Delphi DLL

Connect to FTP Through a SOCKS Proxy

Demonstrates connecting through a SOCKS proxy using SocksVersion, SocksHostname, SocksPort, SocksUsername, and SocksPassword.

Background: SOCKS is a general-purpose TCP relay, so it carries FTP transparently. SocksVersion is the switch — 0 disables it, while 4 or 5 selects the protocol. SOCKS5 supports username/password authentication and is the usual choice; SOCKS4 supports only a user identifier. Because FTP opens separate data connections, a SOCKS proxy combined with passive mode is generally the most reliable arrangement.

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Delphi DLL

var
success: Boolean;
ftp: HCkFtp2;

begin
success := False;

ftp := CkFtp2_Create();

CkFtp2_putHostname(ftp,'ftp.example.com');
CkFtp2_putUsername(ftp,'myFtpLogin');

//  SocksVersion selects the proxy: 0 (default) = none, 4 = SOCKS4, 5 = SOCKS5.
CkFtp2_putSocksVersion(ftp,5);
CkFtp2_putSocksHostname(ftp,'socks.example.com');
CkFtp2_putSocksPort(ftp,1080);

//  SOCKS5 supports username/password authentication; SOCKS4 uses only a user identifier.
CkFtp2_putSocksUsername(ftp,'myProxyLogin');
CkFtp2_putSocksPassword(ftp,'myProxyPassword');

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
CkFtp2_putPassword(ftp,'myPassword');

success := CkFtp2_Connect(ftp);
if (success = False) then
  begin
    Memo1.Lines.Add(CkFtp2__lastErrorText(ftp));
    Exit;
  end;

Memo1.Lines.Add('Connected through the SOCKS proxy.');

success := CkFtp2_Disconnect(ftp);
if (success = False) then
  begin
    Memo1.Lines.Add(CkFtp2__lastErrorText(ftp));
    Exit;
  end;

CkFtp2_Dispose(ftp);