What is Laravel event handling explain in detail with an example

2 years ago
Zaid Bin Khalid
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1

Laravel provides an event-handling system that allows you to manage and respond to events within your application. Events provide a way to decouple components and facilitate communication between different parts of your application. Here’s a detailed explanation of Laravel event handling with an example:

Event and Listener Setup:

In Laravel, events are represented as classes, and listeners are responsible for handling these events. To create an event, you can use the make:event Artisan command:

php artisan make: event OrderCreated

This will generate an OrderCreated event class in the app/Events directory. Similarly, you can create a listener using the make:listener Artisan command:

php artisan make: listener SendOrderConfirmation --event=OrderCreated

This will generate a SendOrderConfirmation listener class in the app/Listeners directory, which is associated with the OrderCreated event.

Defining Event Logic:

Inside the OrderCreated event class, you can define any properties or methods necessary for the event. For example:

namespace App\Events;

use Illuminate\Foundation\Events\Dispatchable;
use Illuminate\Queue\SerializesModels;

class OrderCreated
{
    use Dispatchable, SerializesModels;

    public $order;

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

Handling Events:

In the SendOrderConfirmation listener class, you can define the logic to handle the OrderCreated event. This can include sending notifications, updating records, or performing any other necessary actions. For example:

namespace App\Listeners;

use App\Events\OrderCreated;

class SendOrderConfirmation
{
    public function handle(OrderCreated $event)
    {
        $order = $event->order;

        // Send order confirmation email or perform other actions
    }
}

Event Registration:

To associate the listener with the event, you need to register them. The event registration can be done in the EventServiceProvider class, located in the app/Providers directory. Inside the listen property, you can map events to their respective listeners. For example:

namespace App\Providers;

use App\Events\OrderCreated;
use App\Listeners\SendOrderConfirmation;
use Illuminate\Foundation\Support\Providers\EventServiceProvider as ServiceProvider;

class EventServiceProvider extends ServiceProvider
{
    protected $listen = [
        OrderCreated::class => [
            SendOrderConfirmation::class,
        ],
    ];
}

Triggering Events:

To trigger an event, you can use the event helper function or the Event facade. For example, in your controller or any other relevant part of your application:

use App\Events\OrderCreated;

public function createOrder()
{
    // Create the order

    $order = ...;

    event(new OrderCreated($order));

    // Additional logic
}

Event Handling Order:

By default, Laravel dispatches events synchronously. However, you can configure events to be handled asynchronously using Laravel’s queue system. This allows you to defer the processing of events and improves the performance of your application.

Laravel’s event-handling system provides a flexible way to handle and respond to events within your application. By defining events, creating listeners, and registering them, you can easily manage communication and actions triggered by specific events.