/**
  * Returns the entity rendered via the given printable format.
  *
  * @param \Drupal\Core\Entity\EntityInterface $entity
  *   The entity to be printed.
  * @param string $printable_format
  *   The identifier of the hadcopy format plugin.
  *
  * @return \Symfony\Component\HttpFoundation\Response
  *   The printable response.
  */
 public function showFormat(EntityInterface $entity, $printable_format)
 {
     if ($this->printableFormatManager->getDefinition($printable_format)) {
         $format = $this->printableFormatManager->createInstance($printable_format);
         $content = $this->entityManager()->getViewBuilder($entity->getEntityTypeId())->view($entity, 'printable');
         $format->setContent($content);
         if ($printable_format == 'print') {
             return $format->getResponse();
         } else {
             $format->getResponse($content);
             $source_url = \Drupal::request()->getRequestUri();
             $pos = strpos($source_url, "printable");
             $pos_node = strpos($source_url, '/', $pos + 11);
             $source_url = substr($source_url, 0, $pos) . substr($source_url, $pos_node + 1);
             return new RedirectResponse($source_url);
         }
     } else {
         throw new NotFoundHttpException();
     }
 }