Websocket gateway is registered two times, every events are duplicated.

[SquirrelDeveloper]

Is there an existing issue for this?

• I have searched the existing issues

Current behavior

Hi everyone.

I am following a discussion I had on the NestJS discord server.

I am currently refactoring and migrating my open source project, SquirrelServersManager, to NestJS!
However, I am encountering a problem I cannot solve:

I have one module, called "ssh", that has a websocket gateway. (https://github.com/SquirrelCorporation/SquirrelServersManager/tree/chore-refacto-nestjs/server/src/modules/ssh ; https://github.com/SquirrelCorporation/SquirrelServersManager/blob/chore-refacto-nestjs/server/src/modules/ssh/presentation/gateways/ssh.gateway.ts)

This module is "standalone", its not injected in any other module

However, I am seeing in the logs that the handleConnection methods is called twice (but the client only connect once):

server-1        | SSH Gateway - Connection details: {
server-1        |   id: 'lgFSRJ1pQeQgUDfpAAAL',
server-1        |   nsp: '/ssh',
server-1        |   connected: true,
server-1        |   rooms: [ 'lgFSRJ1pQeQgUDfpAAAL' ]
server-1        | }
server-1        | SSH Gateway - Connection details: {
server-1        |   id: 'lgFSRJ1pQeQgUDfpAAAL',
server-1        |   nsp: '/ssh',
server-1        |   connected: true,
server-1        |   rooms: [ 'lgFSRJ1pQeQgUDfpAAAL' ]
server-1        | }

I tried a lots of stuff:

• Putting the module Global (didn't change anything)
• Having a different chain dependency, no luck either
• Having the gateway in a separate module

What am I missing? I am pretty sure that the module is not explicitely imported two times, however, the logs say the contrary

Minimum reproduction code

https://github.com/SquirrelCorporation/SquirrelServersManager/blob/chore-refacto-nestjs/server/src/modules/ssh/presentation/gateways/ssh.gateway.ts

Steps to reproduce

No response

Expected behavior

Gateway should only be registered once.

Package

• I don't know. Or some 3rd-party package
• @nestjs/common
• @nestjs/core
• @nestjs/microservices
• @nestjs/platform-express
• @nestjs/platform-fastify
• @nestjs/platform-socket.io
• @nestjs/platform-ws
• @nestjs/testing
• @nestjs/websockets
• Other (see below)

Other package

No response

NestJS version

11.0.11

Packages versions

{
  "name": "ssm-server",
  "description": "SSM Server - A simple way to manage all your servers",
  "main": "main.ts",
  "license": "AGPL-3.0 license",
  "scripts": {
    "dev": "nodemon",
    "dev:nest": "nest start --watch",
    "dev:fast": "NODE_ENV=development ts-node-dev --respawn --transpile-only --require tsconfig-paths/register --watch src --clear src/main.ts",
    "start": "npm run build-shared && npm run build && cross-env NODE_ENV=production node -r tsconfig-paths/register dist/index.js",
    "build": "nest build",
    "test": "vitest run",
    "test:python:install": "PIP_BREAK_SYSTEM_PACKAGES=1 pip install -r ./src/ansible/requirements.txt",
    "test:python": "npm run test:python:install && npm run test:python:run",
    "test:python:run": "cd ./src/ansible && python3 -m unittest discover -s . -p \"*.py\"",
    "test:dev": "vitest --disable-console-intercept",
    "coverage": "vitest run --coverage"
  },
  "version": "0.1.31",
  "author": "Squirrel Team",
  "dependencies": {
    "@aws-sdk/client-ecr": "^3.750.0",
    "@nestjs/axios": "^4.0.0",
    "@nestjs/cache-manager": "^3.0.0",
    "@nestjs/common": "^11.0.11",
    "@nestjs/config": "^4.0.1",
    "@nestjs/core": "^11.0.11",
    "@nestjs/event-emitter": "^3.0.1",
    "@nestjs/mongoose": "^11.0.1",
    "@nestjs/passport": "^11.0.5",
    "@nestjs/platform-express": "^11.0.11",
    "@nestjs/platform-socket.io": "^11.0.11",
    "@nestjs/schedule": "^5.0.1",
    "@nestjs/websockets": "^11.0.11",
    "@nestjs/jwt": "11.0.0",
    "axios": "^1.7.9",
    "bcrypt": "^5.1.1",
    "bull": "^4.16.5",
    "cache-manager": "^6.4.1",
    "cache-manager-redis-store": "^3.0.1",
    "class-transformer": "^0.5.1",
    "class-validator": "^0.14.0",
    "connect-mongo": "^5.1.0",
    "cookie-parser": "^1.4.7",
    "debounce": "^2.2.0",
    "dockerode": "^4.0.4",
    "dockerode-compose": "^1.4.0",
    "dotenv": "^16.4.7",
    "dugite": "^2.7.1",
    "express": "^5.0.1",
    "express-validator": "^7.2.1",
    "fs-extra": "^11.3.0",
    "isomorphic-git": "^1.29.0",
    "joi": "^17.13.3",
    "jsonwebtoken": "^9.0.2",
    "lodash": "^4.17.21",
    "luxon": "^3.5.0",
    "mongoose": "^8.10.1",
    "mongoose-autopopulate": "^1.1.0",
    "multer": "^1.4.5-lts.1",
    "nestjs-pino": "^4.3.1",
    "node-cron": "^3.0.3",
    "node-ssh": "^13.2.0",
    "parse-docker-image-name": "^3.0.0",
    "passport": "^0.7.0",
    "passport-anonymous": "^1.0.1",
    "passport-http": "^0.3.0",
    "passport-http-bearer": "^1.0.1",
    "passport-jwt": "^4.0.1",
    "passport-mock-strategy": "^2.0.0",
    "pino": "^9.6.0",
    "pino-http": "^10.4.0",
    "pino-mongodb": "^4.3.0",
    "pino-pretty": "^13.0.0",
    "posthog-node": "^4.7.0",
    "prom-client": "^15.1.3",
    "prometheus-query": "^3.4.1",
    "redis": "^4.7.0",
    "reflect-metadata": "^0.2.1",
    "rewire": "^7.0.0",
    "rxjs": "^7.8.1",
    "semver": "^7.7.1",
    "shelljs": "^0.8.5",
    "socket.io": "^4.8.1",
    "ssh2": "^1.16.0",
    "ssm-shared-lib": "file:../shared-lib/",
    "yaml": "^2.7.0"
  },
  "overrides": {
    "minimatch": "5.1.2",
    "glob": "8.1.0"
  },
  "devDependencies": {
    "@eslint/compat": "^1.2.7",
    "@eslint/eslintrc": "^3.3.0",
    "@eslint/js": "^9.21.0",
    "@nestjs/testing": "^11.0.11",
    "@stylistic/eslint-plugin": "^4.0.1",
    "@types/bcrypt": "^5.0.2",
    "@types/cookie-parser": "^1.4.8",
    "@types/dockerode": "^3.3.35",
    "@types/dockerode-compose": "^1.4.1",
    "@types/express": "^5.0.0",
    "@types/fs-extra": "^11.0.4",
    "@types/js-yaml": "^4.0.9",
    "@types/jsonwebtoken": "^9.0.9",
    "@types/lodash": "^4.17.15",
    "@types/luxon": "^3.4.2",
    "@types/multer": "^1.4.12",
    "@types/node": "^22.13.9",
    "@types/node-cron": "^3.0.11",
    "@types/node-os-utils": "^1.3.4",
    "@types/passport": "^1.0.17",
    "@types/passport-anonymous": "^1.0.5",
    "@types/passport-http": "^0.3.11",
    "@types/passport-http-bearer": "^1.0.41",
    "@types/passport-jwt": "^4.0.1",
    "@types/shelljs": "^0.8.15",
    "@types/ssh2": "^1.15.4",
    "@types/supertest": "^6.0.2",
    "@types/uuid": "^10.0.0",
    "@typescript-eslint/eslint-plugin": "^8.25.0",
    "@typescript-eslint/parser": "^8.25.0",
    "@vitest/coverage-v8": "^3.0.8",
    "eslint": "^9.21.0",
    "eslint-config-prettier": "^10.0.1",
    "eslint-plugin-import-x": "^4.6.1",
    "eslint-plugin-prettier": "^5.2.3",
    "globals": "^16.0.0",
    "memfs": "^4.17.0",
    "mongodb-memory-server": "^10.1.4",
    "node-mocks-http": "^1.16.2",
    "nodemon": "^3.1.9",
    "prettier": "^3.5.2",
    "supertest": "^7.0.0",
    "ts-node": "^10.9.2",
    "ts-node-dev": "^2.0.0",
    "typescript": "^5.7.3",
    "vitest": "^3.0.8",
    "tsconfig-paths": "^4.0.0"
  }
}

Node.js version

23.8.0

In which operating systems have you tested?

• macOS
• Windows
• Linux

Other

No response

[kamilmysliwiec]

Please provide a minimum reproduction repository (Git repository/StackBlitz/CodeSandbox project).

[kamilmysliwiec]

I tried to reproduce your issue with this very simple setup (following what you have in your repository):

@Injectable()
export class SshTerminalService {
  private readonly logger = new Logger(SshTerminalService.name);

  constructor(
    @Inject(forwardRef(() => EventsGateway))
    private readonly sshGateway,
  ) {}
}

@WebSocketGateway({
  cors: {
    origin: '*',
  },
})
export class EventsGateway {
  private readonly logger = new Logger(EventsGateway.name);

  @WebSocketServer()
  server: Server;

  constructor(
    @Inject(forwardRef(() => SshTerminalService))
    private readonly terminalSvc: SshTerminalService,
  ) {}

  afterInit() {
    this.logger.log(`SSH WebSocket Gateway initialized`);
  }

  handleConnection(client: Socket) {
    // Detailed debugging information
    console.log('SSH Gateway - Connection details:', {
      id: client.id,
      nsp: client.nsp?.name,
      connected: client.connected,
      rooms: Array.from(client.rooms || []),
    });
  }

  handleDisconnect(client: Socket) {
    this.logger.log(`Client disconnected (ssh): ${client.id}`);
  }

  @SubscribeMessage('events')
  findAll(@MessageBody() data: any): Observable<WsResponse<number>> {
    return from([1, 2, 3]).pipe(map(item => ({ event: 'events', data: item })));
  }

  @SubscribeMessage('identity')
  async identity(@MessageBody() data: number): Promise<number> {
    return data;
  }
}

and using 02-gateways sample as the base setup, and I was unable to reproduce your issue