使用JWT做RESTful API的身份验证-Go语言实现

在使用Golang和MongoDB构建 RESTful API已经实现了一个简单的 RESTful API应用，但是对于有些API接口需要授权之后才能访问，在这篇文章中就用 jwt 做一个基于Token的身份验证，关于 jwt 请访问 JWT有详细的说明,而且有各个语言实现的库，请根据需要使用对应的版本。

需要先安装 jwt-go 接口 go get github.com/dgrijalva/jwt-go

新增注册登录接口，并在登录时生成token

自定义返回结果，并封装 helper/utils.go

type Response struct {
	Code int         `json:"code"`
	Msg  string      `json:"msg"`
	Data interface{} `json:"data"`
}

func ResponseWithJson(w http.ResponseWriter, code int, payload interface{}) {
	response, _ := json.Marshal(payload)
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(code)
	w.Write(response)
}

模型 models/user.go

type User struct {
	UserName string `bson:"username" json:"username"`
	Password string `bson:"password" json:"password"`
}

type JwtToken struct {
	Token string `json:"token"`
}

控制器 controllers/user.go

func Register(w http.ResponseWriter, r *http.Request) {
	var user models.User
	err := json.NewDecoder(r.Body).Decode(&user)
	if err != nil || user.UserName == "" || user.Password == "" {
		helper.ResponseWithJson(w, http.StatusBadRequest,
			helper.Response{Code: http.StatusBadRequest, Msg: "bad params"})
		return
	}
	err = models.Insert(db, collection, user)
	if err != nil {
		helper.ResponseWithJson(w, http.StatusInternalServerError,
			helper.Response{Code: http.StatusInternalServerError, Msg: "internal error"})
	}
}

func Login(w http.ResponseWriter, r *http.Request) {
	var user models.User
	err := json.NewDecoder(r.Body).Decode(&user)
	if err != nil {
		helper.ResponseWithJson(w, http.StatusBadRequest,
			helper.Response{Code: http.StatusBadRequest, Msg: "bad params"})
	}
	exist := models.IsExist(db, collection, bson.M{"username": user.UserName})
	if exist {
		token, _ := auth.GenerateToken(&user)
		helper.ResponseWithJson(w, http.StatusOK,
			helper.Response{Code: http.StatusOK, Data: models.JwtToken{Token: token}})
	} else {
		helper.ResponseWithJson(w, http.StatusNotFound,
			helper.Response{Code: http.StatusNotFound, Msg: "the user not exist"})
	}
}

生成Token auth/middleware.go

func GenerateToken(user *models.User) (string, error) {
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"username": user.UserName,
    //"exp":      time.Now().Add(time.Hour * 2).Unix(),// 可以添加过期时间
	})

	return token.SignedString([]byte("secret"))//对应的字符串请自行生成，最后足够使用加密后的字符串
}

http中间件

go http的中间件实现起来很简单，只需要实现一个函数签名为func(http.Handler) http.Handler的函数即可。

func middlewareHandler(next http.Handler) http.Handler{
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request){
        // 执行handler之前的逻辑
        next.ServeHTTP(w, r)
        // 执行完毕handler后的逻辑
    })
}

我们使用的 mux 作为路由，本身支持在路由中添加中间件，改造一下之前的路由逻辑

routes/routes.go

type Route struct {
	Method     string
	Pattern    string
	Handler    http.HandlerFunc
	Middleware mux.MiddlewareFunc //添加中间件
}

func NewRouter() *mux.Router {
	router := mux.NewRouter()
	for _, route := range routes {
		r := router.Methods(route.Method).
			Path(route.Pattern)
    //如果这个路由有中间件的逻辑，需要通过中间件先处理一下
		if route.Middleware != nil {
			r.Handler(route.Middleware(route.Handler))
		} else {
			r.Handler(route.Handler)
		}
	}
	return router
}

实现身份验证的中间件

auth/middleware.go

验证的信息放在http Header中

func TokenMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		tokenStr := r.Header.Get("authorization")
		if tokenStr == "" {
			helper.ResponseWithJson(w, http.StatusUnauthorized,
				helper.Response{Code: http.StatusUnauthorized, Msg: "not authorized"})
		} else {
			token, _ := jwt.Parse(tokenStr, func(token *jwt.Token) (interface{}, error) {
				if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
					helper.ResponseWithJson(w, http.StatusUnauthorized,
						helper.Response{Code: http.StatusUnauthorized, Msg: "not authorized"})
					return nil, fmt.Errorf("not authorization")
				}
				return []byte("secret"), nil
			})
			if !token.Valid {
				helper.ResponseWithJson(w, http.StatusUnauthorized,
					helper.Response{Code: http.StatusUnauthorized, Msg: "not authorized"})
			} else {
				next.ServeHTTP(w, r)
			}
		}
	})
}

对需要验证的路由添加中间件

register("GET", "/movies", controllers.AllMovies, auth.TokenMiddleware) //需要中间件逻辑
register("GET", "/movies/{id}", controllers.FindMovie, nil)//不需要中间件

验证

登录之后，返回对应的token信息

//请求 post http://127.0.0.1:8080/login
//返回

{
    "code": 200,
    "msg": "",
    "data": {
        "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VybmFtZSI6ImNvZGVybWluZXIifQ.pFzJLU8vnzWiweFKzHRsawyWA2jfuDIPlDU4zE92O7c"
    }
}

获取所有的电影信息时

//请求 post http://127.0.0.1:8080/movies
在 Header中设置 "authorization":token
如果没有设置header会报 401 错误

{
    "code": 401,
    "msg": "not authorized",
    "data": null
}

源码 Github