Get the message of exception when calling a wcf service from jquery

exception, jquery, wcf

Solution

By default, WCF will not return any exception details - that is a wanted feature, by design, in order not to divulge too much information back to a possible attacker.

If you want to enable detailed exception messages, you can do this by enabling a behavior on the server side:

 <system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior name="debugBehavior">
          <serviceDebug includeExceptionDetailInFaults="True" />
        </behavior>
      </serviceBehaviors>
    </behaviors>

    <services>
        <service name="YourService"
                 behaviorConfiguration="debugBehavior">
             .....
        </service>
    </services>

But even now - you need to be aware that WCF should be interoperable, thus a client might not be running on .NET --> therefore you cannot just simply throw back an exception - that's a .NET specific construct.

Your best option is to catch all exceptions on the server (using e.g. the IErrorHandler interface), and turning those into SOAP faults - the interoperable equivalent of a .NET exception. If you know that the other end is a .NET client at all times, you can easily convert a .NET exception into a `FaultException<T>` where T is your .NET exception.

When you do this, you can catch an exception on the client by trapping the `FaultException<T>`, and its `.Detail` property should contain the normal .NET exception as you know it (and that contains a `.Message` property with the exception message).

Problem

Im calling a WCF service from jquery ajax. Sometimes the service throw some custom errors and when it does I need to get the message of that error. In the error function of my ajax call I have the following code: ``` error: function(data) { alert("responseText: " + data.responseText); } ``` And the responseText when the error is thrown looks something like: ``` responseText: {"ExceptionDetail":{"HelpLink":null,"InnerException":null,"Message":"Denied",......}} ``` I want to get the "Message" from "ExceptionDetail" but I'm not sure how to do it. My WCF service looks like this, to test it I just throw an error: ``` [OperationContract] [WebGet(ResponseFormat = WebMessageFormat.Json)] public string myFunction(string id) { throw new Exception("Denied"); } ``` How can I get the Message of the error?

Original source