function hook_preprocess

Same name and namespace in other branches
  1. 7.x modules/system/theme.api.php \hook_preprocess()
  2. 9 core/lib/Drupal/Core/Render/theme.api.php \hook_preprocess()
  3. 8.9.x core/lib/Drupal/Core/Render/theme.api.php \hook_preprocess()
  4. 10 core/lib/Drupal/Core/Render/theme.api.php \hook_preprocess()

Preprocess theme variables for templates.

This hook allows modules to preprocess theme variables for theme templates. hook_preprocess_HOOK() can be used to preprocess variables for a specific theme hook.

For more detailed information, see the Theme system overview topic.


$variables: The variables array (modify in place).

$hook: The name of the theme hook.

Related topics

5 functions implement hook_preprocess()

Note: this list is generated by pattern matching, so it may include some functions that are not actually implementations of this hook.

common_test_preprocess in core/modules/system/tests/modules/common_test/common_test.module
Implements MODULE_preprocess().
contextual_preprocess in core/modules/contextual/contextual.module
Implements hook_preprocess().
search_langcode_test_search_preprocess in core/modules/search/tests/modules/search_langcode_test/search_langcode_test.module
Implements hook_search_preprocess().
template_preprocess in core/includes/
Adds a default set of helper variables for preprocessors and templates.
template_preprocess_theme_test_deprecations_preprocess in core/modules/system/tests/modules/theme_test/theme_test.module
Implements template_preprocess_HOOK() for theme_test_deprecations_preprocess.


core/lib/Drupal/Core/Render/theme.api.php, line 557


function hook_preprocess(&$variables, $hook) {
    static $hooks;
    // Add contextual links to the variables, if the user has permission.
    if (!\Drupal::currentUser()->hasPermission('access contextual links')) {
    if (!isset($hooks)) {
        $hooks = \Drupal::service('theme.registry')->get();
    // Determine the primary theme function argument.
    if (isset($hooks[$hook]['variables'])) {
        $keys = array_keys($hooks[$hook]['variables']);
        $key = $keys[0];
    else {
        $key = $hooks[$hook]['render element'];
    if (isset($variables[$key])) {
        $element = $variables[$key];
    if (isset($element) && is_array($element) && !empty($element['#contextual_links'])) {
        $variables['title_suffix']['contextual_links'] = contextual_links_view($element);
        if (!empty($variables['title_suffix']['contextual_links'])) {
            $variables['attributes']['class'][] = 'contextual-links-region';

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