如何在MuxChain中使用HttpRouter？

Question

I'd like to use httprouter with muxchain while keeping route parameters like /:user/.

Take the following example:

func log(res http.ResponseWriter, req *http.Request) {
  fmt.Println("some logger")
}

func index(res http.ResponseWriter, req *http.Request) {
  fmt.Fprintf(res, "Hi there, I love %s!", req.URL.Path[1:])
}

func main() {
  logHandler := http.HandlerFunc(log)
  indexHandler := http.HandlerFunc(index)
  chain := muxchain.ChainHandlers(logHandler, indexHandler)
  router := httprouter.New()
  router.Handler("GET", "/:user", chain)
  http.ListenAndServe(":8080", router)
}

When I visit http://localhost:8080/john I obviously don't have access to ps httprouter.Params That's because httprouter needs to see type httprouter.Handle but the function is called with type http.Handler.

Is there any way to use both packages together? The HttpRouter GitHub repo says

The only disadvantage is, that no parameter values can be retrieved when a http.Handler or http.HandlerFunc is used, since there is no efficient way to pass the values with the existing function parameters.

Answer 1

You would have to patch muxchain to accept httprouter.Handle, but it's rather simple to create your own chain handler, for example:

func chain(funcs ...interface{}) httprouter.Handle {
    return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
        for _, h := range funcs {
            switch h := h.(type) {
            case httprouter.Handle:
                h(w, r, p)
            case http.Handler:
                h.ServeHTTP(w, r)
            case func(http.ResponseWriter, *http.Request):
                h(w, r)
            default:
                panic("wth")
            }

        }
    }
}

<kbd>playground</kbd>