🌍 mDNS Network Service Discovery in React Native

This library allows you to discover services on your local network using mDNS (DNS-SD, Bonjour, Zeroconf, Avahi, ...). Devices that support service discovery include printers, webcams, HTTPS servers, and other mobile devices. The library uses NSNetServiceBrowser on iOS and NsdManager on Android.

Installation

npm install @inthepocket/react-native-service-discovery

Add the services you want to search for in Info.plist:

<key>NSBonjourServices</key>
<array>
  <!-- Change to your services -->
  <string>_ssh._tcp</string> 
  <string>_http._tcp</string>
</array>

Add a custom Local Network prompt message in Info.plist:

<key>NSLocalNetworkUsageDescription</key>
<string>${PRODUCT_NAME} uses the local network to discover and connect to devices on your Wi-Fi network.</string>

Usage

import * as ServiceDiscovery from '@inthepocket/react-native-service-discovery';

const foundListener = ServiceDiscovery.addEventListener('serviceFound', (service) => {
  console.log('Service found:', service);
});

const lostListener = ServiceDiscovery.addEventListener('serviceLost', (service) => {
  console.log('Service lost:', service);
});

// Start searching for _http._tcp. services
await ServiceDiscovery.startSearch('http');

// ...
await ServiceDiscovery.stopSearch('http');
foundListener.remove();
lostListener.remove();

startSearch

Start searching for services of a specific type. Searching for multiple services can be done in parallel.

Parameter	Type	Description
type	string	The service type to search for, e.g. 'http'. The device will search for services of type _serviceType._tcp..

Returns

Promise<void> - Resolves when the search has started. Rejects when the search could not be started.

stopSearch

Stop searching for a specific service. This will not stop searching for any other services that are being searched for.

Parameter	Type	Description
type	string	The service type to stop searching for, e.g. 'http'.

Returns

Promise<void> - Resolves when the search has stopped. Rejects when the search could not be stopped. Does not reject when the search was already stopped or was not started in the first place.

addEventListener

Parameter	Type	Description
event	'serviceFound' | 'serviceLost'	Start listening for found or lost services.
listener	(service: Service) => void	The listener that will be called when a service is found or lost.

Returns

An EmitterSubscription that can be used to remove the listener, by calling remove().

Service

Attribute	Type	Description
name	string	Service name.
type	string	Service type, e.g. _http._tcp..
domain	string	Domain, can be local. or any other domain.
hostName	string	The domain name of the IP advertising the service. On local networks this is usually the host name.
addresses	string[]	The IP addresses of the service. This is an array of IPv4 and IPv6 addresses.
port	number	The port number where the service can be reached.
txt	Record<string, string>	The TXT record of the service. The TXT record gives additional information about the service.

Listening for multiple service types

You can listen for multiple service types with the same listener:

import * as ServiceDiscovery from '@inthepocket/react-native-service-discovery';

ServiceDiscovery.addEventListener('serviceFound', (service) => {
  if(service.type === '_http._tcp.') {
    console.log('HTTP service found:', service);
  } else if(service.type === '_ssh._tcp.') {
    console.log('SSH service found:', service);
  }
});

await ServiceDiscovery.startSearch('http');
await ServiceDiscovery.startSearch('ssh');

Contributing

See the contributing guide to learn how to contribute to the repository and the development workflow.

License

MIT

---

Many thanks to

• react-native-dnssd
• create-react-native-library