add auth lib

jwt/jwt.go

@@ -0,0 +1,102 @@
+package jwt
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/google/uuid"
+)
+
+const (
+	TokenTypeAuth    = "auth"
+	TokenTypeRefresh = "refresh"
+)
+
+type Claims struct {
+	UserID    string `json:"userId"`
+	Username  string `json:"username"`
+	TokenType string `json:"tokenType"`
+	jwt.RegisteredClaims
+}
+
+type JWTManager struct {
+	secret     []byte
+	authTTL    time.Duration
+	refreshTTL time.Duration
+}
+
+func NewJWTManager(secret string, authTTL, refreshTTL time.Duration) *JWTManager {
+	return &JWTManager{
+		secret:     []byte(secret),
+		authTTL:    authTTL,
+		refreshTTL: refreshTTL,
+	}
+}
+
+func (m *JWTManager) GenerateAuthToken(userID string, username string) (string, error) {
+	return m.generate(userID, username, TokenTypeAuth, m.authTTL)
+}
+
+func (m *JWTManager) GenerateRefreshToken(userID string, username string) (string, error) {
+	return m.generate(userID, username, TokenTypeRefresh, m.refreshTTL)
+}
+
+func (m *JWTManager) generate(userID string, username, tokenType string, ttl time.Duration) (string, error) {
+	now := time.Now()
+	claims := Claims{
+		UserID:    userID,
+		Username:  username,
+		TokenType: tokenType,
+		RegisteredClaims: jwt.RegisteredClaims{
+			IssuedAt:  jwt.NewNumericDate(now),
+			ExpiresAt: jwt.NewNumericDate(now.Add(ttl)),
+			Subject:   userID,
+			ID:        uuid.NewString(),
+		},
+	}
+
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	return token.SignedString(m.secret)
+}
+
+func (m *JWTManager) ParseAuthToken(tokenStr string) (*Claims, error) {
+	claims, err := m.parse(tokenStr)
+	if err != nil {
+		return nil, err
+	}
+	if claims.TokenType != TokenTypeAuth {
+		return nil, fmt.Errorf("invalid token type")
+	}
+	return claims, nil
+}
+
+func (m *JWTManager) ParseRefreshToken(tokenStr string) (*Claims, error) {
+	claims, err := m.parse(tokenStr)
+	if err != nil {
+		return nil, err
+	}
+	if claims.TokenType != TokenTypeRefresh {
+		return nil, fmt.Errorf("invalid token type")
+	}
+	return claims, nil
+}
+
+func (m *JWTManager) parse(tokenStr string) (*Claims, error) {
+	token, err := jwt.ParseWithClaims(tokenStr, &Claims{}, func(token *jwt.Token) (any, error) {
+		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method")
+		}
+		return m.secret, nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	claims, ok := token.Claims.(*Claims)
+	if !ok || !token.Valid {
+		return nil, fmt.Errorf("invalid token")
+	}
+
+	return claims, nil
+}

jwt/jwt_test.go

@@ -0,0 +1,96 @@
+package jwt
+
+import (
+	"testing"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+func TestJWTManagerGenerateAndParseAuthToken(t *testing.T) {
+	mgr := NewJWTManager("secret", 2*time.Minute, 10*time.Minute)
+
+	token, err := mgr.GenerateAuthToken("user-1", "alice")
+	if err != nil {
+		t.Fatalf("generate auth token: %v", err)
+	}
+
+	claims, err := mgr.ParseAuthToken(token)
+	if err != nil {
+		t.Fatalf("parse auth token: %v", err)
+	}
+	if claims.UserID != "user-1" {
+		t.Fatalf("expected user id user-1, got %q", claims.UserID)
+	}
+	if claims.Username != "alice" {
+		t.Fatalf("expected username alice, got %q", claims.Username)
+	}
+	if claims.TokenType != TokenTypeAuth {
+		t.Fatalf("expected token type %q, got %q", TokenTypeAuth, claims.TokenType)
+	}
+}
+
+func TestJWTManagerRejectsWrongTokenType(t *testing.T) {
+	mgr := NewJWTManager("secret", time.Minute, time.Minute)
+
+	refreshToken, err := mgr.GenerateRefreshToken("user-1", "alice")
+	if err != nil {
+		t.Fatalf("generate refresh token: %v", err)
+	}
+	if _, err := mgr.ParseAuthToken(refreshToken); err == nil {
+		t.Fatal("expected error when parsing refresh token as auth token")
+	}
+
+	authToken, err := mgr.GenerateAuthToken("user-1", "alice")
+	if err != nil {
+		t.Fatalf("generate auth token: %v", err)
+	}
+	if _, err := mgr.ParseRefreshToken(authToken); err == nil {
+		t.Fatal("expected error when parsing auth token as refresh token")
+	}
+}
+
+func TestJWTManagerRejectsInvalidOrTamperedToken(t *testing.T) {
+	mgr := NewJWTManager("secret", time.Minute, time.Minute)
+
+	if _, err := mgr.ParseAuthToken("not-a-token"); err == nil {
+		t.Fatal("expected parse error for malformed token")
+	}
+
+	token, err := mgr.GenerateAuthToken("user-1", "alice")
+	if err != nil {
+		t.Fatalf("generate auth token: %v", err)
+	}
+
+	otherMgr := NewJWTManager("different-secret", time.Minute, time.Minute)
+	if _, err := otherMgr.ParseAuthToken(token); err == nil {
+		t.Fatal("expected signature validation error with different secret")
+	}
+}
+
+func TestJWTManagerRejectsExpiredToken(t *testing.T) {
+	mgr := NewJWTManager("secret", -1*time.Second, time.Minute)
+
+	token, err := mgr.GenerateAuthToken("user-1", "alice")
+	if err != nil {
+		t.Fatalf("generate expired auth token: %v", err)
+	}
+
+	if _, err := mgr.ParseAuthToken(token); err == nil {
+		t.Fatal("expected expired token error")
+	}
+}
+
+func TestJWTManagerRejectsNonHMACAlgorithm(t *testing.T) {
+	mgr := NewJWTManager("secret", time.Minute, time.Minute)
+
+	noneToken := jwt.NewWithClaims(jwt.SigningMethodNone, Claims{UserID: "u", Username: "n", TokenType: TokenTypeAuth})
+	tokenStr, err := noneToken.SignedString(jwt.UnsafeAllowNoneSignatureType)
+	if err != nil {
+		t.Fatalf("sign none token: %v", err)
+	}
+
+	if _, err := mgr.ParseAuthToken(tokenStr); err == nil {
+		t.Fatal("expected error for non-HMAC algorithm")
+	}
+}