Finished login system with refresh-tokens

handlers/account.go

@@ -2,12 +2,14 @@ package handlers
 
 import (
 	"encoding/json"
+	"log"
 	"net/http"
 	"os"
 	"shap-planner-backend/auth"
 	"shap-planner-backend/models"
 	"shap-planner-backend/storage"
 	"shap-planner-backend/utils"
+	"time"
 )
 
 func Register(w http.ResponseWriter, r *http.Request) {
@@ -38,7 +40,6 @@ func Register(w http.ResponseWriter, r *http.Request) {
 
 	w.WriteHeader(http.StatusCreated)
 }
-
 func Login(w http.ResponseWriter, r *http.Request) {
 	var creds struct {
 		Username string `json:"username"`
@@ -51,11 +52,13 @@ func Login(w http.ResponseWriter, r *http.Request) {
 
 	user, err := storage.GetUserByUsername(creds.Username)
 	if err != nil {
+		println("user " + creds.Username + " not found")
 		http.Error(w, "Invalid credentials", http.StatusUnauthorized)
 		return
 	}
 
 	if !auth.CheckPasswordHash(creds.Password, user.Password) {
+		println("invalid password")
 		http.Error(w, "Invalid credentials", http.StatusUnauthorized)
 		return
 	}
@@ -66,29 +69,55 @@ func Login(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	token, err := auth.GenerateJWT(user.ID, user.Role, secret)
+	accessToken, err := auth.GenerateJWT(user.ID, user.Role, secret)
 	if err != nil {
 		http.Error(w, "Could not generate token", http.StatusInternalServerError)
 		return
 	}
 
-	type userResp struct {
-		ID       string `json:"id"`
-		Username string `json:"username"`
-		Role     string `json:"role"`
+	refreshTokenPlain, err := utils.GenerateRefreshToken()
+	if err != nil {
+		http.Error(w, "could not generate refresh token", http.StatusInternalServerError)
+		return
+	}
+	refreshHash := utils.HashToken(refreshTokenPlain)
+	refreshID := utils.GenerateUUID()
+	refreshExpires := time.Now().Add(7 * 24 * time.Hour).Unix() // expiry: 7 days
+
+	deviceInfo := r.Header.Get("User-Agent")
+
+	if err := storage.AddRefreshToken(models.RefreshToken{
+		ID:         refreshID,
+		UserID:     user.ID,
+		Token:      refreshHash,
+		ExpiresAt:  refreshExpires,
+		DeviceInfo: deviceInfo,
+		CreatedAt:  time.Now().Unix(),
+		Revoked:    false,
+	}); err != nil {
+		http.Error(w, "could not save refresh token", http.StatusInternalServerError)
+		return
+	}
+
+	// Return access + refresh token (refresh in plain for client to store securely)
+	resp := map[string]interface{}{
+		"access_token":  accessToken,
+		"refresh_token": refreshTokenPlain,
+		"user": map[string]interface{}{
+			"id":       user.ID,
+			"username": user.Username,
+			"role":     user.Role,
+		},
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]interface{}{
-		"token": token,
-		"user": userResp{
-			ID:       user.ID,
-			Username: user.Username,
-			Role:     user.Role,
-		},
-	})
+	json.NewEncoder(w).Encode(resp)
+}
+func Logout(w http.ResponseWriter, r *http.Request) {
+	claims := r.Context().Value(auth.UserContextKey).(*auth.Claims)
+	storage.RevokeAllRefreshTokensForUser(claims.UserID)
+	w.WriteHeader(204)
 }
-
 func TestHandler(w http.ResponseWriter, r *http.Request) {
 	claimsRaw := r.Context().Value(auth.UserContextKey)
 	if claimsRaw == nil {
@@ -109,3 +138,50 @@ func TestHandler(w http.ResponseWriter, r *http.Request) {
 		"msg":     "access granted to protected endpoint",
 	})
 }
+func RefreshToken(w http.ResponseWriter, r *http.Request) {
+	var req struct {
+		RefreshToken string `json:"refresh_token"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, "Invalid request", http.StatusBadRequest)
+		return
+	}
+
+	hashed := utils.HashToken(req.RefreshToken)
+
+	tokenRow, err := storage.GetRefreshToken(hashed)
+	if err != nil || tokenRow.Revoked || tokenRow.ExpiresAt < time.Now().Unix() {
+		http.Error(w, "Invalid refresh token", http.StatusUnauthorized)
+		return
+	}
+
+	if err := storage.RevokeRefreshToken(tokenRow.ID); err != nil {
+		log.Println(err)
+	}
+
+	newToken, _ := utils.GenerateRefreshToken()
+	newHash := utils.HashToken(newToken)
+	newExpires := time.Now().Add(7 * 24 * time.Hour).Unix() //7 days
+	newID := utils.GenerateUUID()
+	deviceInfo := r.Header.Get("User-Agent")
+	if err = storage.AddRefreshToken(models.RefreshToken{
+		ID:         newID,
+		UserID:     tokenRow.UserID,
+		Token:      newHash,
+		ExpiresAt:  newExpires,
+		CreatedAt:  time.Now().Unix(),
+		Revoked:    false,
+		DeviceInfo: deviceInfo,
+	}); err != nil {
+		return
+	}
+
+	accessToken, _ := auth.GenerateJWT(tokenRow.UserID, "", []byte(os.Getenv("SHAP_JWT_SECRET")))
+
+	if err = json.NewEncoder(w).Encode(map[string]string{
+		"access_token":  accessToken,
+		"refresh_token": newToken,
+	}); err != nil {
+		return
+	}
+}

models/loginmodels.go

@@ -1,10 +1,11 @@
 package models
 
-import "time"
-
 type RefreshToken struct {
 	ID         string `json:id`
 	UserID     string `json:userid`
 	Token      string `json:token`
-	ExpiresAt time.Time `json:expiresat`
+	ExpiresAt  int64  `json:expiresat`
+	CreatedAt  int64  `json:createdat`
+	Revoked    bool   `json:revoked`
+	DeviceInfo string `json:deviceinfo`
 }

server/server.go

@@ -48,6 +48,8 @@ func (server *Server) Run() {
 	// Public
 	mux.HandleFunc("/api/login", handlers.Login)
 	mux.HandleFunc("/api/register", handlers.Register)
+	mux.HandleFunc("/api/refresh", handlers.RefreshToken)
+	mux.HandleFunc("/api/logout", handlers.Logout)
 
 	// Login required
 	mux.Handle("/api/expenses", auth.AuthMiddleware(server.JWTSecret)(http.HandlerFunc(handlers.GetExpenses)))

storage/storage.go

@@ -2,11 +2,13 @@ package storage
 
 import (
 	"database/sql"
+	"errors"
 	"shap-planner-backend/models"
 
 	_ "github.com/glebarez/go-sqlite"
 )
 
+var ErrNotFound = sql.ErrNoRows
 var DB *sql.DB
 
 func InitDB(filepath string) error {
@@ -19,13 +21,33 @@ func InitDB(filepath string) error {
 	//Create Users-Table
 	_, err = DB.Exec(`CREATE TABLE IF NOT EXISTS users(
     	id TEXT PRIMARY KEY,
-    	username TEXT UNIQUE,
-    	password TEXT
+    	username TEXT UNIQUE NOT NULL,
+    	password TEXT NOT NULL,
+    	role TEXT NOT NULL
 	);`)
 	if err != nil {
 		return err
 	}
 
+	//Create refresh token-table
+	_, err = DB.Exec(`CREATE TABLE IF NOT EXISTS refresh_tokens(
+    	id TEXT PRIMARY KEY,
+    	user_id TEXT NOT NULL,
+        token_hash TEXT NOT NULL,
+        expires_at INTEGER NOT NULL,
+        created_at INTEGER NOT NULL,
+        revoked INTEGER NOT NULL DEFAULT 0,
+        device_info TEXT,
+        FOREIGN KEY(user_id) REFERENCES users(id)
+	)`)
+	if err != nil {
+		return err
+	}
+	_, err = DB.Exec(`CREATE INDEX IF NOT EXISTS idx_refresh_token_hash ON refresh_tokens(token_hash)`)
+	if err != nil {
+		return err
+	}
+
 	//Create Expenses-Table
 	_, err = DB.Exec(`CREATE TABLE IF NOT EXISTS expenses(
     	id TEXT PRIMARY KEY
@@ -34,21 +56,67 @@ func InitDB(filepath string) error {
 	return err
 }
 
+// Users
 func AddUser(user models.User) error {
 	_, err := DB.Exec("INSERT INTO users(id, username, password, role) VALUES (?, ?, ?, ?)", user.ID, user.Username, user.Password, user.Role)
 	return err
 }
-
 func GetUserByUsername(username string) (models.User, error) {
 	row := DB.QueryRow("SELECT * FROM users WHERE username = ?", username)
 	var user models.User
-	err := row.Scan(&user.ID, &user.Username, &user.Password)
+	err := row.Scan(&user.ID, &user.Username, &user.Password, &user.Role)
 	return user, err
 }
-
 func GetUserById(id string) (models.User, error) {
 	row := DB.QueryRow("SELECT * FROM users WHERE id = ?", id)
 	var user models.User
 	err := row.Scan(&user.ID, &user.Username, &user.Password)
 	return user, err
 }
+
+// Refresh Tokens
+func AddRefreshToken(token models.RefreshToken) error {
+	_, err := DB.Exec("INSERT INTO refresh_tokens(id, user_id, token_hash, expires_at, created_at, revoked, device_info) VALUES (?, ?, ?, ?, ?, ?, ?)",
+		token.ID, token.UserID, token.Token, token.ExpiresAt, token.CreatedAt, token.Revoked, token.DeviceInfo)
+	return err
+}
+func GetRefreshToken(token string) (models.RefreshToken, error) {
+	row := DB.QueryRow("SELECT * FROM refresh_tokens WHERE token_hash = ?", token)
+	var refresh_token models.RefreshToken
+	err := row.Scan(&refresh_token.ID, &refresh_token.UserID, &refresh_token.Token, &refresh_token.ExpiresAt, &refresh_token.CreatedAt, &refresh_token.Revoked, &refresh_token.DeviceInfo)
+	return refresh_token, err
+}
+func RevokeRefreshToken(tokenID string) error {
+	if DB == nil {
+		return errors.New("db not initialized")
+	}
+
+	res, err := DB.Exec(`
+		UPDATE refresh_tokens
+		SET revoked = 1
+		WHERE id = ?
+	`, tokenID)
+	if err != nil {
+		return err
+	}
+	n, err := res.RowsAffected()
+	if err != nil {
+		return err
+	}
+	if n == 0 {
+		return ErrNotFound
+	}
+	return nil
+}
+func RevokeAllRefreshTokensForUser(userID string) error {
+	if DB == nil {
+		return errors.New("db not initialized")
+	}
+
+	_, err := DB.Exec(`
+		UPDATE refresh_tokens
+		SET revoked = 1
+		WHERE user_id = ?
+	`, userID)
+	return err
+}

utils/util.go

@@ -2,7 +2,9 @@ package utils
 
 import (
 	"crypto/rand"
+	"crypto/sha256"
 	"encoding/base64"
+	"encoding/hex"
 
 	"github.com/google/uuid"
 )
@@ -18,3 +20,14 @@ func GenerateSecret() string {
 	}
 	return base64.StdEncoding.EncodeToString(b)
 }
+func GenerateRefreshToken() (string, error) {
+	b := make([]byte, 32)
+	if _, err := rand.Read(b); err != nil {
+		return "", err
+	}
+	return base64.RawURLEncoding.EncodeToString(b), nil
+}
+func HashToken(token string) string {
+	hash := sha256.Sum256([]byte(token))
+	return hex.EncodeToString(hash[:])
+}