improvements-2.x-dev/src/Cache/IsEntityPageCacheContext.php

<?php

namespace Drupal\improvements\Cache;

use Drupal\Component\Render\MarkupInterface;
use Drupal\Core\Cache\CacheableMetadata;
use Drupal\Core\Cache\Context\CalculatedCacheContextInterface;
use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Cache context ID: 'is_entity_page' (to vary by whether current page is entity page or not).
 * Calculated cache context ID: 'is_entity_page:%entity_type', e.g.'is_entity_page:node' (to vary by whether current page is node page or not) or 'is_entity_page:node,taxonomy_term' (to vary by whether current page is node/taxonomy_term page or not).
 */
class IsEntityPageCacheContext implements CalculatedCacheContextInterface {

  protected RouteMatchInterface $routeMatch;

  /**
   * Class constructor.
   */
  public function __construct(RouteMatchInterface $route_match) {
    $this->routeMatch = $route_match;
  }

  /**
   * {@inheritdoc}
   */
  public static function getLabel(): MarkupInterface {
    return t('Is entity page');
  }

  /**
   * {@inheritdoc}
   */
  public function getContext($entity_type_id = NULL) {
    if (preg_match('/^entity\.(.+)\.canonical$/', $this->routeMatch->getRouteName(), $matches)) {
      if ($entity_type_id) {
        $entity_type_ids = explode(',', $entity_type_id);
        $matched_entity_type_id = $matches[1];
        return (string)(int)in_array($matched_entity_type_id, $entity_type_ids);
      }

      return '1';
    }

    return '0';
  }

  /**
   * {@inheritdoc}
   */
  public function getCacheableMetadata($entity_type_id = NULL) {
    return new CacheableMetadata();
  }

}