Air Link Core

The easiest LAN communication framework for Dart & Flutter.

Stop thinking about sockets, packets, and protocols. Start thinking about communication.

await peer.sendText('Hello!');

Quick Start

1. Add the dependency

dependencies:
  air_link_core:
    git:
      url: https://github.com/DarpanAdhikari/air_link_workspace.git
      path: packages/air_link_core

2. Start a host

import 'package:air_link_core/air_link_core.dart';

void main() async {
  final sessions = await Lan.listen(port: 8080);

  sessions.listen((session) {
    print('Peer connected: ${session.peer.id}');

    session.peer.onMessage.listen((message) {
      print('Received: $message');
    });
  });
}

3. Connect from another device

import 'package:air_link_core/air_link_core.dart';

void main() async {
  final session = await Lan.connect('192.168.1.42', port: 8080);

  await session.peer.sendText('Hello from Air Link!');

  session.peer.onMessage.listen((reply) {
    print('Reply: $reply');
  });
}

Core Concepts

Peer

await peer.sendText('Hey!');        // Send text
await peer.sendBytes(myBytes);      // Send raw bytes

peer.onMessage.listen((msg) {});    // Receive text
peer.onBytes.listen((bytes) {});    // Receive bytes
peer.onDisconnected.listen((_) {}); // Detect disconnection

await peer.disconnect();            // Disconnect

Session

final session = await Lan.connect('192.168.1.42');
print(session.connectedAt);
print(session.peer.id);

session.onDisconnected.listen((_) => print('Lost connection'));
session.onReconnected.listen((_) => print('Reconnected'));

await session.end();  // End the session permanently

Lan

// Host: listen for connections
final sessions = await Lan.listen(port: 8080);

// Client: connect to a host
final session = await Lan.connect('192.168.1.42', port: 8080);

// Instance API for multiple listeners
final lan = Lan();
final stream = await lan.bind(port: 8081);
final peer = await lan.dial('10.0.0.5', port: 8082);
await lan.close();

Heartbeat & Reconnect

final session = Session.start(
  'my-peer',
  transport,
  heartbeat: HeartbeatConfig(
    interval: Duration(seconds: 5),
    timeout: Duration(seconds: 3),
  ),
  reconnect: ReconnectPolicy(
    transportFactory: () async { /* rebuild transport */ },
    maxRetries: 3,
    baseDelay: Duration(seconds: 1),
  ),
);

Reliability

Feature Status
TCP stream framing ✅
Packet serialization ✅
Length-prefixed framing ✅
Partial packet buffering ✅
Clean disconnection ✅
Broadcast event streams ✅
Heartbeat keep-alive (PING/PONG) ✅
Stale connection detection ✅
Exponential-backoff reconnect ✅
Reconnect guard (prevents loops) ✅

Package Ecosystem

Package Purpose
air_link_core Connections, peers, sessions, transport
air_link_secure E2EE (ECDSA auth, AES-256-GCM, HKDF)
air_link_discovery Zero-config UDP broadcast discovery
air_link_stream Live data streaming
air_link_file File transfer with progress
air_link_text Rich text messaging
air_link_rpc Request/response RPC
air_link_mesh Multi-hop mesh routing
air_link_bridge HTTP/WebSocket bridge
air_link_sync CRDT state synchronization

Requirements

  • Dart SDK >=3.0.0 <4.0.0

License

MIT

Libraries