Events

Introduction

Laravel's events provide a simple observer pattern implementation, allowing you to subscribe and listen for various events that occur within your application. Event classes are typically stored in the app/Events directory, while their listeners are stored in app/Listeners. Don't worry if you don't see these directories in your application as they will be created for you as you generate events and listeners using Artisan console commands.

Events serve as a great way to decouple various aspects of your application, since a single event can have multiple listeners that do not depend on each other. For example, you may wish to send a Slack notification to your user each time an order has shipped. Instead of coupling your order processing code to your Slack notification code, you can raise an App\Events\OrderShipped event which a listener can receive and use to dispatch a Slack notification.

Generating Events and Listeners

To quickly generate events and listeners, you may use the make:event and make:listener Artisan commands:

php artisan make:event PodcastProcessed

php artisan make:listener SendPodcastNotification --event=PodcastProcessed

For convenience, you may also invoke the make:event and make:listener Artisan commands without additional arguments. When you do so, Laravel will automatically prompt you for the class name and, when creating a listener, the event it should listen to:

php artisan make:event

php artisan make:listener

Registering Events and Listeners

Event Discovery

By default, Laravel will automatically find and register your event listeners by scanning your application's Listeners directory. When Laravel finds any listener class method that begins with handle or __invoke, Laravel will register those methods as event listeners for the event that is type-hinted in the method's signature:

use App\Events\PodcastProcessed;

class SendPodcastNotification
{
    /**
     * Handle the given event.
     */
    public function handle(PodcastProcessed $event): void
    {
        // ...
    }
}

If you plan to store your listeners in a different directory or within multiple directories, you may instruct Laravel to scan those directories using the withEvents method in your application's bootstrap/app.php file:

->withEvents(discover: [
    __DIR__.'/../app/Domain/Orders/Listeners',
])

The event:list command may be used to list all of the listeners registered within your application:

php artisan event:list

Event Discovery in Production

To give your application a speed boost, you should cache a manifest of all of your application's listeners using the optimize or event:cache Artisan commands. Typically, this command should be run as part of your application's deployment process. This manifest will be used by the framework to speed up the event registration process. The event:clear command may be used to destroy the event cache.

Manually Registering Events

Using the Event facade, you may manually register events and their corresponding listeners within the boot method of your application's AppServiceProvider:

use App\Domain\Orders\Events\PodcastProcessed;
use App\Domain\Orders\Listeners\SendPodcastNotification;
use Illuminate\Support\Facades\Event;

/**
 * Bootstrap any application services.
 */
public function boot(): void
{
    Event::listen(
        PodcastProcessed::class,
        SendPodcastNotification::class,
    );
}

The event:list command may be used to list all of the listeners registered within your application:

php artisan event:list

Closure Listeners

Typically, listeners are defined as classes; however, you may also manually register closure-based event listeners in the boot method of your application's AppServiceProvider:

use App\Events\PodcastProcessed;
use Illuminate\Support\Facades\Event;

/**
 * Bootstrap any application services.
 */
public function boot(): void
{
    Event::listen(function (PodcastProcessed $event) {
        // ...
    });
}

Queueable Anonymous Event Listeners

When registering closure based event listeners, you may wrap the listener closure within the Illuminate\Events\queueable function to instruct Laravel to execute the listener using the queue:

use App\Events\PodcastProcessed;
use function Illuminate\Events\queueable;
use Illuminate\Support\Facades\Event;

/**
 * Bootstrap any application services.
 */
public function boot(): void
{
    Event::listen(queueable(function (PodcastProcessed $event) {
        // ...
    }));
}

Like queued jobs, you may use the onConnection, onQueue, and delay methods to customize the execution of the queued listener:

Event::listen(queueable(function (PodcastProcessed $event) {
    // ...
})->onConnection('redis')->onQueue('podcasts')->delay(now()->addSeconds(10)));

If you would like to handle anonymous queued listener failures, you may provide a closure to the catch method while defining the queueable listener. This closure will receive the event instance and the Throwable instance that caused the listener's failure:

use App\Events\PodcastProcessed;
use function Illuminate\Events\queueable;
use Illuminate\Support\Facades\Event;
use Throwable;

Event::listen(queueable(function (PodcastProcessed $event) {
    // ...
})->catch(function (PodcastProcessed $event, Throwable $e) {
    // The queued listener failed...
}));

Wildcard Event Listeners

You may also register listeners using the * character as a wildcard parameter, allowing you to catch multiple events on the same listener. Wildcard listeners receive the event name as their first argument and the entire event data array as their second argument:

Event::listen('event.*', function (string $eventName, array $data) {
    // ...
});

Defining Events

An event class is essentially a data container which holds the information related to the event. For example, let's assume an App\Events\OrderShipped event receives an Eloquent ORM object:

<?php

namespace App\Events;

use App\Models\Order;
use Illuminate\Broadcasting\InteractsWithSockets;
use Illuminate\Foundation\Events\Dispatchable;
use Illuminate\Queue\SerializesModels;

class OrderShipped
{
    use Dispatchable, InteractsWithSockets, SerializesModels;

    /**
     * Create a new event instance.
     */
    public function __construct(
        public Order $order,
    ) {}
}

As you can see, this event class contains no logic. It is a container for the App\Models\Order instance that was purchased. The SerializesModels trait used by the event will gracefully serialize any Eloquent models if the event object is serialized using PHP's serialize function, such as when utilizing queued listeners.

Defining Listeners

Next, let's take a look at the listener for our example event. Event listeners receive event instances in their handle method. The make:listener Artisan command, when invoked with the --event option, will automatically import the proper event class and type-hint the event in the handle method. Within the handle method, you may perform any actions necessary to respond to the event:

<?php

namespace App\Listeners;

use App\Events\OrderShipped;

class SendShipmentNotification
{
    /**
     * Create the event listener.
     */
    public function __construct()
    {
        // ...
    }

    /**
     * Handle the event.
     */
    public function handle(OrderShipped $event): void
    {
        // Access the order using $event->order...
    }
}

提示

Your event listeners may also type-hint any dependencies they need on their constructors. All event listeners are resolved via the Laravel service container, so dependencies will be injected automatically.

Stopping The Propagation Of An Event

Sometimes, you may wish to stop the propagation of an event to other listeners. You may do so by returning false from your listener's handle method.

Queued Event Listeners

Queueing listeners can be beneficial if your listener is going to perform a slow task such as sending an email or making an HTTP request. Before using queued listeners, make sure to configure your queue and start a queue worker on your server or local development environment.

To specify that a listener should be queued, add the ShouldQueue interface to the listener class. Listeners generated by the make:listener Artisan commands already have this interface imported into the current namespace so you can use it immediately:

<?php

namespace App\Listeners;

use App\Events\OrderShipped;
use Illuminate\Contracts\Queue\ShouldQueue;

class SendShipmentNotification implements ShouldQueue
{
    // ...
}

That's it! Now, when an event handled by this listener is dispatched, the listener will automatically be queued by the event dispatcher using Laravel's queue system. If no exceptions are thrown when the listener is executed by the queue, the queued job will automatically be deleted after it has finished processing.

Customizing The Queue Connection, Name, & Delay

If you would like to customize the queue connection, queue name, or queue delay time of an event listener, you may define the $connection, $queue, or $delay properties on your listener class:

<?php

namespace App\Listeners;

use App\Events\OrderShipped;
use Illuminate\Contracts\Queue\ShouldQueue;

class SendShipmentNotification implements ShouldQueue
{
    /**
     * The name of the connection the job should be sent to.
     *
     * @var string|null
     */
    public $connection = 'sqs';

    /**
     * The name of the queue the job should be sent to.
     *
     * @var string|null
     */
    public $queue = 'listeners';

    /**
     * The time (seconds) before the job should be processed.
     *
     * @var int
     */
    public $delay = 60;
}

If you would like to define the listener's queue connection, queue name, or delay at runtime, you may define viaConnection, viaQueue, or withDelay methods on the listener:

/**
 * Get the name of the listener's queue connection.
 */
public function viaConnection(): string
{
    return 'sqs';
}

/**
 * Get the name of the listener's queue.
 */
public function viaQueue(): string
{
    return 'listeners';
}

/**
 * Get the number of seconds before the job should be processed.
 */
public function withDelay(OrderShipped $event): int
{
    return $event->highPriority ? 0 : 60;
}

Conditionally Queueing Listeners

Sometimes, you may need to determine whether a listener should be queued based on some data that are only available at runtime. To accomplish this, a shouldQueue method may be added to a listener to determine whether the listener should be queued. If the shouldQueue method returns false, the listener will not be queued:

<?php

namespace App\Listeners;

use App\Events\OrderCreated;
use Illuminate\Contracts\Queue\ShouldQueue;

class RewardGiftCard implements ShouldQueue
{
    /**
     * Reward a gift card to the customer.
     */
    public function handle(OrderCreated $event): void
    {
        // ...
    }

    /**
     * Determine whether the listener should be queued.
     */
    public function shouldQueue(OrderCreated $event): bool
    {
        return $event->order->subtotal >= 5000;
    }
}

Manually Interacting With the Queue

If you need to manually access the listener's underlying queue job's delete and release methods, you may do so using the Illuminate\Queue\InteractsWithQueue trait. This trait is imported by default on generated listeners and provides access to these methods:

<?php

namespace App\Listeners;

use App\Events\OrderShipped;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Queue\InteractsWithQueue;

class SendShipmentNotification implements ShouldQueue
{
    use InteractsWithQueue;

    /**
     * Handle the event.
     */
    public function handle(OrderShipped $event): void
    {
        if (true) {
            $this->release(30);
        }
    }
}

Queued Event Listeners and Database Transactions

When queued listeners are dispatched within database transactions, they may be processed by the queue before the database transaction has committed. When this happens, any updates you have made to models or database records during the database transaction may not yet be reflected in the database. In addition, any models or database records created within the transaction may not exist in the database. If your listener depends on these models, unexpected errors can occur when the job that dispatches the queued listener is processed.

If your queue connection's after_commit configuration option is set to false, you may still indicate that a particular queued listener should be dispatched after all open database transactions have been committed by implementing the ShouldQueueAfterCommit interface on the listener class:

<?php

namespace App\Listeners;

use Illuminate\Contracts\Queue\ShouldQueueAfterCommit;
use Illuminate\Queue\InteractsWithQueue;

class SendShipmentNotification implements ShouldQueueAfterCommit
{
    use InteractsWithQueue;
}

提示

To learn more about working around these issues, please review the documentation regarding queued jobs and database transactions.

Handling Failed Jobs

Sometimes your queued event listeners may fail. If the queued listener exceeds the maximum number of attempts as defined by your queue worker, the failed method will be called on your listener. The failed method receives the event instance and the Throwable that caused the failure:

<?php

namespace App\Listeners;

use App\Events\OrderShipped;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Queue\InteractsWithQueue;
use Throwable;

class SendShipmentNotification implements ShouldQueue
{
    use InteractsWithQueue;

    /**
     * Handle the event.
     */
    public function handle(OrderShipped $event): void
    {
        // ...
    }

    /**
     * Handle a job failure.
     */
    public function failed(OrderShipped $event, Throwable $exception): void
    {
        // ...
    }
}

Specifying Queued Listener Maximum Attempts

If one of your queued listeners is encountering an error, you likely do not want it to keep retrying indefinitely. Therefore, Laravel provides various ways to specify how many times or for how long a listener may be attempted.

You may define a $tries property on your listener class to specify how many times the listener may be attempted before it is considered to have failed:

<?php

namespace App\Listeners;

use App\Events\OrderShipped;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Queue\InteractsWithQueue;

class SendShipmentNotification implements ShouldQueue
{
    use InteractsWithQueue;

    /**
     * The number of times the queued listener may be attempted.
     *
     * @var int
     */
    public $tries = 5;
}

As an alternative to defining how many times a listener may be attempted before it fails, you may define a time at which the listener should no longer be attempted. This allows a listener to be attempted any number of times within a given time frame. To define the time at which a listener should no longer be attempted, add a retryUntil method to your listener class. This method should return a DateTime instance:

use DateTime;

/**
 * Determine the time at which the listener should timeout.
 */
public function retryUntil(): DateTime
{
    return now()->addMinutes(5);
}

Dispatching Events

To dispatch an event, you may call the static dispatch method on the event. This method is made available on the event by the Illuminate\Foundation\Events\Dispatchable trait. Any arguments passed to the dispatch method will be passed to the event's constructor:

<?php

namespace App\Http\Controllers;

use App\Events\OrderShipped;
use App\Http\Controllers\Controller;
use App\Models\Order;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;

class OrderShipmentController extends Controller
{
    /**
     * Ship the given order.
     */
    public function store(Request $request): RedirectResponse
    {
        $order = Order::findOrFail($request->order_id);

        // Order shipment logic...

        OrderShipped::dispatch($order);

        return redirect('/orders');
    }
}

If you would like to conditionally dispatch an event, you may use the dispatchIf and dispatchUnless methods:

OrderShipped::dispatchIf($condition, $order);

OrderShipped::dispatchUnless($condition, $order);

提示

When testing, it can be helpful to assert that certain events were dispatched without actually triggering their listeners. Laravel's built-in testing helpers make it a cinch.

Dispatching Events After Database Transactions

Sometimes, you may want to instruct Laravel to only dispatch an event after the active database transaction has committed. To do so, you may implement the ShouldDispatchAfterCommit interface on the event class.

This interface instructs Laravel to not dispatch the event until the current database transaction is committed. If the transaction fails, the event will be discarded. If no database transaction is in progress when the event is dispatched, the event will be dispatched immediately:

<?php

namespace App\Events;

use App\Models\Order;
use Illuminate\Broadcasting\InteractsWithSockets;
use Illuminate\Contracts\Events\ShouldDispatchAfterCommit;
use Illuminate\Foundation\Events\Dispatchable;
use Illuminate\Queue\SerializesModels;

class OrderShipped implements ShouldDispatchAfterCommit
{
    use Dispatchable, InteractsWithSockets, SerializesModels;

    /**
     * Create a new event instance.
     */
    public function __construct(
        public Order $order,
    ) {}
}

Event Subscribers

Writing Event Subscribers

Event subscribers are classes that may subscribe to multiple events from within the subscriber class itself, allowing you to define several event handlers within a single class. Subscribers should define a subscribe method, which will be passed an event dispatcher instance. You may call the listen method on the given dispatcher to register event listeners:

<?php

namespace App\Listeners;

use Illuminate\Auth\Events\Login;
use Illuminate\Auth\Events\Logout;
use Illuminate\Events\Dispatcher;

class UserEventSubscriber
{
    /**
     * Handle user login events.
     */
    public function handleUserLogin(Login $event): void {}

    /**
     * Handle user logout events.
     */
    public function handleUserLogout(Logout $event): void {}

    /**
     * Register the listeners for the subscriber.
     */
    public function subscribe(Dispatcher $events): void
    {
        $events->listen(
            Login::class,
            [UserEventSubscriber::class, 'handleUserLogin']
        );

        $events->listen(
            Logout::class,
            [UserEventSubscriber::class, 'handleUserLogout']
        );
    }
}

If your event listener methods are defined within the subscriber itself, you may find it more convenient to return an array of events and method names from the subscriber's subscribe method. Laravel will automatically determine the subscriber's class name when registering the event listeners:

<?php

namespace App\Listeners;

use Illuminate\Auth\Events\Login;
use Illuminate\Auth\Events\Logout;
use Illuminate\Events\Dispatcher;

class UserEventSubscriber
{
    /**
     * Handle user login events.
     */
    public function handleUserLogin(Login $event): void {}

    /**
     * Handle user logout events.
     */
    public function handleUserLogout(Logout $event): void {}

    /**
     * Register the listeners for the subscriber.
     *
     * @return array<string, string>
     */
    public function subscribe(Dispatcher $events): array
    {
        return [
            Login::class => 'handleUserLogin',
            Logout::class => 'handleUserLogout',
        ];
    }
}

Registering Event Subscribers

After writing the subscriber, you are ready to register it with the event dispatcher. You may register subscribers using the subscribe method of the Event facade. Typically, this should be done within the boot method of your application's AppServiceProvider:

<?php

namespace App\Providers;

use App\Listeners\UserEventSubscriber;
use Illuminate\Support\Facades\Event;
use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     */
    public function boot(): void
    {
        Event::subscribe(UserEventSubscriber::class);
    }
}

Testing

When testing code that dispatches events, you may wish to instruct Laravel to not actually execute the event's listeners, since the listener's code can be tested directly and separately of the code that dispatches the corresponding event. Of course, to test the listener itself, you may instantiate a listener instance and invoke the handle method directly in your test.

Using the Event facade's fake method, you may prevent listeners from executing, execute the code under test, and then assert which events were dispatched by your application using the assertDispatched, assertNotDispatched, and assertNothingDispatched methods:

<?php

use App\Events\OrderFailedToShip;
use App\Events\OrderShipped;
use Illuminate\Support\Facades\Event;

test('orders can be shipped', function () {
    Event::fake();

    // Perform order shipping...

    // Assert that an event was dispatched...
    Event::assertDispatched(OrderShipped::class);

    // Assert an event was dispatched twice...
    Event::assertDispatched(OrderShipped::class, 2);

    // Assert an event was not dispatched...
    Event::assertNotDispatched(OrderFailedToShip::class);

    // Assert that no events were dispatched...
    Event::assertNothingDispatched();
});

<?php

namespace Tests\Feature;

use App\Events\OrderFailedToShip;
use App\Events\OrderShipped;
use Illuminate\Support\Facades\Event;
use Tests\TestCase;

class ExampleTest extends TestCase
{
    /**
     * Test order shipping.
     */
    public function test_orders_can_be_shipped(): void
    {
        Event::fake();

        // Perform order shipping...

        // Assert that an event was dispatched...
        Event::assertDispatched(OrderShipped::class);

        // Assert an event was dispatched twice...
        Event::assertDispatched(OrderShipped::class, 2);

        // Assert an event was not dispatched...
        Event::assertNotDispatched(OrderFailedToShip::class);

        // Assert that no events were dispatched...
        Event::assertNothingDispatched();
    }
}

You may pass a closure to the assertDispatched or assertNotDispatched methods in order to assert that an event was dispatched that passes a given "truth test". If at least one event was dispatched that passes the given truth test then the assertion will be successful:

Event::assertDispatched(function (OrderShipped $event) use ($order) {
    return $event->order->id === $order->id;
});

If you would simply like to assert that an event listener is listening to a given event, you may use the assertListening method:

Event::assertListening(
    OrderShipped::class,
    SendShipmentNotification::class
);

注意

After calling Event::fake(), no event listeners will be executed. So, if your tests use model factories that rely on events, such as creating a UUID during a model's creating event, you should call Event::fake() after using your factories.

Faking a Subset of Events

If you only want to fake event listeners for a specific set of events, you may pass them to the fake or fakeFor method:

test('orders can be processed', function () {
    Event::fake([
        OrderCreated::class,
    ]);

    $order = Order::factory()->create();

    Event::assertDispatched(OrderCreated::class);

    // Other events are dispatched as normal...
    $order->update([...]);
});

/**
 * Test order process.
 */
public function test_orders_can_be_processed(): void
{
    Event::fake([
        OrderCreated::class,
    ]);

    $order = Order::factory()->create();

    Event::assertDispatched(OrderCreated::class);

    // Other events are dispatched as normal...
    $order->update([...]);
}

You may fake all events except for a set of specified events using the except method:

Event::fake()->except([
    OrderCreated::class,
]);

Scoped Event Fakes

If you only want to fake event listeners for a portion of your test, you may use the fakeFor method:

<?php

use App\Events\OrderCreated;
use App\Models\Order;
use Illuminate\Support\Facades\Event;

test('orders can be processed', function () {
    $order = Event::fakeFor(function () {
        $order = Order::factory()->create();

        Event::assertDispatched(OrderCreated::class);

        return $order;
    });

    // Events are dispatched as normal and observers will run ...
    $order->update([...]);
});

<?php

namespace Tests\Feature;

use App\Events\OrderCreated;
use App\Models\Order;
use Illuminate\Support\Facades\Event;
use Tests\TestCase;

class ExampleTest extends TestCase
{
    /**
     * Test order process.
     */
    public function test_orders_can_be_processed(): void
    {
        $order = Event::fakeFor(function () {
            $order = Order::factory()->create();

            Event::assertDispatched(OrderCreated::class);

            return $order;
        });

        // Events are dispatched as normal and observers will run ...
        $order->update([...]);
    }
}