问使用composer cboden/ratchet(websocket)，服务端怎么接收发来的内容？

<?php

use Ratchet\MessageComponentInterface;

use Ratchet\ConnectionInterface;

// Make sure composer dependencies have been installed

require __DIR__ . '/vendor/autoload.php';

/**

* chat.php

* Send any incoming messages to all connected clients (except sender)

*/

class MyChat implements MessageComponentInterface {

protected $clients;

public function __construct() {

$this->clients = new \SplObjectStorage;

}

public function onOpen(ConnectionInterface $conn) {

$this->clients->attach($conn);

}

public function onMessage(ConnectionInterface $from, $msg) {

foreach ($this->clients as $client) {

if ($from != $client) {

$client->send($msg);

}

}

}

public function onClose(ConnectionInterface $conn) {

$this->clients->detach($conn);

}

public function onError(ConnectionInterface $conn, \Exception $e) {

$conn->close();

}

}

// Run the server application through the WebSocket protocol on port 8080

$app = new Ratchet\App('localhost', 8080);

$app->route('/chat', new MyChat);

$app->route('/echo', new Ratchet\Server\EchoServer, array('*'));

$app->run();

上面是服务端的代码，怎么接收客户端传来的内容，并发送内容至客户端？谢谢！！！