Programming with .NET - General

Re: SL WCF can't handle faults?

mbaocha — Tue, 19 May 2009 14:36:47 GMT

thanks for posting these here. It really helped. Silverlight is the way to go. Buts so much headache debugging all those errors.

________________________
Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}

Cheap Affordable Web Hosting | Web Hosting Nigeria | Best Web Design Company

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

davidezordan — Tue, 19 May 2009 12:32:24 GMT

Please refer to the on-line documentation for creating and handling faults with Silverlight 3: http://msdn.microsoft.com/en-us/library/dd470096(VS.96).aspx

Re: SL WCF can't handle faults?

davidezordan — Wed, 21 Jan 2009 22:54:10 GMT

As reported by Eugene Osovetsky in his great article, a sample implementation of SOAP faults can be found here: http://code.msdn.microsoft.com/silverlightws/Release/ProjectReleases.aspx?ReleaseId=1660

Re: SL WCF can't handle faults?

GLittle95 — Wed, 21 Jan 2009 22:09:15 GMT

Eugene Osovetsky explains the issues well here:

Faults and Exceptions when using Web Services in Silverlight 2

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

jemiller — Sat, 06 Sep 2008 07:06:39 GMT

It looks like faults still don't work in Silverlight Beta 2? What I'm seeing is WCF returns a 500 with the fault in it, but, Silverlight reports it as a 404?

System.ServiceModel.ProtocolException was unhandled by user code
Message="The remote server returned an unexpected response: (404) Not Found."
StackTrace:
       at System.ServiceModel.AsyncResult.End[TAsyncResult](IAsyncResult result)
       at System.ServiceModel.Channels.ServiceChannel.SendAsyncResult.End(SendAsyncResult result)
       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 DisplaysSilverlightApplication.ServiceReference1.ServiceClient.ServiceClientChannel.EndSaveRole(IAsyncResult result)
       at DisplaysSilverlightApplication.ServiceReference1.ServiceClient.DisplaysSilverlightApplication.ServiceReference1.Service.EndSaveRole(IAsyncResult result)
       at DisplaysSilverlightApplication.ServiceReference1.ServiceClient.OnEndSaveRole(IAsyncResult result)
       at System.ServiceModel.ClientBase`1.OnAsyncCallCompleted(IAsyncResult result)
InnerException:

I wonder if the part about having to convert 500s to 200s has something to do with a limitation in the browser "network stack?" I think this is what Adobe claims with Flex.

On a related note, someone in another thread mentioned something about how Microsoft was trying to extend the standard for the browser network stack? Is there such a standard? If so, where is it defined? I find it confusing that a browser has such a thing. I don't know why they don't just use normal socket calls. The whole business about all network calls, even socket calls having to be async is quite annoying also.

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

aaronc — Wed, 09 Apr 2008 13:03:04 GMT

Actually I think using an out parameter is going to be good enough for me.

public MyClass WebService(string param1, string param2, out string error)

Silverlight has no problems getting back the error out parameter and while it means the interface will need a change when exceptions are properly supported it will be a quick job since the proxy is autogenerated.

Regards,

Aaron

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

aaronc — Wed, 09 Apr 2008 10:55:01 GMT

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

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

MichaelGG — Wed, 09 Apr 2008 05:33:23 GMT

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);
            }
        }

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

aaronc — Wed, 09 Apr 2008 04:52:59 GMT

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

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

aaronc — Wed, 09 Apr 2008 04:12:10 GMT

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

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

MichaelGG — Wed, 09 Apr 2008 03:44:19 GMT

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?

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

aaronc — Wed, 09 Apr 2008 03:26:23 GMT

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

Re: SL WCF can't handle faults?

MichaelGG — Thu, 27 Mar 2008 07:21:56 GMT

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.

Re: SL WCF can't handle faults?

Kim Johnson — Wed, 26 Mar 2008 16:52:11 GMT

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 - ??

Re: SL WCF can't handle faults?

MichaelGG — Wed, 26 Mar 2008 08:59:51 GMT

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