internalConnect method

@override Future<MqttConnectionStatus> internalConnect(String? hostname, int? port, MqttConnectMessage? connectMessage)

Synchronously connect to the specific Mqtt Connection.

Implementation

@override
Future<MqttConnectionStatus> internalConnect(
    String? hostname, int? port, MqttConnectMessage? connectMessage) async {
  var connectionAttempts = 0;
  MqttLogger.log(
      'MqttSynchronousMqttBrowserConnectionHandler::internalConnect entered');
  do {
    // Initiate the connection
    MqttLogger.log(
        'MqttSynchronousMqttBrowserConnectionHandler::internalConnect - '
        'initiating connection try $connectionAttempts, auto reconnect in progress $autoReconnectInProgress');
    connectionStatus.state = MqttConnectionState.connecting;
    // Don't reallocate the connection if this is an auto reconnect
    if (!autoReconnectInProgress!) {
      connection = MqttBrowserWsConnection(clientEventBus);
      if (websocketProtocols != null) {
        connection.protocols = websocketProtocols;
      }
      connection.onDisconnected = onDisconnected;
    }
    // Connect
    try {
      if (!autoReconnectInProgress!) {
        MqttLogger.log(
            'MqttSynchronousMqttBrowserConnectionHandler::internalConnect - calling connect');
        await connection.connect(hostname, port);
      } else {
        MqttLogger.log(
            'MqttSynchronousMqttBrowserConnectionHandler::internalConnect - calling connectAuto');
        await connection.connectAuto(hostname, port);
      }
    } on Exception {
      // Ignore exceptions in an auto reconnect sequence
      if (autoReconnectInProgress!) {
        MqttLogger.log(
            'MqttSynchronousMqttBrowserConnectionHandler::internalConnect'
            ' exception thrown during auto reconnect - ignoring');
      } else {
        rethrow;
      }
    }
    MqttLogger.log(
        'MqttSynchronousMqttBrowserConnectionHandler::internalConnect - '
        'connection complete');
    // Transmit the required connection message to the broker.
    MqttLogger.log(
        'MqttSynchronousMqttBrowserConnectionHandler::internalConnect '
        'sending connect message');
    sendMessage(connectMessage!);
    MqttLogger.log(
        'MqttSynchronousMqttBrowserConnectionHandler::internalConnect - '
        'pre sleep, state = $connectionStatus');
    // We're the sync connection handler so we need to wait for the
    // brokers acknowledgement of the connections
    await connectTimer.sleep();
    MqttLogger.log(
        'MqttSynchronousMqttBrowserConnectionHandler::internalConnect - '
        'post sleep, state = $connectionStatus');
  } while (connectionStatus.state != MqttConnectionState.connected &&
      ++connectionAttempts < maxConnectionAttempts!);
  // If we've failed to handshake with the broker, throw an exception.
  if (connectionStatus.state != MqttConnectionState.connected) {
    if (!autoReconnectInProgress!) {
      MqttLogger.log(
          'MqttSynchronousMqttBrowserConnectionHandler::internalConnect failed');
      if (connectionStatus.reasonCode == MqttConnectReasonCode.notSet) {
        throw MqttNoConnectionException(
            'The maximum allowed connection attempts '
            '({$maxConnectionAttempts}) were exceeded. '
            'The broker is not responding to the connection request message '
            '(Missing Connection Acknowledgement?');
      } else {
        throw MqttNoConnectionException(
            'The maximum allowed connection attempts '
            '({$maxConnectionAttempts}) were exceeded. '
            'The broker is not responding to the connection request message correctly '
            'The reason code is ${mqttConnectReasonCode.asString(connectionStatus.reasonCode)}');
      }
    }
  }
  MqttLogger.log(
      'MqttSynchronousMqttBrowserConnectionHandler::internalConnect '
      'exited with state $connectionStatus');
  initialConnectionComplete = true;
  return connectionStatus;
}