Delphi ActiveX

Enable FTP MODE Z Compression

Demonstrates the Chilkat Ftp2.SetModeZ method, which enables MODE Z compression for subsequent data connections. It takes no arguments. Call it after connecting and only when the HasModeZ property is true.

Background: MODE Z compresses data on the fly (using zlib) as it crosses the wire, which can meaningfully speed up transfers of compressible content — text, HTML, logs — over a slow link. It is a server extension, so check HasModeZ first and expect it to be unavailable on many servers. There is little benefit for already-compressed data such as images or archives, where the CPU cost of compression buys almost nothing.

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var
success: Integer;
ftp: TChilkatFtp2;

begin
success := 0;

//  Demonstrates the Ftp2.SetModeZ method, which enables MODE Z compression for subsequent data
//  connections.  It takes no arguments.  Call it after connecting, and only when the HasModeZ
//  property indicates the server supports it.

ftp := TChilkatFtp2.Create(Self);

ftp.Hostname := 'ftp.example.com';
ftp.Username := 'myFtpLogin';

//  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.
ftp.Password := 'myPassword';

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

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

//  Only enable compression if the server advertises MODE Z support.
if (ftp.HasModeZ) then
  begin
    success := ftp.SetModeZ();
    if (success = 0) then
      begin
        Memo1.Lines.Add(ftp.LastErrorText);
        Exit;
      end;
    Memo1.Lines.Add('MODE Z compression enabled.');
  end
else
  begin
    Memo1.Lines.Add('The server does not support MODE Z.');
  end;

//  Subsequent uploads, downloads, and listings are transferred compressed.

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