Exploring Local Communication in Flutter Apps Using UDP

Aditya Mangal
3 min readDec 4, 2023

Flutter, Google’s UI toolkit for building natively compiled applications for mobile, web, and desktop from a single codebase, has gained immense popularity for its ease of use and flexibility. When it comes to developing applications that require efficient local communication, understanding and implementing protocols like User Datagram Protocol (UDP) can be a game-changer. In this guide, we’ll delve into the world of local communication in Flutter apps using UDP.

Understanding UDP:

User Datagram Protocol (UDP) is a lightweight, connectionless transport layer protocol that operates on top of IP (Internet Protocol). Unlike Transmission Control Protocol (TCP), UDP does not establish a connection before sending data and does not guarantee the delivery of packets. This makes UDP ideal for scenarios where low latency and real-time communication are crucial, such as in local networks.

Setting Up Your Flutter Project:

To get started with local communication using UDP in Flutter, you need to include the dart:io package, which provides classes for networking operations. Open your pubspec.yaml file and add the following dependency:

dependencies:
dart:io: ^2.16.0

Don’t forget to run flutter pub get in your terminal to fetch and install the dependency.

Implementing UDP Socket in Flutter:

Now, let’s create a simple UDP socket in Flutter. We’ll use the RawDatagramSocket class provided by the dart:io package. Here’s a basic example:

import 'dart:io';
void main() async {
// Bind the UDP socket to a specific port
RawDatagramSocket udpSocket = await RawDatagramSocket.bind('127.0.0.1', 12345);
print('UDP socket is bound to ${udpSocket.address.address}:${udpSocket.port}');
// Listen for incoming messages
udpSocket.listen((RawSocketEvent event) {
if (event == RawSocketEvent.read) {
Datagram datagram = udpSocket.receive();
if (datagram != null) {
String message = String.fromCharCodes(datagram.data);
print('Received message: $message');
}
}
});
// Send a message
udpSocket.send('Hello, UDP!'.codeUnits, InternetAddress('127.0.0.1'), 12346);
}

In this example, we create a UDP socket, bind it to a specific IP address and port, listen for incoming messages, and send a message to another UDP socket.

Handling Communication in Flutter Widgets:

To integrate UDP communication into your Flutter app, you can encapsulate the socket logic within a Dart class and use it within your widgets. Consider creating a class that manages the UDP socket and exposes methods for sending and receiving messages.

class UdpCommunication {
RawDatagramSocket udpSocket;
Future<void> initializeSocket() async {
udpSocket = await RawDatagramSocket.bind('127.0.0.1', 12345);
}
void sendMessage(String message, InternetAddress address, int port) {
udpSocket.send(message.codeUnits, address, port);
}
void listenForMessages(Function(String) onMessageReceived) {
udpSocket.listen((RawSocketEvent event) {
if (event == RawSocketEvent.read) {
Datagram datagram = udpSocket.receive();
if (datagram != null) {
String message = String.fromCharCodes(datagram.data);
onMessageReceived(message);
}
}
});
}
}

Now, you can use this class in your Flutter widgets to handle local communication through UDP.

Conclusion:

Implementing local communication with UDP in Flutter provides a lightweight and efficient way to exchange data in real time within a local network. Whether you’re building a multiplayer game, a collaborative application, or any other system that requires low-latency communication, understanding and utilizing UDP in Flutter can significantly enhance the performance of your app. With the provided examples and guidelines, you’re now equipped to integrate UDP communication seamlessly into your Flutter projects. Happy coding!

--

--

Aditya Mangal

My Personal Quote to overcome problems and remove dependencies - "It's not the car, it's the driver who win the race".