Create custom module but page not found

Question

I'm new on Drupal. I try to follow a tuto in order to build my own module.

Drupal 8 (latest version) is installed on MacOS. For example, I use it through URL : http://localhost/drupal/admin/content

My module is defined like this :

• Drupal
  • code
  • modules
    • hello_world
      • hello_world.info.yml
      • hello_world.links.menu.yml
      • hello_world.routing.yml
        • src
          • Controller
            • HelloController.php
  • ...

File content : hello_world.info.yml

name: Hello World Module
description: Creates a page showing "Hello World".
package: Custom
type: module
version: 1.0
core: 8.x

File content : hello_world.routing.yml

hello_world.hello_world:
  path: '/hello'
  defaults:
    _controller: '\Drupal\hello_world\Controller\HelloController::helloWorld'
    _title: 'Hello World'
  requirements:
    _permission: 'access content'

File content : hello_world.links.menu.yml

hello_world.admin:
  title: 'Hello module settings'
  description: 'example of how to make an admin settings page link'
  parent: system.admin_config_development
  route_name: hello_world.hello_world
  weight: 100

File content : HelloController.php

<?php
/**
 * @file
 * Contains \Drupal\hello_world\Controller\HelloController.
 */

namespace Drupal\hello_world\Controller;
use Drupal\Core\Controller\ControllerBase;

/**
 * Defines HelloController class.
 */
class HelloController extends ControllerBase {

  /**
   * Display the markup.
   *
   * @return array
   *   Return markup array.
   */
  public function helloWorld() {
  $output = array();

  $output['hello_world'] = array(
    '#markup' => $this->t('Hello World!'),
  );
  return $output;

  }

}

Regardless "clear cache", I have a page not found !

I try the urls :

• http://localhost/drupal/hello
• http://localhost/hello

But results are the same. What should be the right url ? And why I'm getting "page not found", where is the issue ?

Answer 1

Creating a module does not automatically enable it.

I tried your code in a clean Drupal 8 installation and /hello show the page as expected.

Try running drush en hello_world to enable you module and you should be ok.

If that is not the case, then you can use drupal route:debug to see a complete list of your site routes, so you can know if your route is registered.

Answer 2

Since it looks like you're just starting out D8 development, additionally to drupal route:debug command I would install devel and admin toolbar modules that help out a lot in dev. Once devel is installed you could checkout the routing information at the taskbar and see all available paths to be sure your new module path is registered.

Another thing you might wanna take a look at is turning cache of completely on your local to see your changes immediately. Take a look at this guide for that.