)] 4: public int? Id { get; set; } 5: public string FirstName { get; set; } 6: public string LastName { get; set; } 7: } Will produce the following HTML if rendered from Htm.EditorForModel() in your view: 1: <div class="editor-label"> 2: <label for="Id">Id</label> 3: </div> 4: <div class="editor-field"> 5: 21<input id="Id" name="Id" type="hidden" value="21" /> 6: <span class="field-validation-valid" id="Id_validationMessage"></span> 7: </div> The key is line #5. We get the text of “21” (which happened to be my DB Id in this instance) and also a hidden input element (again with “21”). So the question is, why would one want to use this? The best answer I’ve found is contained in this MVC 2 whitepaper: When a view lets users edit the ID of an object and it is necessary to display the value as well as to provide a hidden input element that contains the old ID so that it can be passed back to the controller. Well, that actually makes sense. Yes, it seems like something that would happen *rarely* but, for those instances, it would enable them easily. It’s effectively equivalent to doing this in your view: 1: <%: Html.LabelFor(m => m.Id) %> 2: <%: Model.Id %> 3: <%: Html.HiddenFor(m => m.Id) %> But it’s allowing you to specify it in metadata on your view model (and thereby take advantage of templated helpers like Html.EditorForModel() and Html.EditorFor()) rather than having to explicitly specifying everything in your view.

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• Avoiding new operator in JavaScript -- the better way

  - by greengit

  Warning: This is a long post. Let's keep it simple. I want to avoid having to prefix the new operator every time I call a constructor in JavaScript. This is because I tend to forget it, and my code screws up badly. The simple way around this is this... function Make(x) { if ( !(this instanceof arguments.callee) ) return new arguments.callee(x); // do your stuff... } But, I need this to accept variable no. of arguments, like this... m1 = Make(); m2 = Make(1,2,3); m3 = Make('apple', 'banana'); The first immediate solution seems to be the 'apply' method like this... function Make() { if ( !(this instanceof arguments.callee) ) return new arguments.callee.apply(null, arguments); // do your stuff } This is WRONG however -- the new object is passed to the apply method and NOT to our constructor arguments.callee. Now, I've come up with three solutions. My simple question is: which one seems best. Or, if you have a better method, tell it. First – use eval() to dynamically create JavaScript code that calls the constructor. function Make(/* ... */) { if ( !(this instanceof arguments.callee) ) { // collect all the arguments var arr = []; for ( var i = 0; arguments[i]; i++ ) arr.push( 'arguments[' + i + ']' ); // create code var code = 'new arguments.callee(' + arr.join(',') + ');'; // call it return eval( code ); } // do your stuff with variable arguments... } Second – Every object has __proto__ property which is a 'secret' link to its prototype object. Fortunately this property is writable. function Make(/* ... */) { var obj = {}; // do your stuff on 'obj' just like you'd do on 'this' // use the variable arguments here // now do the __proto__ magic // by 'mutating' obj to make it a different object obj.__proto__ = arguments.callee.prototype; // must return obj return obj; } Third – This is something similar to second solution. function Make(/* ... */) { // we'll set '_construct' outside var obj = new arguments.callee._construct(); // now do your stuff on 'obj' just like you'd do on 'this' // use the variable arguments here // you have to return obj return obj; } // now first set the _construct property to an empty function Make._construct = function() {}; // and then mutate the prototype of _construct Make._construct.prototype = Make.prototype; eval solution seems clumsy and comes with all the problems of "evil eval". __proto__ solution is non-standard and the "Great Browser of mIsERY" doesn't honor it. The third solution seems overly complicated. But with all the above three solutions, we can do something like this, that we can't otherwise... m1 = Make(); m2 = Make(1,2,3); m3 = Make('apple', 'banana'); m1 instanceof Make; // true m2 instanceof Make; // true m3 instanceof Make; // true Make.prototype.fire = function() { // ... }; m1.fire(); m2.fire(); m3.fire(); So effectively the above solutions give us "true" constructors that accept variable no. of arguments and don't require new. What's your take on this. -- UPDATE -- Some have said "just throw an error". My response is: we are doing a heavy app with 10+ constructors and I think it'd be far more wieldy if every constructor could "smartly" handle that mistake without throwing error messages on the console.

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• LibGDX Box2D Body and Sprite AND DebugRenderer out of sync

  - by Free Lancer

  I am having a couple issues with Box2D bodies. I have a GameObject holding a Sprite and Body. I use a ShapeRenderer to draw an outline of the Body's and Sprite's bounding boxes. I also added a Box2DDebugRenderer to make sure everything's lining up properly. My problem is the Sprite and Body at first overlap perfectly, but as I turn the Body moves a bit off the sprite then comes back when the Car is facing either North or South. Here's an image of what I mean: (Not sure what that line is, first time to show up) BLUE is the Body, RED is the Sprite, PURPLE is the Box2DDebugRenderer. Also, you probably noticed a purple square in the top right corner. Well that's the Car drawn by the Box2D Debug Renderer. I thought it might be the camera but I've been playing with the Cameras for hours and nothing seems to work. All give me weird results. Here's my code: Screen: public void show() { // --------------------- SETUP ALL THE CAMERA STUFF ------------------------------ // battleStage = new Stage( 720, 480, false ); // Setup the camera. In Box2D we operate on a meter scale, pixels won't do it. So we use // an Orthographic camera with a Viewport of 24 meters in width and 16 meters in height. battleStage.setCamera( new OrthographicCamera( CAM_METER_WIDTH, CAM_METER_HEIGHT ) ); battleStage.getCamera().position.set( CAM_METER_WIDTH / 2, CAM_METER_HEIGHT / 2, 0 ); // The Box2D Debug Renderer will handle rendering all physics objects for debugging debugger = new Box2DDebugRenderer( true, true, true, true ); //debugCam = new OrthographicCamera( CAM_METER_WIDTH, CAM_METER_HEIGHT ); } public void render(float delta) { // Update the Physics World, use 1/45 for something around 45 Frames/Second for mobile devices physicsWorld.step( 1/45.0f, 8, 3 ); // 1/45 for devices // Set the Camera matrices and clear the screen Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); battleStage.getCamera().update(); // Draw game objects here battleStage.act(delta); battleStage.draw(); // Again update the Camera matrices and call the debug renderer debugCam.update(); debugger.render( physicsWorld, debugCam.combined); // Vehicle handles its own interaction with the HUD // update all Actors movements in the game Stage hudStage.act( delta ); // Draw each Actor onto the Scene at their new positions hudStage.draw(); } Car: (extends Actor) public Car( Texture texture, float posX, float posY, World world ) { super( "Car" ); mSprite = new Sprite( texture ); mSprite.setSize( WIDTH * Consts.PIXEL_METER_RATIO, HEIGHT * Consts.PIXEL_METER_RATIO ); mSprite.setOrigin( mSprite.getWidth()/2, mSprite.getHeight()/2); // set the origin to be at the center of the body mSprite.setPosition( posX * Consts.PIXEL_METER_RATIO, posY * Consts.PIXEL_METER_RATIO ); // place the car in the center of the game map FixtureDef carFixtureDef = new FixtureDef(); mBody = Physics.createBoxBody( BodyType.DynamicBody, carFixtureDef, mSprite ); } public void draw() { mSprite.setPosition( mBody.getPosition().x * Consts.PIXEL_METER_RATIO, mBody.getPosition().y * Consts.PIXEL_METER_RATIO ); mSprite.setRotation( MathUtils.radiansToDegrees * mBody.getAngle() ); // draw the sprite mSprite.draw( batch ); } Physics: (Create the Body) public static Body createBoxBody( final BodyType pBodyType, final FixtureDef pFixtureDef, Sprite pSprite ) { float pRotation = 0; float pWidth = pSprite.getWidth(); float pHeight = pSprite.getHeight(); final BodyDef boxBodyDef = new BodyDef(); boxBodyDef.type = pBodyType; boxBodyDef.position.x = pSprite.getX() / Consts.PIXEL_METER_RATIO; boxBodyDef.position.y = pSprite.getY() / Consts.PIXEL_METER_RATIO; // Temporary Box shape of the Body final PolygonShape boxPoly = new PolygonShape(); final float halfWidth = pWidth * 0.5f / Consts.PIXEL_METER_RATIO; final float halfHeight = pHeight * 0.5f / Consts.PIXEL_METER_RATIO; boxPoly.setAsBox( halfWidth, halfHeight ); // set the anchor point to be the center of the sprite pFixtureDef.shape = boxPoly; final Body boxBody = BattleScreen.getPhysicsWorld().createBody(boxBodyDef); boxBody.createFixture(pFixtureDef); } Sorry for all the code and long description but it's hard to pin down what exactly might be causing the problem.

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• Getting input from keyboard

  - by SAMIR BHOGAYTA

  When you type on the keyboard the keystrokes go to a particular application, the active application. The active application receives the input from the keyboard. This means the application has input focus. There are two events for a key on a keyboard, when the key is pressed and when it is released. No it's not a single event as you might expect if you have no prior programming experience, in shooter games for example when you keep the forward key pressed (KeyDown) the player goes forward, and when it isn't pressed (KeyUp) the player stays put. The event that occurs when the key is pressed is called KeyPress. It occurs between KeyDown and KeyUp, and therefore acts similar to KeyDown. Similar to the way we handle OnPaint and other events we also handle the OnKeyDown event (because we want the event to occur when the key is pressed and not when it is released) by overriding it. Try the code below and test it. You will understand the role of each property. protected override void OnKeyDown(KeyEventArgs keyEvent) { // Gets the key code lblKeyCode.Text = "KeyCode: " + keyEvent.KeyCode.ToString(); // Gets the key data; recognizes combination of keys lblKeyData.Text = "KeyData: " + keyEvent.KeyData.ToString(); // Integer representation of KeyData lblKeyValue.Text = "KeyValue: " + keyEvent.KeyValue.ToString(); // Returns true if Alt is pressed lblAlt.Text = "Alt: " + keyEvent.Alt.ToString(); // Returns true if Ctrl is pressed lblCtrl.Text = "Ctrl: " + keyEvent.Control.ToString(); // Returns true if Shift is pressed lblShift.Text = "Shift: " + keyEvent.Shift.ToString(); } How do I find out when the user presses a specific key? As you probably imagine, this will be easily accomplished using 'if'. if (keyEvent.KeyCode == Keys.A) { MessageBox.Show("'A' was pressed."); } Probably most beginners would be tempted to do this: if (keyEvent.KeyCode == "A") .... which is definitely incorrect because we can't compare System.Windows.Forms.Keys to a string. Also note that in the example we are using 'keyEvent.KeyCode', that means that even if we have other shift keys pressed (Alt, Ctrl, Shift, Windows...) simultaneous with A, the if condition returns true because it doesn't recognize key combinations. If we want to ignore key combinations (Alt+A, Ctrl+Shift+A), etc. we need to use 'keyEvent.KeyData' of course: if (keyEvent.KeyData == Keys.A) { MessageBox.Show("'A', and only A, was pressed."); } When you right click on a file in Windows Explorer and you have the Shift key pressed you get the additional 'Open with...' item in the menu. This and many others are cases when you need to use the mouse button together with the keyboard. The following code will change the background color of the form only if the form is clicked while the Ctrl key on the keyboard is pressed. If the Ctrl key is unpressed and the form is clicked nothing happens. private void Form1_Click(object sender, System.EventArgs e) { Keys modKey = Control.ModifierKeys; if(modKey == Keys.Control) { this.BackColor = Color.Yellow; } } If you have further questions feel free to ask them and also check the following pages at MSDN: KeyUp Event KeyPress Event KeyDown Event

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• The enterprise vendor con - connecting SSD's using SATA 2 (3Gbits) thus limiting there performance

  - by tonyrogerson

  When comparing SSD against Hard drive performance it really makes me cross when folk think comparing an array of SSD running on 3GBits/sec to hard drives running on 6GBits/second is somehow valid. In a paper from DELL (http://www.dell.com/downloads/global/products/pvaul/en/PowerEdge-PowerVaultH800-CacheCade-final.pdf) on increasing database performance using the DELL PERC H800 with Solid State Drives they compare four SSD drives connected at 3Gbits/sec against ten 10Krpm drives connected at 6Gbits [Tony slaps forehead while shouting DOH!]. It is true in the case of hard drives it probably doesn’t make much difference 3Gbit or 6Gbit because SAS and SATA are both end to end protocols rather than shared bus architecture like SCSI, so the hard drive doesn’t share bandwidth and probably can’t get near the 600MiBytes/second throughput that 6Gbit gives unless you are doing contiguous reads, in my own tests on a single 15Krpm SAS disk using IOMeter (8 worker threads, queue depth of 16 with a stripe size of 64KiB, an 8KiB transfer size on a drive formatted with an allocation size of 8KiB for a 100% sequential read test) I only get 347MiBytes per second sustained throughput at an average latency of 2.87ms per IO equating to 44.5K IOps, ok, if that was 3GBits it would be less – around 280MiBytes per second, oh, but wait a minute [...fingers tap desk] You’ll struggle to find in the commodity space an SSD that doesn’t have the SATA 3 (6GBits) interface, SSD’s are fast not only low latency and high IOps but they also offer a very large sustained transfer rate, consider the OCZ Agility 3 it so happens that in my masters dissertation I did the same test but on a difference box, I got 374MiBytes per second at an average latency of 2.67ms per IO equating to 47.9K IOps – cost of an 240GB Agility 3 is £174.24 (http://www.scan.co.uk/products/240gb-ocz-agility-3-ssd-25-sata-6gb-s-sandforce-2281-read-525mb-s-write-500mb-s-85k-iops), but that same drive set in a box connected with SATA 2 (3Gbits) would only yield around 280MiBytes per second thus losing almost 100MiBytes per second throughput and a ton of IOps too. So why the hell are “enterprise” vendors still only connecting SSD’s at 3GBits? Well, my conspiracy states that they have no interest in you moving to SSD because they’ll lose so much money, the argument that they use SATA 2 doesn’t wash, SATA 3 has been out for some time now and all the commodity stuff you buy uses it now. Consider the cost, not in terms of price per GB but price per IOps, SSD absolutely thrash Hard Drives on that, it was true that the opposite was also true that Hard Drives thrashed SSD’s on price per GB, but is that true now, I’m not so sure – a 300GByte 2.5” 15Krpm SAS drive costs £329.76 ex VAT (http://www.scan.co.uk/products/300gb-seagate-st9300653ss-savvio-15k3-25-hdd-sas-6gb-s-15000rpm-64mb-cache-27ms) which equates to £1.09 per GB compared to a 480GB OCZ Agility 3 costing £422.10 ex VAT (http://www.scan.co.uk/products/480gb-ocz-agility-3-ssd-25-sata-6gb-s-sandforce-2281-read-525mb-s-write-410mb-s-30k-iops) which equates to £0.88 per GB. Ok, I compared an “enterprise” hard drive with a “commodity” SSD, ok, so things get a little more complicated here, most “enterprise” SSD’s are SLC and most commodity are MLC, SLC gives more performance and wear, I’ll talk about that another day. For now though, don’t get sucked in by vendor marketing, SATA 2 (3Gbit) just doesn’t cut it, SSD need 6Gbit to breath and even that SSD’s are pushing. Alas, SSD’s are connected using SATA so all the controllers I’ve seen thus far from HP and DELL only do SATA 2 – deliberate? Well, I’ll let you decide on that one.

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• initrd.lz is corrupted error occured while installing 11.10

  - by zubendra

  C:\ubuntu\install\boot\initrd.lz is corrupted. Error pop-up comes up every time i am trying to install ubuntu-11.10-desktop-i386 using wubi. error comes when the installation process is almost completed. can anyone suggest a solution for this problem. Its occurring regularly. 03-19 18:01 DEBUG TaskList: ## Running copy_installation_files... 03-19 18:01 DEBUG WindowsBackend: Copying C:\DOCUME~1\HP_OWN~1.YOU\LOCALS~1\Temp\pyl59.tmp\data\custom-installation -> C:\ubuntu\install\custom-installation 03-19 18:01 DEBUG WindowsBackend: Copying C:\DOCUME~1\HP_OWN~1.YOU\LOCALS~1\Temp\pyl59.tmp\winboot -> C:\ubuntu\winboot 03-19 18:01 DEBUG WindowsBackend: Copying C:\DOCUME~1\HP_OWN~1.YOU\LOCALS~1\Temp\pyl59.tmp\data\images\Ubuntu.ico -> C:\ubuntu\Ubuntu.ico 03-19 18:01 DEBUG TaskList: ## Finished copy_installation_files 03-19 18:01 DEBUG TaskList: ## Running get_iso... 03-19 18:01 DEBUG CommonBackend: Trying to use pre-specified ISO X:\ubuntu-11.10-desktop-i386.iso 03-19 18:01 DEBUG TaskList: New task is_valid_iso 03-19 18:01 DEBUG TaskList: ### Running is_valid_iso... 03-19 18:01 DEBUG Distro: checking Ubuntu ISO X:\ubuntu-11.10-desktop-i386.iso 03-19 18:01 INFO Distro: Found a valid iso for Ubuntu: X:\ubuntu-11.10-desktop-i386.iso 03-19 18:01 DEBUG TaskList: ### Finished is_valid_iso 03-19 18:01 DEBUG TaskList: New task check_iso 03-19 18:01 DEBUG TaskList: ### Running check_iso... 03-19 18:01 DEBUG CommonBackend: Checking X:\ubuntu-11.10-desktop-i386.iso 03-19 18:01 DEBUG Distro: checking Ubuntu ISO X:\ubuntu-11.10-desktop-i386.iso 03-19 18:01 INFO Distro: Found a valid iso for Ubuntu: X:\ubuntu-11.10-desktop-i386.iso 03-19 18:01 DEBUG CommonBackend: Using distro Ubuntu i386 instead of Ubuntu amd64 03-19 18:01 DEBUG TaskList: New task get_metalink 03-19 18:01 DEBUG TaskList: #### Running get_metalink... 03-19 18:01 DEBUG downloader: downloading http://releases.ubuntu.com/11.10/ubuntu-11.10-desktop-i386.metalink > C:\ubuntu\install 03-19 18:01 ERROR CommonBackend: Cannot download metalink file http://releases.ubuntu.com/11.10/ubuntu-11.10-desktop-i386.metalink err=[Errno 4] IOError: <urlopen error (7, 'getaddrinfo failed')> 03-19 18:01 DEBUG downloader: downloading http://cdimage.ubuntu.com/daily-live/current/oneiric-desktop-i386.metalink > C:\ubuntu\install 03-19 18:01 ERROR CommonBackend: Cannot download metalink file2 http://cdimage.ubuntu.com/daily-live/current/oneiric-desktop-i386.metalink err=[Errno 4] IOError: <urlopen error (7, 'getaddrinfo failed')> 03-19 18:01 DEBUG TaskList: #### Finished get_metalink 03-19 18:01 ERROR CommonBackend: ERROR: the metalink file is not available, cannot check the md5 for X:\ubuntu-11.10-desktop-i386.iso, ignoring 03-19 18:01 DEBUG TaskList: ### Finished check_iso 03-19 18:01 DEBUG TaskList: New task copy_file 03-19 18:01 DEBUG CommonBackend: Copying X:\ubuntu-11.10-desktop-i386.iso > C:\ubuntu\install\installation.iso 03-19 18:01 DEBUG TaskList: ### Running copy_file... 03-19 18:01 DEBUG TaskList: ### Finished copy_file 03-19 18:01 DEBUG TaskList: ## Finished get_iso 03-19 18:01 DEBUG TaskList: ## Running extract_kernel... 03-19 18:01 DEBUG CommonBackend: Extracting files from ISO C:\ubuntu\install\installation.iso 03-19 18:01 DEBUG WindowsBackend: extracting md5sum.txt from C:\ubuntu\install\installation.iso 03-19 18:01 DEBUG WindowsBackend: extracting casper\vmlinuz from C:\ubuntu\install\installation.iso 03-19 18:01 DEBUG WindowsBackend: extracting casper\initrd.lz from C:\ubuntu\install\installation.iso 03-19 18:01 DEBUG CommonBackend: Checking kernel, initrd and md5sums 03-19 18:01 DEBUG CommonBackend: checking C:\ubuntu\install\boot\vmlinuz 03-19 18:01 DEBUG CommonBackend: C:\ubuntu\install\boot\vmlinuz md5 = fde150f5c6fd2de66ed7876efbfcc4c7 == fde150f5c6fd2de66ed7876efbfcc4c7 03-19 18:01 DEBUG CommonBackend: checking C:\ubuntu\install\boot\initrd.lz 03-19 18:01 DEBUG CommonBackend: C:\ubuntu\install\boot\initrd.lz md5 = 8900200c764438c1b124dff5ae92c763 != d6baee1e11f1d6de6eba6bd43dbde352 03-19 18:01 ERROR TaskList: File C:\ubuntu\install\boot\initrd.lz is corrupted Traceback (most recent call last): File "\lib\wubi\backends\common\tasklist.py", line 197, in __call__ File "\lib\wubi\backends\common\backend.py", line 623, in extract_kernel Exception: File C:\ubuntu\install\boot\initrd.lz is corrupted 03-19 18:01 DEBUG TaskList: # Cancelling tasklist 03-19 18:01 ERROR root: File C:\ubuntu\install\boot\initrd.lz is corrupted Traceback (most recent call last): File "\lib\wubi\application.py", line 58, in run File "\lib\wubi\application.py", line 132, in select_task File "\lib\wubi\application.py", line 158, in run_installer File "\lib\wubi\backends\common\tasklist.py", line 197, in __call__ File "\lib\wubi\backends\common\backend.py", line 623, in extract_kernel Exception: File C:\ubuntu\install\boot\initrd.lz is corrupted 03-19 18:01 DEBUG TaskList: # Finished tasklist

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• C# 4 Named Parameters for Overload Resolution

  - by Steve Michelotti

  C# 4 is getting a new feature called named parameters. Although this is a stand-alone feature, it is often used in conjunction with optional parameters. Last week when I was giving a presentation on C# 4, I got a question on a scenario regarding overload resolution that I had not considered before which yielded interesting results. Before I describe the scenario, a little background first. Named parameters is a well documented feature that works like this: suppose you have a method defined like this: 1: void DoWork(int num, string message = "Hello") 2: { 3: Console.WriteLine("Inside DoWork() - num: {0}, message: {1}", num, message); 4: } This enables you to call the method with any of these: 1: DoWork(21); 2: DoWork(num: 21); 3: DoWork(21, "abc"); 4: DoWork(num: 21, message: "abc"); and the corresponding results will be: Inside DoWork() - num: 21, message: Hello Inside DoWork() - num: 21, message: Hello Inside DoWork() - num: 21, message: abc Inside DoWork() - num: 21, message: abc This is all pretty straight forward and well-documented. What is slightly more interesting is how resolution is handled with method overloads. Suppose we had a second overload for DoWork() that looked like this: 1: void DoWork(object num) 2: { 3: Console.WriteLine("Inside second overload: " + num); 4: } The first rule applied for method overload resolution in this case is that it looks for the most strongly-type match first.  Hence, since the second overload has System.Object as the parameter rather than Int32, this second overload will never be called for any of the 4 method calls above.  But suppose the method overload looked like this: 1: void DoWork(int num) 2: { 3: Console.WriteLine("Inside second overload: " + num); 4: } In this case, both overloads have the first parameter as Int32 so they both fulfill the first rule equally.  In this case the overload with the optional parameters will be ignored if the parameters are not specified. Therefore, the same 4 method calls from above would result in: Inside second overload: 21 Inside second overload: 21 Inside DoWork() - num: 21, message: abc Inside DoWork() - num: 21, message: abc Even all this is pretty well documented. However, we can now consider the very interesting scenario I was presented with. The question was what happens if you change the parameter name in one of the overloads.  For example, what happens if you change the parameter *name* for the second overload like this: 1: void DoWork(int num2) 2: { 3: Console.WriteLine("Inside second overload: " + num2); 4: } In this case, the first 2 method calls will yield *different* results: 1: DoWork(21); 2: DoWork(num: 21); results in: Inside second overload: 21 Inside DoWork() - num: 21, message: Hello We know the first method call will go to the second overload because of normal method overload resolution rules which ignore the optional parameters.  But for the second call, even though all the same rules apply, the compiler will allow you to specify a named parameter which, in effect, overrides the typical rules and directs the call to the first overload. Keep in mind this would only work if the method overloads had different parameter names for the same types (which in itself is weird). But it is a situation I had not considered before and it is one in which you should be aware of the rules that the C# 4 compiler applies.

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