Go net/http 中間件

了我直接寫成了嵌套的中間件

並且在第一層實現了 basic auth 的功能.
可能代碼中間有些變量名 沒有很規範

package main

import (
	"fmt"
	"net/http"
)
// 認證的用戶列表，存儲用戶名以及密碼
var (
	list = map[string]string{
		"jack":"cat",
	}
)
// 第一層中間件的結構體， 他需要實現http.Handler接口
type newhand struct {
	hand http.Handler
}
// 第二層 中間價的基礎結構體， 我用它來添加一個 header caonima:woaini
type hand2 struct {
	handler http.Handler
}

func (hd *hand2) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	fmt.Println("The internal middle")
	w.Header().Add("wocaonima","woaini")
	hd.handler.ServeHTTP(w,r)
}

func (n *newhand) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	fmt.Println("Start")
	// basic auth ---------------------------------
	username, password, ok := r.BasicAuth()
	if !ok {
		unauthenticate(w,"Not auth")
		return
	}
	realPass, ok := list[username]
	if !ok {
		unauthenticate(w, "NO PASS")
		return
	}

	if realPass == password {
		n.hand.ServeHTTP(w,r)
	}
	unauthenticate(w,"not right")
	// --------------------------------------------
	fmt.Println("end")
}
func unauthenticate(w http.ResponseWriter, realm string) {
	w.Header().Add("WWW-Authenticate",fmt.Sprintf("Basic realm=%s",realm))
	w.WriteHeader(http.StatusUnauthorized)
}

func newhandddd(handler http.Handler) *hand2 {
 	return &hand2{handler:handler}
}
func newwhandd(handler http.Handler) *newhand {
	return &newhand{hand:handler}
}

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/", func(writer http.ResponseWriter, r *http.Request) {
		_, _ = writer.Write([]byte("wocaonima"))
	})
//todo dwadwadawd
	nn := newwhandd(newhandddd(mux))
	err := http.ListenAndServe(":90",nn)
	if err != nil {
		fmt.Println(err)
		return
	}
}