/auth/login implemented

Author: mrsumanbiswas

server/controllers/auth.go

@@ -49,6 +49,39 @@ func HandleRegister(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.WriteHeader(http.StatusCreated)
+	_ = json.NewEncoder(w).Encode(models.JSONResponse{
+		Success: true,
+		Data: map[string]interface{}{
+			"user":   user,
+			"tokens": tokens,
+		},
+	})
+}
+
+
+type LoginReq struct {
+	Username string `json:"username"`
+	Password string `json:"password"`
+}
+
+func HandleLogin(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+
+	var req LoginReq
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		_ = json.NewEncoder(w).Encode(models.JSONResponse{Success: false, Error: "Invalid json payload structure"})
+		return
+	}
+
+	svc := services.NewAuthService()
+	user, tokens, err := svc.Login(r.Context(), req.Username, req.Password)
+	if err != nil {
+		w.WriteHeader(http.StatusUnauthorized)
+		_ = json.NewEncoder(w).Encode(models.JSONResponse{Success: false, Error: err.Error()})
+		return
+	}
+
 	_ = json.NewEncoder(w).Encode(models.JSONResponse{
 		Success: true,
 		Data: map[string]interface{}{

server/middlewares/auth.go

@@ -1 +1,48 @@
 package middlewares
+
+import (
+	"context"
+	"net/http"
+	"strings"
+
+	"github.com/commandlinecoding/elephant/server/models"
+	"github.com/commandlinecoding/elephant/server/services"
+	"encoding/json"
+)
+
+type contextKey string
+const UserIDKey contextKey = "userId"
+
+func AuthGuard(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		authHeader := r.Header.Get("Authorization")
+		if authHeader == "" {
+			respondUnauthorized(w)
+			return
+		}
+
+		parts := strings.Split(authHeader, " ")
+		if len(parts) != 2 || strings.ToLower(parts[0]) != "bearer" {
+			respondUnauthorized(w)
+			return
+		}
+
+		uid, err := services.VerifyAccessToken(parts[1])
+		if err != nil {
+			respondUnauthorized(w)
+			return
+		}
+
+		ctx := context.WithValue(r.Context(), UserIDKey, uid)
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+func respondUnauthorized(w http.ResponseWriter) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusUnauthorized)
+	_ = json.NewEncoder(w).Encode(models.JSONResponse{
+		Success: false,
+		Error:   "Access token missing, expired or malformed",
+	})
+}

server/repository/user.go

@@ -49,3 +49,23 @@ func (r *UserRepository) UsernameExists(ctx context.Context, username string) (b
 
 	return exists, nil
 }
+
+func (r *UserRepository) FindByUsername(ctx context.Context, username string) (*models.User, error) {
+	query := `
+		SELECT id, username, display_name, password_hash, created_at 
+		FROM users 
+		WHERE username = $1;
+	`
+	var user models.User
+	err := config.DB.QueryRow(ctx, query, username).Scan(
+		&user.ID,
+		&user.Username,
+		&user.DisplayName,
+		&user.PasswordHash,
+		&user.CreatedAt,
+	)
+	if err != nil {
+		return nil, err
+	}
+	return &user, nil
+}

server/routes/auth.go

@@ -7,4 +7,5 @@ import (
 
 func AuthRoute(router chi.Router) {
 	router.Post("/register", controllers.HandleRegister)
+	router.Post("/login", controllers.HandleLogin)
 }

server/services/auth.go

@@ -1 +1,39 @@
 package services
+
+import (
+	"context"
+	"errors"
+	"strings"
+
+	"github.com/commandlinecoding/elephant/server/models"
+	"github.com/commandlinecoding/elephant/server/repository"
+)
+
+type AuthService struct {
+	repo *repository.UserRepository
+}
+
+func NewAuthService() *AuthService {
+	return &AuthService{repo: repository.NewUserRepository()}
+}
+
+func (s *AuthService) Login(ctx context.Context, username, password string) (*models.User, *TokenPair, error) {
+	username = strings.ToLower(strings.TrimSpace(username))
+
+	user, err := s.repo.FindByUsername(ctx, username)
+	if err != nil {
+		return nil, nil, errors.New("invalid username or password credentials")
+	}
+
+	match, err := VerifyPassword(password, user.PasswordHash)
+	if err != nil || !match {
+		return nil, nil, errors.New("invalid username or password credentials")
+	}
+
+	tokens, err := GenerateTokenPair(user.ID)
+	if err != nil {
+		return nil, nil, errors.New("failed to issue tokens")
+	}
+
+	return user, tokens, nil
+}

server/services/jwt.go

@@ -1,6 +1,7 @@
 package services
 
 import (
+	"fmt"
 	"time"
 
 	"github.com/commandlinecoding/elephant/server/env"
@@ -42,3 +43,27 @@ func GenerateTokenPair(uid string) (*TokenPair, error) {
 		RefreshToken: rtkStr,
 	}, nil
 }
+
+// VerifyAccessToken
+func VerifyAccessToken(tokenStr string) (string, error) {
+	token, err := jwt.Parse(tokenStr, 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(env.JWT_SECRET), nil
+	})
+
+	if err != nil {
+		return "", err
+	}
+
+	if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
+		uid, ok := claims["sub"].(string)
+		if !ok {
+			return "", fmt.Errorf("invalid token claim structure")
+		}
+		return uid, nil
+	}
+
+	return "", fmt.Errorf("invalid token status")
+}