Event Dispatcher
Event Dispatcher will allow you to attach listeners and notify those listeners so they can handle the event that you dispatch. The Event Dispatcher is PSR-14 Compatible with extra features.
Features
- Event Names
- Event Subscribers
- Listener Priorities
Installation
Usage
<?php
use SonsOfPHP\Component\EventDispatcher\EventDispatcher;
$dispatcher = new EventDispatcher();
// If you have a custom ListenerProviderInterface you can inject it into the
// EventDispatcher
//$dispatcher = new EventDispatcher($provider);
$dispatcher->addListener($event::class, function ($event, $eventName, $dispatcher) {});
$dispatcher->addListener('event.name', function ($event, $eventName, $dispatcher) {});
$dispatcher->addSubscriber($subscriber);
$dispatcher->dispatch($event); // PSR-14
$dispatcher->dispatch($event, 'event.name'); // Custom Event Name
Event Subscribers
Must implement EventSubscriberInterface
.
Listener Priorities
The priority will default to 0
. Lower numbers are higher priority. Higher
numbers will be handled later. For example, a listener with a priority of -1
will be handled before a listener of priority 1
.
Stoppable Events
If your code extends the AbstractStoppableEvent
and within your listener or
subscriber code, you execute $this->stopPropagation();
and it will return the
event and no more listeners or subscribers will handle that event.
<?php
use SonsOfPHP\Component\EventDispatcher\AbstractStoppableEvent;
class OrderCreated extends AbstractStoppableEvent
{
// ...
}
class OrderListener
{
public function __invoke(OrderCreated $event): void
{
// ...
$event->stopPropagation();
// ...
}
}
You can also create Stoppable Events by using the StoppableEventInterface
and
StoppableEventTrait
.
<?php
use SonsOfPHP\Component\EventDispatcher\StoppableEventTrait;
use Psr\EventDispatcher\StoppableEventInterface;
class OrderCreated implements StoppableEventInterface
{
use StoppableEventTrait;
// ...
}
Creating an Event Listener
<?php
use Psr\EventDispatcher\EventDispatcherInterface;
class OrderListener
{
public function __invoke(OrderCreated $event, string $eventName, EventDispatcherInterface $dispatcher): void
{
// ...
}
}
The dispatcher will always invoke the Listener with those three arguments in that order. If you do not need to know the event name or if you do not need the event dispatcher, you can ignore those two arguments.
Creating an Event Subscriber
Subscribers allow you to "subscribe" to multiple events.
<?php
use OrderCreated;
use OrderUpdated;
use OrderDeleted;
use SonsOfPHP\Component\EventDispatcher\EventSubscriberInterface;
class OrderSubscriber implements EventSubscriberInterface
{
// ...
public static function getSubscribedEvents()
{
// Can return like this:
yield OrderCreated::class => 'onCreated';
yield OrderUpdated::class => ['onUpdated', 100];
yield OrderDeleted::class => [['onDeleted', 100], ['doFirstOnDeleted', -100]];
// OR like this
return [
OrderCreated::class => 'onCreated',
OrderUpdated::class => ['onUpdated', 100],
OrderDeleted::class => [['onDeleted', 100], ['doFirstOnDeleted', -100]],
];
}
}