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  • Facebook like button for a Facebook feed item

    - by jverdeyen
    Here is what I do: When the admin of a website i'm creating adds a new 'news' item to his website, it directly posts the same item on the Facebook 'fanpage' of the website. This is done by an Facebook app with the permissions to post an item on the Facebook fanpage. So far so good. I'm getting the new post id from the facebook graph. Here is what I want to achieve: I'm adding a 'like' button on the original website, but when this is clicked it should be referenced to the same post item on the facebook page. So if someone likes the news post on the website he should also like the referencing facebook feed post. Which is exactly the same. Can this be done? I've been playing around with the href etc of the like button, without any success. When I hit the like button it likes the url given, but is doesn't recognizes that this is a feed post. Any idea? Thx in advance.

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  • Facebook like button for a Facebook feed item

    - by jverdeyen
    Here is what I do: When the admin of a website i'm creating adds a new 'news' item to his website, it directly posts the same item on the Facebook 'fanpage' of the website. This is done by an Facebook app with the permissions to post an item on the Facebook fanpage. So far so good. I'm getting the new post id from the facebook graph. Here is what I want to achieve: I'm adding a 'like' button on the original website, but when this is clicked it should be referenced to the same post item on the facebook page. So if someone likes the news post on the website he should also like the referencing facebook feed post. Which is exactly the same. Can this be done? I've been playing around with the href etc of the like button, without any success. When I hit the like button it likes the url given, but is doesn't recognizes that this is a feed post. Any idea? Thx in advance.

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  • logging a facebook user ID to a local database from a facebook 'like'

    - by Azzam
    I am creating a site that allow users to vote on webpages similar to digg.com. Users login with 'facebook connect' and logged in users can submit, vote, comment, etc and these details appear in their profile ie. number of submits, votes, comments, etc. I have also added in facebook 'likes' to the system. I would however like to be able replace the internal voting platform with facebook 'likes'. What I would like to be able to do is identify when any of the site users vote on a facebook 'like'. Although a facebook 'like' can be made outside of my site I am only interested when a logged in user submits a 'like' so this can contribute towards their stats. Is this possible, if so how? Thanks Azzam

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  • Getting Facebook Posts Permalink from Facebook Graph API Search

    - by Alexia
    I want to use the Facebook Graph API to search the public status updates concerning a keyword. For example, this works great: http://graph.facebook.com/search?q=obama&type=post It shows me all the posts with the word "obama" in it. If the post is a picture, it actually returns a field called "link" which is the permalink to the picture on the actual Facebook website, in the user's profile. Which is exactly what I want, but for pictures. But if the post in question is just a status update, i.e. just text, all it returns is the 3 fields: message, created_time, and updated_time. How do I view this actual status update on www.facebook.com? I realize I can view it on graph.facebook.com in JSON format, but I want to actually be able to show the permalink to the status update, or post. The final result I would like to retrieve might look something like this: http://www.facebook.com/[user id]/posts/[post id] With the [user id] and [post id] fields swapped out with the actual IDs, obviously. TIA!

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  • What's the term for re-implementing an old API in terms of a newer API

    - by dodgy_coder
    The reason for doing it is to solve the case when a newer API is no longer backwards compatible with an older API. To explain, just say that there is an old API v1.0. The maker of this API decides it is broken and works on a new API v1.1 that intentionally breaks compatibility with the old API v1.0. Now, any programs written against the old API cannot be recompiled as-is with the new API. Then lets say there is a large app written against the old API and the developer doesn't have access to the source code. A solution would be to re-implement a "custom" old API v1.0 in terms of the new API v1.1 calls. So the "custom" v1.0 API is actually keeping the same interface/methods as the v1.0 API but inside its implementation it is actually making calls to the new API v1.1 methods. So the large app can be then compiled and linked against the "custom" v1.0 API and the new v1.1 API without any major source code changes. Is there a term for this practice? There's a recent example of this happening in Jamie Zawinski's port of XScreenSaver to the iPhone - he re-implemented the OpenGL 1.3 API in terms of the OpenGL ES 1.1 API. In this case, OpenGL 1.3 represents the "old" API and OpenGL ES 1.1 represents the "new" API.

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  • Where does ASP.NET Web API Fit?

    - by Rick Strahl
    With the pending release of ASP.NET MVC 4 and the new ASP.NET Web API, there has been a lot of discussion of where the new Web API technology fits in the ASP.NET Web stack. There are a lot of choices to build HTTP based applications available now on the stack - we've come a long way from when WebForms and Http Handlers/Modules where the only real options. Today we have WebForms, MVC, ASP.NET Web Pages, ASP.NET AJAX, WCF REST and now Web API as well as the core ASP.NET runtime to choose to build HTTP content with. Web API definitely squarely addresses the 'API' aspect - building consumable services - rather than HTML content, but even to that end there are a lot of choices you have today. So where does Web API fit, and when doesn't it? But before we get into that discussion, let's talk about what a Web API is and why we should care. What's a Web API? HTTP 'APIs' (Microsoft's new terminology for a service I guess)  are becoming increasingly more important with the rise of the many devices in use today. Most mobile devices like phones and tablets run Apps that are using data retrieved from the Web over HTTP. Desktop applications are also moving in this direction with more and more online content and synching moving into even traditional desktop applications. The pending Windows 8 release promises an app like platform for both the desktop and other devices, that also emphasizes consuming data from the Cloud. Likewise many Web browser hosted applications these days are relying on rich client functionality to create and manipulate the browser user interface, using AJAX rather than server generated HTML data to load up the user interface with data. These mobile or rich Web applications use their HTTP connection to return data rather than HTML markup in the form of JSON or XML typically. But an API can also serve other kinds of data, like images or other binary files, or even text data and HTML (although that's less common). A Web API is what feeds rich applications with data. ASP.NET Web API aims to service this particular segment of Web development by providing easy semantics to route and handle incoming requests and an easy to use platform to serve HTTP data in just about any content format you choose to create and serve from the server. But .NET already has various HTTP Platforms The .NET stack already includes a number of technologies that provide the ability to create HTTP service back ends, and it has done so since the very beginnings of the .NET platform. From raw HTTP Handlers and Modules in the core ASP.NET runtime, to high level platforms like ASP.NET MVC, Web Forms, ASP.NET AJAX and the WCF REST engine (which technically is not ASP.NET, but can integrate with it), you've always been able to handle just about any kind of HTTP request and response with ASP.NET. The beauty of the raw ASP.NET platform is that it provides you everything you need to build just about any type of HTTP application you can dream up from low level APIs/custom engines to high level HTML generation engine. ASP.NET as a core platform clearly has stood the test of time 10+ years later and all other frameworks like Web API are built on top of this ASP.NET core. However, although it's possible to create Web APIs / Services using any of the existing out of box .NET technologies, none of them have been a really nice fit for building arbitrary HTTP based APIs. Sure, you can use an HttpHandler to create just about anything, but you have to build a lot of plumbing to build something more complex like a comprehensive API that serves a variety of requests, handles multiple output formats and can easily pass data up to the server in a variety of ways. Likewise you can use ASP.NET MVC to handle routing and creating content in various formats fairly easily, but it doesn't provide a great way to automatically negotiate content types and serve various content formats directly (it's possible to do with some plumbing code of your own but not built in). Prior to Web API, Microsoft's main push for HTTP services has been WCF REST, which was always an awkward technology that had a severe personality conflict, not being clear on whether it wanted to be part of WCF or purely a separate technology. In the end it didn't do either WCF compatibility or WCF agnostic pure HTTP operation very well, which made for a very developer-unfriendly environment. Personally I didn't like any of the implementations at the time, so much so that I ended up building my own HTTP service engine (as part of the West Wind Web Toolkit), as have a few other third party tools that provided much better integration and ease of use. With the release of Web API for the first time I feel that I can finally use the tools in the box and not have to worry about creating and maintaining my own toolkit as Web API addresses just about all the features I implemented on my own and much more. ASP.NET Web API provides a better HTTP Experience ASP.NET Web API differentiates itself from the previous Microsoft in-box HTTP service solutions in that it was built from the ground up around the HTTP protocol and its messaging semantics. Unlike WCF REST or ASP.NET AJAX with ASMX, it’s a brand new platform rather than bolted on technology that is supposed to work in the context of an existing framework. The strength of the new ASP.NET Web API is that it combines the best features of the platforms that came before it, to provide a comprehensive and very usable HTTP platform. Because it's based on ASP.NET and borrows a lot of concepts from ASP.NET MVC, Web API should be immediately familiar and comfortable to most ASP.NET developers. Here are some of the features that Web API provides that I like: Strong Support for URL Routing to produce clean URLs using familiar MVC style routing semantics Content Negotiation based on Accept headers for request and response serialization Support for a host of supported output formats including JSON, XML, ATOM Strong default support for REST semantics but they are optional Easily extensible Formatter support to add new input/output types Deep support for more advanced HTTP features via HttpResponseMessage and HttpRequestMessage classes and strongly typed Enums to describe many HTTP operations Convention based design that drives you into doing the right thing for HTTP Services Very extensible, based on MVC like extensibility model of Formatters and Filters Self-hostable in non-Web applications  Testable using testing concepts similar to MVC Web API is meant to handle any kind of HTTP input and produce output and status codes using the full spectrum of HTTP functionality available in a straight forward and flexible manner. Looking at the list above you can see that a lot of functionality is very similar to ASP.NET MVC, so many ASP.NET developers should feel quite comfortable with the concepts of Web API. The Routing and core infrastructure of Web API are very similar to how MVC works providing many of the benefits of MVC, but with focus on HTTP access and manipulation in Controller methods rather than HTML generation in MVC. There’s much improved support for content negotiation based on HTTP Accept headers with the framework capable of detecting automatically what content the client is sending and requesting and serving the appropriate data format in return. This seems like such a little and obvious thing, but it's really important. Today's service backends often are used by multiple clients/applications and being able to choose the right data format for what fits best for the client is very important. While previous solutions were able to accomplish this using a variety of mixed features of WCF and ASP.NET, Web API combines all this functionality into a single robust server side HTTP framework that intrinsically understands the HTTP semantics and subtly drives you in the right direction for most operations. And when you need to customize or do something that is not built in, there are lots of hooks and overrides for most behaviors, and even many low level hook points that allow you to plug in custom functionality with relatively little effort. No Brainers for Web API There are a few scenarios that are a slam dunk for Web API. If your primary focus of an application or even a part of an application is some sort of API then Web API makes great sense. HTTP ServicesIf you're building a comprehensive HTTP API that is to be consumed over the Web, Web API is a perfect fit. You can isolate the logic in Web API and build your application as a service breaking out the logic into controllers as needed. Because the primary interface is the service there's no confusion of what should go where (MVC or API). Perfect fit. Primary AJAX BackendsIf you're building rich client Web applications that are relying heavily on AJAX callbacks to serve its data, Web API is also a slam dunk. Again because much if not most of the business logic will probably end up in your Web API service logic, there's no confusion over where logic should go and there's no duplication. In Single Page Applications (SPA), typically there's very little HTML based logic served other than bringing up a shell UI and then filling the data from the server with AJAX which means the business logic required for data retrieval and data acceptance and validation too lives in the Web API. Perfect fit. Generic HTTP EndpointsAnother good fit are generic HTTP endpoints that to serve data or handle 'utility' type functionality in typical Web applications. If you need to implement an image server, or an upload handler in the past I'd implement that as an HTTP handler. With Web API you now have a well defined place where you can implement these types of generic 'services' in a location that can easily add endpoints (via Controller methods) or separated out as more full featured APIs. Granted this could be done with MVC as well, but Web API seems a clearer and more well defined place to store generic application services. This is one thing I used to do a lot of in my own libraries and Web API addresses this nicely. Great fit. Mixed HTML and AJAX Applications: Not a clear Choice  For all the commonality that Web API and MVC share they are fundamentally different platforms that are independent of each other. A lot of people have asked when does it make sense to use MVC vs. Web API when you're dealing with typical Web application that creates HTML and also uses AJAX functionality for rich functionality. While it's easy to say that all 'service'/AJAX logic should go into a Web API and all HTML related generation into MVC, that can often result in a lot of code duplication. Also MVC supports JSON and XML result data fairly easily as well so there's some confusion where that 'trigger point' is of when you should switch to Web API vs. just implementing functionality as part of MVC controllers. Ultimately there's a tradeoff between isolation of functionality and duplication. A good rule of thumb I think works is that if a large chunk of the application's functionality serves data Web API is a good choice, but if you have a couple of small AJAX requests to serve data to a grid or autocomplete box it'd be overkill to separate out that logic into a separate Web API controller. Web API does add overhead to your application (it's yet another framework that sits on top of core ASP.NET) so it should be worth it .Keep in mind that MVC can generate HTML and JSON/XML and just about any other content easily and that functionality is not going away, so just because you Web API is there it doesn't mean you have to use it. Web API is not a full replacement for MVC obviously either since there's not the same level of support to feed HTML from Web API controllers (although you can host a RazorEngine easily enough if you really want to go that route) so if you're HTML is part of your API or application in general MVC is still a better choice either alone or in combination with Web API. I suspect (and hope) that in the future Web API's functionality will merge even closer with MVC so that you might even be able to mix functionality of both into single Controllers so that you don't have to make any trade offs, but at the moment that's not the case. Some Issues To think about Web API is similar to MVC but not the Same Although Web API looks a lot like MVC it's not the same and some common functionality of MVC behaves differently in Web API. For example, the way single POST variables are handled is different than MVC and doesn't lend itself particularly well to some AJAX scenarios with POST data. Code Duplication I already touched on this in the Mixed HTML and Web API section, but if you build an MVC application that also exposes a Web API it's quite likely that you end up duplicating a bunch of code and - potentially - infrastructure. You may have to create authentication logic both for an HTML application and for the Web API which might need something different altogether. More often than not though the same logic is used, and there's no easy way to share. If you implement an MVC ActionFilter and you want that same functionality in your Web API you'll end up creating the filter twice. AJAX Data or AJAX HTML On a recent post's comments, David made some really good points regarding the commonality of MVC and Web API's and its place. One comment that caught my eye was a little more generic, regarding data services vs. HTML services. David says: I see a lot of merit in the combination of Knockout.js, client side templates and view models, calling Web API for a responsive UI, but sometimes late at night that still leaves me wondering why I would no longer be using some of the nice tooling and features that have evolved in MVC ;-) You know what - I can totally relate to that. On the last Web based mobile app I worked on, we decided to serve HTML partials to the client via AJAX for many (but not all!) things, rather than sending down raw data to inject into the DOM on the client via templating or direct manipulation. While there are definitely more bytes on the wire, with this, the overhead ended up being actually fairly small if you keep the 'data' requests small and atomic. Performance was often made up by the lack of client side rendering of HTML. Server rendered HTML for AJAX templating gives so much better infrastructure support without having to screw around with 20 mismatched client libraries. Especially with MVC and partials it's pretty easy to break out your HTML logic into very small, atomic chunks, so it's actually easy to create small rendering islands that can be used via composition on the server, or via AJAX calls to small, tight partials that return HTML to the client. Although this is often frowned upon as to 'heavy', it worked really well in terms of developer effort as well as providing surprisingly good performance on devices. There's still plenty of jQuery and AJAX logic happening on the client but it's more manageable in small doses rather than trying to do the entire UI composition with JavaScript and/or 'not-quite-there-yet' template engines that are very difficult to debug. This is not an issue directly related to Web API of course, but something to think about especially for AJAX or SPA style applications. Summary Web API is a great new addition to the ASP.NET platform and it addresses a serious need for consolidation of a lot of half-baked HTTP service API technologies that came before it. Web API feels 'right', and hits the right combination of usability and flexibility at least for me and it's a good fit for true API scenarios. However, just because a new platform is available it doesn't meant that other tools or tech that came before it should be discarded or even upgraded to the new platform. There's nothing wrong with continuing to use MVC controller methods to handle API tasks if that's what your app is running now - there's very little to be gained by upgrading to Web API just because. But going forward Web API clearly is the way to go, when building HTTP data interfaces and it's good to see that Microsoft got this one right - it was sorely needed! Resources ASP.NET Web API AspConf Ask the Experts Session (first 5 minutes) © 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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  • 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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  • Facebook Authentication Error when using apps.facebook.com as URL

    - by Adi Mathur
    I am trying to login on my website using Facebook Authentication and it works fine . How ever when i access the Application by using https://apps.facebook.com/myApp then i get an error The state does not match. You may be a victim of CSRF Here is the code that i am using from facebook , I think there is a problem in $my_url <?php $app_id = "YOUR_APP_ID"; $app_secret = "YOUR_APP_SECRET"; $my_url = "https://www.example.com/login.php"; session_start(); $code = $_REQUEST["code"]; if(empty($code)) { $_SESSION['state'] = md5(uniqid(rand(), TRUE)); //CSRF protection $dialog_url = "https://www.facebook.com/dialog/oauth?client_id=" . $app_id . "&redirect_uri=" . urlencode($my_url) . "&state=" . $_SESSION['state']; echo("<script> top.location.href='" . $dialog_url . "'</script>"); } if($_REQUEST['state'] == $_SESSION['state']) { $token_url = "https://graph.facebook.com/oauth/access_token?" . "client_id=" . $app_id . "&redirect_uri=" . urlencode($my_url) . "&client_secret=" . $app_secret . "&code=" . $code; $response = file_get_contents($token_url); $params = null; parse_str($response, $params); $graph_url = "https://graph.facebook.com/me?access_token=" . $params['access_token']; $user = json_decode(file_get_contents($graph_url)); echo("Hello " . $user->name); } else { echo("The state does not match. You may be a victim of CSRF."); } ?>

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  • This codes in Actionscript-2, Can anyone help me translate it into AS-3 please ?.......a newby pulli

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  • Facebook link to facebook.com/company-page doesn't work

    - by Teo
    For the last 2 days I'm trying to find the reason why my previous setup, which was a link to my websites Facebook pages doesn't work anymore. I assume that I mistakenly changed something in the Facebook developer area, but I can't remember what it was. The bottom linked my previously to the Facebook.com/company-page, now the same Bottom links me just to Facebook.com. I guess I saw some redirect in the tab, but I'm not sure since it's too fast changing to Facebook.com. The original link in the footer is correct : <a href="http://facebook.com/company-page " target="_blank" class="facebook_ico"></a>. Any ideas?

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  • Links to facebook.com/company-page redirect to facebook.com

    - by Teo
    For the last 2 days I've been trying to find the reason why the link to my website's Facebook page doesn't work anymore. The link went to facebook.com/company-page, but now redirects to facebook.com. I assume that I mistakenly changed something in the Facebook developer area, but I can't remember what it was. I guess I saw some redirect in the tab, but I'm not sure since it's changing too fast to facebook.com. The original link in the footer is correct: <a href="http://facebook.com/company-page " target="_blank" class="facebook_ico"></a> Any ideas?

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  • Facebook events api: Event member (FQL)

    - by sunil-khedar
    I am fetching the event members for facebook events. Till yesterday I was getting the proper counts of members of an event. But suddenly the counts have following issues: For lot of plans on every consecutive request, I am getting random number of members. Strange issue. Seems facebook servers are not synced properly or something similar. Earlier for the same query string (mentioned below), I was getting the correct counts. But now the count is much less. It seems that at least for a few events now they are sending only the members who are connected with our application (we are using facebook connect). Example: for the following query currently I am getting "31" members. But on event page members count is much more. FQL: FB.Facebook.apiClient.fql_query('SELECT uid, eid, rsvp_status FROM event_member WHERE eid=336671213618', function(result, error){alert(result.length);}); Event page: http://www.facebook.com/event.php?eid=109411842404023 Is there any recent change in facebook API or policies? Thanks in advance.

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  • What is the difference between a Facebook Group and a Facebook Page

    - by jmort253
    I created a Project Management Stack Exchange Facebook Page to help promote the new Project Management Stack Exchange Site. One of the users suggested a Facebook Group instead. I use Facebook, and I've searched the help pages, but it's not immediately clear to me what the advantages and disadvantages are. Can you provide a list of uses for Groups and uses for Facebook Pages and perhaps some links to resources that help differentiate one from the other?

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  • Can you load Google Maps API v3 via Google AJAX API loader

    - by Salman A
    Some time ago I used the regular method of loading Google Maps API like this: <script type="text/javascript" src="http://maps.google.com/maps?file=api&v=2&key=abcdefg&sensor=true"> Later I switched to Google AJAX APIs to load Google Maps API. This was because a couple of "widgets" on my website needed the Google Ajax API loader so I chose to be consistent and used the AJAX APIs to load Google Maps as well: <script type="text/javascript" src="http://www.google.com/jsapi?key=abcdef"></script> <script type="text/javascript"> google.load("maps", "2", {"other_params": "sensor=true"}); </script> Now that I have finally decided to use Google Maps API v3, this page does not list API v3 in the available version list. None of the examples on API v3 documentation show the use of AJAX APIs as well. Is is possible (and supported) to load Google Maps API v3 via AJAX API loader?

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  • Diffence between FQL query and Graph API object access

    - by jwynveen
    What's the difference between accessing user data with the Facebook Graph API (http://graph.facebook.com/btaylor) and using the Graph API to make a FQL query of the same user (https://api.facebook.com/method/fql.query?query=QUERY). Also, does anyone know which of them the Facebook Developer Toolkit (for ASP.NET) uses? The reason I ask is because I'm trying to access the logged in user's birthday after they begin a Facebook Connect session on my site, but when I use the toolkit it doesn't return it. However, if I make a manual call to the Graph API for that user object, it does return it. It's possible I might have something wrong with my call from the toolkit. I think I may need to include the session key, but I'm not sure how to get it. Here's the code I'm using: _connectSession = new ConnectSession(APPLICATION_KEY, SECRET_KEY); try { if (!_connectSession.IsConnected()) { // Not authenticated, proceed as usual. statusResponse = "Please sign-in with Facebook."; } else { // Authenticated, create API instance _facebookAPI = new Api(_connectSession); // Load user user user = _facebookAPI.Users.GetInfo(); statusResponse = user.ToString(); ViewData["fb_user"] = user; } } catch (Exception ex) { //An error happened, so disconnect session _connectSession.Logout(); statusResponse = "Please sign-in with Facebook."; }

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  • How to remove a Facebook App from Facebook's search results?

    - by Gavin
    I have a Facebook app so users can login to my website using their Facebook account, but when you type my website name into Facebook's search (the search box right next to the Facebook logo) the app shows up in the search results. When I click it, it says "Misconfigured App - Sorry, the details for AppName cannot be displayed because the app is misconfigured." I want to remove my app from Facebook's search results, because it's not meant for users, but I can't figure out how to do it. Any ideas?

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  • How to send a Facebook notification through their API

    - by at
    I asked this on the Facebook Developers Forum with no responses.. How do I send notifications to users so they show up in the Notifications globe icon tab on the top left of a user's Facebook page? Some applications I use have their notifications show up there, but I don't see how that mechanism works in Facebook's API docs. Neither are there any permissions which seem to be required to send users notifications.

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  • How to define AUTHPARAMS in Amazon EC2 API call

    - by The Joker
    I am trying to make an API call to EC2. I want to add my IP address to the security group. https://ec2.amazonaws.com/ ?Action=AuthorizeSecurityGroupIngress &GroupName=grppp20 &GroupId=sg-b2z982mq &IpPermissions.1.IpProtocol=tcp &IpPermissions.1.FromPort=3389 &IpPermissions.1.ToPort=3389 &IpPermissions.1.IpRanges.1.CidrIp=22.951.17.728/32 &&AWSAccessKeyId=AOPLDRACULALK6U7A And i get the following error. AWS was not able to validate the provided access credentials I have a secret access key & a username. I searched internet & found that we have to make a signature of the secret key & use it in the request instead of adding it directly. Can anyone tell me how to make a signature of my AWS secret key & how to use them with my API call? Let my secret key be: 2WwRiQzBs7RTFG4545PIOJ7812CXZ Username: thejoker

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  • Facebook like and share create a fanpage

    - by nblumoe
    We are using the facebook like plugin with the share button. The URL points to a resource of our app. For example http://apps.facebook.com/appname/resources/id The first time this resource/url is shared or liked, everything works fine. The share for example holds the URL given above. But if the same resource/url is shared again, an error occurs. Facebook did create a fanpage for that resource like http://www.facebook.com/pages/appname So from now on, share/likes refer to that page instead of the resource/url of our app. The URL we use for the like plugin is correct and always points to the app resource URL. The fbappid in there is correct, too. Furthermore the page of the resource holds open graph meta tags like og:url, also pointing to the correct URL. The facebook linter/debugger returns URLs to the correct app resource URLs, when checking the liked/shared resource. Why is a fanpage created instead and the URL exchanged in shares/likes? How to fix it? We want the share to include the URL of the app resource and to increase the like count for that open graph object.

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  • Facebook Canvas Apps, New API

    - by James
    I'm having some trouble with switching to the new JS API for a number of things with creating applications within FB, specifically the "Tab". <!-- function do_perm() { Facebook.showPermissionDialog('publish_stream,email,offline_access', null); } //--> This no longer works for me when called via an onclick command. Also, with the new API and an FBML app. How does this exactly work? The documentation is really poor so I am confused when looking at the old wiki, and the new developer site. Apologies for being pretty vague, but I'm just generally confused with the lack of clear direction with the new API and help would be greatly appreciated. I'm simply just trying to create a call that prompts for the new style user permission dialog, and oncomplete calls another JS function.

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  • Facebook Application Tab URL

    - by Paul
    I have a facebook application that can be added to fan pages as a tab. The application requires that users are authenticated in order to use it. This can be accomplished by using requirelogin=1 in a link which is visible only to users who have NOT added the application. This part works fine. However, after the user has given my application permission from the dhtml pop up that requirelogin opens, I want the tab to reload. In order to do that, I need the full URL to be included in the link as follows: <a href="http://www.facebook.com/pages/PAGE_NAME/PAGE_ID?v=app_APP_ID" requirelogin=1>Authorize</a> I cannot figure out how to get the full url or, at least, the PAGE_NAME to build this url dynamically. Seems like the app should be able to know where it is without any special permissions.

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  • Navigating between pages in a Facebook Platform iframe application

    - by Jimmy Cuadra
    I'm working on a Facebook Platform application that runs in iframe mode, and I'm having trouble understanding how to navigate between pages within the app. Let's say the first page that is loaded within the iframe at my canvas URL is one.html. Within that page, there is a link to two.html that just changes the source of the iframe and doesn't reload the Facebook chrome. When I do this, all the Facebook fb_sig_* query string parameters that Facebook passes to the original page aren't included, and so two.html has no awareness of the connection to Facebook and no ability to make API calls to generate the content for the page. One possible solution would be to manually extract all the Facebook parameters from one.html and append it to the link to two.html myself. This seems really ugly and I figured there had to be a cleaner way. For reference, my application is written in Perl and uses the WWW::Facebook::API module as a client library. I didn't see anything in it that I can use to easily reconstruct the Facebook parameters for use with links in iframe apps. Another possible solution would be to store all the Facebook parameters in a session on my server on the first page load, and just use the values in that session on subsequent page views. But what happens if the data I've stored no longer matches what Facebook would have sent if it were a completely new request (i.e. something in the user's Facebook session changed)? Is there something obvious I'm missing? What is the standard approach to navigating between pages within an iframe app? Facebook's documentation is atrocious and I haven't been able to find anything that clearly explains how this works. I also realize this wouldn't be an issue with an app using FBML instead of an iframe, but my understanding is that iframe apps are now encouraged over FBML apps, though again this seems ambiguous since so much of Facebook's documentation is outdated and contradictory.

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  • Linking a facebook app's page to an existing facebook business page

    - by Dan
    I have a facebook app page, and a separate facebook business profile page. The business page was created, but not by me, some time before the app and its page were created. Is there any way to connect the two pages, or import the content and friends from one to the other? The older profile page has some content; a set of friends and wall posts that I don't want to lose. It was created before I had a chance to set up an app page. Since the app was created more recently, it does not have any content posted to it. I intended the app page to eventually hold some advertising info for my main website itself (non-canvas, just using fb for the connect api etc). The idea being that as people sign up on my site through facebook's OAuth, I could use the graph api to post to their wall. The wall posts are working as expected but naturally they are directing users to the facebook app page, which has no content, friends etc. I'd prefer to be directed to the original business page, where the party is really happening. Now it seems that the two pages are completely separate; what would I need to do to direct the users to the business page?

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  • Auto Login facebook user into application

    - by user537562
    So, Here is the scenario I am trying to fix. A returning user is logged into facebook but not logged into the application. In this case when the user tries to load the application, since the user cookie is not attained yet, it redirects the user to the login page. I googled around and found this solution, FB.Event.subscribe('auth.sessionChange', function(response) { if (response.session) { window.location.reload(); } } basically whats happening here is, we are registering to facebook for a login/logout event and when it receives a response, we reload the page. Now its loads the right page since we have the user cookie on our site domain after the first load. this works, but the problem is the double load. It takes a lot of time. How can I attain the user cookie on server side for returning user? so that I don't have to do the initial page reload. Also, I have looked at yelp, and somehow they are able to load the user information without doing double load, does any body know they are able to do it? Any help is greatly appreciated, Thanks!

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