We have a 3rd party vendor service and an in-house service to communicate with it. Everything works perfectly with our in-house service, but I've been asked to write a fall back clone of our vendor's service. The intention is to be able to run up our clone, swap-out the client end-point and allow our in-house service to continue testing against the clone.
Is it possible to recreate/mimic a service such that an existing client can communicate with it (without modification) as if it were the original service?
So far I’ve tried 3 things and none of them work.
1st approach
Create a simple service, reference the 3rd party service to gain access to the custom types and mimic the [operation Contract]’s.
When I try to communicate with this service I get the following error.
A first chance exception of type 'System.ServiceModel.ActionNotSupportedException' occurred in System.ServiceModel.dll
Additional information: The message with Action '' cannot be processed at the receiver, due to a ContractFilter mismatch at the EndpointDispatcher. This may be because of either a contract mismatch (mismatched Actions between sender and receiver) or a binding/security mismatch between the sender and the receiver. Check that sender and receiver have the same contract and the same binding (including security requirements, e.g. Message, Transport, None).
There is no security requirements as we are using basic http (no ssl). The service model portion of the config file and the service behaviour class attributes are below:
<system.serviceModel>
<bindings>
<basicHttpBinding>
<binding name="SimpleBinding" />
</basicHttpBinding>
</bindings>
<services>
<service behaviorConfiguration="cloneBehavior" name="MyClone">
<endpoint address="" binding="basicHttpBinding" bindingConfiguration="SimpleBinding"
contract="MyService.IMyService" />
<host>
<baseAddresses>
<add baseAddress="http://localhost/clone/" />
</baseAddresses>
</host>
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior name="cloneBehavior">
<serviceMetadata httpGetEnabled="True" httpGetUrl="http://localhost/clone/mex" />
<serviceDebug includeExceptionDetailInFaults="False" />
</behavior>
</serviceBehaviors>
</behaviors>
</system.serviceModel>
and the service behaviour
[ServiceBehavior(Name = "CloneService",
ConfigurationName = "MyClone",
InstanceContextMode = InstanceContextMode.PerCall,
AddressFilterMode = AddressFilterMode.Any)]
public class MyService : IMyService
{
Everything looks good and I have come to my first dead end.
2nd approach
Get rid of my interface/service contract and inherit directly from the interface generated in the reference.cs file.
When I run this service up, I get the following error
System.InvalidOperationException: The operations myMethodA and myMethodB have the same action (). Every operation must have a unique action value.
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ActionDemuxer.Add(String action, DispatchOperationRuntime operation) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime..ctor(DispatchRuntime dispatch) at System.ServiceModel.Dispatcher.DispatchRuntime.GetRuntimeCore() at System.ServiceModel.Dispatcher.ChannelDispatcher.OnOpened() at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout) at System.ServiceModel.ServiceHostBase.OnOpen(TimeSpan timeout) at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout) at Microsoft.Tools.SvcHost.ServiceHostHelper.OpenService(ServiceInfo info)
Taking a look at the generated interface for this method, they are all decorated with the following attribute:
[System.ServiceModel.OperationContractAttribute(Action="", ReplyAction="*")]
My understanding from msdn is that WCF defaults to adding a unique action of the pattern <namespace>/<service>/<operation>[Response].
If I try setting the action to * then I can hit the service (as expected with the catch all / unmatched message handler), but I can't hit a specific method.
Nevertheless, manually making all the actions unique (and conforming to the above pattern), give this error:
The contract ‘IMyService’ in client configuration does not match the name in service contract, or there is no valid method in this contract. …
I have clearly defined methods in the service contract and have come to a second dead end.
3rd approach
Using the wsdl.exe tool to generate a service from the wsdl. I followed the instructions from this SO post to generate an interface and inherit from it.
I’ve also tried generating the service itself by using the clientWsdl.wsdl /l:CS /server command and following the instructions in this post.
After tidying up the generated code and running it up, I’m back to my original error:
A first chance exception of type 'System.ServiceModel.ActionNotSupportedException' occurred in System.ServiceModel.dll
Additional information: The message with Action '' cannot be processed at the receiver, due to a ContractFilter mismatch at the EndpointDispatcher. This may be because of either a contract mismatch (mismatched Actions between sender and receiver) or a binding/security mismatch between the sender and the receiver. Check that sender and receiver have the same contract and the same binding (including security requirements, e.g. Message, Transport, None).
At each attempt I have double checked all the config settings and updated the contract at each stage.
At this stage I'm wondering if it's even possible.
