Laravel WebSockets onSubscribe

Laravel WebSockets is a powerful package that enables real-time communication between clients and servers using WebSockets. The onSubscribe event is a powerful feature that allows you to handle custom logic when a client subscribes to a channel.

Syntax

public function onSubscribe(ConnectionInterface $connection, $topic) {
    // Handle custom logic here
}

Where $connection is the connection object and $topic is the topic name.

Usage

The onSubscribe event can be used to perform any custom logic you want when a client subscribes to a channel. For example, you can use it to set up database connections, fetch data from APIs, or update user statuses.

Here is an example of how to use the onSubscribe event to update the user's online status when they join a channel:

<?php

namespace App\WebSocket;

use Ratchet\ConnectionInterface;
use Ratchet\Wamp\Topic;
use Ratchet\Wamp\WampServerInterface;

class MySocket implements WampServerInterface
{
    // ...

    public function onSubscribe(ConnectionInterface $connection, $topic) {
        $this->users[$connection->resourceId]['topic'] = $topic->getId();
        $this->users[$connection->resourceId]['status'] = 'online';

        // Update user's online status
        $user = User::findOrFail($connection->userId);
        $user->update(['status' => 'online']);

        // Broadcast user's online status to other users
        $this->broadcastUserStatus($user);
    }

    // ...
}

Here, we are first storing the channel ID and the user's online status in the $users array. Then, we are fetching the user record from the database using the connection's user ID and updating their status to "online". Finally, we are broadcasting the user's online status to other users in the channel using the broadcastUserStatus method.

Conclusion

Using the onSubscribe event in Laravel WebSockets can help you handle custom logic when a client subscribes to a channel. This can be used to update user statuses, perform database operations, or fetch data from APIs.