Question

I’m trying to perform a POST to a WCF service.
When using Firefox 8, the browser first sends a OPTIONS HTTP request.

This works fine when I use WebMessageBodyStyle.Bare as the BodyStyle, but what I want is to use the Wrapped body style.
When I switch to Wrapped, the OPTIONS request is refused with 400 status.
I suspect that this is due to the fact that the OPTIONS request has no body hence the BodyStyle parser fails.

Here’s the layout of my web mehod:

[OperationContract(ProtectionLevel = ProtectionLevel.None)]
[WebInvoke(Method = "*",
           BodyStyle = WebMessageBodyStyle.Wrapped,
           RequestFormat = WebMessageFormat.Json,
           ResponseFormat = WebMessageFormat.Json)]
bool Ping(String msg);

And I use the following jquery for invoking:

$.ajax({
            url: "http://localhost/Server/Service.svc/Ping",
            data: JSON.stringify({msg: msg}),
            type: "POST",
            processData: false,
            contentType: "application/json",
            timeout: 10000,
            dataType: "text"
});

I would appreciate any help on this issue…
Thanks!!

Answer 1

I solved this by adding a custom IErrorHandler to the Enpoint Behavior.
General instructions for how to do this are here.

public bool HandleError(Exception error)
{
  if (error.Message.Contains("IsEmpty = true")) return true;

  return false;
}

and

public void ProvideFault(Exception error, MessageVersion version, ref Message fault)
        {
            if (error.Message.Contains("IsEmpty = true"))
            {
                fault = Message.CreateMessage(version, "");
                var jsonFormatting = new WebBodyFormatMessageProperty(WebContentFormat.Json);
                fault.Properties.Add(WebBodyFormatMessageProperty.Name, jsonFormatting);
                var httpResponse = new HttpResponseMessageProperty
                                       {
                    StatusCode = System.Net.HttpStatusCode.OK,
                    StatusDescription = "OK"
                };
                fault.Properties.Add(HttpResponseMessageProperty.Name, httpResponse);
            }
            else
            {
                fault = GetJsonFaultMessage(version, error);

                var jsonFormatting = new WebBodyFormatMessageProperty(WebContentFormat.Json);
                fault.Properties.Add(WebBodyFormatMessageProperty.Name, jsonFormatting);
                var httpResponse = new HttpResponseMessageProperty
                                       {
                    StatusCode = System.Net.HttpStatusCode.BadRequest,
                    StatusDescription = "Bad Request"
                };
                fault.Properties.Add(HttpResponseMessageProperty.Name, httpResponse);
            }
        }