tcp_socket_connection 0.0.6

A flutter package to connect, listen to and send messages over tcp sockets.

tcp_socket_connection

This is a Flutter package that allows you to connect to a socket over the net. All data is then read using UTF-8.

Getting started

To use this plugin, add tcp_socket_connection as a dependency in your pubspec.yaml file.

Main Example

Here is shown an example where a connection is established and the received message is displayed in a Text widget.

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  TcpSocketConnection socketConnection=TcpSocketConnection("192.168.1.113", 10251);
  String message="";

  @override
  void initState() {
    super.initState();
    startConnection();
  }

  //msg is the message received
  void messageReceived(String msg){
    setState(() {
      message=msg;
    });
  }

  //timeout is set to 5000 ms and messageReceived will be called when 'EOF' received
  void startConnection() async{
    await socketConnection.connect(5000, "EOF", messageReceived);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Text(
          'You have received'+ message,
        ),
      ),
    );
  }
}

Usage

First of all declare a new instance of the TcpSocketConnection class:

TcpSocketConnection socketConnection=TcpSocketConnection(IP_ADDRESS, PORT_NUMBER);

Then, to establish a connection it's used the following method:

await socketConnection.connect(TIMEOUT, EOF, CALLBACK_FUNCTION);

The method connect allows you to set a TIMEOUT before finishing attempting to connect, an EOF representing a specific set of characters indicating that the message is finished, a CALLBACK_FUNCTION that is created by the developer and takes a String as parameter. The CALLBACK_FUNCTION will be called when the message is received.

The word await is really important since the connection requires a little bit of time to be initialized. Write that line of code inside an async method to ensure it doesn't impact the UI.

To send a message use the following method:

socketConnection.sendMessage(MESSAGE);

It will automatically append the EOF you specified when calling the connect method at the end of the MESSAGE.

Examples

Imagine you are receiving a String from a server which states "Confirm?%separator%EOF". In order to read it you have to listen to the server asynchronously until you receive the EOF to be sure that the message is finished. After that you have to split the String and keep only the part you need, in this case "Confirm?". This is all done by the connect method in only 1 line of code!

await socketConnection.connect(TIMEOUT, EOF, CALLBACK_FUNCTION);

Imagine you are receiving a String from a server which states "Store%separator%SOME_JSON_DATA%separator%EOF". In order to read it you have to listen to the server asynchronously until you receive the EOF to be sure that the message is finished. After that you have to split the String and keep only the part you need. First of all you have to detect which command is sent by the server, in this case "Store" and then read all the Json data untill it's finished. This is all done by the connectWithCommand method in only 1 line of code!

await socketConnection.connectWithCommand(TIMEOUT, SEPARATOR, EOF, CALLBACK_FUNCTION);