connect method

@override Future<MqttConnectionStatus?> connect(String server, int port)

Connect

Implementation

@override
Future<MqttConnectionStatus?> connect(String server, int port) {
  final completer = Completer<MqttConnectionStatus?>();
  // Add the port if present
  Uri uri;
  try {
    uri = Uri.parse(server);
  } on Exception {
    final message =
        'MqttBrowserWsConnection::connect - The URI supplied for the WS '
        'connection is not valid - $server';
    throw MqttNoConnectionException(message);
  }
  if (uri.scheme != 'ws' && uri.scheme != 'wss') {
    final message =
        'MqttBrowserWsConnection::connect - The URI supplied for the WS has '
        'an incorrect scheme - $server';
    throw MqttNoConnectionException(message);
  }
  uri = uri.replace(port: port);

  final uriString = uri.toString();
  MqttLogger.log('MqttBrowserWsConnection::connect -  WS URL is $uriString');
  try {
    // Connect and save the socket.
    client = WebSocket(uriString, protocols.map((e) => e.toJS).toList().toJS);
    wsClient.binaryType = 'arraybuffer';
    StreamSubscription<Event>? openEvents;
    StreamSubscription<CloseEvent>? closeEvents;
    StreamSubscription<Event>? errorEvents;
    openEvents = wsClient.onOpen.listen((e) {
      MqttLogger.log('MqttBrowserWsConnection::connect - websocket is open');
      openEvents?.cancel();
      closeEvents?.cancel();
      errorEvents?.cancel();
      _startListening();
      return completer.complete();
    });

    closeEvents = wsClient.onClose.listen((e) {
      MqttLogger.log(
          'MqttBrowserWsConnection::connect - websocket is closed');
      openEvents?.cancel();
      closeEvents?.cancel();
      errorEvents?.cancel();
      return completer.complete(MqttConnectionStatus());
    });
    errorEvents = wsClient.onError.listen((e) {
      MqttLogger.log(
          'MqttBrowserWsConnection::connect - websocket has errored');
      openEvents?.cancel();
      closeEvents?.cancel();
      errorEvents?.cancel();
      return completer.complete(MqttConnectionStatus());
    });
  } on Exception {
    final message =
        'MqttBrowserWsConnection::connect - The connection to the message broker '
        '{$uriString} could not be made.';
    throw MqttNoConnectionException(message);
  }
  MqttLogger.log('MqttBrowserWsConnection::connect - connection is waiting');
  return completer.future;
}