so give me back my rep - Page 118

Mocking lambda in rhino mocks

- by Coppermill

I am trying to use Rhino Mocks to mock the following lambda, but keep hitting a brick wall var result = rep.Find<T>(x => (x as IEntity).ID == (entity as IEntity).ID).FirstOrDefault(); Any ideas?

How can I make the intellisense window larger?

In VS2008 it was possible to drag the corner to enlarge the window to see more methods, are there any hidden settings in VS2010 to make this window larger? I tried to post an image but it appears I need more rep.

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How to convert Macess .cra and .acr and .err files to a readable file format?

- by thames

I'm looking for a while to programmatically convert (or use a tool already created) MACESS .cra, .acr, and .err files to a readable format? I'd prefer a .NET way of doing it however at this point I'll take any programmatic way. PS I tried adding tags "MACESS Sungard" but I don't have 250 rep yet to do so.

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JOIN in SQL with one-to-many relationship

- by Kristopher Ives

I'm making a tool to track calls to house/senate reps, and I have 2 tables of importance here: reps rep_id rep_name # and more info comments rep_id status # enum about result of contact comment I want to query for all reps joining the most recent associated comments and in some cases joining comments of a specific status, but there might not be any comments associated with that rep yet. THANKS!

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Array comparion for multidimensinal array in php

- by Learner

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Can I locally place a directory at a different location with Subversion?

- by amoeba

My project in rep: project/dir A/ project/dir B/ (MacOSX) Locally: project/dir A/ ~/somewhere/dir B/ Workflow: Don´t forget to copy "~/somewhere/dir B/" to "project/dir B/" before commit... Alias? Script? Flag? Easiest solution wins as always.

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what is KTM and how does it work?

- by Behrooz

no comment. http://msdn.microsoft.com/en-us/library/Aa366295 someone please add the KTM tag(I don't have enough rep.).

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Can JavaScript connect with MySQL?

- by Anonymous the Great

Can JavaScript connect with MySQL? If so, how? Easy rep! :D

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Where is the error in my code?

- by Lulu Larson

/** Yields: a String that contains each capital Letter (in 'A'..'Z') whose representation is prime */ public static String primeChars() { String s = ""; // inv: s contains each capital in "A'..c-1 whose representation is prime for (char c = 'A'; c <= 'Z'; c=(char)(c+1)) { if (Loops.isPrime((int)c) == true) { s= s+1; } } // s contains each capital in 'A' ..'Z' whose rep is a prime return s; }

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tool to show diagramatic representation of c code

- by JPro

Hi, Is there any tool to show diagrammatic rep of flow of program if we input a C file? Thanks.

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linux kernel idle tick eater (or what will be current task_struct when CPU is 0%)

- by osgx

Hello What process will be pointed by "current" pointer in linux kernel, when CPU load is 0% and there is no any ready-to-run process? Consider situation without any power-saving. What is the name of this porcess? I think task with pid 0 will be running and code will be rep nop or HLT

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Finding a Relative Path in .NET

- by Rick Strahl

Here’s a nice and simple path utility that I’ve needed in a number of applications: I need to find a relative path based on a base path. So if I’m working in a folder called c:\temp\templates\ and I want to find a relative path for c:\temp\templates\subdir\test.txt I want to receive back subdir\test.txt. Or if I pass c:\ I want to get back ..\..\ – in other words always return a non-hardcoded path based on some other known directory. I’ve had a routine in my library that does this via some lengthy string parsing routines, but ran into some Uri processing today that made me realize that this code could be greatly simplified by using the System.Uri class instead. Here’s the simple static method: /// <summary> /// Returns a relative path string from a full path based on a base path /// provided. /// </summary> /// <param name="fullPath">The path to convert. Can be either a file or a directory</param> /// <param name="basePath">The base path on which relative processing is based. Should be a directory.</param> /// <returns> /// String of the relative path. /// /// Examples of returned values: /// test.txt, ..\test.txt, ..\..\..\test.txt, ., .., subdir\test.txt /// </returns> public static string GetRelativePath(string fullPath, string basePath ) { // ForceBasePath to a path if (!basePath.EndsWith("\\")) basePath += "\\"; Uri baseUri = new Uri(basePath); Uri fullUri = new Uri(fullPath); Uri relativeUri = baseUri.MakeRelativeUri(fullUri); // Uri's use forward slashes so convert back to backward slashes return relativeUri.ToString().Replace("/", "\\"); } You can then call it like this: string relPath = FileUtils.GetRelativePath("c:\temp\templates","c:\temp\templates\subdir\test.txt") It’s not exactly rocket science but it’s useful in many scenarios where you’re working with files based on an application base directory. Right now I’m working on a templating solution (using the Razor Engine) where templates live in a base directory and are supplied as relative paths to that base directory. Resolving these relative paths both ways is important in order to properly check for existance of files and their change status in this case. Not the kind of thing you use every day, but useful to remember.© Rick Strahl, West Wind Technologies, 2005-2010Posted in .NET CSharp

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Two pass blur shader using libgdx tile map renderer

- by Alexandre GUIDET

I am trying to apply the following technique: blur effect using two pass shader to my libgdx game using the OrthogonalTiledMapRenderer. The idea is to blur the background wich is also a tilemap but rendered with another camera with a different zoom applied. Here is a screen capture without effect: Using the OrthogonalTiledMapRenderer sprite batch like this: backgroundMapRenderer.getSpriteBatch().setShader(shaderBlurX); backgroundMapRenderer.render(layerBackground); I get the following render: Wich is ok for X blur pass. I then try using frame buffer object like in this example. But the effect seems to be too much zoomed: I may be messing up with the camera and the zoom factor. Here is the code: private ShaderProgram shaderBlurX; private ShaderProgram shaderBlurY; private int FBO_SIZE = 800; private FrameBuffer targetA; private FrameBuffer targetB; targetA = new FrameBuffer(Pixmap.Format.RGBA8888, FBO_SIZE, FBO_SIZE, false); targetB = new FrameBuffer(Pixmap.Format.RGBA8888, FBO_SIZE, FBO_SIZE, false); targetA.begin(); Gdx.gl.glClearColor(1, 1, 1, 0); Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); backgroundMapRenderer.render(layerBackground); targetA.end(); targetB.begin(); Gdx.gl.glClearColor(1, 1, 1, 0); Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); backgroundMapRenderer.getSpriteBatch().setShader(shaderBlurX); backgroundMapRenderer.render(layerBackground); targetB.end(); TextureRegion back = new TextureRegion(targetB.getColorBufferTexture()); back.flip(false, true); backgroundMapRenderer.getSpriteBatch() .setProjectionMatrix(backgroundCamera.combined); backgroundMapRenderer.getSpriteBatch().setShader(shaderBlurY); backgroundMapRenderer.getSpriteBatch().begin(); backgroundMapRenderer.getSpriteBatch().draw(back, 0, 0); backgroundMapRenderer.getSpriteBatch().end(); I know I am making something the wrong way, but I can't find any resources about applying two passes shader using tile map renderer. Does someone know how to achieve this?

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SQL SERVER – Fix : Error 3623 – An invalid floating point operation occurred

- by pinaldave

Going back in time, I always had a problem with mathematics. It was a great subject and I loved it a lot but I only mastered it after practices a lot. I learned that mathematics problems should be addressed systematically and being verbose is not a trick, I learned to solve any problem. Recently one of reader sent me an email with the title “Mathematics problem – please help!” and I was a bit scared. I was good at mathematics but not the best. When I opened the email I was relieved as it was Mathematics problem with SQL Server. My friend received following error while working with SQL Server. Msg 3623, Level 16, State 1, Line 1 An invalid floating point operation occurred. The reasons for the error is simply that invalid usage of the mathematical function is attempted. Let me give you a few examples of the same. SELECT SQRT(-5); SELECT ACOS(-3); SELECT LOG(-9); If you run any of the above functions they will give you an error related to invalid floating point. Honestly there is no workaround except passing the function appropriate values. SQRT of a negative number will give you result in real numbers which is not supported at this point of time as well LOG of a negative number is not possible (because logarithm is the inverse function of an exponential function and the exponential function is NEVER negative). When I send above reply to my friend he did understand that he was passing incorrect value to the function. As mentioned earlier the only way to fix this issue is finding incorrect value and avoid passing it to the function. Every mathematics function is different and there is not a single solution to identify erroneous value passed. If you are facing this error and not able to figure out the solution. Post a comment and I will do my best to figure out the solution. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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ASP.NET MVC Paging/Sorting/Filtering using the MVCContrib Grid and Pager

- by rajbk

This post walks you through creating a UI for paging, sorting and filtering a list of data items. It makes use of the excellent MVCContrib Grid and Pager Html UI helpers. A sample project is attached at the bottom. Our UI will eventually look like this. The application will make use of the Northwind database. The top portion of the page has a filter area region. The filter region is enclosed in a form tag. The select lists are wired up with jQuery to auto post back the form. The page has a pager region at the top and bottom of the product list. The product list has a link to display more details about a given product. The column headings are clickable for sorting and an icon shows the sort direction. Strongly Typed View Models The views are written to expect strongly typed objects. We suffix these strongly typed objects with ViewModel since they are designed specifically for passing data down to the view. The following listing shows the ProductViewModel. This class will be used to hold information about a Product. We use attributes to specify if the property should be hidden and what its heading in the table should be. This metadata will be used by the MvcContrib Grid to render the table. Some of the properties are hidden from the UI ([ScaffoldColumn(false)) but are needed because we will be using those for filtering when writing our LINQ query. public ActionResult Index( string productName, int? supplierID, int? categoryID, GridSortOptions gridSortOptions, int? page) { var productList = productRepository.GetProductsProjected(); // Set default sort column if (string.IsNullOrWhiteSpace(gridSortOptions.Column)) { gridSortOptions.Column = "ProductID"; } // Filter on SupplierID if (supplierID.HasValue) { productList = productList.Where(a => a.SupplierID == supplierID); } // Filter on CategoryID if (categoryID.HasValue) { productList = productList.Where(a => a.CategoryID == categoryID); } // Filter on ProductName if (!string.IsNullOrWhiteSpace(productName)) { productList = productList.Where(a => a.ProductName.Contains(productName)); } // Create all filter data and set current values if any // These values will be used to set the state of the select list and textbox // by sending it back to the view. var productFilterViewModel = new ProductFilterViewModel(); productFilterViewModel.SelectedCategoryID = categoryID ?? -1; productFilterViewModel.SelectedSupplierID = supplierID ?? -1; productFilterViewModel.Fill(); // Order and page the product list var productPagedList = productList .OrderBy(gridSortOptions.Column, gridSortOptions.Direction) .AsPagination(page ?? 1, 10); var productListContainer = new ProductListContainerViewModel { ProductPagedList = productPagedList, ProductFilterViewModel = productFilterViewModel, GridSortOptions = gridSortOptions }; return View(productListContainer); } The following diagram shows the rest of the key ViewModels in our design. We have a container class called ProductListContainerViewModel which has nested classes. The ProductPagedList is of type IPagination<ProductViewModel>. The MvcContrib expects the IPagination<T> interface to determine the page number and page size of the collection we are working with. You convert any IEnumerable<T> into an IPagination<T> by calling the AsPagination extension method in the MvcContrib library. It also creates a paged set of type ProductViewModel. The ProductFilterViewModel class will hold information about the different select lists and the ProductName being searched on. It will also hold state of any previously selected item in the lists and the previous search criteria (you will recall that this type of state information was stored in Viewstate when working with WebForms). With MVC there is no state storage and so all state has to be fetched and passed back to the view. The GridSortOptions is a type defined in the MvcContrib library and is used by the Grid to determine the current column being sorted on and the current sort direction. The following shows the view and partial views used to render our UI. The Index view expects a type ProductListContainerViewModel which we described earlier. <%Html.RenderPartial("SearchFilters", Model.ProductFilterViewModel); %> <% Html.RenderPartial("Pager", Model.ProductPagedList); %> <% Html.RenderPartial("SearchResults", Model); %> <% Html.RenderPartial("Pager", Model.ProductPagedList); %> The View contains a partial view “SearchFilters” and passes it the ProductViewFilterContainer. The SearchFilter uses this Model to render all the search lists and textbox. The partial view “Pager” uses the ProductPageList which implements the interface IPagination. The “Pager” view contains the MvcContrib Pager helper used to render the paging information. This view is repeated twice since we want the pager UI to be available at the top and bottom of the product list. The Pager partial view is located in the Shared directory so that it can be reused across Views. The partial view “SearchResults” uses the ProductListContainer model. This partial view contains the MvcContrib Grid which needs both the ProdctPagedList and GridSortOptions to render itself. The Controller Action An example of a request like this: /Products?productName=test&supplierId=29&categoryId=4. The application receives this GET request and maps it to the Index method of the ProductController. Within the action we create an IQueryable<ProductViewModel> by calling the GetProductsProjected() method. /// <summary> /// This method takes in a filter list, paging/sort options and applies /// them to an IQueryable of type ProductViewModel /// </summary> /// <returns> /// The return object is a container that holds the sorted/paged list, /// state for the fiters and state about the current sorted column /// </returns> public ActionResult Index( string productName, int? supplierID, int? categoryID, GridSortOptions gridSortOptions, int? page) { var productList = productRepository.GetProductsProjected(); // Set default sort column if (string.IsNullOrWhiteSpace(gridSortOptions.Column)) { gridSortOptions.Column = "ProductID"; } // Filter on SupplierID if (supplierID.HasValue) { productList.Where(a => a.SupplierID == supplierID); } // Filter on CategoryID if (categoryID.HasValue) { productList = productList.Where(a => a.CategoryID == categoryID); } // Filter on ProductName if (!string.IsNullOrWhiteSpace(productName)) { productList = productList.Where(a => a.ProductName.Contains(productName)); } // Create all filter data and set current values if any // These values will be used to set the state of the select list and textbox // by sending it back to the view. var productFilterViewModel = new ProductFilterViewModel(); productFilterViewModel.SelectedCategoryID = categoryID ?? -1; productFilterViewModel.SelectedSupplierID = supplierID ?? -1; productFilterViewModel.Fill(); // Order and page the product list var productPagedList = productList .OrderBy(gridSortOptions.Column, gridSortOptions.Direction) .AsPagination(page ?? 1, 10); var productListContainer = new ProductListContainerViewModel { ProductPagedList = productPagedList, ProductFilterViewModel = productFilterViewModel, GridSortOptions = gridSortOptions }; return View(productListContainer); } The supplier, category and productname filters are applied to this IQueryable if any are present in the request. The ProductPagedList class is created by applying a sort order and calling the AsPagination method. Finally the ProductListContainerViewModel class is created and returned to the view. You have seen how to use strongly typed views with the MvcContrib Grid and Pager to render a clean lightweight UI with strongly typed views. You also saw how to use partial views to get data from the strongly typed model passed to it from the parent view. The code also shows you how to use jQuery to auto post back. The sample is attached below. Don’t forget to change your connection string to point to the server containing the Northwind database. NorthwindSales_MvcContrib.zip My name is Kobayashi. I work for Keyser Soze.

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Xubuntu 13.10 64bit - Slow and buggy "log out" process?

- by MrKatSwordfish

I'm a Windows convert who has done only a little bit of dabbling in Ubuntu in the past (back in Dapper Drake a few years back). A lot has changes since then, and I've been yearning to jump back into linux again! So, having just bought a new SSD, I felt that this would be as good of a time as any to set up a dual-boot system again. I've messed around with Ubuntu 13.10 a bit, and while Unity has its issues, I think that it still needs some time to develop. I looked into XFCE and liked it a lot, so I went with Xubuntu. I've installed Xubuntu, and for the most part it's running smoothly and it a pleasure to work with. The customization is great and the minimalistic look and feel is really nice! But here's my problem, whenever I select the "Log Out" option from either the application menu, or the user profiles menu, my PC comes to a crawl, and the dialog box with all the options (shut down, restart, log out, etc.) takes maybe a minute or more to appear. I click the log out button, my PC is brought to a snail's pace, and I have to wait for what seems like an eternity for the logout options to appear! If i try to open something else (even a terminal window) while it's loading the logout options, that other program won't finish loading until the logout screen finally appears. Keep in mind, this is a pretty much vanilla install of Xubuntu 13.10 64bit, on a PC with an intel i7, an SSD, 6gb DDR3 RAM, and a new AMD 7770 gpu (drivers haven't been installed yet, though). Everything else runs fast, most applications open near-instantly! It must be an issue with how the logout options screen initializes or something, but I'm not sure exactly how I can fix it.. Edit - Extra Info: This problem is very consistent when using the "Log Out" buttons in Xubuntu. However, I've found that I'm able to reboot and shutdown much more quickly by going through the "Switch User" screen, and using the reboot or shutdown buttons on that screen. I'm nearly certain that it has something to do with the little Log Out options screen that appears when I select Log Out from the menu, and not the actual process of shutting down.. So what should I do? I really like XFCE so far, and I've never tried a non-ubuntu based distro before, but should I just switch to something else? Is there any known fix for this issue? Are there any work-arounds for logging out/shutting down/rebooting via the terminal so that I can avoid this irritating bug? Is there any that I can monitor the progress of the log out via terminal, allowing me to see which parts are causing the slow-down? What is the best way to report this bug to someone?

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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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Visual Studio 2010 SP1 Beta supports IIS Express

- by DigiMortal

Visual Studio 2010 SP1 Beta and ASP.NET MVC 3 RC2 were both announced today. I made a little test on one of my web applications to see how Visual Studio 2010 works with IIS Express. In this posting I will show you how to make your ASP.NET MVC 3 application work with IIS Express. Installing new stuff You can install IIS Express using Web Platform Installer. It is not part of WebMatrix anymore and you can just install IIS Express without WebMatrix. NB! You have to install IIS Express using Web Platform installer because IIS Express is not installed by SP1. After installing Visual Studio 2010 SP1 Beta on my machine (it took a long-long-long time to install) I installed also ASP.NET MVC 3 RC2. If you have Async CTP installed on your machine you have to uninstall it to get ASP.NET MVC 3 RC2 installed and run without problems. Screenshot on right shows what kinf of horrors my old laptop had to survive to get all new stuff installer. Setting IIS Express as server for web application Now, when you right-click on some web project you should see new menu item in context menu – Use IIS Express…. If you click on it you are asked for confirmation and if you say Yes then your web application is reconfigured to use IIS Express. After configuration you will see dialog box like this. And you are done. You can run your application now. Running web application When you run your application it is run on IIS Express. You can see IIS Express icon on taskbar and when you click it you can open IIS Express settings. If you closed your application in browser you can open it again from IIS Express icon. Modifying IIS Express settings for web application You can modify IIS Express settings for your application. Just open your project properties and move to Web tab. IIS and IIS Express are using same settings. The difference is if you make check to Use IIS Express checkbox or not. Switching back to Visual Studio Development Server If you don’t want or you can’t use IIS Express for some reason you can easily switch back to Visual Studio Development Server. Just right-click on your web application project and select Use Visual Studio Development Server from context menu. Conclusion IIS Express is more independent than full version of IIS and it can be also installed and run on machines where are very strict rules (some corporate and academic environments by example). IIS Express was previously part of WebMatrix package but now it is separate product and Visual Studio 2010 has very nice support for it thanks to SP1. You can easily make your web applications use IIS Express and if you want to switch back to development server it is also very easy.

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SQL SERVER – Quick Look at SQL Server Configuration for Performance Indications

- by pinaldave

Earlier I wrote SQL SERVER – Beginning SQL Server: One Step at a Time – SQL Server Magazine. That was the first article on the series of my real world experience of Performance Tuning experience. I have written second part the same series over here. Read second part over here: Quick Look at SQL Server Configuration for Performance Indications. In this second part I talk about two types of my clients. 1) Those who want instant results 2) Those who want the right results It is really fun to work with both the clients. I talk about various configuration options which I look at when I try to give very early opinion about SQL Server Performance. There are various eight configurations, I give quick look and start talking about performance. Head over to original article over here: Quick Look at SQL Server Configuration for Performance Indications. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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Using DEBUG Mode in Oracle SQL Developer to Log SQL

- by thatjeffsmith

Curious how we’re getting the data you see in SQL Developer when you click on something? While many of the dialogs provide a ‘SQL’ panel that shows you the SQL ABOUT to be generated, I’d rather see the SQL AS it’s executed. True, you could set a TRACE or fire up a Monitor Sessions report, but both of those solutions leave me hungry for more. Did you know that SQL Developer has a ‘debug’ mode? It slows the tool down a bit and spits out a lot of information you don’t care about, but it ALSO shows you ALL the SQL that is sent to the database, as you click around the tool! See ALL the SQL that SQL Developer sends to the database on your behalf Enable DEBUG Mode When you see the splash screen as SQL Developer fires up, frantically hit Up, Up, Down, Down, Left, Right, Left, Right, B, A, SELECT, Start. Wait, wrong game. No, all you need to do is go to your SQL Developer directory and navigate down to the ‘bin’ directory. In that directory, find the ‘sqldeveloper.conf’ file. Install Directory - sqldeveloper - bin - sqldeveloper.conf Open it with a text editor. Find this line IncludeConfFile sqldeveloper-nondebug.conf And replace it with this line IncludeConfFile sqldeveloper-debug.conf Save the file. Start up SQL Developer. Observe the Logging Page – Log Panel for the SQL There’s going to be more than just SQL here. You’ll actually see a LOT of other information. If you’re having general problems with the tool and you want to see the nitty-gritty of what’s going on, then this is a good place to satisfy your curiosity and might help us diagnose your issue if you post to the forums or open a ticket with My Oracle Support. You’ll find ‘INFO’ entries that look a little something like this - This is the query used to populate your Tables list in the connection tree. You can double-click on the sql text and get a pop-up window that’s much easier to read. See all that typing we’re saving you? I don’t recommend running in DEBUG mode all the time. Capturing this information and displaying it is more expensive than not doing so. And it provides a lot of information you don’t normally need to see. But when you DO want to know what’s going on and why, this is an excellent way of getting that information. When you’re ready to go back to ‘normal’ mode, just close SQL Developer, go back to your .conf file, and add the ‘nondebug’ bit back.

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Parallelism in .NET – Part 9, Configuration in PLINQ and TPL

- by Reed

Parallel LINQ and the Task Parallel Library contain many options for configuration. Although the default configuration options are often ideal, there are times when customizing the behavior is desirable. Both frameworks provide full configuration support. When working with Data Parallelism, there is one primary configuration option we often need to control – the number of threads we want the system to use when parallelizing our routine. By default, PLINQ and the TPL both use the ThreadPool to schedule tasks. Given the major improvements in the ThreadPool in CLR 4, this default behavior is often ideal. However, there are times that the default behavior is not appropriate. For example, if you are working on multiple threads simultaneously, and want to schedule parallel operations from within both threads, you might want to consider restricting each parallel operation to using a subset of the processing cores of the system. Not doing this might over-parallelize your routine, which leads to inefficiencies from having too many context switches. In the Task Parallel Library, configuration is handled via the ParallelOptions class. All of the methods of the Parallel class have an overload which accepts a ParallelOptions argument. We configure the Parallel class by setting the ParallelOptions.MaxDegreeOfParallelism property. For example, let’s revisit one of the simple data parallel examples from Part 2: Parallel.For(0, pixelData.GetUpperBound(0), row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re looping through an image, and calling a method on each pixel in the image. If this was being done on a separate thread, and we knew another thread within our system was going to be doing a similar operation, we likely would want to restrict this to using half of the cores on the system. This could be accomplished easily by doing: var options = new ParallelOptions(); options.MaxDegreeOfParallelism = Math.Max(Environment.ProcessorCount / 2, 1); Parallel.For(0, pixelData.GetUpperBound(0), options, row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); Now, we’re restricting this routine to using no more than half the cores in our system. Note that I included a check to prevent a single core system from supplying zero; without this check, we’d potentially cause an exception. I also did not hard code a specific value for the MaxDegreeOfParallelism property. One of our goals when parallelizing a routine is allowing it to scale on better hardware. Specifying a hard-coded value would contradict that goal. Parallel LINQ also supports configuration, and in fact, has quite a few more options for configuring the system. The main configuration option we most often need is the same as our TPL option: we need to supply the maximum number of processing threads. In PLINQ, this is done via a new extension method on ParallelQuery<T>: ParallelEnumerable.WithDegreeOfParallelism. Let’s revisit our declarative data parallelism sample from Part 6: double min = collection.AsParallel().Min(item => item.PerformComputation()); Here, we’re performing a computation on each element in the collection, and saving the minimum value of this operation. If we wanted to restrict this to a limited number of threads, we would add our new extension method: int maxThreads = Math.Max(Environment.ProcessorCount / 2, 1); double min = collection .AsParallel() .WithDegreeOfParallelism(maxThreads) .Min(item => item.PerformComputation()); This automatically restricts the PLINQ query to half of the threads on the system. PLINQ provides some additional configuration options. By default, PLINQ will occasionally revert to processing a query in parallel. This occurs because many queries, if parallelized, typically actually cause an overall slowdown compared to a serial processing equivalent. By analyzing the “shape” of the query, PLINQ often decides to run a query serially instead of in parallel. This can occur for (taken from MSDN): Queries that contain a Select, indexed Where, indexed SelectMany, or ElementAt clause after an ordering or filtering operator that has removed or rearranged original indices. Queries that contain a Take, TakeWhile, Skip, SkipWhile operator and where indices in the source sequence are not in the original order. Queries that contain Zip or SequenceEquals, unless one of the data sources has an originally ordered index and the other data source is indexable (i.e. an array or IList(T)). Queries that contain Concat, unless it is applied to indexable data sources. Queries that contain Reverse, unless applied to an indexable data source. If the specific query follows these rules, PLINQ will run the query on a single thread. However, none of these rules look at the specific work being done in the delegates, only at the “shape” of the query. There are cases where running in parallel may still be beneficial, even if the shape is one where it typically parallelizes poorly. In these cases, you can override the default behavior by using the WithExecutionMode extension method. This would be done like so: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .Select(i => i.PerformComputation()) .Reverse(); Here, the default behavior would be to not parallelize the query unless collection implemented IList<T>. We can force this to run in parallel by adding the WithExecutionMode extension method in the method chain. Finally, PLINQ has the ability to configure how results are returned. When a query is filtering or selecting an input collection, the results will need to be streamed back into a single IEnumerable<T> result. For example, the method above returns a new, reversed collection. In this case, the processing of the collection will be done in parallel, but the results need to be streamed back to the caller serially, so they can be enumerated on a single thread. This streaming introduces overhead. IEnumerable<T> isn’t designed with thread safety in mind, so the system needs to handle merging the parallel processes back into a single stream, which introduces synchronization issues. There are two extremes of how this could be accomplished, but both extremes have disadvantages. The system could watch each thread, and whenever a thread produces a result, take that result and send it back to the caller. This would mean that the calling thread would have access to the data as soon as data is available, which is the benefit of this approach. However, it also means that every item is introducing synchronization overhead, since each item needs to be merged individually. On the other extreme, the system could wait until all of the results from all of the threads were ready, then push all of the results back to the calling thread in one shot. The advantage here is that the least amount of synchronization is added to the system, which means the query will, on a whole, run the fastest. However, the calling thread will have to wait for all elements to be processed, so this could introduce a long delay between when a parallel query begins and when results are returned. The default behavior in PLINQ is actually between these two extremes. By default, PLINQ maintains an internal buffer, and chooses an optimal buffer size to maintain. Query results are accumulated into the buffer, then returned in the IEnumerable<T> result in chunks. This provides reasonably fast access to the results, as well as good overall throughput, in most scenarios. However, if we know the nature of our algorithm, we may decide we would prefer one of the other extremes. This can be done by using the WithMergeOptions extension method. For example, if we know that our PerformComputation() routine is very slow, but also variable in runtime, we may want to retrieve results as they are available, with no bufferring. This can be done by changing our above routine to: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .WithMergeOptions(ParallelMergeOptions.NotBuffered) .Select(i => i.PerformComputation()) .Reverse(); On the other hand, if are already on a background thread, and we want to allow the system to maximize its speed, we might want to allow the system to fully buffer the results: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .WithMergeOptions(ParallelMergeOptions.FullyBuffered) .Select(i => i.PerformComputation()) .Reverse(); Notice, also, that you can specify multiple configuration options in a parallel query. By chaining these extension methods together, we generate a query that will always run in parallel, and will always complete before making the results available in our IEnumerable<T>.

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Make Your 64 bit Computer Look like a Commodore 64

- by Matthew Guay

The Commodore 64 was one of the bestselling home computers ever, and many geeks got their first computing experience on one of these early personal computers. Here’s an easy way to revisit the early years of personal computing with a theme for Windows 7. With only 64Kb of ram and an 8 bit processor, the Commodore 64 is light-years behind today’s computers. But with a Windows 7 themepack, you can turn back the years and give your computer a quick overhaul to look more like its ancient predecessor. Age Windows 7 with a click Download the Commodore 64 theme from PC World (link below), and unzip the files. Now, double-click on the Themepack file to apply the theme. This will open your Personalization panel and will automatically change your system fonts, window style, background, and more. Your desktop will go from your Windows 7 look… to a modified Windows 7 look that is reminiscent of the Commodore 64. Open an application to see all the changes … notice the old-style font in the Window boarder and menus. This theme also changes your Computer, Recycle Bin, and User folder icons to Commodore 64-inspired icons. And, if you want to go back to the standard Windows 7 look and feel, it’s only a click away in the Personalization dialog. Right-click on your desktop, select Personalize, and then choose the theme you want. Conclusion Although this doesn’t give you the real look and feel of the Commodore 64, it is still a fun way to experience a bit of computer nostalgia. There are tons of excellent themes available for Windows 7, so check back for more exciting ways to customize your desktop! Link Download the Commodore 64 theme for Windows 7 Similar Articles Productive Geek Tips Make MSE Create a Restore Point Before Cleaning MalwareMake Ubuntu Automatically Save Changes to Your SessionMake Windows Vista Shut Down Services QuickerChange Your Computer Name in Windows 7 or VistaMake Windows 7 or Vista Log On Automatically TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Dark Side of the Moon (8-bit) Norwegian Life If Web Browsers Were Modes of Transportation Google Translate (for animals) Out of 100 Tweeters Roadkill’s Scan Port scans for open ports

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iTunesConnect Now Allows Automated Release Dates, Price Changes

New options in the App Store interface give developers more marketing options.

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iTunesConnect Now Allows Automated Release Dates, Price Changes

New options in the App Store interface give developers more marketing options.

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DirectX11 Swap Chain RGBA vs BGRA Format

- by Nathan

I was wondering if anyone could elaborate any further on something that's been bugging me. In DirectX9 the main supported back buffer formats were D3DFMT_X8R8B8G8 and D3DFMT_A8R8G8B8 (Both being BGRA in layout). http://msdn.microsoft.com/en-us/library/windows/desktop/bb174314(v=vs.85).aspx With the initial version of DirectX10 their was no support for BGRA and all the textbooks and online tutorials recommend DXGI_FORMAT_R8G8B8A8_UNORM (being RGBA in layout). Now with DirectX11 BGRA is supported again and it seems as if microsoft recommends using a BGRA format as the back buffer format. http://msdn.microsoft.com/en-us/library/windows/apps/hh465096.aspx Are there any suggestions or are there performance implications of using one or the other? (I assume not as obviously by specifying the format of the underlying resource the runtime will handle what bits your passing through and than infer how to utilise them based on the format.)

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