Hosting WCF in SharePoint 2010

SharePoint 2007 provided the capability to add custom ASMX web services. Web Services could be deployed to the LAYOUTS folder, or could be deployed to the ISAPI folder and supported accessing site settings and list data under the SharePoint user context. Since SharePoint 2007 was built on the ASP.NET 2.0 model, it did not natively support web service enhancements that were introduced with Windows Communication Foundation (WCF) in .NET Framework 3.0 and 3.5 or the additional WCF-based service frameworks like ADO.NET Data Services (now WCF Data Services).

For those familiar with writing custom ASMX services for 2007, there were some pitfalls. Since SharePoint requires dynamic service endpoints (the ability to call the web service using any site-relative virtual path under the /_vti_bin/ folder), you had to hand-tool your WSDL files to dynamic service locations. This had to be done every time your changed your web-service signature. Not terribly complicated, but certainly tedious.

The good news is that SharePoint 2010 is based upon ASP.NET 3.5 and now supports WCF custom services including SOAP, REST, and WCF Data Services. The even better news is that is makes it easy to deploy custom WCF services with dynamic endpoints by supporting a number of custom Service Host Factory implementations that can auto-generate. This means it is not necessary to modify the SharePoint web.config to deploy your service endpoint configurations.

In this article, I will walkthrough and highlight the important aspects of the SharePoint 2010 support for custom WCF services.

Run Visual Studio 2010 as an administrator.

Create New Empty SharePoint project.

Visual Studio 2010 now includes templates for developing just about every type of SharePoint customization including Web Parts, List Handlers, custom Site Definitions, List Templates, etc. It does not include a template for a SharePoint Web Service, so we will want to start with the Empty SharePoint Project template. The will automatically create a project that includes references to the core Microsoft.SharePoint assembly, and includes special capabilities for defining Features, and automatically packaging and deploying your solution as a WSP.

Select Deploy as a farm solution and click on finish

Map the ISAP folder into the project as shown below.

To support a custom WCF we need to perform a few additional steps:

• Add a reference to the Microsoft.SharePoint.Client.ServerRuntime assembly. This assembly contains the Service Host Factory classes, as well as some attributes we need later on.
• Add a SharePoint Mapped Folder to the ISAPI folder, and create an empty text file with the .SVC extension. Note that it is always a good practice to create a sub-folder when deploying your custom code to the SharePoint file system. It helps keep you custom code separate from the original installed files.

Select text file template and add Sample.svc file into the directory structure of ISAPI

Similarly select the text file template and add Web.config file into the directory structure.

The next step is to add the WCF service contract and implementation. For my sample, I have written a very simple service that returns the Url of the current SharePoint context. This is a good way to verify that the service endpoints generated for us by SharePoint are dynamic.

The important thing to note here are the attributes required on the implementation class. These attributes allow SharePoint to automatically support metadata exchange endpoints, and is the secret sauce that allows us to develop custom WCF services without having to deploy endpoint configuration to the SharePoint web.config.

Step 6: Configure service host definition.