Qt SCXML FTP Client Example

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#ifndef FTPDATACHANNEL_H
#define FTPDATACHANNEL_H

#include <QObject>
#include <QScopedPointer>
#include <QTcpServer>
#include <QTcpSocket>

class FtpDataChannel : public QObject
{
    Q_OBJECT
public:
    explicit FtpDataChannel(QObject *parent = nullptr);

    // Listen on a local address.
    void listen(const QHostAddress &address = QHostAddress::Any);

    // Send data over the socket.
    void sendData(const QByteArray &data);

    // Close the connection.
    void close();

    // Retrieve the port specification to be announced on the control channel.
    // Something like "a,b,c,d,xxx,yyy" where
    // - a.b.c.d would be the IP address in decimal/dot notation and
    // - xxx,yyy are the upper and lower 8 bits of the TCP port in decimal
    // (This will only work if the local address we're listening on
    // is actually meaningful)
    QString portspec() const;

signals:

    // The FTP server has sent some data.
    void dataReceived(const QByteArray &data);

private:
    QTcpServer m_server;
    QScopedPointer<QTcpSocket> m_socket;
};

#endif // FTPDATACHANNEL_H