WCF Extensibility – IInstanceProvider in mono - wcf

Question

I followed : this article and implemented it in a WCF Service.
It allows us to create a instance of a Service that doesn't have a parameterless constructor, by implementing a custom IServiceBehavior, and then decorating the service with that Service Behavior, so instead of having for example:
[ServiceBehavior]
public class MyService : IMyService
I would have
[InstanceProviderBehavior]
public class MyService : IMyService
I then implement the ApplyDispatchBehavior like this:
foreach (ChannelDispatcher cd in serviceHostBase.ChannelDispatchers) {
foreach (EndpointDispatcher ed in cd.Endpoints) {
if (!ed.IsSystemEndpoint) {
Console.WriteLine("Using InstanceProviderBehaviorAttribute");
ed.DispatchRuntime.InstanceProvider = new ServiceInstanceProvider(Configuration.Instance.Container);
}
}
}
And to provide an instance of the service I just do:
public object GetInstance(InstanceContext instanceContext, Message message)
{
AlertQueryService result = Container.Resolve<AlertQueryService>();
return result;
}
I ran it in windows and it worked as expected. But in linux with mono, it throws the exception
Exception Default constructor not found for type MyService
which indicates that maybe mono is ignoring the InstanceProviderBehaviorAttribute.
Another thing i noticed was that the line:
Console.WriteLine("Using InstanceProviderBehaviorAttribute");
Is executed in windows when the service host is opened. While in linux when the service host is opened, it doesn't write that in the console. Also the exception in linux is not thrown when we open the service host, but when the IsInitiating operation is called in MyService:
[OperationContract(IsInitiating = true)]
void Initialize();
Which indicates that with mono the service instance is only being resolved when we call the IsInitiating operation.
Any idea why this is works in windows and not in linux with mono? And why is the initialization behavior different?
Thanks

Answer 1

Try adding an InstanceContextProvider as well as your InstanceProvider in your EndpointBehavior. It seems the Mono implementation of ChannelDispatcher.ListenerLoopManager.Setup doesn't like the idea of being sans InstanceContextProvider if there is no parameterless constructor.
The InstanceContextProvider can be essentially a no-op implementation. So long as there is an instance, it will pass that check in ListenerLoopManagerSetup and happily proceed to utilize your InstanceProvider.
Re: why the different implementation... Mono is a re-implementation rather than a cross-compilation or even port. Consider the Important Rules section of their Contribution Guidelines. It wasn't until very recently that developers could contribute to the project if they had so much as looked at MS source code.