WCF: Retrieving MethodInfo from OperationContext

Question

Is there an elegant way to get the method that will be executed on a service instance from MessageInspector/AuthorizationPolicy/some other extension point? I could use

Answer 1

If OperationContext.CurrentIncomingMessageHeaders.Action is null, you can do this -- it's a bit terser:

string actionName = OperationContext.Current.IncomingMessageProperties["HttpOperationName"] as string;
Type hostType = operationContext.Host.Description.ServiceType;
MethodInfo method = hostType.GetMethod(actionName);

Answer 2

It took me forever, but I did find a way that's better than finding and slogging through the entire contract:

string action = operationContext.IncomingMessageHeaders.Action;
DispatchOperation operation = 
    operationContext.EndpointDispatcher.DispatchRuntime.Operations.FirstOrDefault(o =>
        o.Action == action);
// Insert your own error-handling here if (operation == null)
Type hostType = operationContext.Host.Description.ServiceType;
MethodInfo method = hostType.GetMethod(operation.Name);

And there you are. You can get the attributes or do whatever else you like.

Note: You might be tempted to try to use the OperationSelector in the DispatchRuntime. The problem I found was that in my case, at the particular stage of processing, the OperationSelector was a null reference. If you have access to this property, it's probably faster and more reliable to use than "scanning" the OperationCollection as above.

Answer 3

Castle WCF integration facility enables you to do just that (among many useful things) by using DynamicProxy proxies. Take a look here.

There's not much documentation on it, so for docs on how to use it it's best to take a look at its tests.

Answer 4

Based on @Aaronaught and @TimDog 's answers, and this SO question I came up with a solution that should work for both REST and SOAP.

///<summary>Returns the Method info for the method (OperationContract) that is called in this WCF request.</summary>
System.Reflection.MethodInfo GetActionMethodInfo(System.ServiceModel.OperationContext operationContext ){
    string bindingName = operationContext.EndpointDispatcher.ChannelDispatcher.BindingName;
    string methodName;
    if(bindingName.Contains("WebHttpBinding")){
            //REST request
            methodName = (string) operationContext.IncomingMessageProperties["HttpOperationName"];
    }else{
            //SOAP request
            string action = operationContext.IncomingMessageHeaders.Action;
            methodName = operationContext.EndpointDispatcher.DispatchRuntime.Operations.FirstOrDefault(o =>o.Action == action).Name;
    }
    // Insert your own error-handling here if (operation == null)
    Type hostType = operationContext.Host.Description.ServiceType;
    return hostType.GetMethod(methodName);
}