Question
The hook boot (hook_boot()) and hook init (hook_init()) are removed from drupal 8. How to use those events and trigger on boot ?
What are the possibilities to replace Hook Boot and Hook Init ?
Use Event Subscriber service.
The EventSubscriber allow to execute an action on boot as hook_boot or hook_init of drupal 7.
Example.
# file should be in /mymodule/mymodule.services.yml
services:
mymodule.mymodule_subscriber:
class: Drupal\mymodule\MyModuleSubscriber
tags:
- { name: 'event_subscriber' }
// file shoud be in /mymodule/src/MyModuleSubscriber.php
<?php
/**
* @file
* Contains \Drupal\mymodule\MyModuleSubscriber.
*/
namespace Drupal\mymodule;
use Symfony\Component\HttpKernel\KernelEvents;
use Symfony\Component\HttpKernel\Event;
use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
/**
* Provides a MyModuleSubscriber.
*/
class MyModuleSubscriber implements EventSubscriberInterface {
/**
* // only if KernelEvents::REQUEST !!!
* @see Symfony\Component\HttpKernel\KernelEvents for details
*
* @param Symfony\Component\HttpKernel\Event\GetResponseEvent $event
* The Event to process.
*/
public function MyModuleLoad(GetResponseEvent $event) {
// @todo remove this debug code
drupal_set_message('MyModule: subscribed');
}
/**
* {@inheritdoc}
*/
static function getSubscribedEvents() {
$events[KernelEvents::REQUEST][] = array('MyModuleLoad', 20); // Like hook_init (Cached)
// Priority greater than 200 alow to skip caching, like functionality of hook_boot.
//$events[KernelEvents::REQUEST][] = array('MyModuleLoad', 300); // Like hook_boot (not Cached)
return $events;
}
}
Using StackMiddleware (Not tested)
Example :
mymodule/mymodule.services.yml
services:
http_middleware.mymodule:
class: Drupal\mymodule\StackMiddleware\MyModule
tags:
- { name: http_middleware, priority: 180, responder: true }
mymodule/src/StackMiddleware/MyModule.php
<?php
namespace Drupal\mymodule\StackMiddleware;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpKernel\HttpKernelInterface;
/**
* Provides a HTTP middleware.
*/
class MyModule implements HttpKernelInterface {
/**
* The wrapped HTTP kernel.
*
* @var \Symfony\Component\HttpKernel\HttpKernelInterface
*/
protected $httpKernel;
/**
* Constructs a MyModule object.
*
* @param \Symfony\Component\HttpKernel\HttpKernelInterface $kernel
* The decorated kernel.
* @param mixed $optional_argument
* (optional) An optional argument.
*/
public function __construct(HttpKernelInterface $http_kernel) {
$this->httpKernel = $http_kernel;
}
/**
* {@inheritdoc}
*/
public function handle(Request $request, $type = self::MASTER_REQUEST, $catch = TRUE) {
// Your code here.
return $this->httpKernel->handle($request, $type, $catch);
}
}
Examples from : https://www.drupal.org/node/1909596
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