public function HeadersCacheContext::getCacheableMetadata in Drupal 9

Same name and namespace in other branches

1. 8 core/lib/Drupal/Core/Cache/Context/HeadersCacheContext.php \Drupal\Core\Cache\Context\HeadersCacheContext::getCacheableMetadata()

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.

Throws

\LogicException Thrown if the passed in parameter is invalid.

Overrides CalculatedCacheContextInterface::getCacheableMetadata

File

core/lib/Drupal/Core/Cache/Context/HeadersCacheContext.php, line 55

Class

HeadersCacheContext

Defines the HeadersCacheContext service, for "per header" caching.

Namespace

Drupal\Core\Cache\Context

Code

public function getCacheableMetadata($header = NULL) {
  return new CacheableMetadata();
}