Recently, I have been implementing a POX (plain ol’ XML) WCF service that needed to route all requests through a single ‘handler’ operation contract. The routing to this single operation was easily implemented by adding a wildcard action to the operation contract:

[OperationContract(Action = "*", ReplyAction = "*")]       
Message HandleRequest(Message request);

However, an additional requirement was for the service to respond to all messages that included the base url in their address. For example, if the service is running at http://localhost/myService, it needed to accept messages addressed to http://localhost/myservice/hello.

In order to implement this we have to alter the WCF services AddressFilterMode, which can be accessed as a setting on the ServiceBehaviour attribute:

[ServiceBehavior(AddressFilterMode = AddressFilterMode.Prefix)]
public class MyServiceImplementation: IMyServiceContract

AddressFilterMode is an enumeration that has three values: Exact, Prefix and Any. This setting determines which message addresses that the WCF service accepts. Exact, the default, will make the service ONLY respond to messages addressed to the exact service url (e.g. http://localhost/myService only). The opposite is Any, which will make the service accept messages for any address. Finally, there is Prefix, which was used in my scenario, which ensures that the message address must include the service url.