Pascal (Lazarus/Delphi)

Download from an SFTP Server Using an Open Handle

Demonstrates the Chilkat SFtp.DownloadFile method, which streams a remote file identified by an open handle to a local path. The first argument is the handle (from OpenFile) and the second is the local file path. Close the handle with CloseHandle when done.

Note: This example uses relative local paths, which are resolved against the application's current working directory. Absolute local paths may also be used. Supply the paths appropriate to your own environment.

Background: The handle-based counterpart to DownloadFileByName. Opening the file yourself lets you set read options — such as requesting exclusive read access — that the convenience method does not expose, and it separates the open step from the transfer so the handle can be used for more than one operation. As with any handle, close it when finished to release the server-side resource.

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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.SFtp;

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

procedure RunDemo;
var
  success: Boolean;
  sftp: TSFtp;
  port: Integer;
  password: string;
  handle: string;

begin
  success := False;

  //  Demonstrates the SFtp.DownloadFile method, which streams a remote file identified by an open
  //  handle to a local path.  The 1st argument is the handle and the 2nd is the local file path.

  sftp := TSFtp.Create;

  //  Connect, authenticate, and initialize the SFTP subsystem.
  port := 22;
  success := sftp.Connect('sftp.example.com',port);
  if (success = False) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;

  //  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.
  password := 'mySshPassword';

  success := sftp.AuthenticatePw('mySshLogin',password);
  if (success = False) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;

  success := sftp.InitializeSftp();
  if (success = False) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;

  //  Open the remote file for reading.  OpenFile returns a handle string.
  handle := sftp.OpenFile('subdir/report.pdf','readOnly','openExisting');
  if (sftp.LastMethodSuccess = False) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;

  //  Stream the remote file to the local filesystem.  The transfer is not limited by memory.
  success := sftp.DownloadFile(handle,'qa_output/report.pdf');
  if (success = False) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;

  //  Close the remote handle when the download is complete.
  success := sftp.CloseHandle(handle);
  if (success = False) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;
  WriteLn('Downloaded.');

  sftp.Disconnect();


  sftp.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.