Question

I’ve been using MassTransit for handling e-mail messages. Using this code: http://meandaspnet.blogspot.com/2009/10/how-to-binary-serialize-mailmessage-for.html I’m able to binary serialize my e-mails and publish them to my service bus. They’re handled correctly too.

Bus.Initialize(
                sbc =>
                    {
                        sbc.EnableMessageTracing();
                        sbc.ReceiveFrom("msmq://localhost/MyQueue");
                        sbc.UseMsmq();                        
                        sbc.VerifyMsmqConfiguration();
                        sbc.UseMulticastSubscriptionClient();
                        sbc.UseBinarySerializer();
                        sbc.Subscribe(subs => subs.Instance(new MessageHandler()));
                    });

Now I added a new type and handler:

       // Check out the sequence of the Consumes<> !
   public class MessageHandler :
               Consumes<SerializeableMailMessage>.All,
       Consumes<AangifteOmzetbelasting>.All
   {
       public void Consume(AangifteOmzetbelasting message)
       {
                       // Some code - method will NOT be called
       }

       public void Consume(SerializeableMailMessage mailMessage)
       {
                       // Some code - this method is called by Mass Transit
       }
   }

The weird thing is that this works if I Publish a SerializableMailMessage – but not for AangifteOmzetbelasting. If I change the interface order – it works for AangifteOmzetbelasting and not for SerializableMailMessage. Like so:

   // Check out the sequence of the Consumes<> !
       public class MessageHandler :
       Consumes<AangifteOmzetbelasting>.All,
       Consumes<SerializeableMailMessage>.All

In the latter case, the SerializedMailMessges do not appear on the service bus either. Both are published using:

Bus.Instance.Publish(object)

What am I doing wrong here?

Answer 1

Publishing messages without type information is a real struggle; the type information is hugely important for routing.

What I would look at doing here, if you must publish as object, is we have FastActivator helpers you can take a peek at (should be in the referenced Magnum library) that would be like Bus.Instance.FastActivator("Publish", message, { message.GetType() }). I might have the order of the parameters wrong, but you need the method name, parameters, and generic type parameters.

Additionally, I’d suggest joining the MT mailing list to help with this issue further if you need it. https://groups.google.com/forum/#!forum/masstransit-discuss