Started Authentication System

auth/jwt.go

@@ -0,0 +1,45 @@
+package auth
+
+import (
+	"os"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+type Claims struct {
+	UserID string `json:"user_id"`
+	Role   string `json:"role"`
+	jwt.RegisteredClaims
+}
+
+var secret = os.Getenv("SHAP_JWT_SECRET")
+
+func GenerateJWT(userID, role string, secret []byte) (string, error) {
+	claims := Claims{
+		UserID: userID,
+		Role:   role,
+		RegisteredClaims: jwt.RegisteredClaims{
+			ExpiresAt: jwt.NewNumericDate(time.Now().Add(15 * time.Minute)),
+			IssuedAt:  jwt.NewNumericDate(time.Now()),
+		},
+	}
+
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	return token.SignedString(secret)
+}
+func ValidateJWT(tokenStr string, secret []byte) (*Claims, error) {
+	token, err := jwt.ParseWithClaims(tokenStr, &Claims{}, func(token *jwt.Token) (interface{}, error) {
+		return secret, nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	claims, ok := token.Claims.(*Claims)
+	if !ok || !token.Valid {
+		return nil, err
+	}
+
+	return claims, nil
+}

auth/middleware.go

@@ -0,0 +1,48 @@
+package auth
+
+import (
+	"context"
+	"net/http"
+	"strings"
+)
+
+type contextKey string
+
+const UserContextKey contextKey = contextKey("user")
+
+func AuthMiddleware(secret []byte) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+
+			authHeader := r.Header.Get("Authorization")
+			if authHeader == "" {
+				http.Error(w, "Missing token", http.StatusUnauthorized)
+				return
+			}
+
+			tokenStr := strings.TrimPrefix(authHeader, "Bearer ")
+
+			claims, err := ValidateJWT(tokenStr, secret)
+			if err != nil {
+				http.Error(w, "Invalid token", http.StatusUnauthorized)
+				return
+			}
+
+			ctx := context.WithValue(r.Context(), UserContextKey, claims)
+			next.ServeHTTP(w, r.WithContext(ctx))
+
+		})
+	}
+}
+func RequireRole(role string) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			claims := r.Context().Value(UserContextKey).(*Claims)
+			if claims.Role != role {
+				http.Error(w, "Forbidden", http.StatusForbidden)
+				return
+			}
+			next.ServeHTTP(w, r)
+		})
+	}
+}

auth/password.go

@@ -0,0 +1,12 @@
+package auth
+
+import "golang.org/x/crypto/bcrypt"
+
+func HashPassword(password string) (string, error) {
+	bytes, err := bcrypt.GenerateFromPassword([]byte(password), 14)
+	return string(bytes), err
+}
+func CheckPasswordHash(password, hash string) bool {
+	err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
+	return err == nil
+}

handlers/account.go

@@ -3,6 +3,7 @@ package handlers
 import (
 	"encoding/json"
 	"net/http"
+	"shap-planner-backend/auth"
 	"shap-planner-backend/models"
 	"shap-planner-backend/storage"
 	"shap-planner-backend/utils"
@@ -11,7 +12,7 @@ import (
 func Register(w http.ResponseWriter, r *http.Request) {
 	var user models.User
 	_ = json.NewDecoder(r.Body).Decode(&user)
-	hashed, _ := utils.HashPassword(user.Password)
+	hashed, _ := auth.HashPassword(user.Password)
 	user.Password = hashed
 	user.ID = utils.GenerateUUID()
 
@@ -36,7 +37,7 @@ func Login(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if !utils.CheckPasswordHash(creds.Password, user.Password) {
+	if !auth.CheckPasswordHash(creds.Password, user.Password) {
 		http.Error(w, "Wrong password", http.StatusUnauthorized)
 		return
 	}

handlers/expenses.go

@@ -0,0 +1,7 @@
+package handlers
+
+import "net/http"
+
+func GetExpenses(w http.ResponseWriter, r *http.Request) {}
+
+func AdminPanel(w http.ResponseWriter, r *http.Request) {}

server/server.go

@@ -4,6 +4,7 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"shap-planner-backend/auth"
 	"shap-planner-backend/config"
 	"shap-planner-backend/handlers"
 )
@@ -42,9 +43,16 @@ func InitServer() *Server {
 }
 
 func (server *Server) Run() {
-	http.HandleFunc("/register", handlers.Register)
-	http.HandleFunc("/login", handlers.Login)
+	mux := http.NewServeMux()
+
+	mux.HandleFunc("/login", handlers.Login)
+
+	protected := auth.AuthMiddleware(server.JWTSecret)(http.HandlerFunc(handlers.GetExpenses))
+	mux.Handle("/expenses", protected)
+
+	adminOnly := auth.AuthMiddleware(server.JWTSecret)(auth.RequireRole("admin")(http.HandlerFunc(handlers.AdminPanel)))
+	mux.Handle("/admin", adminOnly)
 
 	log.Printf("Listening on port %s", server.Port)
-	log.Fatal(http.ListenAndServe(":"+server.Port, nil))
+	log.Fatal(http.ListenAndServe(":"+server.Port, mux))
 }

utils/util.go

@@ -1,45 +1,12 @@
 package utils
 
 import (
-	"os"
-	"time"
-
 	"crypto/rand"
 	"encoding/base64"
 
-	"github.com/golang-jwt/jwt/v5"
 	"github.com/google/uuid"
-	"golang.org/x/crypto/bcrypt"
 )
 
-var secret = []byte(os.Getenv("SHAP_JWT_SECRET"))
-
-// Password Validation
-func HashPassword(password string) (string, error) {
-	bytes, err := bcrypt.GenerateFromPassword([]byte(password), 14)
-	return string(bytes), err
-}
-func CheckPasswordHash(password, hash string) bool {
-	err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
-	return err == nil
-}
-
-// JWT Validation
-func GenerateJWT(userID string) (string, error) {
-	claims := jwt.MapClaims{
-		"userId": userID,
-		"exp":    time.Now().Add(time.Hour * 1).Unix(),
-	}
-
-	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
-	return token.SignedString(secret)
-}
-func ValidateJWT(tokenString string) (*jwt.Token, error) {
-	return jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
-		return secret, nil
-	})
-}
-
 func GenerateUUID() string {
 	return uuid.New().String()
 }