webiny / event-manager
Webiny Event Manager Component
Requires
- php: ^7
- webiny/std-lib: ~1.6
Requires (Dev)
- mybuilder/phpunit-accelerator: dev-master
- phpunit/phpunit: ~6
README
EventManager
allows you to easily manage events throughout your application.
Install the component
The best way to install the component is using Composer.
composer require webiny/event-manager
For additional versions of the package, visit the Packagist page.
Usage
Accessing EventManager
can be done in 2 ways. The preferable way is using EventManagerTrait
, but you can also access it directly, using EventManager::getInstance()
. Let's see a simple example of subscribing to an event called some.event
with an instance of YourHandler
:
class YourClass{ use EventManagerTrait; public function index(){ $this->eventManager()->listen('some.event')->handler(new YourHandler()); } }
You're done! You have just subscribed to an event and the moment some.event
is fired, your handler will process it.
Event handlers
Now let's take a look at YourHandler
. An event handler can be any class. EventManager
will call handle(Event $event)
method on your handler object, by default. You can, however, specify a method you want EventManager
to call:
class YourHandler{ public function customHandle(Event $event){ // Do something with the $event... } } // Using your custom method $this->eventManager()->listen('some.event')->handler(new YourHandler())->method('customHandle');
Besides using classes, you can also respond to an event using a callable:
// Using callable as event handler
$handler = function(Event $event){
// Do something with the $event...
};
$this->eventManager()->listen('some.event')->handler($handler);
Firing events
To fire a simple event use the following code:
$this->eventManager()->fire('some.event');
You can also pass some data when firing an event, which will be passed to every event listener:
$data = [ 'some' => 'data', 'ip' => '192.168.1.10' ]; $this->eventManager()->fire('some.event', $data);
Any given data that is not an Event
object, will be converted to generic Event
object and your data will be accessible either by using array keys, or as object properties:
class YourHandler{ public function customHandle(Event $event){ // Access your data echo $event->some; // 'data' echo $event['some'] // 'data' } }
If you want to use custom Event
data types, refer to section Custom event classes
Firing events using a wildcard
You can also use wildcard to fire multiple events at once. The following code will fire all events starting with event.
and pass $data
to each one of them:
$this->eventManager()->fire('event.*', $data);
Execution priority
EventManager
allows you to specify an execution priority using priority()
method. Here's an example:
// Specify a priority of execution for your event listeners $this->eventManager()->listen('some.event')->handler(new YourHandler())->method('customHandler')->priority(250); $this->eventManager()->listen('some.event')->handler(new YourHandler())->method('secondCustomHandler')->priority(400); $this->eventManager()->listen('some.event')->handler(new YourHandler())->method('thirdCustomHandler'); // Now let's fire an event $this->eventManager()->fire('some.event');
After firing an event, the event listeners will be ordered by priority in descending order. The higher the priority, the sooner the listener will be executed. In this example, the order of execution will be as follows: secondCustomHandler
, customHandler
, thirdCustomHandler
. Default priority is 101
, so thirdCustomHandler
is executed last.
Custom event classes
When firing events, you can also pass your own event classes, that extend generic Event
class. For example, you want to fire an event called cms.page_saved
and pass the Page
object. Of course, you could simply pass an array like ['page' => $pageObject]
, but for the sake of the example, let's pretend it's more complicated than that:
// Create your `PageEvent` class class PageEvent extends Event{ private $_page; public function __construct(Page $page){ // Call constructor of parent Event class parent::__construct(); // Set your page object $this->_page = $page; } public function getPage(){ return $this->_page; } } // Fire an event $pageEvent = new PageEvent($pageObject); $this->eventManager()->fire('cms.page_saved', $pageEvent); // In your handler, you can now access page object using $event->getPage() class YourHandler{ public function customHandle(PageEvent $event){ $pageObject = $event->getPage(); } }
This is a simple example, but it shows the power of creating your own Event
classes and add as much functionality to your events as you need.
Event subscriber
Another cool feature of the EventManager
is the ability to subscribe to multiple events at once. You will need to create a subscriber class implementing EventSubscriberInterface
:
class PageEventSubscriber implements EventSubscriberInterface { use EventManagerTrait; /** * Handle page creation event */ public function onPageCreated($event) { // } /** * Handle page update */ public function onPageUpdated($event) { // } /** * Register the listeners for the subscriber. */ public function subscribe() { $this->eventManager()->listen('cms.page_created')->handler($this)->method('onPageCreated'); $this->eventManager()->listen('cms.page_updated')->handler($this)->method('onPageUpdated'); } } // Subscriber to multiple events using your new subscriber class $this->eventManager()->subscribe($subscriber);
There are situations when you need to temporarily disable EventManager. For example, deleting a huge portion of files that are not directly related to the application (local cache files) does not require firing all of related events. In this case use the following methods:
// Disabling EventManager $this->eventManager()->disable(); // Do some work that would fire loads of unnecessary events... // Enabling EventManager $this->eventManager()->enable();
Resources
To run unit tests, you need to use the following command:
$ cd path/to/Webiny/Component/EventManager/
$ composer.phar install
$ phpunit