Problems with web_socket_channel under MacOS - flutter

Question

I have the following sample application:
import 'package:flutter/material.dart';
import 'package:web_socket_channel/web_socket_channel.dart';
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({super.key});
#override
Widget build(BuildContext context) {
const title = 'WebSocket Demo';
return const MaterialApp(
title: title,
home: MyHomePage(
title: title,
),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({
super.key,
required this.title,
});
final String title;
#override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
final TextEditingController _controller = TextEditingController();
late final WebSocketChannel _channel;
#override
void initState() {
_channel = WebSocketChannel.connect(
Uri.parse('wss://ws.postman-echo.com/raw'),
);
super.initState();
}
#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: [
Form(
child: TextFormField(
controller: _controller,
decoration: const InputDecoration(labelText: 'Send a message'),
),
),
const SizedBox(height: 24),
StreamBuilder(
stream: _channel.stream,
builder: (context, snapshot) {
return Text(snapshot.hasData ? '${snapshot.data}' : '');
},
)
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _sendMessage,
tooltip: 'Send message',
child: const Icon(Icons.send),
);
}
void _sendMessage() {
if (_controller.text.isNotEmpty) {
_channel.sink.add(_controller.text);
}
}
#override
void dispose() {
_channel.sink.close();
_controller.dispose();
super.dispose();
}
}
everything works fine when run on iOS simulator, in Android emulator and in Chrome. However, same code run as MacOS app doesn't work!
Do I have to change anything in the configuration of the desktop app? Anything in plist.info? Runner Workspace? Anywhere else?
Here is my flutter configuration:
[✓] Flutter (Channel stable, 3.3.3, on macOS 12.6 21G115 darwin-arm, locale de-DE)
[✓] Android toolchain - develop for Android devices (Android SDK version 32.1.0-rc1)
[✓] Xcode - develop for iOS and macOS (Xcode 14.0.1)
Any idea what's going wrong?

Answer 1

I faced quite a similar issue. I make an app using web socket on flutter.
Although I use different web socket library (websocket_universal), it works on iOS and web but not on MacOS.
I follow this comment and it works for my case.
https://github.com/flutter/flutter/issues/47606#issuecomment-568522318
Add
<key>com.apple.security.network.client</key>
<true/>
to file DebugProfile.entitlements under directory macos/Runner/