chatgpt帮我创建一个由go+mysql+jwt+gorm搭建的restapi

好的，以下是一个基于go+mysql+jwt+gorm搭建的restapi：

1. 首先安装好Go语言环境和MySQL数据库，并将Gorm和jwt-go添加到你的Go项目中。

2. 创建一个名为"main.go"的文件，编写以下代码：

package main

import (
	"fmt"
	"log"
	"net/http"

	"github.com/dgrijalva/jwt-go"
	"github.com/gin-gonic/gin"
	"gorm.io/driver/mysql"
	"gorm.io/gorm"
)

type User struct {
	ID       uint   `gorm:"primaryKey"`
	Username string `json:"username"`
	Password string `json:"password"`
}

var db *gorm.DB

func main() {
	var err error
	dsn := "root:password@tcp(127.0.0.1:3306)/test?charset=utf8mb4&parseTime=True&loc=Local"
	db, err = gorm.Open(mysql.Open(dsn), &gorm.Config{})
	if err != nil {
		log.Fatal(err)
	}

	err = db.AutoMigrate(&User{})
	if err != nil {
		log.Fatal(err)
	}

	r := gin.Default()

	r.POST("/login", login)
	auth := r.Group("/auth")
	auth.Use(authMiddleware())
	auth.GET("/user/:id", getUser)

	err = r.Run()
	if err != nil {
		log.Fatal(err)
	}
}

func login(c *gin.Context) {
	var user User
	err := c.ShouldBindJSON(&user)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	var foundUser User
	result := db.Where("username = ?", user.Username).First(&foundUser)
	if result.Error != nil {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid username or password"})
		return
	}

	if foundUser.Password != user.Password {
		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid username or password"})
		return
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"username": foundUser.Username,
		"id":       foundUser.ID,
	})
	tokenString, err := token.SignedString([]byte("secret"))
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to generate token"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"token": tokenString})
}

func getUser(c *gin.Context) {
	id := c.Param("id")

	var user User
	result := db.First(&user, id)
	if result.Error != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "User not found"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"data": user})
}

func authMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		tokenString := c.GetHeader("Authorization")
		if tokenString == "" {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Authorization header required"})
			return
		}

		token, err := jwt.Parse(tokenString, 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("secret"), nil
		})

		if err != nil {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token"})
			return
		}

		claims, ok := token.Claims.(jwt.MapClaims)
		if !ok || !token.Valid {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token"})
			return
		}

		var user User
		result := db.First(&user, claims["id"])
		if result.Error != nil {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token"})
			return
		}

		c.Set("user", user)
		c.Next()
	}
}

3. 运行以上代码，你将得到一个具有以下功能的REST API：

• 注册或登入用户，并返回JWT令牌。
• 验证JWT令牌，并在请求中提供验证后的用户。
• 获取特定ID的用户。

希望这能对你有所帮助！