MessageBus (Legacy)

WARNING

This documents the old Node.js API. In v2, namespace-based messaging is handled by Node::send(), Node::broadcast(), and Node::subscribe() in Rust. See the Architecture guide.

The message bus provides namespace-based pub/sub messaging across devices.

Getting the Bus

const bus = node.getMessageBus();

Methods

subscribe(namespace, handler): () => void

Subscribe to messages in a namespace. Returns an unsubscribe function.

const unsubscribe = bus.subscribe('chat', (message) => {
  console.log(message.from, message.type, message.payload);
});

// Later:
unsubscribe();

publish(targetId, namespace, type, payload): boolean

Send a message to a specific device. Returns true if sent.

bus.publish('device-123', 'chat', 'message', { text: 'Hello!' });

broadcast(namespace, type, payload): void

Broadcast a message to all connected devices.

bus.broadcast('chat', 'message', { text: 'Hello everyone!' });

BusMessage

interface BusMessage {
  from: string | undefined;
  namespace: string;
  type: string;
  payload: unknown;
}

Patterns

Request/Response

// Responder
bus.subscribe('rpc', (msg) => {
  if (msg.type === 'ping' && msg.from) {
    bus.publish(msg.from, 'rpc', 'pong', { time: Date.now() });
  }
});

// Requester
bus.broadcast('rpc', 'ping', {});
bus.subscribe('rpc', (msg) => {
  if (msg.type === 'pong') {
    console.log('Response from', msg.from, msg.payload);
  }
});