Why am I getting "Page not found" for a simple "hello world" custom page

Question

In my custom module, ed_helper, I have this ed_helper.routing.yml:

ed_helper.my_page:
  path: '/mypage/page'
  defaults:
    _controller: '\Drupal\ed_helper\Controller\EdHelperController::myPage'
    _title: 'My first page in D8'
  requirements:
    _permission: 'access content'

In ed_helper/src/Controller, I have this EdHelperController.php:

<?php
namespace Drupal\ed_helper\Controller;

use Drupal\Core\Controller\ControllerBase;

/**
 * Utility pages.
 */
class EdHelperController extends ControllerBase {

  /**
   * Returns a simple page.
   *
   * @return array
   *   A simple renderable array.
   */
  public function myPage() {
    return [
      '#markup' => 'Hello, world',
    ];
  }

}

I have confirmed that the module is installed, and I cleared the cache, but am still getting "Page not found" at /mypage/page. What am I missing?

I tried switching the theme to Claro, but I still get "page not found" at my custom route. I also tried uninstalling ed_helper and re-installing it.

My Drupal version is 10.1.

Answer 1

You can create the same simple hello world custom page with Drush:

drush generate module

Enter a module name mymodule and skip all questions except the one for a controller where you answer yes.

Install the module

drush en mymodule

and then visit www.example.com/mymodule/example to see the controller result.