WebSocketException: Connection not upgraded to websocket

[austin047]

I am attempting to connect to a WebSocket API delivered via the AWS API gateway, currently, I am able to establish a successful connection via PostMan and Python scripts ran from my local terminal, but when I attempt a connection with dart I keep getting this error of WebSocketException: Connection was not upgraded to websocket

My code

main() async {
  final wsUrl = Uri.parse('wss://xxxxxxxxxx.execute-api.eu-west-1.amazonaws.com/qa');
  final channel = IOWebSocketChannel.connect(wsUrl);

  // await channel.ready;

  channel.stream.listen((message) {
    print(message);
    channel.sink.add('received!');
  });
}

Error:

Unhandled exception:
WebSocketChannelException: WebSocketChannelException: WebSocketException: Connection to 'https://xxxxxxxxxx.execute-api.eu-west-1.amazonaws.com:0/qa#' was not upgraded to websocket
#0      new IOWebSocketChannel._withoutSocket.<anonymous closure> (package:web_socket_channel/io.dart:98:24)
#1      Stream.handleError.<anonymous closure> (dart:async/stream.dart:931:16)
#2      _HandleErrorStream._handleError (dart:async/stream_pipe.dart:269:17)
#3      _ForwardingStreamSubscription._handleError (dart:async/stream_pipe.dart:157:13)
#4      _RootZone.runBinaryGuarded (dart:async/zone.dart:1606:10)
#5      _BufferingStreamSubscription._sendError.sendError (dart:async/stream_impl.dart:358:15)
#6      _BufferingStreamSubscription._sendError (dart:async/stream_impl.dart:376:7)
#7      _BufferingStreamSubscription._addError (dart:async/stream_impl.dart:280:7)
#8      _SyncStreamControllerDispatch._sendError (dart:async/stream_controller.dart:788:19)
#9      _StreamController._addError (dart:async/stream_controller.dart:666:7)
#10     _RootZone.runBinaryGuarded (dart:async/zone.dart:1606:10)
#11     _BufferingStreamSubscription._sendError.sendError (dart:async/stream_impl.dart:358:15)
#12     _BufferingStreamSubscription._sendError (dart:async/stream_impl.dart:376:7)
#13     _BufferingStreamSubscription._addError (dart:async/stream_impl.dart:280:7)
#14     _SyncStreamControllerDispatch._sendError (dart:async/stream_controller.dart:788:19)
#15     _StreamController._addError (dart:async/stream_controller.dart:666:7)
#16     new Stream.fromFuture.<anonymous closure> (dart:async/stream.dart:253:18)
#17     _RootZone.runBinary (dart:async/zone.dart:1666:54)
#18     _FutureListener.handleError (dart:async/future_impl.dart:177:22)
#19     Future._propagateToListeners.handleError (dart:async/future_impl.dart:858:47)
#20     Future._propagateToListeners (dart:async/future_impl.dart:879:13)
#21     Future._completeError (dart:async/future_impl.dart:655:5)
#22     Future._asyncCompleteError.<anonymous closure> (dart:async/future_impl.dart:745:7)
#23     _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
#24     _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
#25     _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:118:13)
#26     _Timer._runTimers (dart:isolate-patch/timer_impl.dart:405:11)
#27     _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:429:5)
#28     _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)

Any help on this will be much appreciated

[Avril1]

Please check your server is opening first.
I had the same issue, finally I found that the server was closed.

[austin047]

My server in current up and running, I am able to create a websocket connection via the Postman client and a python script, but not Dart.

[Avril1]

Have you tried this way? I'm using WebSocketChannel.connect(wsUrl).

[austin047]

Yes I have tried that before, it's work aswell.