feat: jwt token generation (todo: create jwt validation middleware)

internal/auth/jwt.go

@@ -0,0 +1,37 @@
+package auth
+
+import (
+	"fmt"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+func GenerateJWT(key string, user User, expiryTimestamp uint64) (string, error) {
+	claims := jwt.MapClaims{
+		"user": user,
+		"exp":  expiryTimestamp,
+	}
+
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	return token.SignedString([]byte(key))
+}
+
+func ValidateJWT(jwtString, key string) (jwt.MapClaims, error) {
+	token, err := jwt.Parse(jwtString, func(token *jwt.Token) (any, error) {
+		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("Invalid signing method!")
+		}
+
+		return []byte(key), nil
+	})
+
+	if err != nil {
+		return nil, err
+	}
+
+	if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
+		return claims, nil
+	}
+
+	return nil, fmt.Errorf("Invalid token!")
+}