Pascal (Lazarus/Delphi)

Throttle FTP Transfer Bandwidth

Demonstrates the bandwidth properties BandwidthThrottleUp and BandwidthThrottleDown, and the read-only UploadTransferRate and DownloadTransferRate.

Note: The local paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Throttling caps the approximate transfer rate in bytes per second (0 means unlimited), which is how a background sync avoids starving interactive traffic on a shared or metered link. The rate properties report the current measured throughput, updated during transfers, so you can display progress or confirm the throttle is taking effect. Treat the limits as approximate targets rather than hard ceilings.

Chilkat Pascal (Lazarus/Delphi) Downloads

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Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Ftp2;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  ftp: TFtp2;

begin
  success := False;

  ftp := TFtp2.Create;

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

  //  Limit the approximate transfer rate in bytes per second.  0 (the default) means no limit.
  //  Throttling is useful to avoid saturating a shared link.
  ftp.BandwidthThrottleDown := 1048576;
  ftp.BandwidthThrottleUp := 524288;

  //  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 = False) then
    begin
      WriteLn(ftp.LastErrorText);
      Exit;
    end;

  success := ftp.GetFile('public_html/bigfile.zip','qa_output/bigfile.zip');
  if (success = False) then
    begin
      WriteLn(ftp.LastErrorText);
      Exit;
    end;

  //  The current average rates are updated during transfers.
  WriteLn('Download rate: ' + ftp.DownloadTransferRate + ' bytes/sec');
  WriteLn('Upload rate: ' + ftp.UploadTransferRate + ' bytes/sec');

  success := ftp.Disconnect();
  if (success = False) then
    begin
      WriteLn(ftp.LastErrorText);
      Exit;
    end;


  ftp.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.