<?php

namespace Drupal\Core\EventSubscriber;

use Drupal\Core\Extension\ModuleHandlerInterface;
use Symfony\Component\HttpKernel\KernelEvents;
use Symfony\Component\HttpKernel\Event\PostResponseEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Subscriber for all responses.
 */
class RequestCloseSubscriber implements EventSubscriberInterface {

  /**
   * @var \Drupal\Core\Extension\ModuleHandlerInterface
   */
  protected $moduleHandler;

  /**
   * Constructs a new RequestCloseSubscriber instance.
   *
   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
   *   The module handler.
   */
  public function __construct(ModuleHandlerInterface $module_handler) {
    $this->moduleHandler = $module_handler;
  }

  /**
   * Performs end of request tasks.
   *
   * @todo The body of this function has just been copied almost verbatim from
   *   drupal_page_footer(). There's probably a lot in here that needs to get
   *   removed/changed. Also, if possible, do more light-weight shutdowns on
   *   AJAX requests.
   *
   * @param Symfony\Component\HttpKernel\Event\PostResponseEvent $event
   *   The Event to process.
   */
  public function onTerminate(PostResponseEvent $event) {
    $this->moduleHandler->writeCache();
  }

  /**
   * Registers the methods in this class that should be listeners.
   *
   * @return array
   *   An array of event listener definitions.
   */
  public static function getSubscribedEvents() {
    $events[KernelEvents::TERMINATE][] = ['onTerminate', 100];

    return $events;
  }

}