Socket.IO Postgres adapter

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

Table of contents

• Supported features
• Installation
• Usage
  • Standalone
  • With Node.js cluster
• Options
• License

Supported features

| Feature | socket.io version | Support | |---------------------------------|---------------------|------------------------------------------------| | Socket management | 4.0.0 | :white_check_mark: YES (since version 0.1.0) | | Inter-server communication | 4.1.0 | :white_check_mark: YES (since version 0.1.0) | | Broadcast with acknowledgements | 4.5.0 | :white_check_mark: YES (since version 0.3.0) | | Connection state recovery | 4.6.0 | :x: NO |

Installation

npm install @socket.io/postgres-adapter

Usage

Standalone

import { Server } from "socket.io";
import { createAdapter } from "@socket.io/postgres-adapter";
import pg from "pg";

const io = new Server();

const pool = new pg.Pool({
  user: "postgres",
  host: "localhost",
  database: "postgres",
  password: "changeit",
  port: 5432,
});

pool.query(`
  CREATE TABLE IF NOT EXISTS socket_io_attachments (
      id          bigserial UNIQUE,
      created_at  timestamptz DEFAULT NOW(),
      payload     bytea
  );
`);

pool.on("error", (err) => {
  console.error("Postgres error", err);
});

io.adapter(createAdapter(pool));
io.listen(3000);

With Node.js cluster

import cluster from "node:cluster";
import { createServer } from "node:http";
import { availableParallelism } from "node:os";
import { Server } from "socket.io";
import { setupPrimary } from "@socket.io/postgres-adapter"
import { createAdapter } from "@socket.io/cluster-adapter";
import pg from "pg";

if (cluster.isPrimary) {
  const pool = new pg.Pool({
    user: "postgres",
    password: "changeit",
  });
  
  await pool.query(`
    CREATE TABLE IF NOT EXISTS socket_io_attachments (
        id          bigserial UNIQUE,
        created_at  timestamptz DEFAULT NOW(),
        payload     bytea
    );
  `);

  setupPrimary(pool);

  for (let i = 0; i < availableParallelism(); i++) {
    cluster.fork();
  }
} else {
  const io = new Server({
    adapter: createAdapter(),
  });

  io.on("connection", (socket) => {
    /* ... */
  });

  io.listen(3000);
}

Options

| Name | Description | Default value | |---------------------|------------------------------------------------------------------------------------------------------------|-------------------------| | channelPrefix | The prefix of the notification channel. | socket.io | | tableName | The name of the table for payloads over the 8000 bytes limit or containing binary data. | socket_io_attachments | | payloadThreshold | The threshold for the payload size in bytes (see https://www.postgresql.org/docs/current/sql-notify.html). | 8_000 | | cleanupInterval | Number of ms between two cleanup queries. | 30_000 | | heartbeatInterval | The number of ms between two heartbeats. | 5_000 | | heartbeatTimeout | The number of ms without heartbeat before we consider a node down. | 10_000 |

License

MIT