Nestjs server does not serve socket.io client

Question

I have a split app using nestjs on the server and an Angular app as the client. Setting up websockets with socket.io seemed pretty easy using the @nestjs/websockets module and on the client I used ngx-socket-io. I used this repo as basis. Now when I update the project's @nestjs/websockets dependency to the latest version I get

• CORS errors and
• an error that the client couldn't load the socket.io client js file

I expected CORS problems and after the update, I could fix them by adding

  app.enableCors({
    origin: 'http://localhost:4200',
    credentials: true,
  });

to my main.ts file, but I don't know why the client file is not served. With the version of the repo (5.7.x) there are neither CORS errors nor problems with serving the file.

I tried a couple of settings of @WebSocketGateway(), moving to a different port, setting serveClient (even though it should be true by default), but nothing seemed to work. Any advice?

thanks

Answer 1

In my case I replaced

app.useWebSocketAdapter(new WsAdapter(app));

from

import { WsAdapter } from '@nestjs/platform-ws';

with

app.useWebSocketAdapter(new IoAdapter(app));

in main .ts from

import { IoAdapter } from '@nestjs/platform-socket.io';

Worked like a charm!

Answer 2

The problem was that nestjs did separate the lower level platform (socket.io, express, fastify, ...) from the nestjs modules. The websocket module requires to install an underlying platform, for socket.io

npm install --save @nestjs/platform-socket.io

To serve the socket.io client file it seems like there also needs to be an HTTP platform installed, for express

npm install --save @nestjs/platform-express

More info in the migration guide for v6.