Redis からサブスクリプション メッセージを実装し、WebSocket クライアントに転送します。

$server = new swoole_websocket_server("0.0.0.0", 9501);
$server->on('workerStart', function ($server, $workerId) {
    $client = new swoole_redis;
    $client->on('message', function (swoole_redis $client, $result) use ($server) {
        if ($result[0] == 'message') {
            foreach($server->connections as $fd) {
                $server->push($fd, $result[1]);
            }
        }
    });
    $client->connect('127.0.0.1', 6379, function (swoole_redis $client, $result) {
        $client->subscribe('msg_0');
    });
});
$server->on('open', function ($server, $request) {
});
$server->on('message', function (swoole_websocket_server $server, $frame) {
    $server->push($frame->fd, "hello");
});
$server->on('close', function ($serv, $fd) {
});
$server->start();