Delphi DLL

Connect to FTP Through an HTTP Proxy

Demonstrates connecting through an HTTP proxy using HttpProxyHostname, HttpProxyPort, HttpProxyUsername, HttpProxyPassword, HttpProxyAuthMethod, and HttpProxyDomain.

Background: Many corporate networks force outbound traffic through an HTTP proxy, which reaches the FTP control connection via the CONNECT method — so the proxy must permit CONNECT to the FTP port. HttpProxyAuthMethod is Basic or NTLM, with HttpProxyDomain supplying the Windows domain for NTLM. This is distinct from a traditional FTP proxy, which speaks FTP itself.

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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');

//  The HTTP proxy through which the FTP control connection is made.  Common ports are 8080 and
//  3128.
CkFtp2_putHttpProxyHostname(ftp,'proxy.example.com');
CkFtp2_putHttpProxyPort(ftp,8080);

//  Proxy authentication, if required.  HttpProxyAuthMethod is "Basic" or "NTLM"; HttpProxyDomain
//  is the Windows domain used for NTLM.
CkFtp2_putHttpProxyUsername(ftp,'myProxyLogin');
CkFtp2_putHttpProxyPassword(ftp,'myProxyPassword');
CkFtp2_putHttpProxyAuthMethod(ftp,'NTLM');
CkFtp2_putHttpProxyDomain(ftp,'CORP');

//  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 HTTP proxy.');

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

CkFtp2_Dispose(ftp);