class CookiesCacheContext

class CookiesCacheContext extends RequestStackCacheContextBase implements CalculatedCacheContextInterface {
  
  /**
   * {@inheritdoc}
   */
  public static function getLabel() {
    return t('HTTP cookies');
  }
  
  /**
   * {@inheritdoc}
   */
  public function getContext($cookie = NULL) {
    if ($cookie === NULL) {
      $cookies = $this->requestStack
        ->getCurrentRequest()->cookies
        ->all();
      // Sort the cookies by names, to always set the same context if the
      // cookies are the same but in a different order.
      ksort($cookies);
      // Use http_build_query() to get a short string from the cookies array.
      return http_build_query($cookies);
    }
    else {
      return $this->requestStack
        ->getCurrentRequest()->cookies
        ->get($cookie);
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function getCacheableMetadata($cookie = NULL) {
    return new CacheableMetadata();
  }

}