access-socketio-from-another-file

// utils/socket-io.service.ts

// utils/socket-io.service.ts

import {Server, ServerOptions} from "socket.io";
import {Server as HttpServer} from "http";

export class SocketIOService {
  private static _instance: SocketIOService | undefined;
  private static server: Server | undefined;

  private constructor() {
    // Private constructor ensures singleton instance
  }

  static instance(): SocketIOService {
    if (!this._instance) {
      return new SocketIOService();
    }

    return this._instance;
  }

  initialize(httpServer: HttpServer, opts?: Partial<ServerOptions>) {
    SocketIOService.server = new Server(httpServer, opts);

    return SocketIOService.server;
  }

  ready() {
    return SocketIOService.server !== null;
  }

  getServer(): Server {
    if (!SocketIOService.server) {
      throw new Error('IO server requested before initialization');
    }

    return SocketIOService.server;
  }

  sendMessage(roomId: string | string[], key: string, message: string) {
    this.getServer().to(roomId).emit(key, message)
  }

  emitAll(key: string, message: string) {
    this.getServer().emit(key, message)
  }

  getRooms() {
    return this.getServer().sockets.adapter.rooms;
  }
}

The service must be initialized before use:

// app.ts
import express from "express";
import log from "./logger";
import cors from "cors";
import {createServer} from "http";
import {SocketIOService} from "./utils/socket-io.service";


const app = express();
const httpServer = createServer(app);

SocketIOService.instance().initialize(httpServer, {
  cors: {
    origin: ['http://localhost:4200']
  }
});

const io = SocketIOService.instance().getServer();

io.on('connection', (socket) => {
  log.info('a user connected');

  socket.on('disconnect', () => {
    log.info('user disconnected');
  });

  socket.on('my message', (msg) => {
    console.log('message: ' + msg);

    io.emit('my broadcast', `server: ${msg}`);
  });

  socket.on('room_update', (msg) => {
    console.log('message: ' + msg);
  })
});

// ...

And then to call the service from another file (e.g. a HTTP Handler)

import {SocketIOService} from "../utils/socket-io.service";
import log from "../logger";

function notifyUpdatedRoom(roomId: string) {
  log.info(`Notifying on updated room: ${roomId}`);

  if (roomId && SocketIOService.instance().ready()) {
    SocketIOService.instance().emitAll('room_update', roomId);
  }
}

source: https://stackoverflow.com/a/69587948/10791809

murprakoso/access-socketio-from-another-file.md