openStreamingConnection method

Future<void> openStreamingConnection({ bool disconnectOnLostInternetConnection = true, })

Open a streaming connection to the server.

Implementation

Future<void> openStreamingConnection({
  bool disconnectOnLostInternetConnection = true,
}) async {
  if (_webSocket != null) return;
  if (disconnectOnLostInternetConnection) {
    assert(
      _connectivityMonitor != null,
      'To enable automatic disconnect on lost internet connection, you need to set the connectivityMonitor propery.',
    );
  }
  _disconnectOnLostInternetConnection = disconnectOnLostInternetConnection;

  try {
    // Connect to the server.
    _firstMessageReceived = false;
    var host = await websocketHost;
    _webSocket = WebSocketChannel.connect(Uri.parse(host));

    // We are sending the ping message to the server, so that we are
    // guaranteed to get a first message in return. This will verify that we
    // have an open connection to the server.
    await _sendControlCommandToStream('ping');
    unawaited(_listenToWebSocketStream());

    // Time out and close the connection if we haven't got a pong response
    // within the timeout period.
    _connectionTimer = Timer(streamingConnectionTimeout, () async {
      if (!_firstMessageReceived) {
        await _webSocket?.sink.close();
        _webSocket = null;
        _cancelConnectionTimer();
        _notifyWebSocketConnectionStatusListeners();
      }
    });
  } catch (e) {
    _webSocket = null;
    _cancelConnectionTimer();
    rethrow;
  }

  // If everything is going according to plan, we are now connected to the
  // server.
  _notifyWebSocketConnectionStatusListeners();
}