The Flow of Dispatch Event in Symfony - php

Question

I'm studying Symfony and I'm trying with Dispatch Event Component.
I Understand that there are
Dispatcher (component)
Event ( that pass information to Listener )
Listener ( the logic )
I created a simple example in my route
/**
* #Route("/evento", name="evento")
*/
public function eventoAction()
{
$dispatcher = new EventDispatcher();
$listener = new StoreListener($this->get('mailer'));
$dispatcher->addListener(StoreEvents::STORE_ORDER,array($listener,'onFooAction'),25);
$order = new Ordini();
$order->setName('ordine nuovo -'.rand(0,100));
$em = $this->getDoctrine()->getManager();
$em->persist($order);
$em->flush();
$event = new FilterOrderEvent($order);
$dispatcher->dispatch(StoreEvents::STORE_ORDER,$event);
return $this->render('::event.html.twig');
}
StoreEvent with Contain the Const String
namespace AppBundle\Events;
final class StoreEvents
{
/**
* The store.order event is thrown each time an order is created
* in the system.
*
* The event listener receives an
* Acme\StoreBundle\Event\FilterOrderEvent instance.
*
* #var string
*/
const STORE_ORDER = 'store.order';
}
The Event that I pass to Listener
<?php
namespace AppBundle\Events;
use AppBundle\Entity\Ordini;
use Symfony\Component\EventDispatcher\Event;
class FilterOrderEvent extends Event
{
protected $order;
public function __construct(Ordini $order)
{
$this->order = $order;
}
/**
* #return Ordini
*/
public function getOrder()
{
return $this->order;
}
}
And The Listener
<?php
namespace AppBundle\Events;
use Symfony\Component\EventDispatcher\Event;
class StoreListener
{
protected $mail;
/**
* StoreListener constructor.
* #param $mail
*/
public function __construct($mail)
{
$this->mail = $mail;
}
public function onFooAction(Event $event)
{
var_dump($event);
var_dump($event->getOrder());
echo "fooAction";
$message = \Swift_Message::newInstance()
->setSubject($event->getOrder()->getName())
->setFrom('send#example.com')
->setTo('send#example2.com)
->setBody('Test')
;
$this->mail->send($message);
}
}
all these stuff Work but I want to Understand where I have to declare the dispatcher.
I have to declare for each controller ?
$dispatcher = new EventDispatcher();
even the add listener ( or addSubscriber)
$dispatcher->addListener(StoreEvents::STORE_ORDER,array($listener,'onFooAction'),25);
I don't think this is the best practice to Declare every Time the new Dispatcher
or new addListener
UPDATE
I created another Action
/**
* #Route("/evento2", name="evento2")
*/
public function evento2Action()
{
$order = new Ordini();
$order->setName('ordine nuovo -'.rand(0,100));
$em = $this->getDoctrine()->getManager();
$em->persist($order);
$em->flush();
$event = new FilterOrderEvent($order);
$this->get('event_dispatcher')->dispatch(StoreEvents::STORE_ORDER,$event);
return $this->render('::event.html.twig');
}
And create my service:
services:
create_order_listener:
class: AppBundle\Events\StoreListener
arguments: ["#swiftmailer.mailer"]
tags:
- { name: kernel.event_listener, event: store.order, method: onFooAction
all work. But now I'd like to know the best practice or when Create listener by service and when I have to use addListener or addSubscriber