Flutter cannot connect to AWS with Web Socket Channel - amazon-web-services

Question

I'm writing a program that required connecting to a Web Server using the Web Socket Channel package. I am following the guide https://flutter.dev/docs/cookbook/networking/web-sockets to connect to an AWS Server. The link is something like this:
wss://xxxxxxx.execute-api.ap-southeast-1.amazonaws.com/dev/
Using the package I was able to connect and get the connectionState.waiting, but I cannot seem to listen to any data from the server nor send data to the server. For the data send, the format is below:
Map message = {
"action": 'subscribe',
"channel": 'contentTest',
};
channel.sink.add(jsonEncode(message));
The rest of my code is similar to the guide, however the server does not seem to receive any data and neither can my client. Can anyone share a working example for above problem? Thank you in advance.

Answer 1

I have a working example to share, you can see how the connection is done and the message is sent, this example is using the WebSocket class in dart:io. When I was coding this I had some issues with Web Socket Channel, can't remember why, so I opted for Dart WebSocket class.
Future<WatchResponse> WatchCollection(
CollectionRequest collectionRequest, String token) async {
try {
WebSocket ws = await WebSocket.connect(
"ws://${this.authority}/gapi/collection/watch?token=$token");
if (ws.readyState == WebSocket.open) {
ws.add(jsonEncode(collectionRequest.toMap()));
return WatchResponse(ok: true, streamSubscription: ws.listen(null));
}
} on WebSocketException catch (err) {
return WatchResponse(ok: false, webSocketExecption: err);
}
return WatchResponse(ok: false, webSocketExecption: null);
}