drupal-caching

name	drupal-caching
description	Drupal Cache API — cache tags, contexts, max-age, cache bins, invalidation, and adding cache metadata to render arrays.

Drupal Caching

Always add cache metadata. Missing cache metadata causes stale content.

Cache Metadata in Render Arrays

$build['content'] = [
  '#markup' => $output,
  '#cache' => [
    'tags' => ['node:' . $node->id(), 'node_list'],
    'contexts' => ['user.permissions', 'url.query_args'],
    'max-age' => Cache::PERMANENT,
  ],
];

Cache Tags

Tag	Invalidated when
node:{nid}	Node {nid} is saved/deleted
node_list	Any node is created or deleted
user:{uid}	User {uid} is saved
taxonomy_term:{tid}	Term {tid} is saved
config:{name}	Config object {name} is saved

Cache Contexts

Context	Varies by
user.permissions	User's permissions (prefer over user)
user.roles	User's roles
url.path	URL path
url.query_args	Query parameters
languages	Current language

Reading/Writing Cache

$cached = $this->cacheBackend->get('my_module:my_key');
if ($cached !== FALSE) {
  return $cached->data;
}

$this->cacheBackend->set('my_module:my_key', $data, Cache::PERMANENT, ['node_list']);
$this->cacheBackend->set('my_module:my_key', $data, \Drupal::time()->getRequestTime() + 3600, ['node_list']);
$this->cacheBackend->delete('my_module:my_key');

Cache::invalidateTags(['node:123', 'node_list']);

Inject Cache Service

use Drupal\Core\Cache\CacheBackendInterface;

public function __construct(
  private readonly CacheBackendInterface $cacheBackend,
) {}

# services.yml
my_module.my_service:
  arguments: ['@cache.default']

CacheableDependencyInterface

$build['#cache']['tags'] = Cache::mergeTags(
  $build['#cache']['tags'] ?? [],
  $node->getCacheTags()
);