Using a Custom Endpoint Behavior with WCF and Autofac

问题

I'm trying to implement a UoW like shown here: http://blog.iannelson.systems/wcf-global-exception-handling/

But I can't for the life of me figure out how to wire it up with Autofac. I have absolutely no idea where to start.

I've got WCF working fine with Autofac from using http://autofac.readthedocs.org/en/latest/integration/wcf.html

But to inject or add the IEndpointBehavior? No idea...

If there's a better way to implement a UoW I would like to hear.

Edit:

For now I've just done:

builder.RegisterType(typeof (UnitOfWork))
    .As(typeof (IUnitOfWork))
    .InstancePerLifetimeScope()
    .OnRelease(x =>
    {
        Trace.WriteLine("Comitted of UoW");
        ((IUnitOfWork) x).Commit();
        // OnRelease inhibits the default Autofac Auto-Dispose behavior so explicitly chain to it
        x.Dispose(); 
    });

Though I don't know if this is an acceptable way of doing it, seems like a hack :(

Edit2:

Doesn't seem like it's possible to run a UoW in WCF :/

Edit 3:

I've posted my solution here: http://www.philliphaydon.com/2011/11/06/unit-of-work-with-wcf-and-autofac/

回答1:

I have found a solution to this problem, where the unit of work only will be committed if no errors is thrown.

    builder.RegisterType(typeof (UnitOfWork))
    .As(typeof (IUnitOfWork)).InstancePerLifetimeScope();

Then i have created a combined EndpointBehavior and a ErrorHandler.

public class UnitOfWorkEndpointBehavior : BehaviorExtensionElement, IEndpointBehavior
{
    public void Validate(ServiceEndpoint endpoint)
    {
    }

    public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
    {
    }

    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
        var unitOfWorkInstanceHandler = new UnitOfWorkInstanceHandler();

        endpointDispatcher.ChannelDispatcher.ErrorHandlers.Add(unitOfWorkInstanceHandler);
        endpointDispatcher.DispatchRuntime.InstanceContextInitializers.Add(unitOfWorkInstanceHandler);
    }

    public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
    }

    protected override object CreateBehavior()
    {
        return new UnitOfWorkEndpointBehavior();
    }

    public override Type BehaviorType
    {
        get { return typeof (UnitOfWorkEndpointBehavior); }
    }
}



public class UnitOfWorkInstanceHandler : IInstanceContextInitializer, IErrorHandler
{
    private bool _doCommit = true;

    public void Initialize(InstanceContext instanceContext, Message message)
    {
        instanceContext.Closing += CommitUnitOfWork;
    }

    void CommitUnitOfWork(object sender, EventArgs e)
    {
        //Only commit if no error has occured
        if (_doCommit)
        {
            //Resolve the UnitOfWork form scope in Autofac
            OperationContext.Current.InstanceContext.Extensions.Find<AutofacInstanceContext>().Resolve<IUnitOfWork>().Commit();
        }
    }

    public void ProvideFault(Exception error, MessageVersion version, ref Message fault)
    {
        _doCommit = false;
    }

    public bool HandleError(Exception error)
    {
        _doCommit = false;
        return false;
    }
}

The registration of the Endpoint Behavior in web.config

<system.serviceModel>
    ...
    <extensions>
      <behaviorExtensions>
        <add name="UnitOfWork" type="Namespace.UnitOfWorkBehavior, Namespace"/>
      </behaviorExtensions>
    </extensions>
      <behaviors>
        <endpointBehaviors>
          <behavior name="">
            <UnitOfWork/>
          </behavior>
        </endpointBehaviors>
    ...
    </behaviors>
    ...
</system.serviceModel>

来源：https://stackoverflow.com/questions/7989918/using-a-custom-endpoint-behavior-with-wcf-and-autofac

标签

wcf

autofac

unit-of-work

endpointbehavior