gozero自定义jwt中间件

在Go语言中，使用go-zero库创建自定义JWT中间件通常涉及到以下几个步骤：

1. 首先，你需要安装`github.com/go-kit/kit` 和 `github.com/dgrijalva/jwt-go` 这两个库，它们分别提供了HTTP路由管理和JWT解析功能。

2. 创建一个JWT认证结构体，它应该包含对`jwt-go`包的配置，如秘钥和算法等：

type JWTMiddleware struct {
	TokenKey string
	SignFunc jwt.SigningMethod
}

3. 实现认证函数，通常包括从请求头中提取JWT、解密并验证JWT的过程：

func (m *JWTMiddleware) Authenticate(context.Context, next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		tokenString := r.Header.Get("Authorization")
		if tokenString == "" {
			http.Error(w, "Missing authorization header", http.StatusUnauthorized)
			return
		}

		token, err := jwt.ParseWithClaims(tokenString, &MyClaims{}, func(token *jwt.Token) (interface{}, error) {
			if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
				return nil, fmt.Errorf("Unexpected signing method: %v", token.Header["alg"])
			}
			return []byte(m.Secret), nil
		})
		if err != nil {
			if verr, ok := err.(*jwt.ValidationError); ok {
				switch verr.Errors[0] {
				case jwt.ErrSignatureInvalid:
					http.Error(w, "Invalid signature", http.StatusUnauthorized)
				case jwt.ErrTokenExpired:
					http.Error(w, "Token has expired", http.StatusUnauthorized)
				default:
					http.Error(w, "Invalid token", http.StatusUnauthorized)
				}
			} else {
				http.Error(w, "Invalid token", http.StatusUnauthorized)
			}
			return
		}

		if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
			// 接下来的请求就附带了验证后的用户信息
			ctx = context.WithValue(ctx, "claims", claims)
			next.ServeHTTP(w, r)
		} else {
			http.Error(w, "Failed to validate token", http.StatusInternalServerError)
		}
	})
}

4. 将这个中间件添加到go-zero的路由中：

router.UseMiddleware(JWTMiddleware{TokenKey: "your_token_key", SignFunc: jwt.SigningMethodHS256}, authMiddleware)