WCF: Data contract names: don’t use names with "Response" suffix!

by | Jun 2, 2008 | BizTalk Community Blogs via Syndication

After creating simple WCF service I’ve got strange errors (see below).
Th issue was in the names of the response messages.
I used the simple custom rule to name request and response messages (.NET DataContract classes):
<OperationName>Request and <OperationName>Response
For instance I created GetTokenResponse class for the response message of the GetToken operation.
And this isthe wrong rule!
Why? Because the WCF creates these names for the WSDL metadata files:
For instance I’ve got:
…
<wsdl:message name=”ITokenStore_GetToken_OutputMessage“>
<wsdl:part name=”parameters“ element=”tns:GetTokenResponse“ /> …
….<wsdl:operation name=”GetToken“>
<wsdl:input wsaw:Action=”http://Clearmedia.Services/TokenStore/2008-05-29/ITokenStore/GetToken“ message=”tns:ITokenStore_GetToken_InputMessage“ />
<wsdl:output wsaw:Action=”http://Clearmedia.Services/TokenStore/2008-05-29/ITokenStore/GetTokenResponse“ message=”tns:ITokenStore_GetToken_OutputMessage“ />
When I changed the name to the GetToken_Response the errors disappeared.
It is not an error in the WCF it is just undocumented feature.
The problem is the error text gives us unhelpful and ambiguous information.
See the article in MSDN: http://msdn.microsoft.com/en-us/library/ms731045.aspx
Not a clue about these rules.
Conclusion:
Don’t use the name convention for the request and response messages (.NET classes) like <OperationName>Request and <OperationName>Response !
Error in SoapUI
, when we’ve tried to get the metadata:
… ERROR:javax.wsdl.WSDLException: WSDLException (at /HTML): faultCode=INVALID_WSDL: Expected element ‘{http://schemas.xmlsoap.org/wsdl/}definitions’.
Error in IE: by address the<ServiceAddressURL>

The service encountered an error.

An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is:
System.InvalidOperationException: An exception was thrown in a call to a WSDL export extension: System.ServiceModel.Description.DataContractSerializerOperationBehavior
 contract: http://MyServices/TokenStore/2008-05-29:ITokenStore ----> System.Xml.Schema.XmlSchemaException: The global element 'http://MyServices/TokenStore/2008-05-29:GetTokenResponse' has already been declared.
   at System.Xml.Schema.XmlSchemaSet.InternalValidationCallback(Object sender, ValidationEventArgs e)
   at System.Xml.Schema.BaseProcessor.AddToTable(XmlSchemaObjectTable table, XmlQualifiedName qname, XmlSchemaObject item)
   at System.Xml.Schema.Preprocessor.Preprocess(XmlSchema schema, String targetNamespace, ArrayList imports)
   at System.Xml.Schema.Preprocessor.Execute(XmlSchema schema, String targetNamespace, Boolean loadExternals)
   at System.Xml.Schema.XmlSchemaSet.PreprocessSchema(XmlSchema& schema, String targetNamespace)
   at System.Xml.Schema.XmlSchemaSet.Reprocess(XmlSchema schema)
   at System.ServiceModel.Description.MessageContractExporter.Compile()
   at System.ServiceModel.Description.DataContractSerializerMessageContractExporter.Compile()
   at System.ServiceModel.Description.MessageContractExporter.ExportMessage(Int32 messageIndex, Object state)
   at System.ServiceModel.Description.MessageContractExporter.ExportMessageContract()
   at System.ServiceModel.Description.WsdlExporter.CallExtension(WsdlContractConversionContext contractContext, IWsdlExportExtension extension)
   --- End of inner ExceptionDetail stack trace ---
   at System.ServiceModel.Description.ServiceMetadataBehavior.MetadataExtensionInitializer.GenerateMetadata()
   at System.ServiceModel.Description.ServiceMetadataExtension.EnsureInitialized()
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.InitializationData.InitializeFrom(ServiceMetadataExtension extension)
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.GetInitData()
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.TryHandleDocumentationRequest(Message httpGetRequest, String[] queries, Message& replyMessage)
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.ProcessHttpRequest(Message httpGetRequest)
   at SyncInvokeGet(Object , Object[] , Object[] )
   at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
   at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)
Error in IE: by address the<ServiceAddressURL>?wsdl

The service encountered an error.

An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is:
System.InvalidOperationException: An exception was thrown in a call to a WSDL export extension: System.ServiceModel.Description.DataContractSerializerOperationBehavior
 contract: http://MyServices/TokenStore/2008-05-29:ITokenStore ----> System.Xml.Schema.XmlSchemaException: The global element 'http://MyServices/TokenStore/2008-05-29:GetTokenResponse' has already been declared.
   at System.Xml.Schema.XmlSchemaSet.InternalValidationCallback(Object sender, ValidationEventArgs e)
   at System.Xml.Schema.BaseProcessor.AddToTable(XmlSchemaObjectTable table, XmlQualifiedName qname, XmlSchemaObject item)
   at System.Xml.Schema.Preprocessor.Preprocess(XmlSchema schema, String targetNamespace, ArrayList imports)
   at System.Xml.Schema.Preprocessor.Execute(XmlSchema schema, String targetNamespace, Boolean loadExternals)
   at System.Xml.Schema.XmlSchemaSet.PreprocessSchema(XmlSchema& schema, String targetNamespace)
   at System.Xml.Schema.XmlSchemaSet.Reprocess(XmlSchema schema)
   at System.ServiceModel.Description.MessageContractExporter.Compile()
   at System.ServiceModel.Description.DataContractSerializerMessageContractExporter.Compile()
   at System.ServiceModel.Description.MessageContractExporter.ExportMessage(Int32 messageIndex, Object state)
   at System.ServiceModel.Description.MessageContractExporter.ExportMessageContract()
   at System.ServiceModel.Description.WsdlExporter.CallExtension(WsdlContractConversionContext contractContext, IWsdlExportExtension extension)
   --- End of inner ExceptionDetail stack trace ---
   at System.ServiceModel.Description.ServiceMetadataBehavior.MetadataExtensionInitializer.GenerateMetadata()
   at System.ServiceModel.Description.ServiceMetadataExtension.EnsureInitialized()
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.InitializationData.InitializeFrom(ServiceMetadataExtension extension)
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.GetInitData()
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.TryHandleMetadataRequest(Message httpGetRequest, String[] queries, Message& replyMessage)
   at System.ServiceModel.Description.ServiceMetadataExtension.HttpGetImpl.ProcessHttpRequest(Message httpGetRequest)
   at SyncInvokeGet(Object , Object[] , Object[] )
   at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
   at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc)
   at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)