socketio/socket.io-redis-adapter

Socket.IO Redis adapter

The @socket.io/redis-adapter package allows broadcasting packets between multiple Socket.IO servers.

Table of contents

• Supported features
• Security notice
• Installation
• Compatibility table
• Usage
  • With the redis package
  • With the redis package and a Redis cluster
  • With the ioredis package
  • With the ioredis package and a Redis cluster
  • With Redis sharded Pub/Sub
    • With redis
    • With ioredis
• Options
  • Default adapter
  • Sharded adapter
• License

Supported features

Security notice

The Redis adapter assumes that Redis is part of the trusted internal infrastructure.

Messages exchanged through Redis Pub/Sub are not signed, encrypted, or authenticated by the adapter. Anyone able to publish to the adapter channels may be able to inject packets or control messages. Redis should therefore not be exposed to untrusted networks or shared with untrusted clients.

Please use Redis ACLs, authentication, TLS, firewall rules, private networking, and dedicated credentials/channel permissions where appropriate.

Installation

npm install @socket.io/redis-adapter

Compatibility table

Usage

With the redis package

import { createClient } from "redis";
import { Server } from "socket.io";
import { createAdapter } from "@socket.io/redis-adapter";

const pubClient = createClient({ url: "redis://localhost:6379" });
const subClient = pubClient.duplicate();

await Promise.all([
  pubClient.connect(),
  subClient.connect()
]);

const io = new Server({
  adapter: createAdapter(pubClient, subClient)
});

io.listen(3000);

With the redis package and a Redis cluster

import { createCluster } from "redis";
import { Server } from "socket.io";
import { createAdapter } from "@socket.io/redis-adapter";

const pubClient = createCluster({
  rootNodes: [
    {
      url: "redis://localhost:7000",
    },
    {
      url: "redis://localhost:7001",
    },
    {
      url: "redis://localhost:7002",
    },
  ],
});
const subClient = pubClient.duplicate();

await Promise.all([
  pubClient.connect(),
  subClient.connect()
]);

const io = new Server({
  adapter: createAdapter(pubClient, subClient)
});

io.listen(3000);

With the ioredis package

import { Redis } from "ioredis";
import { Server } from "socket.io";
import { createAdapter } from "@socket.io/redis-adapter";

const pubClient = new Redis();
const subClient = pubClient.duplicate();

const io = new Server({
  adapter: createAdapter(pubClient, subClient)
});

io.listen(3000);

With the ioredis package and a Redis cluster

import { Cluster } from "ioredis";
import { Server } from "socket.io";
import { createAdapter } from "@socket.io/redis-adapter";

const pubClient = new Cluster([
  {
    host: "localhost",
    port: 7000,
  },
  {
    host: "localhost",
    port: 7001,
  },
  {
    host: "localhost",
    port: 7002,
  },
]);
const subClient = pubClient.duplicate();

const io = new Server({
  adapter: createAdapter(pubClient, subClient)
});

io.listen(3000);

With Redis sharded Pub/Sub

Sharded Pub/Sub was introduced in Redis 7.0 in order to help scaling the usage of Pub/Sub in cluster mode.

Reference: https://redis.io/docs/interact/pubsub/#sharded-pubsub

A dedicated adapter can be created with the createShardedAdapter() method:

With redis

Minimum requirements:

• Redis 7.0
• [email protected]

import { Server } from "socket.io";
import { createClient } from "redis";
import { createShardedAdapter } from "@socket.io/redis-adapter";

const pubClient = createClient({ host: "localhost", port: 6379 });
const subClient = pubClient.duplicate();

await Promise.all([
  pubClient.connect(),
  subClient.connect()
]);

const io = new Server({
  adapter: createShardedAdapter(pubClient, subClient)
});

io.listen(3000);

With ioredis

Minimum requirements:

• Redis 7.0
• [email protected]

Please note that the shardedSubscribers option is required to enable sharded Pub/Sub.

import { Cluster } from "ioredis";
import { Server } from "socket.io";
import { createShardedAdapter } from "@socket.io/redis-adapter";

const pubClient = new Cluster(
  [
    {
      host: "localhost",
      port: 7000,
    },
    {
      host: "localhost",
      port: 7001,
    },
    {
      host: "localhost",
      port: 7002,
    },
  ],
  {
    shardedSubscribers: true,
  }
);
const subClient = pubClient.duplicate();

const io = new Server({
  adapter: createShardedAdapter(pubClient, subClient)
});

io.listen(3000);

Options

Default adapter

Sharded adapter

License

MIT