I do prefer to use one message module for all the object with PerRequest lifecycle. What if you needed another one, you'd copy the module?

HandleBeingMessage should be HandleBeginMessage

// Ryan

I was worried when I first saw this post but after re-reading the following it seems ok:

"The biggest challenge relates to not having a “final”-type method. While message modules do expose HandleEndMessage and HandleError, we have no way of knowing which will be called last. True, HandleError will always be called after HandleEndMessage, but we have no way to determine if HandleError will be called once HandleEndMessage is invoked. Note that HandleEndMessage is always called, even in error conditions."

http://blog.jonathanoliver.com/2010/04/extending-nservicebus-thread-specific-message-modules/

would it make sense if the message handlers get injected an interface to an IDocumentSession that does not have functionality to open, close, commit, dispose etc. for e.g. an ICurrentDocumentSession or something like that. that way we are more explicitly modelling the fact that the session instance injected to message handlers is only providing a window into an open session... your thoughts?

what do you think about this approach? https://github.com/NServiceBus/NServiceBus-Contrib/blob/master/src/SagaPersisters/RavenDB/NServiceBus.SagaPersisters.RavenDB/RavenDBMessageModule.cs

btw. i think "RavenSessionModuleStore store;" should be "IDocumentStore store;" viktor

sorry for my bad explanation. with "RavenSessionModuleStore store;" i mean that your RavenSessionMessageModule will not compile, because "RavenSessionMessageModule store;" should be "IDocumentStore store;" or see below Viktor

public class RavenSessionMessageModule : IMessageModule { readonly ThreadLocal<IDocumentSession> currentSession = new ThreadLocal<IDocumentSession>();

    readonly IDocumentStore store;
    public RavenSessionMessageModule(IDocumentStore store)
    {
        this.store = store;
    }

    public IDocumentSession CurrentSession
    {
        get { return currentSession.Value; }
    }

    public void HandleBeginMessage()
    {
        currentSession.Value = store.OpenSession();
        currentSession.Value.Advanced.UseOptimisticConcurrency = true;
    }

    public void HandleEndMessage()
    {
        using (var old = currentSession.Value)
        {
            currentSession.Value = null;
            old.SaveChanges();
        }
    }

    public void HandleError()
    {
        using (var old = currentSession.Value)
            currentSession.Value = null;
    }
}

The code shown does not work, since nservice bus calls HandleEndMessage() before HandleError() and thus, even if an error occurs, changes would get saved.