socket-io.adapter.ts

import { INestApplicationContext } from '@nestjs/common';
import { IoAdapter } from '@nestjs/platform-socket.io';
import { Server, ServerOptions } from 'socket.io';
import { AppConfigService } from '../config/app-config.service';

/**
 * Socket.IO adapter that sources its CORS policy from configuration, so the
 * WebSocket layer honours the same `CORS_ORIGIN` allow-list as the HTTP layer
 * instead of a hardcoded `origin: true`.
 */
export class ConfiguredIoAdapter extends IoAdapter {
  constructor(
    app: INestApplicationContext,
    private readonly config: AppConfigService,
  ) {
    super(app);
  }

  createIOServer(port: number, options?: ServerOptions): Server {
    return super.createIOServer(port, {
      ...options,
      cors: {
        origin: this.config.corsOrigins,
        credentials: true,
      },
    }) as Server;
  }
}