Dynamic routes can now be registered easier using the RouteSubscriberBase

Previously registering dynamic routes was full of boilerplate code. Now it's easier and you don't have to deal with the event system anymore.

To alter a route, you just extend the \Drupal\Core\Routing\RouteSubscriberBase class which provides an alterRoutes method. To define dynamic routes you declare a route callback in the .routing.yml file.

Before

class RouteSubscriber implements EventSubscriberInterface {
  
  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() {
    $events[RoutingEvents::DYNAMIC] = 'dynamicRoutes';
    $events[RoutingEvents::ALTER] = 'alterRoutes';
    return $events;
  }

  public function alterRoutes(RouteBuildEvent $event) {
    $collection = $event->getRouteCollection();

    // Do something ...
  }

  public function dynamicRoutes(RouteBuildEvent $event) {
    $collection = $event->getRouteCollection();

    // Do something ...
  }

}

After

Alter a route by extending RouteSubscriberBase.
See the API documentation Altering existing routes for implementation details.

use \Drupal\Core\Routing\RouteSubscriberBase;

class RouteSubscriber extends RouteSubscriberBase {

  public function alterRoutes(RouteCollection $collection) {
    // Do something ...
  }

}

Dynamic routes use a yaml file to declare a route callback and a route callback class.
See the API documentation Providing dynamic routes for implementation details.

# @file example.routing.yml
route_callbacks:
  - '\Drupal\example\Routing\ExampleRoutes::routes'

use Symfony\Component\Routing\Route;
use Symfony\Component\Routing\RouteCollection;

class ExampleRoutes {

  /**
   * Dynamic route callback.
   *
   * @return \Symfony\Component\Routing\Route[]
   *   An array of route objects.
   */
  public function routes() {
    // Do something ...

    return $routes;
  }

}