kelvinmo / f3-event-dispatcher
A PSR-14 compliant event dispatcher for the Fat-Free Framework
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Requires
- php: ^7.2 || ^8.0
- bcosca/fatfree-core: ^3.5
- psr/event-dispatcher: ^1.0
Requires (Dev)
- phpstan/phpstan: ^1.3
- phpunit/phpunit: ^8.0 || ^9.3
Provides
README
This is a simple PSR-14 compliant event dispatcher and listener provider library for the Fat-Free Framework.
Requirements
- PHP 7.2 or later
- Fat-Free Framework 3.5 or later
Installation
You can install via Composer.
composer require kelvinmo/f3-event-dispatcher
Usage
Listener Provider
The listener provider is implemented by the \Listeners
class. Listeners
is a subclass of Fat-Free's \Prefab
class.
$listeners = \Listeners::instance();
To add a listener, call the on()
method. The name of the event is
specified in the first parameter and the listener in the second
parameter.
As required by PSR-14, if the name of the event is the name of a class, then the listener will also be triggered for all subclasses of that event class.
The listener can be a PHP callable, or a string that can be resolved
by Fat-Free's call()
method
// Object method $listeners->on(FooEvent::class, 'Bar->listener'); // Static method $listeners->on(FooEvent::class, 'Bar::listener'); // PHP callable $listeners->on(FooEvent::class, [ $object, 'listener' ]); // Closure $listeners->on(FooEvent::class, function($event) { // listener });
The on()
method also takes a third, optional parameter, specifying the
priority which the listeners should be called. Listeners are called
from the highest priority to the lowest.
// Baz->listener is called first, then Bar->listener $listeners->on(FooEvent::class, 'Bar->listener', 10); $listeners->on(FooEvent::class, 'Baz->listener', 20);
You can use Listeners
with any PSR-14-compliant event dispatcher.
Generic Events
Sometimes it is too cumbersome to create a new event class for every single event. You can use generic events to group a set of related events into a single class.
A generic event implements GenericEventInterface
and provides the
name of the event through the getEventName()
method.
class BarEvent implements GenericEventInterface { private $eventName; public function __construct($eventName) { $this->eventName = $eventName; } public function getEventName() { return $this->eventName; } } $listeners->on('foo', 'Baz->listener'); $event = new BarEvent('foo');
Adding Listeners via Reflection
You can also add listeners using reflection by the map()
method. This
method takes a name or an instantiated object of a class. A listener
will be added based on a method of this class if:
- It is a
public
method (whether or not it is alsostatic
) - The name of the method starts with
on
- The method takes exactly one parameter, and the parameter is type-hinted with an event class.
The name of the event the method will listen to depends on the name of
the method. If the name of the method is the same as the short name
of the type hint of the parameter, then the name of the event is the
fully qualified name of the parameter type. Otherwise, the name of the
event is the method name converted to snake case, in which case
the event type must be a generic event (i.e. implements
GenericEventInterface
).
class TestListener { // Will be mapped to FooEvent (with namespace) public function onFooEvent(FooEvent $event) { } // Will be mapped to custom_event // (BarEvent must implement GenericEventInterface) public function onCustomEvent(BarEvent $event) { } } $listeners = \Listeners::instance(); $listeners->map(TestListener::class);
Event Dispatcher
The event dispatcher is implemented by the \Events
class. Events
is a subclass of Fat-Free's \Prefab
class.
$dispatcher = \Events::instance();
By default, Events
uses the Listeners
listener provider included in this
library. To use a different listener provider, pass the provider as
an argument in the constructor.
use League\Event\PrioritizedListenerRegistry; $listenerProvider = new PrioritizedListenerRegistry(); $dispatcher = \Events::instance($listenerProvider);
To use the event dispatcher, call the standard PSR-14 dispatch()
method:
$dispatcher->dispatch(new FooEvent());
Licence
GPL 3 or later