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Event Manager Component

EventManager allows you to easily manage events throughout your application.

Install the component

The best way to install the component is using Composer.

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:

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:

Besides using classes, you can also respond to an event using a callable:

Firing events

To fire a simple event use the following code:

You can also pass some data when firing an event, which will be passed to every event listener:

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:

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:

Execution priority

EventManager allows you to specify an execution priority using priority() method. Here's an example:

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:

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:

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:

Resources

To run unit tests, you need to use the following command:

$ cd path/to/Webiny/Component/EventManager/
$ composer.phar install
$ phpunit