alterRoutes example

  }

  /** * Delegates the route altering to self::alterRoutes(). * * @param \Drupal\Core\Routing\RouteBuildEvent $event * The route build event. */
  public function onAlterRoutes(RouteBuildEvent $event) {
    $collection = $event->getRouteCollection();
    $this->alterRoutes($collection);
  }

}

return $events;
  }

  /** * Delegates the route altering to self::alterRoutes(). * * @param \Drupal\Core\Routing\RouteBuildEvent $event * The route build event. */
  public function onAlterRoutes(RouteBuildEvent $event) {
    $collection = $event->getRouteCollection();
    $this->alterRoutes($collection);
  }

}

  protected function alterRoutes(RouteCollection $collection) {
    foreach ($this->getViewsDisplayIDsWithRoute() as $pair) {
      [$view_id, $display_id] = explode('.', $pair);
      $view = $this->viewStorage->load($view_id);
      // @todo This should have an executable factory injected.       if (($view = $view->getExecutable()) && $view instanceof ViewExecutable) {
        if ($view->setDisplay($display_id) && $display = $view->displayHandlers->get($display_id)) {
          if ($display instanceof DisplayRouterInterface) {
            // If the display returns TRUE a route item was found, so it does not             // have to be added.             $view_route_names = $display->alterRoutes($collection);
            $this->viewRouteNames = $view_route_names + $this->viewRouteNames;
            foreach ($view_route_names as $id_display => $route_name) {
              $view_route_name = $this->viewsDisplayPairs[$id_display];
              unset($this->viewsDisplayPairs[$id_display]);
              $collection->remove("views.$view_route_name");
            }
          }
        }
        $view->destroy();
      }
    }
  }

$view] = $this->setupViewExecutableAccessPlugin();

    $display = [];
    $display['display_plugin'] = 'page';
    $display['id'] = 'page_1';
    $display['display_options'] = [
      'path' => 'test_route',
    ];
    $this->pathPlugin->initDisplay($view, $display);

    $view_route_names = $this->pathPlugin->alterRoutes($collection);
    $this->assertEquals(['test_id.page_1' => 'test_route'], $view_route_names);

    // Ensure that the test_route is overridden.     $route = $collection->get('test_route');
    $this->assertInstanceOf(Route::class, $route);
    $this->assertEquals('test_id', $route->getDefault('view_id'));
    $this->assertEquals('page_1', $route->getDefault('display_id'));
    $this->assertEquals('Drupal\views\Routing\ViewPageController::getTitle', $route->getDefault('_title_callback'));

    // Ensure that the test_route_2 is not overridden.     $route = $collection->get('test_route_2');