在棘轮中路由并使用路由作为变量

I have a server set up as so

$server = IoServer::factory(
new HttpServer(
    new WsServer(
        new Person()
    )
),
8080
);

$server->run();

This works if the client uses ws://localhost:8080.

What I would like to do is set a route like ws://localhost:8080/chat/{name} ie. ws://localhost:8080/chat/Bob and then be able to use Bob as a variable in the onMessage() function, ie.

$name = $route->name;

echo 'Welcome, ' . $name . '!'; // Welcome, Bob!

I have found examples like

$app = new Ratchet\App("localhost", 8080, '0.0.0.0', $loop);
$app->route('/chat', new Chat, array('*'));

$app->run();

but none mention a using a variable in the route.

How can this be accomplished?