WebSocket

$app->ws(
    '/ws/chat',
    // Each handler receives the same 3rd argument: $g — RequestContext::instance()
    // for the coroutine the handler is dispatched in. Use $g->session for
    // auth lookups (CoSessionManager seeds it from the upgrade request's
    // PHPSESSID cookie before onOpen fires), Store/Counter for cross-worker
    // shared state, or $g->server for the original upgrade request's headers.
    onMessage: function($server, $frame, $g) {
        // $frame->data   — message text
        // $frame->fd     — connection id
        // $frame->opcode — 1=TEXT, 2=BINARY (PING/PONG filtered automatically)
        $server->push($frame->fd, 'echo: ' . $frame->data);
    },
    onOpen: function($server, $request, $g) {
        // $request->fd     — connection id
        // $request->cookie — cookies from upgrade request
        // $request->get    — query params from ws://host/path?key=val
        $server->push($request->fd, json_encode(['event' => 'connected']));
    },
    onClose: function($server, $fd, $g) {
        // clean up per-connection state
    }
);

// app.php — flip Store to Redis. ALL nodes share the same view.
Store::defaultBackend(Store::BACKEND_REDIS);

// Track which server owns each client (cross-node visible).
Store::make('ws_owner', 4096, [
    'server_id' => [Store::TYPE_STRING, 32],
]);
$myServerId = gethostname() . ':' . getmypid();

// Subscribe to YOUR identity channel — only THIS server's subscriber
// receives messages routed here.
App::subscribe("ws:server:$myServerId", function (string $payload) use ($server, $localFds) {
    $msg = json_decode($payload, true);
    $fd  = $localFds[$msg['client_id']] ?? null;
    if ($fd !== null && $server->isEstablished($fd)) {
        $server->push($fd, $msg['data']);
    }
});

// Anywhere — send to a specific client by id, on ANY server.
$owner = Store::get('ws_owner', $clientId, 'server_id');
Store::publish("ws:server:$owner", json_encode([
    'client_id' => $clientId,
    'data'      => json_encode($message),
]));

// Or broadcast to a room across all servers:
App::subscribe('chat:room:42', function (string $payload) use ($server, $roomMembers) {
    foreach ($roomMembers as $fd) {
        if ($server->isEstablished($fd)) { $server->push($fd, $payload); }
    }
});
Store::publish('chat:room:42', json_encode(['user' => 'alice', 'text' => 'hi']));

const endpoint = '/ws/echo';
const scheme = location.protocol === 'https:' ? 'wss://' : 'ws://';
const socket = new WebSocket(scheme + location.host + endpoint);

socket.addEventListener('open', () => {
    socket.send('Hello from the browser');
});

socket.addEventListener('message', event => {
    console.log('received:', event.data);
});

function sendWhenReady(message) {
    if (socket.readyState === WebSocket.OPEN) {
        socket.send(message);
        return;
    }

    socket.addEventListener('open', () => socket.send(message), { once: true });
}