MSDN Magazine - January 2008 - (Page 78)

Figure 4 Using WebHttpBinding and WebHttpBehavior ServiceHost host = new ServiceHost(typeof(IPictureContract), new Uri(“http://localhost:5000”)); // instantiate a WebHttpBinding WebHttpBinding binding = new WebHttpBinding(); // add an endpoint, using the WebHttpBinding ServiceEndpoint ep = host.AddServiceEndpoint( typeof(IPictureContract), binding, String.Empty); // add the WebHttpBehavior to the endpoint ep.Behaviors.Add(new WebHttpBehavior()); // open the ServiceHost to start listening host.Open(); So far, you’ve seen how to map URI segments to application functionality, how to map operations to HTTP verbs, and how to interact with HTTP headers. Now let’s see how to connect these features together into a functioning service. To do this, you’ll need to look at a few more types that are new in WCF. WCF in the .NET Framework 3.0 introduced the concept of a binding, the abstraction over the transport and protocols of an endpoint. The .NET Framework 3.0 shipped with several bindings that included support for a wide array of transport and protocol choices. WCF in the .NET Framework 3.5 includes a new binding named System.ServiceModel.WebHttpBinding. This binding is the abstraction of the principles of the Web and follows the same usage model as the binding types in the .NET Framework 3.0, so you can add it to an endpoint just like you would any other binding. WCF in the .NET Framework 3.0 also introduced the concept of an endpoint behavior. A behavior is a way to extend the execution path of the messaging infrastructure. There are several behaviors that ship with the .NET Framework, and it is also easy to create your own. WCF in the .NET Framework 3.5 includes a new endpoint behavior named System.ServiceModel.Description.WebHttpBehavior. This behavior does several tasks. For receiving applications, it sets up the filtering infrastructure to ensure, among other things, that received messages are dispatched to the appropriate method on the service object. In the .NET Framework 3.0 WCF used a combination of SOAP Action and target address as dispatch keys. The filtering mechanism setup by the WebHttpBehavior extends the existing filtering mechanisms to key off of UriTemplate matches and HTTP verbs. Figure 4 shows how you can use WebHttpBinding and WebHttpBehavior to build a receiving application that embraces the principles of the Web. The advantage of this approach is that you can add one of these endpoints to an existing ServiceHost and by doing this you end up with one ServiceHost that has both SOAP/ WS-* endpoints and REST endpoints. Sending applications follow the same usage model, but the WebHttpBehavior should be added to the endpoint behavior collection on the ChannelFactory object. As per typical WCF practice, these options are also available in configuration files. 78 msdnmagazine WCF Syndication Binding and Hosting WCF in the .NET Framework 3.5 takes this easy-to-use model even further so that you don’t have to add either WebHttpBinding or WebHttpBehavior in some cases. The new API includes two types that serve this purpose: System.ServiceModel.Web.WebServiceHost and System.ServiceModel.Web.WebServiceHostFactory. The WebServiceHost type automatically adds the WebHttpBehavior to all endpoints and does some extra validation at run time to ensure that all endpoints are compatible with the behavior. This saves you the step of adding the WebHttpBehavior to an endpoint. The WebServiceHostFactory type was designed for use in IIShosted scenarios to remove the need for any imperative or configuration file hosting information. WCF in the .NET Framework 3.0 introduced the .svc file as an activation target for hosting WCF services in IIS. These files contain directives that look similar to page directives in ASP.NET. Adding WebServiceHostFactory to the Factory property of the .svc file directive creates a ServiceHost, adds an endpoint that uses the appropriate contract with the WebHttpBinding, adds WebHttpBehavior to that endpoint, and opens the ServiceHost: The web.config file for the service does not contain any WCFrelated entries. The New Syndication API Imagine an RSS feed. If you are at all like me, you immediately think of a news feed or a blog. Syndications—RSS and ATOM are syndication formats—are able to express much more. In the abstract, syndicated content is simply a way to represent a set of data. That set of data could be practically anything: the number of wombats in residence within a 50-mile radius of Sydney, the last 10 purchase orders over $100, or the number of boomerangs Contoso produced last month. The .NET Framework 3.5 includes rich support for creating and consuming syndicated content. It supports creating and consuming both RSS 2.0 and ATOM 1.0 formats, various means of adding syndication extensions, and even the capability to implement additional formats. The programming model shields the developer from syndication format particulars, thereby helping to make it easy to use. Up until version 3.5, there was no standard way to create or Additional Resources Windows Communication Foundation Developer Center msdn2.microsoft.com/library/ms735119 .NET Framework Developer Center msdn2.microsoft.com/netframework Visual Studio 2008 Downloads msdn2.microsoft.com/vstudio/aa700831 PictureServices Sample App www.cloudsamples.net/pictureservices http://msdn2.microsoft.com/library/ms735119 http://msdn2.microsoft.com/netframework http://msdn2.microsoft.com/vstudio/aa700831 http://www.cloudsamples.net/pictureservices

Table of Contents Feed for the Digital Edition of MSDN Magazine - January 2008

MSDN Magazine - January 2008 Contents Toolbox CLR Inside Out Data Points Advanced Basics Cutting Edge IIS 7.0 - Enhance Your Apps with the Integrated ASP.NET Pipeline World Ready - Around the World with ASP.NET AJAX Applications WCF Syndication - HTTP Programming with WCF and the .NET Framework 3.5 Wicked Code Foundations Extreme ASP.NET {End Bracket}

MSDN Magazine - January 2008

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