nimbly/announce

PSR-14 event dispatcher with subscriber support.

2.0.1 2023-08-06 13:23 UTC

This package is auto-updated.

Last update: 2024-02-06 14:28:32 UTC


README

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A simple framework agnostic PSR-14 event dispatcher for your event-driven application.

Features

  • Uses PHP's #Attribute feature to register class methods as event handlers
  • Optional PSR-11 Container support
  • Full autowiring support for your subscribers and listeners - pass in not just the event but any needed services or other dependencies!

Installation

composer require nimbly/announce

Quick start

Create an event class

Your events can be standalone classes or they can extend the StoppableEvent abstract class. By extending the StoppableEvent abstract you gain the ability to stop event propogation if needed.

namespace App\Events;

use App\Models\User;
use Nimbly\Announce\Event;

class UserRegisteredEvent extends StoppableEvent
{
	public function __construct(public User $user)
	{
	}
}

Create a subscriber

Subscribers are classes that will handle your events. You can have as many subscribers as you would like.

To register a subscriber's method to handle a particular event or set of events, use the Nimbly\Announce\Subscribe attribute and pass in a comma separated list of event names to listen for.

namespace App\Subscribers;

use App\Events\UserRegisteredEvent;
use App\Services\EmailService;
use Nimbly\Announce\Subscribe;

class EmailSubscriber
{
	#[Subscribe(UserRegisteredEvent::class)]
	public function onUserRegistered(
		UserRegisteredEvent $event,
		EmailService $emailService): void
	{
		$emailService->send("registration_email", $event->user->email);
	}
}

Initiate Dispatcher

To register your subscriber's with the event dispatcher, pass in an array of class names or instances into the Dispatcher constructor.

You can also pass in a PSR-11 compliant container instance to be used in autowiring your subscribers as well as for event handlers on your subscribers.

$dispatcher = new Dispatcher(
	subscribers: [
		EmailSubscriber::class,
		new FooSubscriber,
	],
	container: $container
);

Dispatch event

To trigger an event, just call the dispatch method with the event instance.

$event = new UserRegisteredEvent($user);
$dispatcher->dispatch($event);

Stopping event propagation

If you need to stop event propagation during its lifetime, just call the stop() method on the event instance. The event will no longer be propagated to any further subscribed listeners. This requires the event to extend from the StoppableEvent abstract.

class EmailSubscriber
{
	#[Subscribe(UserRegisteredEvent::class)]
	public function onUserRegistered(
		UserRegisteredEvent $event,
		EmailService $emailService): void
	{
		$emailService->send("registration_email", $event->user->email);

		// Prevent any further handlers from processing this event
		$event->stop();
	}
}

Registering individual listeners

Alternatively, you can register individual events using the listen method.

$dispatcher = new Dispatcher;
$dispatcher->listen(
	UserRegisteredEvent::class,
	function(UserRegisteredEvent $event): void {
		// do some event stuff
	}
);

Wildcard listeners

You can register a "wild card" listener by using the * event name. This will subscribe to all events fired.

$dispatcher = new Dispatcher;
$dispatcher->listen(
	"*",
	function($event): void {
		// Respond to all events...
	}
);