Gorilla Side Effects

ctxtest.go

package main

import (
	"fmt"
	"log"
	"net/http"
	"github.com/gorilla/mux"
	"github.com/gorilla/context"
)

func main() {
	r := mux.NewRouter()
	r.PathPrefix("/subhandler").Handler(Wrapper(http.StripPrefix("/subhandler", NewHandler())))
	http.ListenAndServe("localhost:8080", r)
}

type Handler struct{
	*mux.Router
}

func NewHandler() *Handler {
	h := &Handler{}
	h.Router = mux.NewRouter()
	h.Router.Path("/").HandlerFunc(func (w http.ResponseWriter, r *http.Request){
		fmt.Fprintf(w, "Root!\n")
	})
	h.Router.Path("/bla").HandlerFunc(func (w http.ResponseWriter, r *http.Request){
		fmt.Fprintf(w, "/bla\n")
	})
	return h
}

// Comment this in to disable the mux.Router and make the context work again
// func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// 		}

func Wrapper(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		log.Printf("Pointer before delegation: %p\n", r)
		context.Set(r, "id", "the_id")
		h.ServeHTTP(w, r)
		log.Printf("Pointer after delegation:  %p\n", r)
		fmt.Fprintf(w, "Also, your id is: %s\n", context.Get(r, "id").(string))
	})
}