Laravel 监听器监听多个事件

Laravel listener listen to multiple event

提问by Park Lai

So according to the laravel event doc, when defining listeners, it can receive the event instance in their handle method and perform any logic necessary:

因此，根据 laravel event doc，在定义侦听器时，它可以在其 handle 方法中接收事件实例并执行任何必要的逻辑：

public function handle(FoodWasPurchased $event)

So if my FoodWasPurchasedevent is defined as below (assumed EventServiceProvider is set):

因此，如果我的FoodWasPurchased事件定义如下（假设设置了 EventServiceProvider）：

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

I could access the $foodin event from listener by doing:

我可以通过执行以下操作从侦听器访问事件中的$food：

$event->food->doSomething();

But now my question is what if a listener listen to multiple events?

但现在我的问题是，如果一个听众监听多个事件呢？

Event FoodWasPurchased -> Listener Bill
Event DrinksWasPurchased -> Listener Bill

What I did now is I did not specify the event instance in the listener handle method:

我现在所做的是我没有在侦听器句柄方法中指定事件实例：

public function handle($event)

where I can later use an if condition to check what is received in the $event:

稍后我可以使用 if 条件来检查 $event 中收到的内容：

if (isset($event->food)) {

    // Do something...

} elseif (isset($event->drinks)) {

    // Do something else...

}

I'm sure there is a better way.

我相信有更好的方法。

Or the best practice is ensure that one listener only listens to one single event ?

或者最好的做法是确保一个听众只听一个事件？

回答by jagzviruz

You can listen to multiple events by using Event Subscriberswhich are placed in the Listeners folder but are capable of listening to multiple events.

您可以使用放置在 Listeners 文件夹中但能够侦听多个事件的事件订阅者来侦听多个事件。

<?php

namespace App\Listeners;

class UserEventListener{
    /**
     * Handle user login events.
     */
    public function onUserLogin($event) {}

    /**
     * Handle user logout events.
     */
    public function onUserLogout($event) {}

    /**
     * Register the listeners for the subscriber.
     *
     * @param  Illuminate\Events\Dispatcher  $events
     * @return array
     */
    public function subscribe($events){
        $events->listen(
            'App\Events\UserLoggedIn',
            'App\Listeners\UserEventListener@onUserLogin'
        );

        $events->listen(
            'App\Events\UserLoggedOut',
            'App\Listeners\UserEventListener@onUserLogout'
        );
    }

}

回答by RobDW1984

If your events conform to a contract or interface it seems you can pass as many as you like to a listener...

如果您的事件符合合同或接口，那么您似乎可以将任意数量的事件传递给侦听器...

class MyEventOne extends Event implements MyEventInterface

Then in the EventServiceProvider you connect up your events and listeners as so...

然后在 EventServiceProvider 中，您将事件和侦听器连接起来……

protected $listen = [
    'App\Events\MyEventOne' => [
        'App\Listeners\MyListener',
    ],
    'App\Events\MyEventTwo' => [
        'App\Listeners\MyListener',
    ],
];

And finally in your listener you type hint your handler to accept the event object based on the contract/interface...

最后在您的侦听器中键入提示处理程序以接受基于合同/接口的事件对象...

public function handle(MyEventInterface $event)

I've unit tested this, it may not be appropriate for every scenario, but it seems to work. I hope it helps.

我已经对此进行了单元测试，它可能不适用于所有场景，但它似乎有效。我希望它有帮助。

回答by The Alpha

You may try something like this as well:

你也可以尝试这样的事情：

// Instead of Food or Drink use parent Type
use Illuminate\Database\Eloquent\Model;

class DrinWasPurchased extends Event
{
    // Instead of Food or Drink typehint Model        
    public function __construct(Model $model)
    {
        // Instead of $this->food or $this->drink use a generic name
        $this->item = $model;
    }
}

Then in the handlemethod of listener try something like this:

然后在handle侦听器的方法中尝试这样的事情：

public function handle(\App\Events\Event $event)
{
    if($event->item instanceof \App\Food)
    {
        $item->eat(); // Just an example
    }

    if($event->item instanceof \App\Drink)
    {
        $item->drink(); // Just an example
    }
}

回答by jvicab

1- Add to EventServiceProvider:

1- 添加到 EventServiceProvider：

'App\Events\NewMessageSent' => [
    'App\Listeners\SendNewMessageNotificationToRecipients',
],
'App\Events\MessageReplied' => [
    'App\Listeners\SendNewMessageNotificationToRecipients',
],
'App\Events\MessageForwarded' => [
    'App\Listeners\SendNewMessageNotificationToRecipients',
],

2- Generate events and listener:

2- 生成事件和监听器：

php artisan event:generate

3- On SendNewMessageNotificationToRecipients.php (listener):

3- 在 SendNewMessageNotificationToRecipients.php（侦听器）上：

use App\Events\Event;
use App\Events\NewMessageSent;
use App\Events\MessageReplied;
use App\Events\MessageForwarded;

public function handle(Event $event)
{
    if ($event instanceof NewMessageSent) {
        dd('message sent');
    } else if ($event instanceof MessageReplied) {
        dd('message replied');
    } else if ($event instanceof MessageForwarded) {
       dd('message forwarded');
    }
}