Hooks

In Drupal, hooks are the main way to interact with the Drupal core.

In Drupal, hooks are the main way to interact with the Drupal core. Hooks are functions that are called at specific times in the Drupal core. For example, when a node is saved, a hook is called. When a user logs in, a hook is called. When a page is loaded, a hook is called. There are many hooks that are called in Drupal and they are all documented in the Drupal API.

Hooks are called from the module_name.module file or from the THEME_NAME.theme file. The module_name.module file is where you put all the code that is related to the module. The THEME_NAME.theme file is where you put all the code that is related to the theme.

Templates - hooks that interact with templates

Create template suggestions

function THEMENAME_theme_suggestions_page_alter(array &$suggestions, array $variables){
 $suggestions[] = 'page__roads';  //page--roads.html.twig
}

Add current path as css class

$current_path = \Drupal::service('path.current')->getPath();
$path_alias = \Drupal::service('path_alias.manager')->getAliasByPath($current_path);
$path_alias = ltrim($path_alias, '/');
$variables['attributes']['class'][] = 'path-' . \Drupal\Component\Utility\Html::cleanCssIdentifier($path_alias);

Get current language

$parameters = \Drupal::routeMatch()->getParameters()->all();
$variables['language'] = \Drupal::languageManager()->getCurrentLanguage();
$variables['language'] = \Drupal::languageManager()->getCurrentLanguage()->getId();

Get base path

$variables['base_path'] = base_path();