NestGateway

Kind: Interface

Source: packages/websockets/interfaces/nest-gateway.interface.ts

Part of: Websockets

NestGateway defines lifecycle hooks for WebSocket gateway classes in NestJS. Implement these optional methods to access the initialized server, react to client connections, and clean up when clients disconnect.

Properties

Diagram

mermaid
graph LR
  A[WebSocket Server Initialized] --> B[afterInit(server)]
  B --> C[Client Connects]
  C --> D[handleConnection(...args)]
  D --> E[Client Disconnects]
  E --> F[handleDisconnect(client)]

Usage

ts
import { WebSocketGateway } from '@nestjs/websockets';
import type { NestGateway } from '@nestjs/websockets';

@WebSocketGateway()
export class EventsGateway implements NestGateway {
  afterInit(server: any): void {
    console.log('WebSocket server initialized');
  }

  handleConnection(client: any, ...args: any[]): void {
    console.log(`Client connected: ${client.id}`);
  }

  handleDisconnect(client: any): void {
    console.log(`Client disconnected: ${client.id}`);
  }
}

AI Coding Instructions

• Implement NestGateway on classes decorated with @WebSocketGateway() when lifecycle callbacks are needed.
• Use afterInit to configure or inspect the underlying WebSocket server after it is created.
• Keep handleConnection(...args) flexible because adapter-specific connection arguments may follow the client object.
• Release client-specific resources, subscriptions, and session state in handleDisconnect.
• Avoid assuming a specific client or server API when supporting multiple WebSocket adapters; narrow any values to the adapter type in use.