I have an angular SPA application running on port 4200 http://localhost:4200. I’m forwarding my NestJS api using proxy.conf.js :

  '/api': {
    secure: false,
    target: `http://localhost:3000`,
    headers: { 'X-Forwarded-Host': process.env.X_Forwarded_Host },
    ws: true,
  },
};

All basic HTTP routes are working. For example http://localhost:3000/health and http://localhost:4200/api/health are working correctly.

But for WS, http://localhost:3000/socket.io is working, but http://localhost:4200/api/socket.io is not. I’m having a timeout without any error (no CORS errors for example)

I am missing something ? Here is my WebsocketGateway declaration in NestJS:

@WebSocketGateway({
  cors: {
    origin: [process.env.PWA_URL],
    credentials: true,
  },
})

PWA_URL is http://localhost:4200.

I need to acces my Websocket app using http://localhost:4200 because my production environment only expose the public facing PWA application. My API is only accessible from this port-forwarding.

Thanks a lot for your help !