Question

Is it possible to control the execution order of custom message handlers?

As an example, I might want a logging handler to execute first, so I always log a request.

Apart from adding the logging handler last, I’m failing to see how to achieve this.

config.MessageHandlers.Add(new CustomHandlerOne()); 
config.MessageHandlers.Add(new CustomHandlerTwo());
config.MessageHandlers.Add(new LoggingHandler());

Answer 1

The order in which you register the handlers determines when they are called but as Aliostad points out they work in a Russian doll model so the first one in is also called as the last one out and so forth.

The registered handlesr are invoked in a bottom-up fashion in the incoming path and top-down in the outgoing. That is, the last entry is called first for an incoming request message but invoked last for an outgoing response message.