feat: add token auto-refresh functionality - Add token refresh threshold and refresh functions in auth package - Implement token refresh in HTTP middleware and gRPC interceptor - Return new token in response headers when token is close to expiration

pkg/auth/auth.go

@@ -11,6 +11,8 @@ import (
 var (
 	jwtSecret = []byte("m7s_secret_key") // In production, this should be properly configured
 	tokenTTL  = 24 * time.Hour
+	// Add refresh threshold - refresh token if it expires in less than 30 minutes
+	refreshThreshold = 30 * time.Minute
 )
 
 // JWTClaims represents the JWT claims
@@ -55,3 +57,30 @@ func ValidateJWT(tokenString string) (*JWTClaims, error) {
 
 	return nil, errors.New("invalid token")
 }
+
+// ShouldRefreshToken checks if a token should be refreshed based on its expiration time
+func ShouldRefreshToken(tokenString string) (bool, error) {
+	token, err := jwt.ParseWithClaims(tokenString, &jwt.RegisteredClaims{}, func(token *jwt.Token) (interface{}, error) {
+		return jwtSecret, nil
+	})
+	if err != nil {
+		return false, err
+	}
+
+	if claims, ok := token.Claims.(*jwt.RegisteredClaims); ok && token.Valid {
+		if claims.ExpiresAt != nil {
+			timeUntilExpiry := time.Until(claims.ExpiresAt.Time)
+			return timeUntilExpiry < refreshThreshold, nil
+		}
+	}
+	return false, errors.New("invalid token")
+}
+
+// RefreshToken validates the old token and generates a new one if it's still valid
+func RefreshToken(oldToken string) (string, error) {
+	claims, err := ValidateJWT(oldToken)
+	if err != nil {
+		return "", err
+	}
+	return GenerateToken(claims.Username)
+}

pkg/auth/middleware.go

@@ -30,6 +30,17 @@ func Middleware(validator TokenValidator) func(http.Handler) http.Handler {
 				return
 			}
 
+			// Check if token needs refresh
+			shouldRefresh, err := ShouldRefreshToken(tokenString)
+			if err == nil && shouldRefresh {
+				newToken, err := RefreshToken(tokenString)
+				if err == nil {
+					// Add new token to response headers
+					w.Header().Set("New-Token", newToken)
+					w.Header().Set("Access-Control-Expose-Headers", "New-Token")
+				}
+			}
+
 			// Add claims to context
 			ctx := context.WithValue(r.Context(), "claims", claims)
 			next.ServeHTTP(w, r.WithContext(ctx))

server.go

@@ -654,6 +654,19 @@ func (s *Server) AuthInterceptor() grpc.UnaryServerInterceptor {
 			return nil, errors.New("invalid token")
 		}
 
+		// Check if token needs refresh
+		shouldRefresh, err := auth.ShouldRefreshToken(tokenString)
+		if err == nil && shouldRefresh {
+			newToken, err := auth.RefreshToken(tokenString)
+			if err == nil {
+				// Add new token to response headers
+				header := metadata.New(map[string]string{
+					"new-token": newToken,
+				})
+				grpc.SetHeader(ctx, header)
+			}
+		}
+
 		// Add claims to context
 		newCtx := context.WithValue(ctx, "claims", claims)
 		return handler(newCtx, req)