Matevz Gacnik's Weblog

POX (Plain Old XML) support in Orcas is brilliant.

Consider the following service contract:

[ServiceContract(Namespace = "")]
interface IPOXService
{
   [OperationContract]
   [HttpTransferContract(Path = "Echo", Method = "GET")]
   string Echo(string strString1, ref string strString2, out string strString3);
}

And the following service (or, better Echo method) implementation:

public class POXService : IPOXService
{
   public string Echo(string strString1,
      ref string strString2, out string strString3)
   {
      strString2 = "strString2: " + strString2;
      strString3 = "strString3";
      return "Echo: " + strString1;
   }
}

Host it using this:

ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
smb.HttpGetEnabled = true;

ServiceHost sh = new ServiceHost(typeof(POXService), new Uri
   ("http://localhost:666"));
ServiceEndpoint ep = sh.AddServiceEndpoint(typeof(IPOXService),
   new WebHttpBinding(), "POX");
ep.Behaviors.Add(new HttpTransferEndpointBehavior());
sh.Description.Behaviors.Add(smb);

sh.Open();
Console.WriteLine("POX Service Running...");
Console.ReadLine();
sh.Close();

If you open IE and hit the service endpoint (http://localhost:666/POX/Echo) without URL encoded parameters, you get the following XML back:

<EchoResponse>
   <EchoResult>Echo:</EchoResult>
   <strString2>strString2:</strString2>
   <strString3>strString3</strString3>
</EchoResponse>

Now, drop some parameters in (http://localhost:666/POX/Echo?strString1=boo&strString2=foo&strString3=bar), this is returned:

<EchoResponse>
   <EchoResult>Echo: boo</EchoResult>
   <strString2>strString2: foo</strString2>
   <strString3>strString3</strString3>
</EchoResponse>

Nice. I especially like the fact that ref and out parameters are serialized with the metod return value.

Reach in with //EchoResponse/strString2 for ref parameter and //EchoResponse/strString3 for out parameter. Return value is available on //EchoResponse/EchoResult. Simple and effective.