internalConnect method

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

Synchronously connect to the specific Mqtt Connection.

Implementation

@override
Future<MqttClientConnectionStatus> internalConnect(
  String hostname,
  int port,
  MqttConnectMessage? connectMessage,
) async {
  var connectionAttempts = 0;
  MqttLogger.log(
    'SynchronousMqttBrowserConnectionHandler::internalConnect entered',
  );
  do {
    // Initiate the connection
    MqttLogger.log(
      'SynchronousMqttBrowserConnectionHandler::internalConnect - '
      'initiating connection try $connectionAttempts, auto reconnect in progress $autoReconnectInProgress',
    );
    connectionStatus.state = MqttConnectionState.connecting;
    connectionStatus.returnCode = MqttConnectReturnCode.noneSpecified;
    // Don't reallocate the connection if this is an auto reconnect
    if (!autoReconnectInProgress) {
      final connection = MqttBrowserWsConnection(clientEventBus);

      final websocketProtocols = this.websocketProtocols;
      if (websocketProtocols != null) {
        connection.protocols = websocketProtocols;
      }
      connection.onDisconnected = onDisconnected;

      this.connection = connection;
    }
    // Connect
    try {
      if (!autoReconnectInProgress) {
        MqttLogger.log(
          'SynchronousMqttBrowserConnectionHandler::internalConnect - calling connect',
        );
        await connection.connect(hostname, port);
      } else {
        MqttLogger.log(
          'SynchronousMqttBrowserConnectionHandler::internalConnect - calling connectAuto',
        );
        await connection.connectAuto(hostname, port);
      }
    } on Exception {
      // Ignore exceptions in an auto reconnect sequence
      if (autoReconnectInProgress) {
        MqttLogger.log(
          'SynchronousMqttBrowserConnectionHandler::internalConnect'
          ' exception thrown during auto reconnect - ignoring',
        );
      } else {
        rethrow;
      }
    }
    MqttLogger.log(
      'SynchronousMqttBrowserConnectionHandler::internalConnect - '
      'connection complete',
    );
    // Transmit the required connection message to the broker.
    MqttLogger.log(
      'SynchronousMqttBrowserConnectionHandler::internalConnect '
      'sending connect message',
    );
    sendMessage(connectMessage);
    MqttLogger.log(
      'SynchronousMqttBrowserConnectionHandler::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();
    connectionAttempts++;
    MqttLogger.log(
      'SynchronousMqttBrowserConnectionHandler::internalConnect - '
      'post sleep, state = $connectionStatus',
    );
    if (connectionStatus.state != MqttConnectionState.connected) {
      if (!autoReconnectInProgress) {
        MqttLogger.log(
          'SynchronousMqttBrowserConnectionHandler::internalConnect failed, attempt $connectionAttempts',
        );
        if (onFailedConnectionAttempt != null) {
          MqttLogger.log(
            'SynchronousMqttBrowserConnectionHandler::calling onFailedConnectionAttempt',
          );
          onFailedConnectionAttempt!(connectionAttempts);
        }
      }
    }
  } while (connectionStatus.state != MqttConnectionState.connected &&
      connectionAttempts < maxConnectionAttempts!);
  // If we've failed to handshake with the broker, throw an exception.
  if (connectionStatus.state != MqttConnectionState.connected) {
    if (!autoReconnectInProgress) {
      MqttLogger.log(
        'SynchronousMqttBrowserConnectionHandler::internalConnect failed',
      );
      if (onFailedConnectionAttempt == null) {
        if (connectionStatus.returnCode ==
            MqttConnectReturnCode.noneSpecified) {
          throw NoConnectionException(
            'The maximum allowed connection attempts '
            '({$maxConnectionAttempts}) were exceeded. '
            'The broker is not responding to the connection request message '
            '(Missing Connection Acknowledgement?',
          );
        } else {
          throw NoConnectionException(
            'The maximum allowed connection attempts '
            '({$maxConnectionAttempts}) were exceeded. '
            'The broker is not responding to the connection request message correctly '
            'The return code is ${connectionStatus.returnCode}',
          );
        }
      } else {
        connectionStatus.state = MqttConnectionState.faulted;
      }
    }
  }
  MqttLogger.log(
    'SynchronousMqttBrowserConnectionHandler::internalConnect '
    'exited with state $connectionStatus',
  );
  initialConnectionComplete = true;
  return connectionStatus;
}