WebSockets

The nexus-http-ws package adds WebSocket routes to the HTTP application. Two flavours of route are available:

ws() — per-connection WebSocketHandler class. One instance per upgraded connection. Use for echo, per-user state, and command-style protocols.
channel() — actor-backed broadcast room. Many connections share one WebSocketChannelActor. Use for chat rooms, pub/sub, and collaborative editors. Thread mode only.

Setup

Switch from HttpApplication to WsApplication and enable WebSocket on the server config:

server.php
use Monadial\Nexus\Http\Server\Swoole\Threads\Server\{SwooleThreadConfig, SwooleThreadServer};
use Monadial\Nexus\Http\Ws\{CompiledApplication, WsApplication};

SwooleThreadServer::run(
    SwooleThreadConfig::bind('0.0.0.0', 8080)
        ->threads(4)
        ->enableWebSocket(true),
    static function (ActorSystem $system, WorkerNode $node): CompiledApplication {
        return WsApplication::create($system)
            ->get('/', static fn() => Response::ok())
            ->ws('/ws/echo', EchoHandler::class)
            ->compile();
    },
);

enableWebSocket(true) swaps the underlying Swoole server from Swoole\Http\Server to Swoole\WebSocket\Server, which adds the upgrade handshake support.

Per-connection handlers

Extend WebSocketHandler and override three lifecycle methods:

src/Http/Handler/EchoHandler.php
use Monadial\Nexus\Http\Ws\WebSocket\Attribute\FromContext;
use Monadial\Nexus\Http\Ws\WebSocket\{WebSocketContext, WebSocketFrame, WebSocketHandler};

final class EchoHandler extends WebSocketHandler
{
    public function __construct(
        #[FromContext] private readonly WebSocketContext $ctx,
    ) {}

    #[\Override]
    public function onOpen(): void
    {
        $this->ctx->send('welcome');
    }

    #[\Override]
    public function onMessage(WebSocketFrame $frame): void
    {
        $this->ctx->send('echo:' . $frame->text);
    }

    #[\Override]
    public function onClose(int $code): void
    {
        // cleanup
    }
}

server.php
$app->ws('/ws/echo', EchoHandler::class);

One EchoHandler instance is created per connection at upgrade time. State on $this is per-connection — no locking needed.

Lifecycle

onOpen() and onClose() fire exactly once per connection. onMessage() fires zero or more times. Throwing from any of them closes the connection with 1011 (server error) and logs the exception.

`WebSocketContext`

Per-connection handle. Inject via #[FromContext]:

src/Http/Handler/ChatHandler.php
$ctx->id();                            // int — connection fd, unique within this thread
$ctx->request();                       // ServerRequestInterface — the original upgrade request
$ctx->send($text);                     // send a TEXT frame
$ctx->sendBinary($data);               // send a BINARY frame
$ctx->sendPing();                      // send a control PING
$ctx->close($code, $reason);          // close with WebSocket close code
$ctx->isAlive();                       // bool — still connected

WebSocket routes accept path parameters identical to HTTP routes:

src/Http/Handler/ChatHandler.php
$app->ws('/ws/chat/{room}', ChatHandler::class);

// Inside onOpen():
$room = (string) $this->ctx->request()->getAttribute('room');

`WebSocketFrame`

Immutable frame value object:

src/Http/Handler/BinaryHandler.php
public function onMessage(WebSocketFrame $frame): void
{
    if ($frame->kind === 2) {          // 1 = TEXT, 2 = BINARY
        $this->processBinary($frame->text);
        return;
    }

    $this->processText($frame->text);
}

Channel-backed routes (broadcast)

For broadcast and fan-out scenarios — chat rooms, presence, live updates — route to an actor instead of a per-connection handler:

src/Http/Actor/ChatRoomActor.php
use Monadial\Nexus\Http\Ws\WebSocket\{WebSocketChannelActor, WebSocketContext, WebSocketFrame};

final class ChatRoomActor extends WebSocketChannelActor
{
    #[\Override]
    public function onOpen(WebSocketContext $ctx): void
    {
        $this->broadcast("user {$ctx->id()} joined");
    }

    #[\Override]
    public function onMessage(WebSocketContext $ctx, WebSocketFrame $frame): void
    {
        $this->broadcast("{$ctx->id()}: {$frame->text}");
    }

    #[\Override]
    public function onClose(WebSocketContext $ctx, int $code): void
    {
        $this->broadcast("user {$ctx->id()} left");
    }
}

server.php
$app->channel('/ws/chat/{room}', ChatRoomActor::class, key: 'room');

The key parameter selects which path attribute partitions the actor — each {room} value gets its own actor instance with its own connection set. $this->broadcast() sends to every open connection in that partition, across all threads.

Thread mode only

channel() routes require a shared Swoole\Thread\Map for the channel registry. Worker-mode Swoole has no equivalent shared memory store, so channel() routes throw at compile time. Use plain ws() routes with per-connection handlers in worker mode.

For targeted sends to one user:

src/Http/Actor/ChatRoomActor.php
public function onMessage(WebSocketContext $ctx, WebSocketFrame $frame): void
{
    if (str_starts_with($frame->text, '/whisper ')) {
        [$target, $msg] = $this->parseWhisper($frame->text);
        $this->sendTo($target, "[private] {$msg}");
        return;
    }

    $this->broadcast($frame->text);
}

Dependency injection in WebSocket handlers

The same attributes used for HTTP handlers work here:

src/Http/Handler/ChatHandler.php
final class ChatHandler extends WebSocketHandler
{
    public function __construct(
        #[FromContext] private readonly WebSocketContext $ctx,
        #[FromActor('chat-room')] private readonly ActorRef $room,
        #[FromService(LoggerInterface::class)] private readonly LoggerInterface $log,
    ) {}
}

#[FromContext] is WebSocket-specific. #[FromActor] and #[FromService] behave identically to HTTP. #[FromBody] does not apply — WebSocket frames arrive on onMessage() as WebSocketFrame objects.

Close codes

Use standard WebSocket close codes with $ctx->close($code):

Code	Meaning
`1000`	Normal closure
`1001`	Going away (server shutdown)
`1002`	Protocol error
`1003`	Unsupported data
`1008`	Policy violation (auth fail, bad room)
`1009`	Message too large
`1011`	Internal server error
`4000+`	Application-defined

Sending from outside `onMessage()`

A handler can hold its WebSocketContext and call send() from outside onMessage() — for instance, in response to an external event delivered by an actor:

src/Http/Handler/NotificationHandler.php
final class NotificationHandler extends WebSocketHandler
{
    public function __construct(
        #[FromContext] private readonly WebSocketContext $ctx,
        #[FromActor('notifications')] private readonly ActorRef $hub,
    ) {}

    #[\Override]
    public function onOpen(): void
    {
        $this->hub->tell(new Subscribe($this->ctx->id(), $this));
    }

    public function notify(string $message): void
    {
        if ($this->ctx->isAlive()) {
            $this->ctx->send($message);
        }
    }
}

Always check isAlive() before sending — the client may have disconnected between events.

Setup​

Per-connection handlers​

Lifecycle​

WebSocketContext​

WebSocketFrame​

Channel-backed routes (broadcast)​

Dependency injection in WebSocket handlers​

Close codes​

Sending from outside onMessage()​

See also​