Delphi ActiveX

Upgrade an FTP Control Channel to TLS (ConvertToTls)

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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var
success: Integer;
ftp: TChilkatFtp2;

begin
success := 0;

//  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.

ftp := TChilkatFtp2.Create(Self);

ftp.Hostname := 'ftp.example.com';
ftp.Port := 21;

//  Connect in clear text first (Ssl is false).
success := ftp.ConnectOnly();
if (success = 0) then
  begin
    Memo1.Lines.Add(ftp.LastErrorText);
    Exit;
  end;

//  Upgrade the control channel to explicit TLS (AUTH TLS).
success := ftp.ConvertToTls();
if (success = 0) then
  begin
    Memo1.Lines.Add(ftp.LastErrorText);
    Exit;
  end;

//  Now authenticate over the encrypted control channel.
ftp.Username := 'myFtpLogin';
ftp.Password := 'myPassword';
success := ftp.LoginAfterConnectOnly();
if (success = 0) then
  begin
    Memo1.Lines.Add(ftp.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add('Control channel upgraded to TLS and logged in.');

success := ftp.Disconnect();
if (success = 0) then
  begin
    Memo1.Lines.Add(ftp.LastErrorText);
    Exit;
  end;