Microsoft Silverlight

Member

86 points

http://blogs.sparknettech.com/blog/2007/10/31/flex-webservice-error-handeling/

Re: SL WCF can't handle faults?

03-26-2008 4:43 AM |

OK, I found a brute-force way to quickly fix the HTTP 500 problem:

Rewrites all 500s to 200s. It probably isn't too hard to filter it down to only doing this for WCF service responses if the client is a webbrowser/silverlight. Unfortunately, Silverlight still fails:

Error: System.Runtime.Serialization.SerializationException: OperationFormatter encountered an invalid Message body. Expected to find node type 'Element' with name 'DeletePartitionResponse' and namespace 'http://schemas.packetrino.com/management/v2/00'. Found node type 'Element' with name 's:Fault' and namespace 'http://schemas.xmlsoap.org/soap/envelope/'
   at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeBody(XmlDictionaryReader reader, MessageVersion version, String action, MessageDescription messageDescription, Object[] parameters, Boolean isRequest)
   at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeBodyContents(Message message, Object[] parameters, Boolean isRequest)
   at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeReply(Message message, Object[] parameters)
   at System.ServiceModel.Dispatcher.ProxyOperationRuntime.AfterReply(ProxyRpc& rpc)
   at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc)
   at System.ServiceModel.Channels.ServiceChannel.EndCall(String action, Object[] outs, IAsyncResult result)
   at System.ServiceModel.ClientBase`1.ChannelBase`1.EndInvoke(String methodName, Object[] args, IAsyncResult result)
...

Any ideas from here?

Member

86 points

Re: SL WCF can't handle faults?

03-26-2008 4:59 AM |

I tried adding a typed fault to my service, just on the off-chance that this somehow would help. Turns out Silverlight 2 Beta 1 doesn't even have the bits necesary to reference such a service.

I get the FaultContractAttribute applied to the generated interface in SL, but apparently that type doesn't exist. So I'm guessing that yes, fault support is nowhere to be found (despite the fact that FaultException exists).

I guess I just have to wait 'till Beta 2?

-Michael

Kim Johnson

Member

6 points

6 Posts

Re: SL WCF can't handle faults?

03-26-2008 12:52 PM |

We're really hoping to see FaultException<T> / FaultContract support too - having to add an error code to every return type is not a good answer. Hope to see this fixed in Beta2 - ??

Member

86 points

Re: SL WCF can't handle faults?

03-27-2008 3:21 AM |

Well I got a cheap hackaround to at least allow some faulting with Silverlight: http://www.atrevido.net/blog/2008/03/27/Hacking+SOAP+Faults+Into+Silverlight+2+Beta+1.aspx

It's cheap, it's hacky, but it gives me enough to deal with until Beta 2.

Member

78 points

Re: Re: SL WCF can't handle faults?

04-08-2008 11:26 PM |

Is there any trick to getting the System.Runtime.Serialization.SerializationException exception in the Silverlight proxy?

I'm modifying the response code from 500 to 200 on the reponses being sent to Silverlight but instead of the SerializationException I'm getting a NullReferenceException presumamby when Silverlight tries and fails to deserialise the return object from the response.

Regards,

Aaron

Member

86 points

Re: Re: SL WCF can't handle faults?

04-08-2008 11:44 PM |

I have sample code on my site. But no, I didn't have to do anything that I recall. Can you post a full stacktrace?

Member

78 points

Re: Re: Re: SL WCF can't handle faults?

04-09-2008 12:12 AM |

If I send back valid XML from global.asax I don't get an exception until I try and use the result object which is where the NullReference comes in.

If I send back invalid XML from global.asax I get a stack trace of:

{System.Xml.XmlException: [Xml_TagMismatch]
Arguments:faultstring,1,soap:Fault
Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=2.0.30226.2&File=System.Xml.dll&Key=Xml_TagMismatch [Xml_ErrorPosition]
Arguments:1,187
Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=2.0.30226.2&File=System.Xml.dll&Key=Xml_ErrorPosition
   at System.Xml.XmlTextReaderImpl.Throw(Exception e)
   at System.Xml.XmlTextReaderImpl.Throw(String res, String[] args)
   at System.Xml.XmlTextReaderImpl.ThrowTagMismatch(NodeData startTag)
   at System.Xml.XmlTextReaderImpl.ParseEndElement()
   at System.Xml.XmlTextReaderImpl.ParseElementContent()
   at System.Xml.XmlTextReaderImpl.Read()
   at System.Xml.XmlDictionaryReader.XmlWrappedReader.Read()
   at System.Xml.XmlReader.SkipSubtree()
   at System.Xml.XmlReader.Skip()
   at System.ServiceModel.Dispatcher.OperationFormatter.TraceAndSkipElement(XmlReader xmlReader)
   at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeParameters(XmlDictionaryReader reader, PartInfo[] parts, Object[] parameters, Boolean isRequest)
   at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeBody(XmlDictionaryReader reader, MessageVersion version, String action, MessageDescription messageDescription, Object[] parameters, Boolean isRequest)
   at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeBodyContents(Message message, Object[] parameters, Boolean isRequest)
   at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeReply(Message message, Object[] parameters)
   at System.ServiceModel.Dispatcher.ProxyOperationRuntime.AfterReply(ProxyRpc& rpc)
   at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc)
   at System.ServiceModel.Channels.ServiceChannel.EndCall(String action, Object[] outs, IAsyncResult result)
   at System.ServiceModel.ClientBase`1.ChannelBase`1.EndInvoke(String methodName, Object[] args, IAsyncResult result)
   at

I'm playing around with sending back different payloads from global.asax to try and somehow get an exception thrown with the payload in the e.Error.Message but so far haven't been able to. An example of a payload I've tried sending is:

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <soap:Fault><faultcode>soap:Server</faultcode><faultstring>Test fault message</faultstring><detail /></soap:Fault> </soap:Body></soap:Envelope>

Regards,

Aaron

Member

78 points

Re: Re: Re: Re: SL WCF can't handle faults?

04-09-2008 12:52 AM |

Does using the following script for global.asax generate an exception in Silverlight?

protected void Application_EndRequest(object sender, EventArgs e)
{
    if (Context.Response.StatusCode == 500)
    {
        Context.Response.ContentType = "text/xml";
        Context.Response.StatusCode = 200;
        Context.Response.ClearContent();

        string soapFault =
            "<soap:Envelope xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">" +
            " <soap:Body>" +
     " <SomeNS.SomeClass xmlns=\"test 1 2 3 4\" />" +
            " </soap:Body>" +
            "</soap:Envelope>";

Context.Response.Output.Write(soapFault);
}
}

</script>

For me it gets accepted and puts a System.NullReferenceException into e.Error.

Regards,

Aaron

Member

86 points

Re: Re: Re: Re: SL WCF can't handle faults?

04-09-2008 1:33 AM |

Here is the exact code I have in a production system and it works fine in conjunction with the rest of the code:

        protected void Application_EndRequest(object sender, EventArgs e)
        {
            // In all fairness, I was drinking eiswein at the time
            if (Context.Items.Contains("HackFault")) {
                Context.Response.ContentType = "text/xml";
                Context.Response.StatusCode = 200;
                Context.Response.ClearContent();

                var hackEx = Context.Items["HackFault"] as Exception;
                var hackFaultXml = string.Format(
                    "<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\"><s:Body><{0} xmlns=\"{1}\" /></s:Body></s:Envelope>",
                    hackEx.GetType().ToString(), Context.Server.HtmlEncode(hackEx.Message));
                Context.Response.Output.Write(hackFaultXml);
            }
        }

Member

78 points

Re: Re: Re: Re: Re: SL WCF can't handle faults?

04-09-2008 6:55 AM |

Where abouts do you have the exception handler code on the Siverlight side? Is it before or after the auto-generated service proxy?

Regards,

Aaron

Member

78 points