By Crell on
Change record status: 
Published (View all published change records)
Project: 
Drupal core
Introduced in branch: 
8.x
Issue links: 
https://www.drupal.org/node/1860026
https://www.drupal.org/node/1911178
Description: 

In Drupal 7, hook_exit would fire at the end of all requests, even "bootstrap only" requests, to allow modules to take action after a response has been generated but before the PHP process terminates. In Drupal 8, it has been removed as redundant.

Its most direct equivalent in Drupal 8 is the kernel.terminate event. Modules may implement a subscriber for that event to perform actions such as logging and cleanup that happen after the response has been sent to the client and the connection closed, but before the PHP process terminates. The kernel.terminate event will fire on every request, so be careful to avoid excessively expensive operations if possible.

Note that some uses of hook_exit() in Drupal 7 and contrib were not fully appropriate. A hook_exit() implementation that was (incorrectly) generating output, for instance, should likely instead be converted to a kernel.response event. Before converting a hook_exit() implementation, verify that it is appropriate for the event it is being converted into or that there is not some other approach that is more appropriate. See the discussion in #1911178: Remove hook_exit() about the overlay module for an example of how some uses may not map directly to kernel.terminate.

Impacts: 
Module developers

Comments

mmerrill219’s picture

mmerrill219 commented

Here how you do HOOK_exit() in Drupal 8.

example.services.yml

services:
  example_exit:
    class: Drupal\sitename_by_path\EventSubscriber\exampleExit
    tags:
      - {name: event_subscriber}

exampleExit.php

<?php
namespace Drupal\example\EventSubscriber;

use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\HttpKernel\KernelEvents;
use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

class ExampleExit implements EventSubscriberInterface {

  public function terminate() {
    print 'Drupal 8 hook_exit()';
  }

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

}
jbd44’s picture

jbd44 commented

https://drupalize.me/blog/201502/responding-events-drupal-8

elijah lynn’s picture

elijah lynn
Location Portland, Oregon
commented

Just read through this entire article and it is GOLD!

Definitely give it a read if you are tasked with implementing this!

-----------------------------------------------
The Future is Open!

elijah lynn’s picture

elijah lynn
Location Portland, Oregon
commented

Great example, thank you!

The example above needs the class casing fixed in the example.services.yml declaration, file and the namespace declaration too, here is my working example:

custom_module.services.yml

services:
  custom_module.subscriber:
    class: Drupal\custom_module\EventSubscriber\ExampleExit
    tags:
      - {name: event_subscriber}

src/EventSubscriber/ExampleExit.php


<?php

namespace Drupal\custom_module\EventSubscriber;

use Symfony\Component\HttpKernel\KernelEvents;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

class ExampleExit implements EventSubscriberInterface {

  public function terminate() {
    print 'Drupal 8 hook_exit()';
  }

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

}

-----------------------------------------------
The Future is Open!