golang學習總結（五）-http token傳遞

最近開發的項目涉及到login後生成token驗證，同時還要傳遞userID，用於頁面跳轉後進行權限校驗，流程如下：

下面直接上代碼：

func loginHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		http.ServeFile(w, r, "tmpl/login.html")
		return
	}
	// grab user info from the submitted form
	userid := r.FormValue("usrid")
	password := r.FormValue("psw")
	log.Println(userid)
	var creds = &Credentials{
		usrid: userid,
		psw:   password,
	}

	// query database to get match username
	var user User
	err = db.QueryRow("SELECT user_id, user_password FROM users WHERE user_id=?",
		userid).Scan(&user.User_id, &user.User_password)
	checkInternalServerError(err, w)
	// validate password
	err = bcrypt.CompareHashAndPassword([]byte(user.User_password), []byte(password))
	if err != nil {
		http.Redirect(w, r, "/login", 301)
		fmt.Println(err)
	}

	// Declare the expiration time of the token
	// here, we have kept it as 10 minutes
	expirationTime := time.Now().Add(10 * time.Minute)
	// Create the JWT claims, which includes the username and expiry time
	claims := &Claims{
		Username: creds.usrid,
		StandardClaims: jwt.StandardClaims{
			// In JWT, the expiry time is expressed as unix milliseconds
			ExpiresAt: expirationTime.Unix(),
		},
	}

	// Declare the token with the algorithm used for signing, and the claims
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	// Create the JWT string
	tokenString, err := token.SignedString(jwtKey)
	if err != nil {
		// If there is an error in creating the JWT return an internal server error
		w.WriteHeader(http.StatusInternalServerError)
		http.Redirect(w, r, "/login", 500)
		fmt.Println(err)
		return
	}

	http.SetCookie(w, &http.Cookie{
		Name:    "token",
		Value:   tokenString,
		Expires: expirationTime,
	})

	http.Redirect(w, r, "/list", 301)
}

//
func listHandler(w http.ResponseWriter, r *http.Request) {
//獲取cookie
	cookie, err := r.Cookie("token")
	if err != nil {
		if err == http.ErrNoCookie {
			// If the cookie is not set, return an unauthorized status
			w.WriteHeader(http.StatusUnauthorized)
			return
		}
		// For any other type of error, return a bad request status
		w.WriteHeader(http.StatusBadRequest)
		return
	}
//獲取token
	tokenStr := cookie.Value
	claims := &Claims{}
	tkn, err := jwt.ParseWithClaims(tokenStr, claims, func(token *jwt.Token) (interface{}, error) {
		return jwtKey, nil
	})
	log.Println("token str is ", tokenStr)
	log.Println("the tkn is ", tkn)
	if tkn.Valid {
		log.Println("the expire time is ", claims.ExpiresAt)
	}
//獲取userID
	username := claims.Username
	fmt.Println(username)
	rows, err := db.Query("SELECT * FROM cost")
	checkInternalServerError(err, w)
	var funcMap = template.FuncMap{
		"multiplication": func(n float64, f float64) float64 {
			return n * f
		},
		"addOne": func(n int) int {
			return n + 1
		},
	}
	var costs []Cost
	var cost Cost
	for rows.Next() {
		err = rows.Scan(&cost.Id, &cost.Request_type,
			&cost.Field, &cost.Description, &cost.Creator, &cost.Start_time)
		checkInternalServerError(err, w)
		costs = append(costs, cost)
	}
	t, err := template.New("list.html").Funcs(funcMap).ParseFiles("tmpl/list.html")
	checkInternalServerError(err, w)
	err = t.Execute(w, costs)
	checkInternalServerError(err, w)

}