Qt SCXML FTP Client Example

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 #include "ftpdatachannel.h"

 FtpDataChannel::FtpDataChannel(QObject *parent) : QObject(parent)
 {
     connect(&m_server, &QTcpServer::newConnection, this, [this]() {
         m_socket.reset(m_server.nextPendingConnection());
         connect(m_socket.data(), &QTcpSocket::readyRead, [this]() {
             emit dataReceived(m_socket->readAll());
         });
     });
 }

 void FtpDataChannel::listen(const QHostAddress &address)
 {
     m_server.listen(address);
 }

 void FtpDataChannel::sendData(const QByteArray &data)
 {
     if (m_socket)
         m_socket->write(QByteArray(data).replace("\n", "\r\n"));
 }

 void FtpDataChannel::close()
 {
     if (m_socket)
         m_socket->disconnectFromHost();
 }

 QString FtpDataChannel::portspec() const
 {
     // Yes, this is a weird format, but say hello to FTP.
     QString portSpec;
     quint32 ipv4 = m_server.serverAddress().toIPv4Address();
     quint16 port = m_server.serverPort();
     portSpec += QString::number((ipv4 & 0xff000000) >> 24);
     portSpec += ',' + QString::number((ipv4 & 0x00ff0000) >> 16);
     portSpec += ',' + QString::number((ipv4 & 0x0000ff00) >> 8);
     portSpec += ',' + QString::number(ipv4 & 0x000000ff);
     portSpec += ',' + QString::number((port & 0xff00) >> 8);
     portSpec += ',' + QString::number(port &0x00ff);
     return portSpec;
 }