TcpEvents

Kind: Type

Source: packages/microservices/events/tcp.events.ts

Part of: Microservices

TCP events map for the net TCP socket. Key is the event name and value is the corresponding callback function.

TcpEvents defines the event-to-callback map used by the microservices TCP transport. It connects Node.js net.Socket lifecycle and data events—such as incoming data, connection errors, and socket closure—to the handlers responsible for processing them.

Definition

ts
{ error: OnErrorCallback; connect: VoidCallback; end: VoidCallback; close: VoidCallback; timeout: VoidCallback; drain: VoidCallback; lookup: OnLookupCallback; }

Diagram

mermaid
graph LR
  Socket[net.Socket] -->|data| DataHandler[TcpEvents.data callback]
  Socket -->|error| ErrorHandler[TcpEvents.error callback]
  Socket -->|close| CloseHandler[TcpEvents.close callback]

  DataHandler --> Transport[TCP transport processing]
  ErrorHandler --> Transport
  CloseHandler --> Transport

Usage

ts
import type { Socket } from 'node:net';
import type { TcpEvents } from './tcp.events';

function registerSocketEvents(socket: Socket, events: TcpEvents): void {
  for (const [eventName, callback] of Object.entries(events)) {
    socket.on(eventName, callback);
  }
}

const events: TcpEvents = {
  data: (chunk: Buffer) => {
    console.log('Received TCP payload:', chunk.toString());
  },
  error: (error: Error) => {
    console.error('TCP socket error:', error);
  },
  close: () => {
    console.log('TCP socket closed');
  },
};

registerSocketEvents(socket, events);

AI Coding Instructions

• Keep event keys aligned with supported Node.js net.Socket event names and ensure each callback matches that event's argument signature.
• Always provide an error handler when registering TCP socket events to prevent unhandled socket errors.
• Treat data payloads as stream chunks; buffer and frame them when application messages may span multiple chunks.
• Remove listeners or release associated connection state after close to avoid memory leaks.
• Register TcpEvents handlers immediately after creating or accepting a socket, before writing application data.