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Role: Documentation
Content type: text/plain
Description: Documentation
Class: PHP Event Dispatcher
Register events and call registered listeners
Author: By
Last change: Fixed typos. Small cleanup.
Date: 3 years ago
Size: 3,190 bytes


Class file image Download
EventDispatcher Component

EventDispatcher implements a lightweight version of the Observer design pattern.

use Wingu\OctopusCore\EventDispatcher\EventDispatcher;
use Wingu\OctopusCore\EventDispatcher\EventInterface;
use Wingu\OctopusCore\EventDispatcher\Event;

$dispatcher = new EventDispatcher();
$dispatcher->on('event_name', function (EventInterface $event) {
    // ...

$dispatcher->raiseEvent('event_name', new Event($sender));

Listening to events

Events are raised through the EventDispatcher. The easiest way to register listeners to handle events is using the `on()` method:
$dispatcher->on($eventName, $callback, $priority)

The $eventName can be a specific event name, a wildcard event name or a regular expression to match an event name.

$dispatcher->on('core', function(Event $e){}); // by event name
$dispatcher->on('core.*', function(Event $e){}); // wildcard, match anything after *
$dispatcher->on('core.#.error', function(Event $e){}); // wildcard, match a namespace (core.log.error, core.db.error, etc)
$dispatcher->on('/^core\.(.+)$/', function(Event $e){}); // regex

There are other several methods to subscribe to events.
// By passing an event name matcher.
$eventNameMatcher = new \Wingu\OctopusCore\EventDispatcher\EventNameMatcher\AllNamesMatcher();
$callback = function (EventInterface $e) {
	// do something ...
$dispatcher->subscribe($eventNameMatcher, $callback, $priority); // Will actually subscribe to all events.

// By passing a subscription object.
$eventNameMatcher = new \Wingu\OctopusCore\EventDispatcher\EventNameMatcher\NameMatcher('core.mail');
$callback = function (EventInterface $e) {
	// do something ...
$subscription = new \Wingu\OctopusCore\EventDispatcher\Subscription($eventNameMatcher, $callback);

To unsubscribe use:

$dispatcher->off($eventNameMatcher, $callback);
$dispatcher->unsubscribe($eventNameMatcher, $callback); // $eventNameMatcher doesn't have to be the same instance, but has to match the same event(s).

When an event is raised the return of each listener is stacked into a ResponseCollectionInterface object.

Raising / dispatching events

Events can be raised / dispatched by calling the `raiseEvent($event)` or `raiseEventUntil($event, $callback)` method. 
The arguments of the event must be an array with the key as the argument name.

$dispatcher = new EventDispatcher();

$args = ['param1' => 1, 'param2' => 2, 'date' => new \Datetime()];
$event = new Event($sender, $args);

$dispatcher->raiseEvent('event_name', $event);
$dispatcher->raiseEventUntil('event_name', $event, function() {
    echo "Event processed!";

For object instance event dispatching the EventDispatcherTrait trait can be attached to any object and then the API is the same as for the dispatcher.


You can run the unit tests with the following command:

    $ cd path/to/Wingu/OctopusCore/EventDispatcher/
    $ composer.phar install --dev
    $ phpunit