dns-sd

A powerful, cross-platform DNS-SD (Zeroconf/Bonjour/Avahi) library for Node.js, built with Rust.

dns-sd provides a unified API for discovering and advertising services on the local network. It intelligently selects the best available backend:

• Native: Uses the system's native DNS-SD implementation (Avahi on Linux, Bonjour on macOS/Windows) for optimal performance and compatibility.
• Fallback: Automatically degrades to a pure Rust implementation (mdns-sd) if the native service is unavailable.

Features

• 🚀 High Performance: Native bindings via Neon for low overhead.
• 🔄 Dual Backend: Robust fallback mechanism ensures your app works everywhere.
• 📦 Zero Configuration: Works out of the box without complex setup.
• 📡 Discovery & Advertising: Support for both browsing and publishing services.
• 📝 TypeScript Support: First-class types included.

Installation

npm install dns-sd

Prebuilt binaries are available for major platforms:

• Windows (x64, arm64)
• macOS (x64, arm64)
• Linux (x64, arm64)

Usage

Discover Services

Browsing for services is simple. Use the search method to start listening for services of a specific type.

import DnsSd, { Service } from 'dns-sd';

// Search for HTTP services
const browser = DnsSd.search('_http._tcp');

browser.on('serviceFound', (service: Service) => {
  console.log('Found service:', service.name);
  console.log('IP Addresses:', service.addresses);
  console.log('Port:', service.port);
  if (service.txt) {
    console.log('TXT Records:', service.txt);
  }
});

browser.on('serviceLost', (service: Service) => {
  console.log('Lost service:', service.name);
});

browser.on('error', (err) => {
  console.error('Browser error:', err);
});

// Stop browsing after 30 seconds
setTimeout(() => {
  browser.stop();
}, 30000);

Advertise a Service

Publish your own service to the network using advertise.

import DnsSd, { DnsSdAdvertisement } from 'dns-sd';

const ad = DnsSd.advertise({
  name: 'My Cool Service',
  type: '_http._tcp',
  port: 8080,
  txt: {
    version: '1.0.0',
    path: '/api'
  }
});

ad.on('registered', (name) => {
  console.log(`Service registered successfully as "${name}"`);
});

ad.on('error', (err) => {
  console.error('Advertisement error:', err);
});

// Stop advertising when closing
// ad.stop();

Check Backend

You can check which backend is currently active (dependent on system availability).

import DnsSd from 'dns-sd';

console.log('Current Backend:', DnsSd.getBackendInfo());
// Outputs: "bonjour", "native" (Avahi), or "mdns-sd"

API Reference

DnsSd

The main entry point.

• static search(serviceType: string): DnsSdBrowse: Start a browser for the given service type (e.g., _http._tcp).
• static advertise(options: AdvertiseOptions): DnsSdAdvertisement: Start advertising a service.
• static getBackendInfo(): string: Returns the name of the active backend.

DnsSdBrowse

Emits events for service discovery.

Events:

• 'serviceFound': Emitted when a service is discovered or updated. Payload: Service.
• 'serviceLost': Emitted when a service goes offline. Payload: Service.
• 'error': Emitted on failure. Payload: Error.

Methods:

• stop(): Stops the browser.

DnsSdAdvertisement

Manages a published service.

Events:

• 'registered': Emitted when the service is successfully registered with the daemon. Payload: string (registered name).
• 'error': Emitted on failure. Payload: Error.

Methods:

• stop(): Stops advertising.

Types

Service

interface Service {
  name: string;
  type: string;
  domain: string;
  hostName: string;
  addresses: string[]; // IPv4 and IPv6 addresses
  port: number;
  txt?: Record<string, string>;
  ttl?: number;
}

AdvertiseOptions

interface AdvertiseOptions {
  name: string;
  type: string;
  domain?: string;
  hostName?: string;
  port: number;
  txt?: Record<string, string>;
}

Contributing

This project uses cargo for the Rust backend and npm for the Node.js frontend.

1. Install Dependencies: npm install
2. Build: npm run build
3. Test: npm test

Licensed under MIT.