什么是JWT

JWT,全称 JSON Web Token,是一种开放标准(RFC 7519),用于安全地在双方之间传递信息。尤其适用于身份验证和授权场景。JWT 的设计允许信息在各方之间安全地、 compactly(紧凑地)传输,因为其自身包含了所有需要的认证信息,从而减少了需要查询数据库或会话存储的需求。

JWT主要由三部分组成,通过
.
连接:

  1. Header(头部)
    :描述JWT的元数据,通常包括类型(通常是
    JWT
    )和使用的签名算法(如
    HS256

    RS256
    等)。
  2. Payload(载荷)
    :包含声明(claims),即用户的相关信息。这些信息可以是公开的,也可以是私有的,但应避免放入敏感信息,因为该部分可以被解码查看。载荷中的声明可以验证,但不加密。
  3. Signature(签名)
    :用于验证JWT的完整性和来源。它是通过将Header和Payload分别进行Base64编码后,再与一个秘钥(secret)一起通过指定的算法(如HMAC SHA256)计算得出的。

JWT的工作流程大致如下:

  • 认证阶段
    :用户向服务器提供凭证(如用户名和密码)。服务器验证凭证无误后,生成一个JWT,其中包含用户标识符和其他声明,并使用秘钥对其进行签名。
  • 使用阶段
    :客户端收到JWT后,可以在后续的每个请求中将其放在HTTP请求头中发送给服务器,以此证明自己的身份。
  • 验证阶段
    :服务器收到JWT后,会使用相同的秘钥验证JWT的签名,确保其未被篡改,并检查过期时间等其他声明,从而决定是否允许执行请求。

JWT的优势在于它的无状态性,服务器不需要存储会话信息,这减轻了服务器的压力,同时也方便了跨域认证。但需要注意的是,JWT的安全性依赖于秘钥的安全保管以及对JWT过期时间等的合理设置。

API设计

这里设计两个公共接口和一个受保护的接口。

API 描述
/api/login 公开接口。用于用户登录
/api/register 公开接口。用于用户注册
/api/admin/user 保护接口,需要验证JWT

开发准备

初始化项目目录并切换进入

mkdir gin-jwt
cd gin-jwt

使用
go mod
初始化工程

go mod init gin-jwt

安装依赖

go get -u github.com/gin-gonic/gin
go get -u gorm.io/gorm
go get -u gorm.io/driver/postgres
go get -u github.com/golang-jwt/jwt/v5
go get -u github.com/joho/godotenv
go get -u golang.org/x/crypto

创建第一个API

一开始我们可以在项目的根目录中创建文件
main.go

touch main.go

添加以下内容

package main

import (
	"net/http"

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

func main() {
	r := gin.Default()
	public := r.Group("/api")
	{
		public.POST("/register", func(c *gin.Context) {
			c.JSON(http.StatusOK, gin.H{
				"data": "test. register api",
			})
		})
	}

	r.Run("0.0.0.0:8000")
}

测试运行

go run main.go

客户端测试。正常的话会有以下输出

$ curl -X POST http://127.0.0.1:8000/api/register
{"data":"test. register api"}

完善register接口

现在register接口已经准备好了,但一般来说我们会把接口业务逻辑放在单独的文件中,而不是和接口定义写在一块。

创建一个控制器的包目录,并添加文件

mkdir controllers
touch controllers/auth.go

auth.go
文件内容

package controllers

import (
	"net/http"

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

func Register(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{
		"data": "hello, this is register endpoint",
	})
}

更新
main.go
文件

package main

import (
	"github.com/gin-gonic/gin"

	"gin-jwt/controllers"
)

func main() {
	r := gin.Default()
	public := r.Group("/api")
	{
		public.POST("/register", controllers.Register)
	}

	r.Run("0.0.0.0:8000")
}

重新运行测试

go run main.go

客户端测试

$ curl -X POST http://127.0.0.1:8000/api/register
{"data":"hello, this is register endpoint"}

解析register的客户端请求

客户端请求register api需要携带用户名和密码的参数,服务端对此做解析。编辑文件
controllers/auth.go

package controllers

import (
	"net/http"

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

// /api/register的请求体
type ReqRegister struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password" binding:"required"`
}

func Register(c *gin.Context) {
	var req ReqRegister

	if err := c.ShouldBindBodyWithJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"data": err.Error(),
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"data": req,
	})
}

客户端请求测试

$ curl -X POST http://127.0.0.1:8000/api/register -d '{"username": "zhangsan", "password": "123456"}' -H 'Content-Type=application/json'

{"data":{"username":"zhangsan","password":"123456"}}

连接关系型数据库

一般会将数据保存到专门的数据库中,这里用PostgreSQL来存储数据。Postgres使用docker来安装。安装完postgres后,创建用户和数据库:

create user ginjwt encrypted password 'ginjwt';
create database ginjwt owner = ginjwt;

创建目录
models
,这个目录将包含连接数据库和数据模型的代码。

mkdir models

编辑文件
models/setup.go

package models

import (
	"fmt"
	"log"
	"os"

	"github.com/joho/godotenv"
	"gorm.io/driver/postgres"
	"gorm.io/gorm"
)

var DB *gorm.DB

func ConnectDatabase() {
	err := godotenv.Load(".env")
	if err != nil {
		log.Fatalf("Error loading .env file. %v\n", err)
	}

	// DbDriver := os.Getenv("DB_DRIVER")
	DbHost := os.Getenv("DB_HOST")
	DbPort := os.Getenv("DB_PORT")
	DbUser := os.Getenv("DB_USER")
	DbPass := os.Getenv("DB_PASS")
	DbName := os.Getenv("DB_NAME")

	dsn := fmt.Sprintf("host=%s port=%s user=%s dbname=%s sslmode=disable TimeZone=Asia/Shanghai password=%s", DbHost, DbPort, DbUser, DbName, DbPass)

	DB, err = gorm.Open(postgres.Open(dsn), &gorm.Config{})
	if err != nil {
		log.Fatalf("Connect to database failed, %v\n", err)
	} else {
		log.Printf("Connect to database success, host: %s, port: %s, user: %s, dbname: %s\n", DbHost, DbPort, DbUser, DbName)
	}

	// 迁移数据表
	DB.AutoMigrate(&User{})
}

新建并编辑环境配置文件
.env

DB_HOST=127.0.0.1
DB_PORT=5432
DB_USER=ginjwt
DB_PASS=ginjwt
DB_NAME=ginjwt

创建用户模型,编辑代码文件
models/user.go

package models

import (
	"html"
	"strings"

	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"
)

type User struct {
	gorm.Model
	Username string `gorm:"size:255;not null;unique" json:"username"`
	Password string `gorm:"size:255;not null;" json:"password"`
}

func (u *User) SaveUser() (*User, error) {
	err := DB.Create(&u).Error
	if err != nil {
		return &User{}, err
	}
	return u, nil
}

// 使用gorm的hook在保存密码前对密码进行hash
func (u *User) BeforeSave(tx *gorm.DB) error {
	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(u.Password), bcrypt.DefaultCost)
	if err != nil {
		return err
	}
	u.Password = string(hashedPassword)
	u.Username = html.EscapeString(strings.TrimSpace(u.Username))
	return nil
}

更新
main.go

package main

import (
	"github.com/gin-gonic/gin"

	"gin-jwt/controllers"
	"gin-jwt/models"
)

func init() {
	models.ConnectDatabase()
}

func main() {
	r := gin.Default()
	public := r.Group("/api")
	{
		public.POST("/register", controllers.Register)
	}

	r.Run("0.0.0.0:8000")
}

更新
controllers/auth.go

package controllers

import (
	"net/http"

	"gin-jwt/models"

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

// /api/register的请求体
type ReqRegister struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password" binding:"required"`
}

func Register(c *gin.Context) {
	var req ReqRegister

	if err := c.ShouldBindBodyWithJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"data": err.Error(),
		})
		return
	}

	u := models.User{
		Username: req.Username,
		Password: req.Password,
	}

	_, err := u.SaveUser()
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"data": err.Error(),
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"message": "register success",
		"data":    req,
	})
}

重新运行服务端后,客户端测试

$ curl -X POST http://127.0.0.1:8000/api/register -d '{"username": "zhangsan", "password": "123456"}' -H 'Content-Type=application/json'

{"data":{"username":"zhangsan","password":"123456"},"message":"register success"}

添加login接口

登录接口实现的也非常简单,只需要提供用户名和密码参数。服务端接收到客户端的请求后到数据库中去匹配,确认用户是否存在和密码是否正确。如果验证通过则返回一个token,否则返回异常响应。

首先在
main.go
中注册API

// xxx
func main() {
	// xxx
	r := gin.Default()
	public := r.Group("/api")
	{
		public.POST("/register", controllers.Register)
		public.POST("/login", controllers.Login)
	}
}


auth.go
中添加Login控制器函数

// api/login 的请求体
type ReqLogin struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password" binding:"required"`
}

func Login(c *gin.Context) {
	var req ReqLogin
	if err := c.ShouldBindBodyWithJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	u := models.User{
		Username: req.Username,
		Password: req.Password,
	}

	// 调用 models.LoginCheck 对用户名和密码进行验证
	token, err := models.LoginCheck(u.Username, u.Password)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"error": "username or password is incorrect.",
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"token": token,
	})
}

LoginCheck
方法在
models/user.go
文件中实现

package models

import (
	"gin-jwt/utils/token"
	"html"
	"strings"

	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"
)

func VerifyPassword(password, hashedPassword string) error {
	return bcrypt.CompareHashAndPassword([]byte(hashedPassword), []byte(password))
}


func LoginCheck(username, password string) (string, error) {
	var err error
	u := User{}

	err = DB.Model(User{}).Where("username = ?", username).Take(&u).Error
	if err != nil {
		return "", err
	}
	err = VerifyPassword(password, u.Password)
	if err != nil && err == bcrypt.ErrMismatchedHashAndPassword {
		return "", err
	}

	token, err := token.GenerateToken(u.ID)
	if err != nil {
		return "", err
	}
	return token, nil
}

这里将token相关的函数放到了单独的模块中,新增相关目录并编辑文件

mkdir -p utils/token
touch utils/token/token.go

以下代码为
token.go
的内容,包含的几个函数在后面会用到

package token

import (
	"fmt"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
)

func GenerateToken(user_id uint) (string, error) {
	token_lifespan, err := strconv.Atoi(os.Getenv("TOKEN_HOUR_LIFESPAN"))
	if err != nil {
		return "", err
	}

	claims := jwt.MapClaims{}
	claims["authorized"] = true
	claims["user_id"] = user_id
	claims["exp"] = time.Now().Add(time.Hour * time.Duration(token_lifespan)).Unix()
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)

	return token.SignedString([]byte(os.Getenv("API_SECRET")))
}

func TokenValid(c *gin.Context) error {
	tokenString := ExtractToken(c)
	fmt.Println(tokenString)
	_, err := jwt.Parse(tokenString, func(token *jwt.Token) (any, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}
		return []byte(os.Getenv("API_SECRET")), nil
	})
	if err != nil {
		return err
	}

	return nil
}

// 从请求头中获取token
func ExtractToken(c *gin.Context) string {
	bearerToken := c.GetHeader("Authorization")
	if len(strings.Split(bearerToken, " ")) == 2 {
		return strings.Split(bearerToken, " ")[1]
	}
	return ""
}

// 从jwt中解析出user_id
func ExtractTokenID(c *gin.Context) (uint, error) {
	tokenString := ExtractToken(c)
	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (any, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}
		return []byte(os.Getenv("API_SECRET")), nil
	})
	if err != nil {
		return 0, err
	}
	claims, ok := token.Claims.(jwt.MapClaims)
	// 如果jwt有效,将user_id转换为浮点数字符串,然后再转换为 uint32
	if ok && token.Valid {
		uid, err := strconv.ParseUint(fmt.Sprintf("%.0f", claims["user_id"]), 10, 32)
		if err != nil {
			return 0, err
		}
		return uint(uid), nil
	}

	return 0, nil
}


.env
文件中添加两个环境变量的配置。
TOKEN_HOUR_LIFESPAN
设置token的过期时长,
API_SECRET
是jwt的密钥。

TOKEN_HOUR_LIFESPAN=1
API_SECRET="wP3-sN6&gG4-lV8>gJ9)"

测试,这里改用python代码进行测试

import requests
import json

headers = {
    "Content-Type": "application/json",
}

resp = requests.get("http://127.0.0.1:8000/api/admin/user", headers=headers)

def register(username: str, password: str):
    req_body = {
        "username": username,
        "password": password,
    }
    resp = requests.post("http://127.0.0.1:8000/api/register", data=json.dumps(req_body), headers=headers)
    print(resp.text)

def login(username: str, password: str):
    req_body = {
        "username": username,
        "password": password,
    }
    resp = requests.post("http://127.0.0.1:8000/api/login", data=json.dumps(req_body), headers=headers)
    print(resp.text)
    if resp.status_code == 200:
        return resp.json()["token"]
    else:
        return ""

if __name__ == "__main__":
    username = "lisi"
    password = "123456"
    register(username, password)
    token = login(username, password)
	print(token)

创建JWT认证中间件

创建中间件目录和代码文件

mkdir middlewares
touch middlewares/middlewares.go

内容如下

package middlewares

import (
	"gin-jwt/utils/token"
	"net/http"

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

func JwtAuthMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		err := token.TokenValid(c)
		if err != nil {
			c.String(http.StatusUnauthorized, err.Error())
			c.Abort()
			return
		}
		c.Next()
	}
}


main.go
文件中注册路由的时候使用中间件

func main() {
	models.ConnectDatabase()
	r := gin.Default()
	public := r.Group("/api")
	{
		public.POST("/register", controllers.Register)
		public.POST("/login", controllers.Login)
	}

	protected := r.Group("/api/admin")
	{
		protected.Use(middlewares.JwtAuthMiddleware())
		protected.GET("/user", func(c *gin.Context) {
			c.JSON(http.StatusOK, gin.H{
				"status":  "success",
				"message": "authorized",
			})
		})
	}

	r.Run("0.0.0.0:8000")
}


controllers/auth.go
文件中实现
CurrentUser

func CurrentUser(c *gin.Context) {
	// 从token中解析出user_id
	user_id, err := token.ExtractTokenID(c)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"error": err.Error(),
		})
		return
	}

	// 根据user_id从数据库查询数据
	u, err := models.GetUserByID(user_id)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"error": err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"message": "success",
		"data": u,
	})
}


models/user.go
文件中实现
GetUserByID

// 返回前将用户密码置空
func (u *User) PrepareGive() {
	u.Password = ""
}

func GetUserByID(uid uint) (User, error) {
	var u User
	if err := DB.First(&u, uid).Error; err != nil {
		return u, errors.New("user not found")
	}

	u.PrepareGive()
	return u, nil
}

至此,一个简单的gin-jwt应用就完成了。

客户端测试python脚本

服务端的三个接口这里用python脚本来测试

import requests
import json

headers = {
    # "Authorization": f"Bearer {token}",
    "Content-Type": "application/json",
}

resp = requests.get("http://127.0.0.1:8000/api/admin/user", headers=headers)

def register(username: str, password: str):
    req_body = {
        "username": username,
        "password": password,
    }
    resp = requests.post("http://127.0.0.1:8000/api/register", data=json.dumps(req_body), headers=headers)
    print(resp.text)

def login(username: str, password: str):
    req_body = {
        "username": username,
        "password": password,
    }
    resp = requests.post("http://127.0.0.1:8000/api/login", data=json.dumps(req_body), headers=headers)
    print(resp.text)
    if resp.status_code == 200:
        return resp.json()["token"]
    else:
        return ""

def test_protect_api(token: str):
    global headers
    headers["Authorization"] = f"Bearer {token}"

    resp = requests.get("http://127.0.0.1:8000/api/admin/user", headers=headers)
    print(resp.text)

if __name__ == "__main__":
    username = "lisi"
    password = "123456"
    register(username, password)
    token = login(username, password)
    test_protect_api(token)

运行脚本结果

{"message":"register success"}
{"token":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJhdXRob3JpemVkIjp0cnVlLCJleHAiOjE3MTk5NDA0NjAsInVzZXJfaWQiOjZ9.qkzn0Ot9hAb54l3RFbGUohHJ9oezGia5x_oXppbD2jQ"}
{"data":{"ID":6,"CreatedAt":"2024-07-03T00:14:20.187725+08:00","UpdatedAt":"2024-07-03T00:14:20.187725+08:00","DeletedAt":null,"username":"wangwu","password":""},"message":"success"}

完整示例代码

目录结构

├── client.py  # 客户端测试脚本
├── controllers  # 控制器相关包
│   └── auth.go  # 控制器方法实现
├── gin-jwt.bin  # 编译的二进制文件
├── go.mod  # go 项目文件
├── go.sum  # go 项目文件
├── main.go  # 程序入口文件
├── middlewares  # 中间件相关包
│   └── middlewares.go  # 中间件代码文件
├── models  # 存储层相关包
│   ├── setup.go  # 配置数据库连接
│   └── user.go  # user模块相关数据交互的代码文件
├── README.md  # git repo的描述文件
└── utils  # 工具类包
    └── token  # token相关工具类包
        └── token.go  # token工具的代码文件

main.go

package main

import (
	"log"

	"github.com/gin-gonic/gin"

	"gin-jwt/controllers"
	"gin-jwt/middlewares"
	"gin-jwt/models"

	"github.com/joho/godotenv"
)

func init() {
	err := godotenv.Load(".env")
	if err != nil {
		log.Fatalf("Error loading .env file. %v\n", err)
	}
}

func main() {
	models.ConnectDatabase()
	r := gin.Default()
	public := r.Group("/api")
	{
		public.POST("/register", controllers.Register)
		public.POST("/login", controllers.Login)
	}

	protected := r.Group("/api/admin")
	{
		protected.Use(middlewares.JwtAuthMiddleware()) // 在路由组中使用中间件
		protected.GET("/user", controllers.CurrentUser)
	}

	r.Run("0.0.0.0:8000")
}

controllers

  • auth.go
package controllers

import (
	"net/http"

	"gin-jwt/models"
	"gin-jwt/utils/token"

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

// /api/register的请求体
type ReqRegister struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password" binding:"required"`
}

// api/login 的请求体
type ReqLogin struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password" binding:"required"`
}

func Login(c *gin.Context) {
	var req ReqLogin
	if err := c.ShouldBindBodyWithJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	u := models.User{
		Username: req.Username,
		Password: req.Password,
	}

	// 调用 models.LoginCheck 对用户名和密码进行验证
	token, err := models.LoginCheck(u.Username, u.Password)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"error": "username or password is incorrect.",
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"token": token,
	})
}

func Register(c *gin.Context) {
	var req ReqRegister

	if err := c.ShouldBindBodyWithJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"data": err.Error(),
		})
		return
	}

	u := models.User{
		Username: req.Username,
		Password: req.Password,
	}

	_, err := u.SaveUser()
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"data": err.Error(),
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"message": "register success",
	})
}


func CurrentUser(c *gin.Context) {
	// 从token中解析出user_id
	user_id, err := token.ExtractTokenID(c)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"error": err.Error(),
		})
		return
	}

	// 根据user_id从数据库查询数据
	u, err := models.GetUserByID(user_id)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"error": err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"message": "success",
		"data": u,
	})
}

models

  • setup.go
package models

import (
	"fmt"
	"log"
	"os"

	"gorm.io/driver/postgres"
	"gorm.io/gorm"
)

var DB *gorm.DB

func ConnectDatabase() {
	var err error
	DbHost := os.Getenv("DB_HOST")
	DbPort := os.Getenv("DB_PORT")
	DbUser := os.Getenv("DB_USER")
	DbPass := os.Getenv("DB_PASS")
	DbName := os.Getenv("DB_NAME")

	dsn := fmt.Sprintf("host=%s port=%s user=%s dbname=%s sslmode=disable TimeZone=Asia/Shanghai password=%s", DbHost, DbPort, DbUser, DbName, DbPass)

	DB, err = gorm.Open(postgres.Open(dsn), &gorm.Config{})
	if err != nil {
		log.Fatalf("Connect to database failed, %v\n", err)
	} else {
		log.Printf("Connect to database success, host: %s, port: %s, user: %s, dbname: %s\n", DbHost, DbPort, DbUser, DbName)
	}

	// 迁移数据表
	DB.AutoMigrate(&User{})
}
  • user.go
package models

import (
	"errors"
	"gin-jwt/utils/token"
	"html"
	"strings"

	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"
)

type User struct {
	gorm.Model
	Username string `gorm:"size:255;not null;unique" json:"username"`
	Password string `gorm:"size:255;not null;" json:"password"`
}

func (u *User) SaveUser() (*User, error) {
	err := DB.Create(&u).Error
	if err != nil {
		return &User{}, err
	}
	return u, nil
}

// 使用gorm的hook在保存密码前对密码进行hash
func (u *User) BeforeSave(tx *gorm.DB) error {
	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(u.Password), bcrypt.DefaultCost)
	if err != nil {
		return err
	}
	u.Password = string(hashedPassword)
	u.Username = html.EscapeString(strings.TrimSpace(u.Username))
	return nil
}

// 返回前将用户密码置空
func (u *User) PrepareGive() {
	u.Password = ""
}

// 对哈希加密的密码进行比对校验
func VerifyPassword(password, hashedPassword string) error {
	return bcrypt.CompareHashAndPassword([]byte(hashedPassword), []byte(password))
}


func LoginCheck(username, password string) (string, error) {
	var err error
	u := User{}

	err = DB.Model(User{}).Where("username = ?", username).Take(&u).Error
	if err != nil {
		return "", err
	}
	err = VerifyPassword(password, u.Password)
	if err != nil && err == bcrypt.ErrMismatchedHashAndPassword {
		return "", err
	}

	token, err := token.GenerateToken(u.ID)
	if err != nil {
		return "", err
	}
	return token, nil
}

func GetUserByID(uid uint) (User, error) {
	var u User
	if err := DB.First(&u, uid).Error; err != nil {
		return u, errors.New("user not found")
	}

	u.PrepareGive()
	return u, nil
}

utils

  • token/token.go
package token

import (
	"fmt"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
)

func GenerateToken(user_id uint) (string, error) {
	token_lifespan, err := strconv.Atoi(os.Getenv("TOKEN_HOUR_LIFESPAN"))
	if err != nil {
		return "", err
	}

	claims := jwt.MapClaims{}
	claims["authorized"] = true
	claims["user_id"] = user_id
	claims["exp"] = time.Now().Add(time.Hour * time.Duration(token_lifespan)).Unix()
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)

	return token.SignedString([]byte(os.Getenv("API_SECRET")))
}

func TokenValid(c *gin.Context) error {
	tokenString := ExtractToken(c)
	fmt.Println(tokenString)
	_, err := jwt.Parse(tokenString, func(token *jwt.Token) (any, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}
		return []byte(os.Getenv("API_SECRET")), nil
	})
	if err != nil {
		return err
	}

	return nil
}

// 从请求头中获取token
func ExtractToken(c *gin.Context) string {
	bearerToken := c.GetHeader("Authorization")
	if len(strings.Split(bearerToken, " ")) == 2 {
		return strings.Split(bearerToken, " ")[1]
	}
	return ""
}

// 从jwt中解析出user_id
func ExtractTokenID(c *gin.Context) (uint, error) {
	tokenString := ExtractToken(c)
	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (any, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}
		return []byte(os.Getenv("API_SECRET")), nil
	})
	if err != nil {
		return 0, err
	}
	claims, ok := token.Claims.(jwt.MapClaims)
	// 如果jwt有效,将user_id转换为浮点数字符串,然后再转换为 uint32
	if ok && token.Valid {
		uid, err := strconv.ParseUint(fmt.Sprintf("%.0f", claims["user_id"]), 10, 32)
		if err != nil {
			return 0, err
		}
		return uint(uid), nil
	}

	return 0, nil
}

middlewares

  • middlewares.go
package middlewares

import (
	"gin-jwt/utils/token"
	"net/http"

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

func JwtAuthMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		err := token.TokenValid(c)
		if err != nil {
			c.String(http.StatusUnauthorized, err.Error())
			c.Abort()
			return
		}
		c.Next()
	}
}

参考

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