code: public function handleRequest($request)
      {
          if (empty($this->catchAll)) {
              list ($route, $params) = $request->resolve();
          } else {
              $route = $this->catchAll[0];
              $params = $this->catchAll;
              unset($params[0]);
          }
          try {
              Yii::trace("Route requested: '$route'", __METHOD__);
              $this->requestedRoute = $route;
              $result = $this->runAction($route, $params);
              if ($result instanceof Response) {
                  return $result;
              } else {
                  $response = $this->getResponse();
                  if ($result !== null) {
                      $response->data = $result;
                  }
  
                  return $response;
              }
          } catch (InvalidRouteException $e) {
              throw new NotFoundHttpException(Yii::t('yii', 'Page not found.'), $e->getCode(), $e);
          }
      }
docs: Handles the specified request.
  @param Request $request the request to be handled
  @return Response the resulting response
  @throws NotFoundHttpException if the requested route is invalid