Handling Invalid URI passed to a WCF service - wcf

Question

I have WebGet, and WebInvoke attributes describing my contract, but what is the best method of handling invalid URI's? Right now, if a user passes an URI that does not match my current operations, they get an "Endpoint not found." message. I want to pass back a more descriptive message.
For example, my URI template looks like:
/Stuff/{ID}/subStuff
but say they type
/Stuff/{ID}/OtherStuff
There is no such thing as OtherStuff, and I do not have a template for that.
Is there a way to cover all non mapped URI's with a single contract?
Thanks!

Answer 1

If you want to catch all the unhandled requests at a global level in WCF REST then you have to create a custom WebHttpBehavior and custom IOperationInvoker as described in this post.
If you want to return a custom error text with custom status code(404) you can also look into the WebOperationContext.OutgoingResponse property as described here.

Answer 2

While I did follow the links mark provided, and they did give a hint of what I needed. The answers that were linked did not actually answer my original question.
I was able to follow the steps, and I wanted to list my steps to solve this problem on this question as well.
To create my own response to any URI that was not mapped to a method in my contract I created the following:
A custom ServiceHostFactory
Behavior that I mapped to my end points within the custom ServiceHostFactory
a dispatcher that would handle all unmapped uri's that were provided to the service.
Below are the full definitions of the object's I created:
using System.ServiceModel;
using System.ServiceModel.Activation;
namespace your.namespace.here
{
public class CustomServiceHostFactory : WebServiceHostFactory
{
protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
{
ServiceHost host = base.CreateServiceHost(serviceType, baseAddresses);
//note: these endpoints will not exist yet, if you are relying on the svc system to generate your endpoints for you
// calling host.AddDefaultEndpoints provides you the endpoints you need to add the behavior we need.
var endpoints = host.AddDefaultEndpoints();
foreach (var endpoint in endpoints)
{
endpoint.Behaviors.Add(new WcfUnkownUriBehavior());
}
return host;
}
}
}
As you can see above, we are adding a new behavior: WcfUnknownUriBehavior. This new custom behavior's soul duty is to replace the UnknownDispatcher. below is that implementation:
using System.ServiceModel.Dispatcher;
using System.ServiceModel.Channels;
using System.ServiceModel.Web;
namespace your.namespace.here
{
public class UnknownUriDispatcher : IOperationInvoker
{
public object[] AllocateInputs()
{
//no inputs are really going to come in,
//but we want to provide an array anyways
return new object[1];
}
public object Invoke(object instance, object[] inputs, out object[] outputs)
{
var responeObject = new YourResponseObject()
{
Message = "Invalid Uri",
Code = "Error",
};
Message result = Message.CreateMessage(MessageVersion.None, null, responeObject);
WebOperationContext.Current.OutgoingResponse.ContentType = "text/html";
outputs = new object[1]{responeObject};
return result;
}
public System.IAsyncResult InvokeBegin(object instance, object[] inputs, System.AsyncCallback callback, object state)
{
throw new System.NotImplementedException();
}
public object InvokeEnd(object instance, out object[] outputs, System.IAsyncResult result)
{
throw new System.NotImplementedException();
}
public bool IsSynchronous
{
get { return true; }
}
}
}
Once you have these objects specified, you can now use the new factory within your svc's "markup":
<%# ServiceHost Language="C#" Debug="true" Service="your.service.namespace.here" CodeBehind="myservice.svc.cs"
Factory="your.namespace.here.CustomServiceHostFactory" %>
And that should be it. as long as your object "YourResponseObject" can be serialized, it's serialized representation will be sent back to the client.