Yet another in-memory message bus for .NET. "It's getting there."

SeptaBus is an in-memory message bus. It allows you to structure the logic of your application using the pub-sub pattern. When used properly it'll help keep your code clean so that you focus on expressing your domain logic.

In SeptaBus, there are two types of messages:

1. Commands, which tell the system to do something. Commands should have exactly 1 handler.
2. Events, which indicate that something has happened. Events may have 0 to many handlers.

Messages are handled by message handlers (which implement IHandler<T>). Messages are connected to their handlers via a DI container. At present, only StructureMap is supported but adding support for additional containers is pretty easy.

SeptaBus provides the ability to add contextual information to messages via decorators. Included out-of-the-box are the following decorators, which take care of common cross-cutting concerns:

1. TimeStampDecorator - Adds a timestamp to the On header indicating when the message was sent/published on the bus.
2. UserNameDecorator - Adds the current user's name to the By header. (You'll need to write a quick implemnentation of IUserNameProvider, which may be as simple as return HttpContext.Current.User.Identity.Name;.
3. RolesDecorator - Adds the roles that the current user is a member of to the Roles. (You'll need to write a quick implementation of IRolesProvider which may be as simple as return Roles.GetRolesForUser();

// This is a command.  Sending it on the bus tells the system to submit 
// the order with the supplied id.
public class SubmitOrder : ICommand
{
  public Guid Id { get; set; }
}

// This is the controller that gets hit when the user clicks the 
// Submit Order button in the UI.
public class OrderController : Controller
{
  private IBus _bus;

  // ctor...

  [HttpPost]
  public ActionResult Submit(Guid id)
  {
    _bus.Send(new SubmitOrder { Id = id });

    // maybe redirect the user to a confirmation page...
  }
}

// This is the handler for the SubmitOrder command.
// Each command should have exactly 1 handler - no more, no less.
public class SubmitOrderHandler : IHander<SubmitOrder> 
{
  private IBus _bus;

  pubic void Handle(SubmitOrder message)
  {
    // change the order status to Submitted, save changes to the db

    _bus.Publish(new OrderSubmitted { Id = message.Id });
  }
}

// This is the event that gets published when an order is successfully submitted.
public class OrderSubmitted : IEvent
{
  public Guid Id { get; set; }
}

// This is an event handler for the OrderSubmitted event.
// Events may have 0 to many handlers.
public class OrderSubmittedHandler : IHandler<OrderSubmitted>
{
  public void Handle()
  {
    // send the customer an email
  }
}

The architecture of SeptaBus is influenced by the writings of Udi Dahan, creator of NServiceBus.