The processing chains of ServiceStack

The following contexts and their base classes are all derived from ServiceStack.ServiceStackHost; they can be used for your HTTP hosted service:

The pipeline is the same for every scenario, as shown in the following diagram:

Before any request goes into the ServiceStack pipeline, the functions in your AppHost's RawHttpHandlers are executed and the result is in the favor of further processing in ServiceStack if the value is not null. The processing in ServiceStack is done in the following order:

The following MQ server implementations are available (the packages are listed in brackets for easier searching on NuGet) for your ServiceStack service:

In contrast to the processing chain of an HTTP context, the steps in an MQ context are as follows:

In contrast to this, you can easily combine an MQ service and an HTTP service and leverage a trimmed-down processing pipeline of the HTTP service. This is possible as one of the core concepts of ServiceStack is the Message Pattern, which comes quite handy in this scenario:

public class AppHost : ServiceStack.AppSelfHostBase
{
  public AppHost()
    : base ("Ticket Service",
            typeof (TaskService).Assembly)
  { }

  public override void Configure(Funq.Container container)
  {
    var messageService = container.Resolve<ServiceStack.Messaging.IMessageService>();
    messageService.RegisterHandler<FindTasks> (this.ServiceController.ExecuteMessage);
    messageService.Start();
  }
}

The preceding code relies on the registration of a ServiceStack.Interfaces.IMessageService implementation, which gets resolved inside the Configure method. Then all the plumbing is done to register the handlers and start the MQ client.

If you do not want to provide an HTTP endpoint but still use the internals of ServiceStack such as the powerful IoC-Container, which is an unusual common use-case, you can use the generic BasicAppHost for an extended processing pipeline such as:

var basicAppHost = new ServiceStack.Testing.BasicAppHost(typeof(TaskService.Assembly))
{
  ConfigureAppHost = host =>
  {
    var messageService = host.Container.Resolve <ServiceStack.Interfaces.IMessageService>();
    messageService.RegisterHandler <FindTasks>(host.ServiceController.ExecuteMessage);
    messageService.Start();
  }
};

This is especially helpful in testing scenarios, where you want to deal with the endpoints directly.