After building routes (e.g. when a module is enabled or when caches are cleared), the RoutingEvents::ALTER event triggers the route alter process. The \Drupal\Core\Routing\RouteSubscriberBase class contains an event listener that listens to this event. You can alter existing routes by implementing the alterRoutes(RouteCollection $collection) method of this class.
To alter existing routes in Drupal 8 we need to create a service that extends RouteSubscriberBase. Below is how to do it with examples of how to disable the user registration page and user password reset page.
Create the mymodule.info.yml
name: 'My Module'
description: 'Custom Module'
package: Custom
type: module
core: 8.x
Create the mymodule.services.yml file:
services:
mymodule.route_subscriber:
class: Drupal\mymodule\RouteSubscriber
arguments: []
tags:
- { name: event_subscriber }
Create the src/RouteSubscriber.php Class :
<?php
namespace Drupal\mymodule;
use Drupal\Core\Routing\RouteSubscriberBase;
use Symfony\Component\Routing\RouteCollection;
/**
* Class RouteSubscriber
* @package Drupal\mymodule
*/
class RouteSubscriber extends RouteSubscriberBase {
/**
* @param RouteCollection $collection
*/
public function alterRoutes(RouteCollection $collection) {
// Disable access to the registration page.
if ($route = $collection->get('user.register')) {
$route->setRequirement('_access', 'FALSE');
}
// Remove user password reset page.
if ($route = $collection->get('user.pass')) {
$route->setRequirement('_access', 'FALSE');
}
}
}
