SockManage

SockManage is a utility library for managing WebSocket connections, ensuring each user has a single active socket connection at any given time. It uses Redis for persistence, making it suitable for scalable and distributed WebSocket applications.

Features

• Ensures one active socket per user.
• Manages user sockets with Redis for persistence across multiple instances.
• Provides methods to register, deregister, and retrieve user sockets.
• Supports emitting events to specific users.

Installation

To install with npm:

npm install sockmanage

or with Yarn:

yarn add sockmanage

Usage

Importing and Setting Up

import { createClient } from "redis";
import { Server as SocketIOServer } from "socket.io";
import { SockManage } from "sockmanage";

// Initialize Redis and Socket.IO
const redisClient = createClient();
const io = new SocketIOServer(server); // assume 'server' is an HTTP server

// Initialize SockManage
const socketManager = new SockManage({ redis: redisClient });

// Set up the Socket.IO server and specify the namespace (optional)
socketManager.setup({ io, namespace: "/your-namespace" });

// Assuming top-level await is supported, otherwise wrap the following line in an async function
await socketManager.initialize();

Methods

setup

Sets up Socket.IO server and optional namespace.

socketManager.setup({ io, namespace: "/your-namespace" });

Parameters:

• io: Instance of SocketIOServer.
• namespace (optional): Namespace for Socket.IO events.

initialize

Initializes user sockets from Redis.

await socketManager.initialize();

getSockets

Retrieves all user sockets from local map.

const userSockets = socketManager.getSockets();

Returns: Map<string, string>: A map of user IDs to socket IDs, or an empty map.

getSocket

Retrieves the socket ID for a specific user.

const socketId = socketManager.getSocket("userId");

Parameters:

• userId: ID of the user.

Returns: string | null: Socket ID of the user or null if not found.

register

Registers a socket for a user and ensures only one active socket per user.
Note: The data parameter must be a JSON string containing the userId.

await socketManager.register(socket, JSON.stringify({ userId: "user1" }));

Parameters:

• socket: The socket instance.
• data: A JSON string containing the userId.

deRegister

De-registers a socket for a user.

socketManager.deRegister(socket);

Parameters:

• socket: The socket instance to deregister.

inform

Emits an event to a specific socket.

socketManager.inform({
    socketId: "socket1",
    _event: "message",
    data: { message: "Hello, User!" },
});

Parameters:

• socketId: ID of the socket to emit the event to.
• _event: Event name.
• data: Data to send with the event.

Example

import { createClient } from "redis";
import { Server as SocketIOServer } from "socket.io";
import { SockManage } from "sockmanage";

const redisClient = createClient();
const io = new SocketIOServer(server);

const socketManager = new SockManage({ redis: redisClient });
socketManager.setup({ io });

// Assuming top-level await is supported, otherwise wrap the following line in an async function
await socketManager.initialize();

io.on("connection", (socket) => {
    // You be getting the userId from anywhere, it doesn't matter where you get it from
    // as long as you pass it to the register method.
    const userId = socket.handshake.query.userId;

    socketManager.register(socket, JSON.stringify({ userId }));

    socket.on("disconnect", () => {
        socketManager.deRegister(socket);
    });

    // this following block is completely optional, you shall proceed with using your own event sending logic
    socket.on("message", (data) => {
        socketManager.inform({
            socketId: socket.id,
            _event: "message",
            data: { message: "Hello, User!" },
        });
    });
});

Testing

To run the tests, use the following command:

yarn test

Changelog

Detailed changes for each version are documented in the History.md file.

License

MIT License. See LICENSE for details.