How to execute a middleware after the app?

[1989car]

How to execute a middleware after the app?

[justinas]

It's really the same principle. Your middleware has to execute the wrapped handler and then do the necessary actions.

func loggingMiddleware(h http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        log.Println("request started")
        h(w, r)
        log.Println("request finished")
    })
}

Django illustrates the order middleware are generally executed in really well ("View" here is the "app" handler). Basically, whatever middleware processes the request first, processes the response last. If you think about the call stack, it becomes quite obvious.

recovery processes request
recovery calls logging
  logging processes request
  logging calls csrf
     .. more nesting...
  logging processes response (if any yet)
  logging returns
recovery processes response (if any yet)
recovery returns

Of course, any part of processing is optional.

All of this stands for net/http as well. Again, one has to think of Alice as just some syntatic sugar for wrapping the handlers.

[1989car]

Oh, I get it. Thanks a lot.