Golang的JWT权限校验解析

package config

type JWT struct {
	SigningKey  string `json:"signingKey" yaml:"signing-key"`   // jwt签名
	ExpiresTime int64  `json:"expiresTime" yaml:"expires-time"` // 过期时间
	Issuer      string `json:"issuer" yaml:"issuer"`            // 签发者
}

package pkg

import (
	"errors"
	"time"

	"catering/global"
	"catering/model/system/request"

	"github.com/dgrijalva/jwt-go"
)

type JWT struct {
	SigningKey []byte
}

var (
	ErrTokenExpired     = errors.New("token is expired")
	ErrTokenNotValidYet = errors.New("token not active yet")
	ErrTokenMalformed   = errors.New("that's not even a token")
	ErrTokenInvalid     = errors.New("couldn't handle this token")
)

func NewJWT() *JWT {
	return &JWT{
		[]byte(global.Config.JWT.SigningKey),
	}
}

//生成claims
func (j *JWT) CreateClaims(baseClaims request.BaseClaims) request.CustomClaims {
	claims := request.CustomClaims{
		BaseClaims: baseClaims,
		StandardClaims: jwt.StandardClaims{
			NotBefore: time.Now().Unix() - 1000,                          // 签名生效时间
			ExpiresAt: time.Now().Unix() + global.Config.JWT.ExpiresTime, // 过期时间 7天  配置文件
			Issuer:    global.Config.JWT.Issuer,                          // 签名的发行者
		},
	}
	return claims
}

// 创建一个token
func (j *JWT) CreateToken(claims request.CustomClaims) (string, error) {
	//对token进行签名加密
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString(j.SigningKey)
}

// CreateTokenByOldToken 旧token 换新token 用concurrency_control对token进行加锁避免并发问题（加锁粒度为oldToken）
func (j *JWT) CreateTokenByOldToken(oldToken string, claims request.CustomClaims) (string, error) {
	v, err, _ := global.Concurrency_Control.Do("JWT:"+oldToken, func() (interface{}, error) {
		return j.CreateToken(claims)
	})
	return v.(string), err
}

// 解析 token
func (j *JWT) ParseToken(tokenString string) (*request.CustomClaims, error) {
	token, err := jwt.ParseWithClaims(tokenString, &request.CustomClaims{}, func(token *jwt.Token) (i interface{}, e error) {
		return j.SigningKey, nil
	})
	if err != nil {
		if ve, ok := err.(*jwt.ValidationError); ok {
			if ve.Errors&jwt.ValidationErrorMalformed != 0 {
				return nil, ErrTokenMalformed
			} else if ve.Errors&jwt.ValidationErrorExpired != 0 {
				// Token is expired
				return nil, ErrTokenExpired
			} else if ve.Errors&jwt.ValidationErrorNotValidYet != 0 {
				return nil, ErrTokenNotValidYet
			} else {
				return nil, ErrTokenInvalid
			}
		}
	}
	if token != nil {
		if claims, ok := token.Claims.(*request.CustomClaims); ok && token.Valid {
			return claims, nil
		}
		return nil, ErrTokenInvalid

	} else {
		return nil, ErrTokenInvalid
	}
}

func (b *BaseApi) Login(c *gin.Context) {
	var l systemReq.Login
	msg, err := valid.BindAndValid(c, &l)
	if err != nil {
		response.FailWithMessage(msg, c)
		return
	}
	if store.Verify(l.CaptchaId, l.Captcha, true) {
		u := &system.SysUser{Username: l.Username, Password: l.Password}
		if err, user := userService.Login(u); err != nil {
			global.Log.Error("登陆失败! 用户名不存在或者密码错误!", zap.Error(err))
			response.FailWithMessage("用户名不存在或者密码错误", c)
		} else {
			//登录成功，生成token
			b.tokenNext(c, *user)
		}
	} else {
		response.FailWithMessage("验证码错误", c)
	}
}

// 登录以后签发jwt
func (b *BaseApi) tokenNext(c *gin.Context, user system.SysUser) {
	j := pkg.NewJWT()
	//新建claims
	claims := j.CreateClaims(systemReq.BaseClaims{
		UUID:        user.UUID,
		ID:          uint(user.ID),
		NickName:    user.NickName,
		Username:    user.Username,
		AuthorityId: user.AuthorityId,
	})
	//生成token
	token, err := j.CreateToken(claims)
	if err != nil {
		global.Log.Error("获取token失败!", zap.Error(err))
		response.FailWithMessage("获取token失败", c)
		return
	}
	//生成session
	session, err := global.SESSION.Get(c.Request, "SessionId")
	if err != nil {
		fmt.Println(err)
	}
	session.Values["token"] = token
	//把session数据存放到cookie并在response的head中返回
	session.Save(c.Request, c.Writer)
	//返回token
	response.OkWithDetailed(systemRes.LoginResponse{
		User:      user,
		Token:     token,
		ExpiresAt: claims.StandardClaims.ExpiresAt * 1000,
	}, "登录成功", c)
	return
}

package middleware

import (
	"strconv"
	"time"

	"catering/pkg"

	"catering/global"
	"catering/model/common/response"

	"github.com/gin-gonic/gin"
)

func JWTAuth() gin.HandlerFunc {
	return func(c *gin.Context) {
		// 我们这里jwt鉴权取头部信息 x-token 登录时回返回token信息
		token := c.Request.Header.Get("x-token")
		if token == "" {
			response.FailWithDetailed(gin.H{"reload": true}, "未登录或非法访问", c)
			c.Abort()
			return
		}

		// 获取session
		session, _ := global.SESSION.Get(c.Request, "SessionId")
		t := session.Values["token"]

		//判断session和对session中的token进行比对
		if tk, ok := t.(string); !ok {
			response.FailWithDetailed(gin.H{"reload": true}, "授权已过期", c)
			c.Abort()
			return
		} else if tk != token {
			response.FailWithDetailed(gin.H{"reload": true}, "授权已过期", c)
			c.Abort()
			return
		}

		j := pkg.NewJWT()
		// parseToken 解析token包含的信息
		// 判断该token是否已经到达有效期
		claims, err := j.ParseToken(token)
		if err != nil {
			if err == pkg.ErrTokenExpired {
				response.FailWithDetailed(gin.H{"reload": true}, "授权已过期", c)
				c.Abort()
				return
			}
			response.FailWithDetailed(gin.H{"reload": true}, err.Error(), c)
			c.Abort()
			return
		}
		//把解析出来的用户数据存入上下文中，方便后续的调用
		c.Set("claims", claims)
		c.Next()
	}
}

//获取用户动态路由,返回包括系统菜单详情列表
func (a *AuthorityMenuApi) GetMenu(c *gin.Context) {
    //其中pkg.GetUserAuthorityId是通过上下文获取，也就是ctx.Get("claims")
	if err, menus := menuService.GetMenuTree(pkg.GetUserAuthorityId(c)); err != nil {
		global.Log.Error("获取失败!", zap.Error(err))
		response.FailWithMessage("获取失败", c)
	} else {
		if menus == nil {
			menus = []system.SysMenu{}
		}
		response.OkWithDetailed(systemRes.SysMenusResponse{Menus: menus}, "获取成功", c)
	}
}


// pakcage pkg
// 从Gin的Context中获取从jwt解析出来的用户角色id
func GetUserAuthorityId(c *gin.Context) string {
	if claims, exists := c.Get("claims"); !exists {
		if cl, err := GetClaims(c); err != nil {
			return ""
		} else {
			return cl.AuthorityId
		}
	} else {
		waitUse := claims.(*systemReq.CustomClaims)
		return waitUse.AuthorityId
	}
}