在ListenAndServe内部调用多个句柄

Question

I want to use multiple handlers inside the ListenAndServe method from the http package. For example:

if err := http.ListenAndServe(":"+s.config.Port,
    handlers.LoggingHandler(os.Stdout, s.router),
    handlers.CORS()(r.router)
); err != nil {

Problem:

Everytime I'm getting the following error:

pkg/server/server.go:30:31: too many arguments in call to http.ListenAndServe have (string, http.Handler, http.Handler) want (string, http.Handler) pkg/server/server.go:30:113: undefined: r

Question:

Now it's not accepting more than 2 arguments, so is there any alternative of doing this?

Answer 1

ListenAndServe only takes a single http.Handler.

The simplest way to do this without bringing in a library is to build a http.Handler that encompasses both:

func simpleChain(hs ...http.Handler) http.Handler {
  return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request){
    for _, h := range hs {
      h.ServeHTTP(w, r)
    }
  })
}

This has some problems though if any of the handlers want to do something to the Request.Body or write to the ResponseWriter.

For example, you might want a handler to check if the request has permission and then prevent the other handlers from getting invoked. This implies that the ResponseWriter's status code needs to be checked. I would say bring in a library at this point.