add user service

internal/user/middleware/auth.go

@@ -0,0 +1,52 @@
+package middleware
+
+import (
+	"context"
+	"strings"
+
+	"github.com/golang-jwt/jwt/v5"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
+)
+
+type UserIDKey struct{}
+
+func AuthInterceptor(jwtSecret string) grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
+		md, ok := metadata.FromIncomingContext(ctx)
+		if !ok {
+			return nil, status.Errorf(codes.Unauthenticated, "metadata is not provided")
+		}
+
+		authHeader, ok := md["authorization"]
+		if !ok || len(authHeader) == 0 {
+			return nil, status.Errorf(codes.Unauthenticated, "authorization token is not provided")
+		}
+
+		tokenString := strings.TrimPrefix(authHeader[0], "Bearer ")
+
+		token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
+			if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+				return nil, status.Errorf(codes.Unauthenticated, "unexpected signing method: %v", token.Header["alg"])
+			}
+			return []byte(jwtSecret), nil
+		})
+		if err != nil {
+			return nil, status.Errorf(codes.Unauthenticated, "invalid token: %v", err)
+		}
+
+		if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
+			userID, ok := claims["user_id"].(string)
+			if !ok {
+				return nil, status.Errorf(codes.Unauthenticated, "invalid token: user_id is not a string")
+			}
+
+			newCtx := context.WithValue(ctx, UserIDKey{}, userID)
+			return handler(newCtx, req)
+		}
+
+		return nil, status.Errorf(codes.Unauthenticated, "invalid token")
+	}
+}