Laravel - Event Handling

Events provide a simple observer implementation which allows a user to subscribe and listen to various events triggered in the web application. All the event classes in Laravel are stored in theapp/Eventsfolder and the listeners are stored in theapp/Listenersfolder.

The artisan command for generating events and listeners in your web application is shown below −

php artisan event:generate

This command generates the events and listeners to the respective folders as discussed above.

Events and Listeners serve a great way to decouple a web application, since one event can have multiple listeners which are independent of each other. The events folder created by the artisan command includes the following two files: event.php and SomeEvent.php. They are shown here −

Event.php

        

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As mentioned above,event.phpincludes the basic definition of classEventand calls for namespaceAppEvents. Please note that the user defined or custom events are created in this file.

SomeEvent.php

        

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Observe that this file uses serialization for broadcasting events in a web application and that the necessary parameters are also initialized in this file.

For example, if we need to initialize order variable in the constructor for registering an event, we can do it in the following way −

public function __construct(Order $order) { $this->order = $order; }

Listeners

Listeners handle all the activities mentioned in an event that is being registered. The artisan commandevent:generatecreates all thelistenersin theapp/listenersdirectory. The Listeners folder includes a fileEventListener.phpwhich has all the methods required for handling listeners.

EventListener.php

        

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As mentioned in the code, it includeshandlefunction for managing various events. We can create various independent listeners that target a single event.

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