RavenDb Contextual Listener

gistfile1.cs

// The same principle can be applyed to pass Container scope to the Listener and extract events published by entities via change tracking.
// Has the nice addition to audit messages and can enable async dispatching


// register documentstore on container
  cb.Register<IDocumentSession>(r => 
  {
      var s = r.Resolve<IDocumentStore>().OpenSession(database);
      s.Advanced.ExternalState["ILifetimeScope"] = r.Resolve<ILifetimeScope>();
      return s;
  }).InstancePerLifetimeScope();
  
// Extensions method to handle messages
public static class Extensions
{
    private static string StateKey = "PendingCommit";

    public static void Send(this IDocumentSession session, object command)
    {
        var commit = GetCurrentCommit(session);
        commit.Send(command);
    }

    public static void Publish(this IDocumentSession session, object evnt)
    {
        var commit = GetCurrentCommit(session);
        commit.Events.Add(evnt);
    }

    static Commit GetCurrentCommit(IDocumentSession session)
    {
        if (session.Advanced.ExternalState.ContainsKey(StateKey) == false)
        {
            var scope = session.Advanced.ExternalState["ILifetimeScope"] as ILifetimeScope;
            var c = new Commit(scope);
            session.Advanced.ExternalState[StateKey] = c;
            session.Store(c);
        }
        return session.Advanced.ExternalState[StateKey] as Commit;
    }
}

// Dispatching RavenDb Listener
class DistpatchDocumentStoreListener : IDocumentStoreListener
{
    public void AfterStore(string key, object entityInstance, RavenJObject metadata)
    {
        var commit = entityInstance as Commit;
        if (commit == null)
            return;

        // dispatch
        //var bus = commit.CurrentScope.Resolve<IBus>();

        commit.Reset();
    }

    public bool BeforeStore(string key, object entityInstance, RavenJObject metadata, RavenJObject original)
    {
        return false;
    }
}

// Commit abstraction
public class Commit
{
    public string Id { get; private set; }
    public List<object> Events { get; private set; }
    public List<object> Commands { get; private set; }

    [Raven.Imports.Newtonsoft.Json.JsonIgnore]
    public ILifetimeScope CurrentScope { get; private set; }

    public Commit(ILifetimeScope scope)
    {
        Events = new List<object>();
        Commands = new List<object>();
        CurrentScope = scope;
    }

    internal void Send(object command)
    {
        Commands.Add(command);
    }

    internal void Publish(object evnt)
    {
        Events.Add(evnt);
    }

    public void Reset()
    {
        Events.Clear();
        Commands.Clear();
    }
}