Automatic documentation is another cool feature introduced in the WCF REST Starter kit. While documentation is an important aspect in the development process, unfortunately there is not an standard mode or guidance yet about how this should be done for REST services. This new feature comes to help a little in this aspect of the process.
As part of the starter kit, the WCF team has created a new [WebHelp] attribute that can be used to annotate existing web operations with human-readable descriptions. The [WebHelp] attribute (as the WebCache attribute) is an operation behavior implementation that receives a simple string to describe the operation behavior. The operation arguments are automatically reflected and shown as part of the service documentation.
[WebInvoke(UriTemplate = "DoWork?json", ResponseFormat = WebMessageFormat.Json)]
[WebHelp(Comment="This method returns a HTTP status code Conflict with a custom json error body")]
SampleResponseBody DoWorkJson(SampleRequestBody request)
Now, the question is, once we have this attribute applied to all the web operations of an existing service, where is the documentation actually published ?. Well, this feature also requires the use of a new service host "WebServiceHost2" that comes with the starter kit, which among other things publishes a new endpoint "/help" for the service. Therefore, the final documentation for a service will be available at "ServiceUri" + "/help". For example, http://localhost/MyService.svc/help
As you can see in the image above, an Atom feed is created and published in the /help endpoint. Each entry in the feed provides some documentation about any of the available web operations.
The new service host can be configured in a existing service modifying the .svc file (If the service runs on IIS),
<%@ ServiceHost Language="C#" Debug="true" Service="Service.Service" Factory="Microsoft.ServiceModel.Web.WebServiceHost2Factory"%>