Capture response when a service returns a 500 error using WCF

Question

I'm getting data from a 3rd party web service using REST (using WebHttpBinding and WebHttpBehavior). When I pass an invalid parameter in the querystring, the service responds with a 500 status and describes the problem. The response looks something like this:

HTTP/1.1 500 Internal Server Error
Date: Tue, 14 Jun 2011 16:12:48 GMT
... more headers

<Error>Invalid integer value for ID</Error>

I would really like to be able to capture that error message. My WCF client looks like this:

public class DataClient : ClientBase<IDataClient>, IDataClient
{
    public DataClient (string endpointAddress)
        : base(new WebHttpBinding(), new EndpointAddress(endpointAddress))
    {
        this.Endpoint.Behaviors.Add(new WebHttpBehavior());
    }

    public string GetData(string id)
    {
        // This is where the exception is thrown
        return base.Channel.GetData(id);
    }
}

When I catch the exception that is thrown, that data is nowhere to be found. It just says, "System.ServiceModel.CommunicationException: Internal Server Error".

I tried creating a custom behavior and added a message inspector, but my custom message inspector code doesn't get executed before the exception is thrown (it does get executed if no exception is thrown).

Do you have `` added in the web.config of the service web dir? — Chris O, Jun 14 '11 at 17:06
I am just the client consuming someone else's service. I don't have control over the service. — dontangg, Jun 14 '11 at 17:15
You'll have to contact whoever is providing this service and ask how to get detailed exception information. — Chris O, Jun 14 '11 at 17:23
He is already passing the information that I want. I just want to know, "Invalid integer value for ID" — dontangg, Jun 14 '11 at 17:50

score 3 · Accepted Answer · answered Jun 14 '11 at 22:54

3

I finally figured it out. Creating a custom behavior and adding a message inspector is the way that I needed to do it. I just needed to add my custom behavior before the WebHttpBehavior. Then I can look at the whole response and throw my own exception with all the data in it!

answered Jun 14 '11 at 22:54

dontangg

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What do you mean by adding your custom beahvior *before* the WebHttpBehavior ? – Numid Feb 03 '14 at 21:20
Actually you can add your custom behaviour after the WebHttpBehavior if you enable FaultExceptionEnabled on the WebHttpBehavior. – François Nov 15 '18 at 17:37

score 1 · Answer 2 · answered Jun 14 '11 at 19:26

(Can't get my test project to actually send the HTTP 500, only seems to do that when I don't want it to ;-)

In the off-chance that this will help you, try wrapping you client service call and inspect the response in the debugger to see if it contains the error string you are trying to capture.

    using (new OperationContextScope(service1.InnerChannel))
    {
        try
        {
            result = service1.GetData("5");
        }
        catch (System.Exception e)
        {
            string msg = e.ToString();
        }
        HttpResponseMessageProperty response = (HttpResponseMessageProperty)
            OperationContext.Current.IncomingMessageProperties[HttpResponseMessageProperty.Name];
    }

I realise this is a 11 year old answer, but this was the most elegant solution for me, and able to slot nicely right into my existing code. — Dekks, Feb 01 '21 at 16:17

Capture response when a service returns a 500 error using WCF

2 Answers2

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