[Library] QFtpCompat – async FTP client for Qt6

[J.Hilk]

Hi all,

while migrating a Qt5 project to Qt6 I ran into the problem – QFtp is gone and QNetworkAccessManager apparently doesn't do FTP anymore. I needed to talk to an embedded PLC over FTP and couldn't find anything that was CMake-ready and covered the commands I needed, so I ended up writing my own.

The API is queue-based and signal-driven like the old QFtp, but it's not a drop-in replacement – URLs are used instead of separate host/port parameters, and credentials are passed via QUrl rather than a dedicated login call.

auto *ftp = new QFtpCompat(this);

connect(ftp, &QFtpCompat::commandFinished, this, [ftp](int, bool error) {
    if (error) qWarning() << ftp->errorString();
});
connect(ftp, &QFtpCompat::listInfo, this, [](const QFtpCompatDirEntry &e) {
    qDebug() << e.name() << e.size();
});

ftp->open(QUrl("ftp://user:pass@192.168.1.1/"));
ftp->list(QUrl("ftp://192.168.1.1/data/"));

QByteArray buf;
ftp->get(QUrl("ftp://192.168.1.1/data/config.cfg"), &buf);
ftp->put(QUrl("ftp://192.168.1.1/data/config.cfg"), buf);

Explicit FTPS (AUTH TLS) and Implicit FTPS are supported as well:

ftp->open(QUrl("ftps://192.168.1.1/"), QFtpCompat::EncryptionMode::Explicit);
connect(ftp, &QFtpCompat::sslErrors, ftp, &QFtpCompat::ignoreSslErrors);

Posting this as-is – it works for my use case and has a small integration test suite, but hasn't seen much use beyond that. Feedback and PRs welcome.

https://github.com/DeiVadder/QFtpCompat

[JonB]

@J.Hilk
Hi there. Excellent stuff for the community, thank you.

I had a brief look through https://github.com/DeiVadder/QFtpCompat text, and some of the code.

If I were to use FTP again --- as I did years ago --- I would "miss" these features:

• NLST command. Clients may map this to a DIR command rather than LIST, IIRC.
• ASCII mode states "Command sent; CRLF normalisation not yet applied". If that means it does not do LF<->CR-LF translation.
• Active rather than just Passive mode.

Just noting these. Quite understand if you want to stop at what you have now. :)

[J.Hilk]

@JonB

Like I said, this is currently just the bare minimum viable project for my port 😄

Feel free to contribute if you'd like ^^
Otherwise, development will probably continue once I have a bit more free time again.

Any help, feedback, or pull requests are always appreciated!