Web API – message handlers – usage
The delegating handler in WebAPI is the most basic mechanism to intercept HTTP message lifecycle. We can find a very clear and useful visualisation of on WebAPI poster. We can see that message handlers is the first place in HTTP request processing which is able to read of modify the message. It is many cases when we would need to place some code before request will be executed and after. But first, we will introduce how to write that kind of handlers.