Gateway Configuration
Configure WebSocket gateways in NestJS, handling connection events, messages, and room management.
Unlocking Real-time with Gateways
Welcome back! In the previous lesson, we learned about WebSockets. Now, let's dive into how NestJS makes real-time communication easy with Gateways.
Think of a Gateway as a special controller for WebSocket connections. It listens for messages from clients and sends responses back, enabling dynamic, two-way communication.
Creating Your First Gateway
To create a Gateway, we use the @WebSocketGateway() decorator. This decorator marks a class as a WebSocket gateway.
By default, NestJS uses Socket.IO. You can specify a port, namespace, or other options. Let's start with a basic gateway:
import { WebSocketGateway,
WebSocketServer } from '@nestjs/websockets';
import { Server } from 'socket.io';
// src/events.gateway.ts
@WebSocketGateway(3001) // Listens on port 3001 for WS
export class EventsGateway {
@WebSocketServer() server: Server;
}
// src/app.module.ts (minimal)
import { Module } from '@nestjs/common';
import { EventsGateway } from './events.gateway';
@Module({
providers: [EventsGateway],
})
export class AppModule {}
// src/main.ts (minimal)
import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
async function bootstrap() {
const app = await NestFactory.create(AppModule);
await app.listen(3000); // HTTP app, WS runs alongside
}
bootstrap();