Drupal 8

1. Install coder
drush dl coder
composer global require drupal/coder
sudo ln -s ~/.composer/vendor/bin/phpcs /usr/local/bin
sudo ln -s ~/.composer/vendor/bin/phpcbf /usr/local/bin
phpcs --config-set installed_paths ~/.composer/vendor/drupal/coder/coder_sniffer

Probleme 1.

If you are activated 'Aggregate CSS files' on admin/config/development/performance, Disable it and refresh the page.

If the page display correctly, Probleme is in CSS Aggregation.

1. Define route in module.routing.yml

Exemple :

module.view.settings:

  path: '/url/to/the/page'

  defaults:

    _controller: '\Drupal\module\Controller\Demo::view'

    _title: ''

This is due to file/folder permission. so drupal cant write twig tempory files.

This is due to trusted host configuration of the serveur. It can produce when you change the domain name or 'trusted_host_patterns'. To resolve the probleme, add your new domain to the DRUPAL_ROOT/sites/SITE_FOLDER/settings.php (Ex: sites/defaults/settings.php)

To set configuration at the module installation



Exemple:

$site_name = \Drupal::config('system.site')->get('name');

// Set the site name.

\Drupal::configFactory()->getEditable('system.site')->set('name', 'My site')->save();

You can do that using Symfony JsonResponse.

Exemple 1.

return new \Symfony\Component\HttpFoundation\JsonResponse($array);

As the solution depend on your error, first of all, you must find why drupal crash.

1. First thing is, You must check the serveur error log.

# tail -f /var/log/apache2/error.log

Exemple:

Here an exemple : Module name : mymodule