README

A PSR-14 event dispatcher with autowiring support.

Table of Contents

• Getting started
  • Requirements
  • Highlights
  • Simple Example
• Documentation
  • Listeners
    • Create Listeners
    • Defining And Add Listener
    • Retrieve Listeners
  • Dispatcher
    • Create Dispatcher
    • Dispachting Events
  • Events
    • Create Events
    • Add Listeners
    • Dispatch Events
    • Supporting Events
• Credits

Getting started

Add the latest version of the event service running this command.

composer require tobento/service-event

Requirements

• PHP 8.4 or greater

Highlights

• Framework-agnostic, will work with any project
• Decoupled design
• Autowiring support

Simple Example

Here is a simple example of how to use the Event service.

use Tobento\Service\Event\Dispatcher;
use Tobento\Service\Event\Listeners;

class FooEvent {}

$listeners = new Listeners();

$listeners->add(function(FooEvent $event) {
 // do something
});

$dispatcher = new Dispatcher($listeners);

$event = $dispatcher->dispatch(new FooEvent());

Using Events

use Tobento\Service\Event\Events;

class FooEvent {}

$events = new Events();

$events->listen(function(FooEvent $event) {
 // do something
});

$event = $events->dispatch(new FooEvent());

Documentation

Listeners

The listeners class uses reflection to scan listeners for its events.

Create Listeners

use Tobento\Service\Event\Listeners;
use Tobento\Service\Event\ListenersInterface;
use Tobento\Service\Event\CallableFactoryInterface;
use Tobento\Service\Event\ListenerEventsResolverInterface;
use Psr\EventDispatcher\ListenerProviderInterface;
 
$listeners = new Listeners(
 callableFactory: null, // null|CallableFactoryInterface
 listenerEventsResolver: null, // null|ListenerEventsResolverInterface
);

var_dump($listeners instanceof ListenersInterface);
// bool(true)

var_dump($listeners instanceof ListenerProviderInterface);
// bool(true)

Using Autowiring

You might want to use autowiring for creating your listeners.

use Tobento\Service\Event\Listeners;
use Tobento\Service\Event\AutowiringCallableFactory;
use Tobento\Service\Container\Container;

class FooListener
{
 public function foo(FooEvent $event): void
 {
 // do something
 }
}

// any PSR-11 container
$container = new Container();
 
$listeners = new Listeners(
 callableFactory: new AutowiringCallableFactory($container),
);

$listeners->add(FooListener::class);

Defining And Add Listener

As the listeners class uses reflection to scan listeners for its events named $event, there is no need to define its event(s) when adding a listener. But you might do so if you have multiple events in your listener and want only to listen for the specific events.

Class using invoke

class FooListener
{
 public function __invoke(FooEvent $event): void
 {
 // do something
 }
}

class FooBuildInListener
{
 public function __construct(protected int $number) {}
 
 public function __invoke(FooEvent $event): void
 {
 // do something
 }
}

$listeners->add(new FooListener());

// using autowiring:
$listeners->add(FooListener::class);

// using autowiring with build-in parameters:
$listeners->add([FooBuildInListener::class, ['number' => 5]]);

Class defining multiple events to listen

class FooBarListener
{
 public function foo(FooEvent $event): void
 {
 // do something
 }
 
 public function bar(BarEvent $event): void
 {
 // do something
 }
 
 public function another(AnotherEvent $event): void
 {
 // do something
 } 
 
 public function fooAndBar(FooEvent|BarEvent $event): void
 {
 // do something
 } 
}

// only listen to foo and bar event: 
$listeners->add(new FooBarListener())
 ->event(FooEvent::class, BarEvent::class);
 
// using autowiring:
$listeners->add(FooBarListener::class)
 ->event(FooEvent::class, BarEvent::class);

Using closure

$listeners->add(function(FooEvent $event) {
 // do something
});

Prioritize

You might prioritize listeners by the following way:

$listeners->add(function(FooEvent $event) {
 // do something
})->priority(1500);

// gets called first as higher priority.
$listeners->add(function(FooEvent $event) {
 // do something
})->priority(2000);

Add a custom listener

You might add a custom listener by implementing the following interface:

use Tobento\Service\Event\ListenerInterface;
use Tobento\Service\Event\CallableFactoryInterface;

interface ListenerInterface
{
 /**
 * Returns the listener.
 * 
 * @return mixed
 */
 public function getListener(): mixed;

 /**
 * Returns the listener events.
 * 
 * @return array<string, array<mixed>>
 */
 public function getListenerEvents(): array;
 
 /**
 * Returns the listeners for the specified event.
 *
 * @param object $event
 * @param CallableFactoryInterface $callableFactory
 * @return iterable<callable>
 * An iterable (array, iterator, or generator) of callables. Each
 * callable MUST be type-compatible with $event.
 */
 public function getForEvent(object $event, CallableFactoryInterface $callableFactory): iterable;
 
 /**
 * Returns the priority.
 * 
 * @return int
 */
 public function getPriority(): int; 
}

$listeners->addListener(new AnyCustomListener());

Retrieve Listeners

use Tobento\Service\Event\ListenerInterface;

foreach($listeners->all() as $listener) {
 var_dump($listener instanceof ListenerInterface);
 // bool(true)
}

Dispatcher

Create Dispatcher

use Tobento\Service\Event\Dispatcher;
use Psr\EventDispatcher\EventDispatcherInterface;
use Psr\EventDispatcher\ListenerProviderInterface;
use Psr\Container\ContainerInterface;
use Tobento\Service\Event\Listeners;

$listeners = new Listeners();

$dispatcher = new Dispatcher(
 listenerProvider: $listeners, // ListenerProviderInterface
 container: null, // null|ContainerInterface
);

var_dump($dispatcher instanceof EventDispatcherInterface);
// bool(true)

Using Autowire

You might set a container for autowiring events methods. This will break PSR-14 definition although.

use Tobento\Service\Event\Dispatcher;
use Tobento\Service\Event\Listeners;
use Tobento\Service\Container\Container;

class FooEvent {}
class Bar {}

$listeners = new Listeners();

// adding more parameters after the $event.
$listeners->add(function(FooEvent $event, Bar $bar) {
 // do something
});

// Any PSR-11 container
$container = new Container();

$dispatcher = new Dispatcher(
 listenerProvider: $listeners,
 container: $container,
);

$dispatcher->dispatch(new FooEvent());

Dispatching Events

$dispatcher->dispatch(new AnyEvent());

Events

Create Events

use Tobento\Service\Event\Events;
use Tobento\Service\Event\EventsInterface;
use Tobento\Service\Event\ListenersInterface;
use Tobento\Service\Event\DispatcherFactoryInterface;
use Psr\EventDispatcher\EventDispatcherInterface;

$events = new Events(
 listeners: null, // null|ListenersInterface
 dispatcherFactory: null, // null|DispatcherFactoryInterface
);

var_dump($events instanceof EventsInterface);
// bool(true)

var_dump($events instanceof EventDispatcherInterface);
// bool(true)

Using the events factory

use Tobento\Service\Event\EventsFactory;
use Tobento\Service\Event\EventsFactoryInterface;
use Tobento\Service\Event\ListenersInterface;
use Tobento\Service\Event\DispatcherFactoryInterface;
use Tobento\Service\Event\EventsInterface;

$eventsFactory = new EventsFactory();

var_dump($eventsFactory instanceof EventsFactoryInterface);
// bool(true)

$events = $eventsFactory->createEvents(
 listeners: null, // null|ListenersInterface
 dispatcherFactory: null, // null|DispatcherFactoryInterface
);

var_dump($events instanceof EventsInterface);
// bool(true)

Using the autowiring events factory

use Tobento\Service\Event\AutowiringEventsFactory;
use Tobento\Service\Event\EventsFactoryInterface;
use Tobento\Service\Event\EventsInterface;
use Tobento\Service\Container\Container;

// Any PSR-11 container
$container = new Container();

$eventsFactory = new AutowiringEventsFactory(
 container: $container,
 withAutowiringDispatching: true,
);

var_dump($eventsFactory instanceof EventsFactoryInterface);
// bool(true)

$events = $eventsFactory->createEvents();

var_dump($events instanceof EventsInterface);
// bool(true)

Add Listeners

Using listen method

$events->listen(FooListener::class);

$events->listen(AnyListener::class)
 ->event(FooEvent::class)
 ->priority(2000);

Using listeners method

use Tobento\Service\Event\ListenersInterface;

$listeners = $events->listeners();

var_dump($listeners instanceof ListenersInterface);
// bool(true)

$listeners->add(AnyListener::class);

For more detail see Defining And Add Listener

Dispatch Events

$events->dispatch(new AnyEvent());

Supporting Events

You might use the HasEvents trait with the EventsAware interface for any classes supporting events.

use Tobento\Service\Event\EventsAware;
use Tobento\Service\Event\HasEvents;
use Tobento\Service\Event\EventsInterface;
use Tobento\Service\Event\Events;

class AnyService implements EventsAware
{
 use HasEvents;
 
 public function __construct(EventsInterface $events)
 {
 $this->events = $events;
 }
}

$service = new AnyService(new Events());

var_dump($service->events() instanceof EventsInterface);
// bool(true)

Credits

• Tobias Strub
• All Contributors