public function FacetBlock::getCacheMaxAge in Facets 8

The maximum age for which this object may be cached.

Return value

int The maximum time in seconds that this object may be cached.

Overrides ContextAwarePluginBase::getCacheMaxAge

File

src/Plugin/Block/FacetBlock.php, line 123

Class

FacetBlock

Exposes a facet rendered as a block.

Namespace

Drupal\facets\Plugin\Block

Code

public function getCacheMaxAge() {

  // A facet block cannot be cached, because it must always match the current
  // search results, and Search API gets those search results from a data
  // source that can be external to Drupal. Therefore it is impossible to
  // guarantee that the search results are in sync with the data managed by
  // Drupal. Consequently, it is not possible to cache the search results at
  // all. If the search results cannot be cached, then neither can the facets,
  // because they must always match.
  // Fortunately, facet blocks are rendered using a lazy builder (like all
  // blocks in Drupal), which means their rendering can be deferred (unlike
  // the search results, which are the main content of the page, and deferring
  // their rendering would mean sending an empty page to the user). This means
  // that facet blocks can be rendered and sent *after* the initial page was
  // loaded, by installing the BigPipe (big_pipe) module.
  //
  // When BigPipe is enabled, the search results will appear first, and then
  // each facet block will appear one-by-one, in DOM order.
  // See https://www.drupal.org/project/big_pipe.
  //
  // In a future version of Facet API, this could be refined, but due to the
  // reliance on external data sources, it will be very difficult if not
  // impossible to improve this significantly.
  //
  // Note: when using Drupal core's Search module instead of the contributed
  // Search API module, the above limitations do not apply, but for now it is
  // not considered worth the effort to optimize this just for Drupal core's
  // Search.
  return 0;
}