Upgrade an FTP Control Channel to TLS (ConvertToTls)

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Demonstrates the Chilkat Ftp2.ConvertToTls method, which upgrades an already-connected clear FTP control channel to explicit TLS. It takes no arguments and is used with a manually staged connection created by ConnectOnly while Ssl is disabled.

Background: This exposes the explicit-FTPS AUTH TLS upgrade as a discrete step for the rare case where you need to do something on the clear connection first — inspect the greeting, apply a workaround — before securing it. In the normal case you simply set AuthTls and let Connect perform the upgrade automatically; this manual path exists for staged control.

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bool success = false;

//  Demonstrates the Ftp2.ConvertToTls method, which upgrades an already-connected clear FTP control
//  channel to explicit TLS.  It takes no arguments.  It is used with a manually staged connection
//  created by ConnectOnly while Ssl is disabled.

Chilkat.Ftp2 ftp = new Chilkat.Ftp2();

ftp.Hostname = "ftp.example.com";
ftp.Port = 21;

//  Connect in clear text first (Ssl is false).
success = ftp.ConnectOnly();
if (success == false) {
    Debug.WriteLine(ftp.LastErrorText);
    return;
}

//  Upgrade the control channel to explicit TLS (AUTH TLS).
success = ftp.ConvertToTls();
if (success == false) {
    Debug.WriteLine(ftp.LastErrorText);
    return;
}

//  Now authenticate over the encrypted control channel.
ftp.Username = "myFtpLogin";
ftp.Password = "myPassword";
success = ftp.LoginAfterConnectOnly();
if (success == false) {
    Debug.WriteLine(ftp.LastErrorText);
    return;
}

Debug.WriteLine("Control channel upgraded to TLS and logged in.");

success = ftp.Disconnect();
if (success == false) {
    Debug.WriteLine(ftp.LastErrorText);
    return;
}