Kq7BnhJ1

1package main
2
3import (
4	"net/http"
5	"time"
6
7	"github.com/gin-gonic/gin"
8	"github.com/golang-jwt/jwt/v5"
9	"golang.org/x/crypto/bcrypt"
10)
11
12var (
13	jwtSecret = []byte("your_strong_secret_key")
14	users     = make(map[string]string)
15)
16
17type Credentials struct {
18	Username string `json:"username" binding:"required"`
19	Password string `json:"password" binding:"required"`
20}
21
22type Claims struct {
23	Username string `json:"username"`
24	jwt.RegisteredClaims
25}
26
27func main() {
28	r := gin.Default()
29
30	r.POST("/register", registerHandler)
31	r.POST("/login", loginHandler)
32	r.GET("/protected", authMiddleware, protectedHandler)
33
34	r.Run(":8080")
35}
36
37func registerHandler(c *gin.Context) {
38	var creds Credentials
39	if err := c.ShouldBindJSON(&creds); err != nil {
40		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request"})
41		return
42	}
43
44	if _, exists := users[creds.Username]; exists {
45		c.JSON(http.StatusConflict, gin.H{"error": "User already exists"})
46		return
47	}
48
49	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(creds.Password), bcrypt.DefaultCost)
50	if err != nil {
51		c.JSON(http.StatusInternalServerError, gin.H{"error": "Could not hash password"})
52		return
53	}
54
55	users[creds.Username] = string(hashedPassword)
56	c.JSON(http.StatusCreated, gin.H{"message": "User created"})
57}
58
59func loginHandler(c *gin.Context) {
60	var creds Credentials
61	if err := c.ShouldBindJSON(&creds); err != nil {
62		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request"})
63		return
64	}
65
66	storedHash, exists := users[creds.Username]
67	if !exists {
68		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid credentials"})
69		return
70	}
71
72	if err := bcrypt.CompareHashAndPassword([]byte(storedHash), []byte(creds.Password)); err != nil {
73		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid credentials"})
74		return
75	}
76
77	expirationTime := time.Now().Add(15 * time.Minute)
78	claims := &Claims{
79		Username: creds.Username,
80		RegisteredClaims: jwt.RegisteredClaims{
81			ExpiresAt: jwt.NewNumericDate(expirationTime),
82		},
83	}
84
85	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
86	tokenString, err := token.SignedString(jwtSecret)
87	if err != nil {
88		c.JSON(http.StatusInternalServerError, gin.H{"error": "Could not generate token"})
89		return
90	}
91
92	c.JSON(http.StatusOK, gin.H{"token": tokenString})
93}
94
95func authMiddleware(c *gin.Context) {
96	tokenString := c.GetHeader("Authorization")
97	if tokenString == "" {
98		c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "Missing authorization header"})
99		return
100	}
101
102	token, err := jwt.ParseWithClaims(tokenString, &Claims{}, func(token *jwt.Token) (interface{}, error) {
103		return jwtSecret, nil
104	})
105
106	if err != nil || !token.Valid {
107		c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "Invalid token"})
108		return
109	}
110
111	claims, ok := token.Claims.(*Claims)
112	if !ok {
113		c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{"error": "Invalid token claims"})
114		return
115	}
116
117	c.Set("username", claims.Username)
118	c.Next()
119}
120
121func protectedHandler(c *gin.Context) {
122	username, exists := c.Get("username")
123	if !exists {
124		c.JSON(http.StatusInternalServerError, gin.H{"error": "User not found in context"})
125		return
126	}
127
128	c.JSON(http.StatusOK, gin.H{"message": "Hello " + username.(string) + "! This is protected content"})
129}