Using Socket in Flutter apps?
As attdona mentioned,
Your server does not speak the websocket protocol but it exposes a plain tcp socket.
So you need a TCP socket and there is a great tutorial on Sockets
and ServerSockets
which you can find here.
Here's a snippet:
import 'dart:io';
import 'dart:async';
Socket socket;
void main() {
Socket.connect("localhost", 4567).then((Socket sock) {
socket = sock;
socket.listen(dataHandler,
onError: errorHandler,
onDone: doneHandler,
cancelOnError: false);
}).catchError((AsyncError e) {
print("Unable to connect: $e");
});
//Connect standard in to the socket
stdin.listen((data) => socket.write(new String.fromCharCodes(data).trim() + '\n'));
}
void dataHandler(data){
print(new String.fromCharCodes(data).trim());
}
void errorHandler(error, StackTrace trace){
print(error);
}
void doneHandler(){
socket.destroy();
}
Your server does not speak the websocket protocol but it exposes a plain tcp socket.
This is an example that works with a plain tcp socket, adapted from https://flutter.io/cookbook/networking/web-sockets flutter cookbook example:
import 'package:flutter/foundation.dart';
import 'dart:io';
import 'package:flutter/material.dart';
void main() async {
// modify with your true address/port
Socket sock = await Socket.connect('192.168.1.129', 10000);
runApp(MyApp(sock));
}
class MyApp extends StatelessWidget {
Socket socket;
MyApp(Socket s) {
this.socket = s;
}
@override
Widget build(BuildContext context) {
final title = 'TcpSocket Demo';
return MaterialApp(
title: title,
home: MyHomePage(
title: title,
channel: socket,
),
);
}
}
class MyHomePage extends StatefulWidget {
final String title;
final Socket channel;
MyHomePage({Key key, @required this.title, @required this.channel})
: super(key: key);
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
TextEditingController _controller = TextEditingController();
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Padding(
padding: const EdgeInsets.all(20.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Form(
child: TextFormField(
controller: _controller,
decoration: InputDecoration(labelText: 'Send a message'),
),
),
StreamBuilder(
stream: widget.channel,
builder: (context, snapshot) {
return Padding(
padding: const EdgeInsets.symmetric(vertical: 24.0),
child: Text(snapshot.hasData
? '${String.fromCharCodes(snapshot.data)}'
: ''),
);
},
)
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _sendMessage,
tooltip: 'Send message',
child: Icon(Icons.send),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
void _sendMessage() {
if (_controller.text.isNotEmpty) {
widget.channel.write(_controller.text);
}
}
@override
void dispose() {
widget.channel.close();
super.dispose();
}
}