feat: added refresh tokens

internal/api/handler/auth.go

@@ -25,7 +25,7 @@ func NewAuthHandler(authService *domain.AuthService) *AuthHandler {
 // @Accept json
 // @Produce json
 // @Param payload body request.LoginPayload true "Login payload"
-// @Success 200 {object} domain.AuthToken
+// @Success 200 {object} domain.TokenPair
 // @Error 400 {object} response.ErrorResponse "failed to decode request body"
 // @Error 500 {object} response.ErrorResponse "failed to login"
 // @Router /api/v1/login [post]
@@ -39,12 +39,45 @@ func (h *AuthHandler) Login(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	token, err := h.AuthService.Login(ctx, payload.Email, payload.Password)
+	tokens, err := h.AuthService.Login(ctx, payload.Email, payload.Password)
 	if err != nil {
 		slog.ErrorContext(ctx, "failed to login", slog.Any("error", err))
 		response.Error(ctx, w, http.StatusInternalServerError, "failed to login")
 		return
 	}
 
-	response.JSON(ctx, w, http.StatusOK, token)
+	response.JSON(ctx, w, http.StatusOK, tokens)
+}
+
+// Refresh handles refreshing an access token
+//
+// @Summary Refresh route
+// @Description Token issuing with refresh token
+// @Tags Authorization
+// @Accept json
+// @Produce json
+// @Param payload body request.RefreshPayload true "Refresh payload"
+// @Success 200 {object} domain.TokenPair
+// @Error 400 {object} response.ErrorResponse "failed to decode request body"
+// @Error 500 {object} response.ErrorResponse "failed to refresh token"
+// @Router /api/v1/refresh [post]
+func (h *AuthHandler) Refresh(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+
+	payload, err := request.DecodeRefresh(r)
+	if err != nil {
+		slog.ErrorContext(ctx, "failed to decode refresh payload", slog.Any("error", err))
+		response.Error(ctx, w, http.StatusBadRequest, "failed to decode request body")
+		return
+	}
+
+	tokens, err := h.AuthService.Refresh(ctx, payload.RefreshToken)
+	if err != nil {
+		slog.ErrorContext(ctx, "failed to refresh token", slog.Any("error", err))
+		// TODO: Add error definition to repository, respond with Unauthorized when token is invalid
+		response.Error(ctx, w, http.StatusInternalServerError, "failed to refresh token")
+		return
+	}
+
+	response.JSON(ctx, w, http.StatusOK, tokens)
 }

internal/api/middleware/jwt.go

@@ -28,7 +28,7 @@ func WithJWT(authService *domain.AuthService) func(http.HandlerFunc) http.Handle
 				return
 			}
 
-			authContext, err := authService.ParseToken(ctx, parts[1])
+			authContext, err := authService.ParseAccessToken(ctx, parts[1])
 			if err != nil {
 				slog.ErrorContext(ctx, "invalid token", slog.Any("error", err))
 				response.Error(ctx, w, http.StatusUnauthorized, "invalid or expired token")

internal/api/request/auth.go

@@ -11,6 +11,10 @@ type LoginPayload struct {
 	Password string `json:"password"`
 }
 
+type RefreshPayload struct {
+	RefreshToken string `json:"refresh_token"`
+}
+
 func DecodeLogin(r *http.Request) (LoginPayload, error) {
 	var payload LoginPayload
 
@@ -23,3 +27,16 @@ func DecodeLogin(r *http.Request) (LoginPayload, error) {
 
 	return payload, nil
 }
+
+func DecodeRefresh(r *http.Request) (RefreshPayload, error) {
+	var payload RefreshPayload
+
+	decoder := json.NewDecoder(r.Body)
+	decoder.DisallowUnknownFields()
+
+	if err := decoder.Decode(&payload); err != nil {
+		return payload, fmt.Errorf("error decoding refresh payload: %w", err)
+	}
+
+	return payload, nil
+}

internal/domain/auth.go

@@ -2,6 +2,9 @@ package domain
 
 import (
 	"context"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"log/slog"
@@ -12,7 +15,10 @@ import (
 )
 
 type AuthRepository interface {
-	GetByEmail(ctx context.Context, email string) (*AuthUser, error)
+	GetUserById(ctx context.Context, id string) (*AuthUser, error)
+	GetUserByEmail(ctx context.Context, email string) (*AuthUser, error)
+	StoreRefreshToken(ctx context.Context, userID string, tokenHash string, expiresAt time.Time) error
+	ConsumeRefreshToken(ctx context.Context, tokenHash string) (string, error)
 }
 
 type AuthService struct {
@@ -20,8 +26,9 @@ type AuthService struct {
 	jwtSecret []byte
 }
 
-type AuthToken struct {
+type TokenPair struct {
-	Token string `json:"token"`
+	AccessToken  string `json:"access_token"`
+	RefreshToken string `json:"refresh_token"`
 }
 
 type AuthUser struct {
@@ -54,7 +61,7 @@ func NewAuthService(r AuthRepository, jwtSecret []byte) *AuthService {
 }
 
 func (s *AuthService) authenticate(ctx context.Context, email string, password string) (*AuthUser, error) {
-	user, err := s.repo.GetByEmail(ctx, email)
+	user, err := s.repo.GetUserByEmail(ctx, email)
 	if err != nil {
 		return user, err
 	}
@@ -70,20 +77,29 @@ func (s *AuthService) authenticate(ctx context.Context, email string, password s
 	return user, nil
 }
 
-func (s *AuthService) Login(ctx context.Context, email string, password string) (AuthToken, error) {
+func (s *AuthService) Login(ctx context.Context, email string, password string) (*TokenPair, error) {
-	var authToken AuthToken
-
 	user, err := s.authenticate(ctx, email, password)
 	if err != nil {
-		return authToken, err
+		return nil, err
 	}
 
-	authToken.Token, err = s.GenerateToken(user)
+	return s.issueTokens(ctx, user)
+}
+
+func (s *AuthService) Refresh(ctx context.Context, refreshToken string) (*TokenPair, error) {
+	tokenHash := hashToken(refreshToken)
+
+	userID, err := s.repo.ConsumeRefreshToken(ctx, tokenHash)
 	if err != nil {
-		return authToken, err
+		return nil, err
 	}
 
-	return authToken, nil
+	authUser, err := s.repo.GetUserById(ctx, userID)
+	if err != nil {
+		return nil, err
+	}
+
+	return s.issueTokens(ctx, authUser)
 }
 
 type JWTClaims struct {
@@ -97,13 +113,35 @@ type contextKey string
 
 const AuthContextKey = contextKey("auth")
 
-func (s *AuthService) GenerateToken(authUser *AuthUser) (string, error) {
+func (s *AuthService) issueTokens(ctx context.Context, authUser *AuthUser) (*TokenPair, error) {
+	accessToken, err := s.GenerateAccessToken(authUser)
+	if err != nil {
+		return nil, fmt.Errorf("failed to issue access token: %s", err)
+	}
+
+	refreshToken, err := s.GenerateRefreshToken()
+	if err != nil {
+		return nil, fmt.Errorf("failed to issue refresh token: %s", err)
+	}
+
+	err = s.repo.StoreRefreshToken(ctx, authUser.ID, hashToken(refreshToken), time.Now().Add(time.Hour*24*7))
+	if err != nil {
+		return nil, fmt.Errorf("failed to store refresh token: %s", err)
+	}
+
+	return &TokenPair{
+		AccessToken:  accessToken,
+		RefreshToken: refreshToken,
+	}, nil
+}
+
+func (s *AuthService) GenerateAccessToken(authUser *AuthUser) (string, error) {
 	claims := JWTClaims{
 		UserID: authUser.ID,
 		Email:  authUser.Email,
 		Name:   authUser.Name,
 	}
-	claims.ExpiresAt = jwt.NewNumericDate(time.Now().Add(time.Hour * 24))
+	claims.ExpiresAt = jwt.NewNumericDate(time.Now().Add(time.Minute * 15))
 
 	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
 
@@ -115,7 +153,16 @@ func (s *AuthService) GenerateToken(authUser *AuthUser) (string, error) {
 	return tokenString, nil
 }
 
-func (s *AuthService) ParseToken(ctx context.Context, tokenString string) (*AuthContext, error) {
+func (s *AuthService) GenerateRefreshToken() (string, error) {
+	rawToken, err := generateSecureToken(32)
+	if err != nil {
+		return "", fmt.Errorf("failed to generate refresh token: %w", err)
+	}
+
+	return rawToken, nil
+}
+
+func (s *AuthService) ParseAccessToken(ctx context.Context, tokenString string) (*AuthContext, error) {
 	claims := &JWTClaims{}
 	token, err := jwt.ParseWithClaims(tokenString, claims, func(token *jwt.Token) (any, error) {
 		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
@@ -134,3 +181,16 @@ func (s *AuthService) ParseToken(ctx context.Context, tokenString string) (*Auth
 		Name:   claims.Name,
 	}, nil
 }
+
+func generateSecureToken(n int) (string, error) {
+	bytes := make([]byte, n)
+	if _, err := rand.Read(bytes); err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(bytes), nil
+}
+
+func hashToken(token string) string {
+	hash := sha256.Sum256([]byte(token))
+	return hex.EncodeToString(hash[:])
+}

internal/repository/auth.go

@@ -3,7 +3,9 @@ package repository
 import (
 	"context"
 	"database/sql"
+	"errors"
 	"fmt"
+	"time"
 
 	"github.com/robindittmar/dttmr-api/internal/domain"
 )
@@ -16,7 +18,21 @@ func NewAuthRepo(db *sql.DB) *AuthRepo {
 	return &AuthRepo{db: db}
 }
 
-func (r *AuthRepo) GetByEmail(ctx context.Context, email string) (*domain.AuthUser, error) {
+func (r *AuthRepo) GetUserById(ctx context.Context, id string) (*domain.AuthUser, error) {
+	user := &domain.AuthUser{}
+
+	err := r.db.QueryRowContext(ctx,
+		"SELECT id, email, name, password_hash FROM users WHERE id = $1",
+		id,
+	).Scan(&user.ID, &user.Email, &user.Name, &user.PasswordHash)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get user: %w", err)
+	}
+
+	return user, nil
+}
+
+func (r *AuthRepo) GetUserByEmail(ctx context.Context, email string) (*domain.AuthUser, error) {
 	user := &domain.AuthUser{}
 
 	err := r.db.QueryRowContext(ctx,
@@ -29,3 +45,30 @@ func (r *AuthRepo) GetByEmail(ctx context.Context, email string) (*domain.AuthUs
 
 	return user, nil
 }
+
+func (r *AuthRepo) StoreRefreshToken(ctx context.Context, userID string, tokenHash string, expiresAt time.Time) error {
+	_, err := r.db.ExecContext(ctx,
+		"INSERT INTO refresh_tokens (user_id, token_hash, expires_at) VALUES ($1, $2, $3)",
+		userID, tokenHash, expiresAt,
+	)
+	if err != nil {
+		return fmt.Errorf("failed to store refresh token: %w", err)
+	}
+
+	return nil
+}
+func (r *AuthRepo) ConsumeRefreshToken(ctx context.Context, tokenHash string) (string, error) {
+	var userID string
+	err := r.db.QueryRowContext(ctx,
+		"DELETE FROM refresh_tokens WHERE token_hash = $1 AND expires_at > NOW() RETURNING user_id",
+		tokenHash,
+	).Scan(&userID)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return "", fmt.Errorf("refresh token not found or expired: %w", err)
+		}
+		return "", fmt.Errorf("failed to consume refresh token: %w", err)
+	}
+
+	return userID, nil
+}