PsrResponseSubscriber.php

<?php

namespace Drupal\Core\EventSubscriber;

use Psr\Http\Message\ResponseInterface;
use Symfony\Bridge\PsrHttpMessage\HttpFoundationFactoryInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpKernel\Event\ViewEvent;
use Symfony\Component\HttpKernel\KernelEvents;

/**
 * Response subscriber for handling PSR-7 responses.
 */
class PsrResponseSubscriber implements EventSubscriberInterface {

  /**
   * The httpFoundation factory.
   *
   * @var \Symfony\Bridge\PsrHttpMessage\HttpFoundationFactoryInterface
   */
  protected $httpFoundationFactory;

  /**
   * Constructs a new PathRootsSubscriber instance.
   *
   * @param \Symfony\Bridge\PsrHttpMessage\HttpFoundationFactoryInterface $http_foundation_factory
   *   The httpFoundation factory.
   */
  public function __construct(HttpFoundationFactoryInterface $http_foundation_factory) {
    $this->httpFoundationFactory = $http_foundation_factory;
  }

  /**
   * Converts a PSR-7 response to a Symfony response.
   *
   * @param \Symfony\Component\HttpKernel\Event\ViewEvent $event
   *   The Event to process.
   */
  public function onKernelView(ViewEvent $event) {
    $controller_result = $event
      ->getControllerResult();
    if ($controller_result instanceof ResponseInterface) {
      $event
        ->setResponse($this->httpFoundationFactory
        ->createResponse($controller_result));
    }
  }

  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() : array {
    $events[KernelEvents::VIEW][] = [
      'onKernelView',
    ];
    return $events;
  }

}