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

$3

`js
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);
`

$3

`js
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