Broadcast Groups

Same API as the core createGroup plugin, but membership is stored in Redis so groups work across multiple server instances. Local WebSocket tracking is maintained per-instance, and cross-instance events are relayed via Redis pub/sub.

When to use over the built-in plugin: The core groups plugin only tracks members on the local process. If your game lobby or editor room spans instances, members on one instance cannot send to members on another. The Redis version keeps a shared membership list and relays publishes through Redis pub/sub.

Setup

// src/lib/server/lobby.js
import { redis } from './redis.js';
import { createGroup } from 'svelte-adapter-uws-extensions/redis/groups';

export const lobby = createGroup(redis, 'lobby', {
  maxMembers: 50,
  meta: { game: 'chess' }
});

Note: the API signature is createGroup(client, name, options) instead of createGroup(name, options) - the Redis client is the first argument.

Usage

// src/hooks.ws.js
import { lobby } from '$lib/server/lobby';

export async function subscribe(ws, topic, { platform }) {
  if (topic === 'lobby') await lobby.join(ws, platform);
}

export async function close(ws, { platform }) {
  await lobby.leave(ws, platform);
}

Options

API