Feat: Add JWT config, auth middleware, and token parsing using username.

Signed-off-by: Goldbro233 <bowensun_06@outlook.com>

utils/utils.go

@@ -2,6 +2,8 @@ package utils
 
 import (
 	"GinTutorial/config"
+	"errors"
+	"fmt"
 	"time"
 
 	"github.com/golang-jwt/jwt/v5"
@@ -19,7 +21,7 @@ func GenerateJWT(username string) (string, error) {
 		"exp":      time.Now().Add(time.Hour * 72).Unix(),
 	})
 
-	signedToken, err := token.SignedString([]byte("secret"))
+	signedToken, err := token.SignedString([]byte(config.AppConfig.Jwtconfig.Secret))
 	return "Bearer " + signedToken, err
 }
 
@@ -27,3 +29,29 @@ func CheckPassword(password, hash string) bool {
 	err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
 	return err == nil
 }
+
+func ParseToken(tokenString string) (string, error) {
+	if len(tokenString) > 7 && tokenString[0:7] == "Bearer " {
+		tokenString = tokenString[7:]
+	}
+	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(config.AppConfig.Jwtconfig.Secret), nil
+	})
+
+	if err != nil {
+		return "", err
+	}
+
+	if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
+		username, ok := claims["username"].(string)
+		if !ok {
+			return "", errors.New("username invalid")
+		}
+		return username, nil
+	}
+
+	return "", errors.New("token invalid")
+}