Gets the cacheability metadata for the context based on the parameter value.

There are three valid cases for the returned CacheableMetadata object:

• An empty object means this can be optimized away safely.
• A max-age of 0 means that this context can never be optimized away. It will never bubble up and cache tags will not be used.
• Any non-zero max-age and cache tags will bubble up into the cache item if this is optimized away to allow for invalidation if the context value changes.

Parameters

string|null $parameter: The parameter, or NULL to indicate all possible parameter values.

Return value

\Drupal\Core\Cache\CacheableMetadata A cacheable metadata object.

Overrides CalculatedCacheContextInterface::getCacheableMetadata

File

core/modules/node/src/Cache/NodeAccessGrantsCacheContext.php, line 84

Class

NodeAccessGrantsCacheContext

Defines the node access view cache context service.

Namespace

Drupal\node\Cache

Code

public function getCacheableMetadata($operation = NULL) {
  $cacheable_metadata = new CacheableMetadata();
  if (!\Drupal::moduleHandler()->hasImplementations('node_grants')) {
    return $cacheable_metadata;
  }
  // The node grants may change if the user is updated. (The max-age is set to
  // zero below, but sites may override this cache context, and change it to a
  // non-zero value. In such cases, this cache tag is needed for correctness.)
  $cacheable_metadata->setCacheTags([
    'user:' . $this->user
      ->id(),
  ]);
  // If the site is using node grants, this cache context can not be
  // optimized.
  return $cacheable_metadata->setCacheMaxAge(0);
}

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