Nest: Inject Websocket into component

[BorntraegerMarc]

I'm submitting a...

[ ] Regression 
[ ] Bug report
[X] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Current behavior

Adding these lines:

@WebSocketServer()
public socketServer: SocketIO.Server;

Results in this.socketServer being null in Components.

It would be awesome if one could get the native web socket server from everywhere. So I do not need to create a Gateway everytime I want to emit a simple message.

Expected behavior

Attribute is not null.

Minimal reproduction of the problem with instructions

@Component()
export class SocketService {
    // Only connections that are correctly authenticated get into this array
    protected authenticatedConnections: Array<SocketConnection> = [];

    // this is the SocketIO server (can be used for emit etc.)
    @WebSocketServer()
    public socketServer: SocketIO.Server;
}

What is the motivation / use case for changing the behavior?

Environment

Nest version: 4.6.7


For Tooling issues:
- Node version: 8  
- Platform:  

Others:

[kamilmysliwiec]

Honestly, it's not that easy. What if someone uses multiple gateways at the same time? IMO, you should inject a gateway to the component instead and pick up the server then.

[shekohex]

I was having the same issue, but i had to inject it in one gateway, that gateway dose not do anything, you can think of it as wrapper around the underlying socket server, and then i used it as a dependency in another gateways. Idk if this the only way to do this, but it works :)

[zry656565]

@kamilmysliwiec hi, I met a problem when I injected a WebSocketGateway. Here's the sample code.

// event.module.ts

import { Module } from '@nestjs/common'

import { EventGateway } from './event.gateway'
import { EventController } from './event.controller'

@Module({
  providers: [EventGateway],
  controllers: [EventController],
})
export class EventModule {}

// event.gateway.ts
import { SubscribeMessage, WebSocketGateway, WebSocketServer, WsResponse } from '@nestjs/websockets'
import { of, from, Observable } from 'rxjs'
import { map } from 'rxjs/operators'
import { Client, Server } from 'socket.io'

export const store: any = {}

@WebSocketGateway()
export class EventGateway {
  @WebSocketServer()
  server!: Server

  @SubscribeMessage('action:join-room')
  joinRoom(client: Client, room_name: string): Observable<WsResponse<string>> {
    const socket = this.server.sockets.connected[client.id]
    console.log(this.server.sockets.connected)     // will print:  { KUTCDbFhek0BS1YCAAAA: { ... }}
    store.server = this.server
    socket.join(room_name)
    return of({ event: 'events', data: 'join room success' })
  }
}

// event.controller.ts
import { Controller, Post, Inject, Body } from '@nestjs/common'
import { EventGateway, store } from './event.gateway'

@Controller()
export class EventController {
  constructor(
    private readonly eventGateway: EventGateway,
  ) {}

  @Post('/v1/broadcast')
  broadcast(@Body() body: string): string {
    console.log(`broadcast something...`)
    if (!store.server) {
      console.log('no server')
    } else {
      console.log(store.server===this.eventGateway.server)
    }
    console.log(this.eventGateway.server.sockets.connected)  // will print `{}`, it's empty
    this.eventGateway.server
      .to('default-room')
      .emit('broadcast', `POST/broadcast is called. ${body}`)
    return 'ok';
  }
}

And my client could connect successfully to gateway, and could receive "join room success" after send action:join-room message.
But when I call that /v1/broadcast api, I found the server injected doesn't equal to that server which I cached in store object, so the .sockets.connected looks different. It's quite weird to me. Is it expected behavior? If yes, how could I get a singleton injectable instance?

[zry656565]

And I tried @shekohex 's solution, to make EventController and EventGateway both depend on a seperated AnotherGateway. And these two injected gateway are still different instances.

[zry656565]

Hi, all.

I used socket.io-redis and socket.io-emitter to solve my problem. I could create a singleton server object by socket.io-redis, and it has same data source with the server created in WebSocketGateway.

[lock[bot]]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.