How do I invalidate the cache of an entity?

Question

Is there any easy way to clear the cache for a custom entity? I know there is an entry in the cache_entity-Table. If i manually delete it, everything is fine. I tried doing the same as in \Drupal\Core\Entity->invalidateTagsOnSave() or \Drupal\Core\Entity->invalidateTagsOnDelete(). This does not seem to change anything.

Unfortunately I can't just load the entity and resave it in this situation.

Answer 1

But you know the entity ID that you want to have invalidated?

Then use \Drupal::entityTypeManager()->getStorage($entity_type_id)->resetCache([$id]);

Answer 2

To invalidate a cache you should use the Drupal cache invalidator service : cache_tags.invalidator.

Static call

// Invalide a Node cache.
\Drupal::service('cache_tags.invalidator')->invalidateTags(['node:5']);
// Invalidate a custom entity cache.
\Drupal::service('cache_tags.invalidator')->invalidateTags(['custom_entity:5']);
// Invalidate a custom cache tag.
\Drupal::service('cache_tags.invalidator')->invalidateTags(['thing:identifier']);

Dependency injection call

my_module.services.yml

services:
  hello.service:
    class: \Drupal\my_module\Service\Hello
    arguments:
      - '@cache.default'
      - '@cache_tags.invalidator'

Hello.php

use Drupal\Core\Cache\Cache;
use Drupal\Core\Cache\CacheBackendInterface;
use Drupal\Core\Cache\CacheTagsInvalidator;

class Hello {

 /**
   * Cache backend.
   *
   * @var Drupal\Core\Cache\CacheBackendInterface
   */
  protected $cacheBackend;

 /**
   * Cache tags invalidator.
   *
   * @var Drupal\Core\Cache\CacheTagsInvalidator
   */
  protected $cacheInvalidator;

  /**
   * {@inheritdoc}
   */
  public function __construct(
    CacheBackendInterface $cacheBackend,
    CacheTagsInvalidator $cacheInvalidator
  ) {
    $this->cacheBackend = $cacheBackend;
    $this->cacheInvalidator = $cacheInvalidator;
  }
  
  /**
   * Function getting something from cache.
   */
  public function getSomething() {
    $cid = 'thing:identifier';
    $data = NULL;
    $cache = $this->cacheBackend->get($cid);

    if ($cache) {
      $data = $cache->data;
    }
    else {
      $data = my_module_complicated_calculation();
      $this->cacheBackend->set(
        $cid,               // Cache tag identifier.
        $data,              // Data to store in cache.
        Cache::PERMANENT,   // Save permanently.
        ['node:5', 'user:7']// Automatically invalidated if these entities are modified.
      );
    }

    return $data;
  }
  
  /**
   * Function invalidating a cache tag.
   */
  public function invalidateSomething() {
    $cid = 'thing:identifier';
    $this->cacheInvalidator->invalidateTags([$cid]);

    return;
  }
}    

Links

• Cache.php
• Cache tags docs
• Cacheability of render arrays
• Cache context
• Cache max-age

Answer 3

In your custom entity you should override the function

public function getCacheTagsToInvalidate();

of the EntityInterface.

Then, to clear that entity's cache you simply call

\Drupal\Core\Cache\Cache::invalidateTags($entity->getCacheTagsToInvalidate());

If you do not override getCacheTagsToInvalidate() the default implementation in entity.php should also work:

public function getCacheTagsToInvalidate() {
    if ($this->isNew()) {
      return [];
    }
    return [$this->entityTypeId . ':' . $this->id()];
  }

The tags[] is just the name plus the id.