Channels

Mesh lets clients subscribe to Redis pub/sub channels over WebSocket. Useful for chat, notifications, dashboards, and more.

Server: expose channels

Allow clients to subscribe to specific channels or patterns:


server.exposeChannel("notifications:global");
server.exposeChannel(/^chat:.+$/);
 
// restrict access per connection
server.exposeChannel(/^private:chat:.+$/, async (conn, channel) => {
  const meta = await server.connectionManager.getMetadata(conn);
  return meta?.isPremium === true;
});

Server: publish messages

Send messages to all subscribers. Optionally store recent history:


// publish with no history
await server.publishToChannel(
  "notifications:global",
  JSON.stringify({
    alert: "Red alert!",
  })
);
 
// publish with history (keeps last 50)
await server.publishToChannel(
  "chat:room1",
  JSON.stringify({
    type: "user-message",
    user: "1",
    text: "Hi",
  }),
  50
);

History is stored in Redis under "mesh:history:<channel>" and trimmed to the specified size.

Server: enable persistence

For long-term storage beyond Redis, enable persistence for specific channels:


// Enable persistence for all chat channels
server.enablePersistenceForChannels(/^chat:.+$/);
 
// With custom options
server.enablePersistenceForChannels("notifications:global", {
  historyLimit: 1000,
  maxMessageSize: 20480, // 20KB
});

Persistence stores messages in a durable backend (SQLite by default), surviving server restarts.


const { success, history } = await client.subscribeChannel(
  "chat:room1",
  (message) => {
    console.log("Live message:", message);
  },
  { historyLimit: 3 }
);
 
console.log("History:", history); // ["msg3", "msg2", "msg1"]

Client: unsubscribe


await client.unsubscribeChannel("chat:room1");

Use cases

Chat systems
Notification feeds
Live dashboards
Cross-server pub/sub

See Server SDK → Channels and Client SDK → Channels for full API details.