c# - WCF contract mismatch problem

Question

I have a client console app talking to a WCF service and I get the following error: "The server did not provide a meaningful reply; this might be caused by a contract mismatch, a premature session shutdown or an internal server error."

I think it's because of a contract mismatch but i can't figure out why. The service runs just fine by itself and the 2 parts were working together until i added the impersonation code.

Can anyone see what is wrong?

Here is the client, all done in code:

NetTcpBinding binding = new NetTcpBinding();
binding.Security.Mode = SecurityMode.Message;
binding.Security.Message.ClientCredentialType = MessageCredentialType.Windows;

EndpointAddress endPoint = new EndpointAddress(new Uri("net.tcp://serverName:9990/TestService1"));
ChannelFactory<IService1> channel = new ChannelFactory<IService1>(binding, endPoint);
channel.Credentials.Windows.AllowedImpersonationLevel = TokenImpersonationLevel.Impersonation;
IService1 service = channel.CreateChannel();

And here is the config file of the WCF service:

<configuration>
  <system.serviceModel>
    <bindings>
      <netTcpBinding>
        <binding name="MyBinding">
          <security mode="Message">
            <transport clientCredentialType="Windows"/>
            <message clientCredentialType="Windows" />
          </security>
        </binding>
      </netTcpBinding>
    </bindings>
    <behaviors>
      <serviceBehaviors>
        <behavior name="WCFTest.ConsoleHost2.Service1Behavior">
          <serviceMetadata httpGetEnabled="true"  />
          <serviceDebug includeExceptionDetailInFaults="true" />
          <serviceAuthorization impersonateCallerForAllOperations="true" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <services>
      <service behaviorConfiguration="WCFTest.ConsoleHost2.Service1Behavior"
          name="WCFTest.ConsoleHost2.Service1">
        <endpoint address="" binding="wsHttpBinding" contract="WCFTest.ConsoleHost2.IService1">
          <identity>
            <dns value="" />
          </identity>
        </endpoint>
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
        <endpoint binding="netTcpBinding" bindingConfiguration="MyBinding"
            contract="WCFTest.ConsoleHost2.IService1" />
        <host>
          <baseAddresses>
            <add baseAddress="http://serverName:9999/TestService1/" />
            <add baseAddress="net.tcp://serverName:9990/TestService1/" />
          </baseAddresses>
        </host>
      </service>
    </services>
  </system.serviceModel>
</configuration>

Answer 1

Other possible causes:

• Trying to serialize an object without a default constructor.
• Trying to serialize some other kind of non serializable object (such as an Exception). To prevent the item from being serialized apply [IgnoreDataMember] attribute to the field or property.
• Check your enum fields to make sure they are set to a valid value (or are nullable). You may need to add a 0 value to the enum in some cases. (not sure about fine details of this point).

What to test:

• Configure WCF tracing for at least critical errors or exceptions. Be careful to watch filesize if you enable any further traces. This will give some very useful information in many cases.

  Just add this under <configuration> in your web.config ON THE SERVER. Create the log directory if it doesn't exist.

 <system.diagnostics>
     <sources>
       <source name="System.ServiceModel"
               switchValue="Error, Critical"
               propagateActivity="true">
         <listeners>
           <add name="traceListener"
               type="System.Diagnostics.XmlWriterTraceListener"
               initializeData= "c:logWCF_Errors.svclog" />
         </listeners>
       </source>
     </sources>
   </system.diagnostics>

• Make sure the .svc file will actually come up in a browser without error. This will give you some 'first chance' help. For instance if you have a non serializable object you'll get this message below. Note that it clearly tells you what can't be serialized. Make sure you have 'mex' endpoint enabled and bring up the .svc file in your browser.

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://tempuri.org/:IOrderPipelineService ----> System.Runtime.Serialization.InvalidDataContractException: Type 'RR.MVCServices.PipelineStepResponse' cannot be serialized. Consider marking it with the DataContractAttribute attribute, and marking all of its members you want serialized with the DataMemberAttribute attribute.