Golang http mux更改处理函数

type HasHandleFunc interface { //this is just so it would work for gorilla and http.ServerMux
    HandleFunc(pattern string,handler func(w http.ResponseWriter,req *http.Request))
}
type Handler struct {
    http.HandlerFunc
    Enabled bool
}
type Handlers map[string]*Handler

func (h Handlers) ServeHTTP(w http.ResponseWriter,r *http.Request) {
    path := r.URL.Path
    if handler,ok := h[path]; ok && handler.Enabled {
        handler.ServeHTTP(w,r)
    } else {
        http.Error(w,"Not Found",http.StatusNotFound)
    }
}

func (h Handlers) HandleFunc(mux HasHandleFunc,pattern string,handler http.HandlerFunc) {
    h[pattern] = &Handler{handler,true}
    mux.HandleFunc(pattern,h.ServeHTTP)
}

func main() {
    mux := http.NewServeMux()
    handlers := Handlers{}
    handlers.HandleFunc(mux,"/",func(w http.ResponseWriter,r *http.Request) {
        w.Write([]byte("this will show once"))
        handlers["/"].Enabled = false
    })
    http.Handle("/",mux)
    http.ListenAndServe(":9020",nil)
}