netlink

A drop-in Flutter widget that discovers servers on the local network over Bonjour/mDNS and saves the selected one locally. Add the dependency, use NetworkConfigScreen — the code stays in the package; nothing is copied into your app.

Install

flutter pub add netlink

Use

import 'package:flutter/material.dart';
import 'package:netlink/netlink.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});
  @override
  Widget build(BuildContext context) {
    return const MaterialApp(home: NetworkConfigScreen());
  }
}

Tap Scan network → discovered servers appear → tap one to save it locally.

Configure

NetworkConfigScreen is a normal widget — configure it via constructor args, no forking required:

NetworkConfigScreen(
  storageKey: 'my_app_server',              // shared_preferences key
  targetName: 'Server',                     // highlight/sort matching names first
  scanTimeout: const Duration(seconds: 6),
  title: 'Pick a server',
  onSaved: (server) {
    // navigate into your app once a server is chosen
    Navigator.of(context).pushReplacementNamed('/home');
  },
)

Read the saved server anywhere:

final saved = await const ServerStore(storageKey: 'my_app_server').load();
if (saved != null) print(saved.url); // e.g. ws://192.168.1.42:8080

Or run discovery yourself:

final devices = await MdnsDiscovery.scan(targetName: 'Server');

Platform setup (required for mDNS)

Android — automatic

The permissions needed for discovery are provided transitively by bonsoir and merged into your app. Nothing to do.

iOS — one manual step

Apple requires the app itself to declare Local Network + Bonjour usage; a package cannot inject this. Add to ios/Runner/Info.plist:

<key>NSLocalNetworkUsageDescription</key>
<string>This app discovers servers on your local network.</string>
<key>NSBonjourServices</key>
<array>
  <string>_ws._tcp</string>
  <string>_http._tcp</string>
</array>

Prefer it automated? The companion netlink_cli package patches Info.plist (and the Android manifest), and wires NetworkConfigScreen as your default route:

dart pub global activate netlink_cli
netlink setup      # or: 4bnetlink setup

Discovered service types

Protocol	mDNS service type	URL scheme
WebSocket	_ws._tcp	ws://
Socket.IO	_http._tcp	http://

Notes

• Discovery uses bonsoir (native NSD / NSNetServiceBrowser), so it works on real iOS devices under Local Network Privacy — the first scan triggers the system permission prompt.
• Run on a real device or two machines on the same Wi-Fi; a server must be advertising _ws._tcp or _http._tcp for anything to appear.