Read Text at a 64-bit Offset from a Remote SFTP File

See more SFTP Examples

Demonstrates the Chilkat SFtp.ReadFileText64 method, which reads up to a number of bytes from a specific 64-bit byte offset of an open handle and decodes them to text. The arguments are the handle, the offset, the maximum number of bytes, and the charset. The 64-bit offset supports very large files.

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,
  Chilkat.int64;

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

procedure RunDemo;
var
  success: Boolean;
  sftp: TSFtp;
  port: Integer;
  password: string;
  handle: string;
  offset: Tint64;
  numBytes: Integer;
  text: string;

begin
  success := False;

  //  Demonstrates the SFtp.ReadFileText64 method, which reads up to a number of bytes from a
  //  specific 64-bit byte offset of an open handle and decodes them to text.  The 1st argument is
  //  the handle, the 2nd is the offset, the 3rd is the maximum number of bytes, and the 4th is the
  //  charset.  The 64-bit offset supports very large files.

  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;

  handle := sftp.OpenFile('subdir/hugefile.dat','readOnly','openExisting');
  if (sftp.LastMethodSuccess = False) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;

  //  Read 6 bytes starting at a byte offset beyond the 32-bit (4 GB) range.
  offset := 5000000000;
  numBytes := 6;
  text := sftp.ReadFileText64(handle,offset,numBytes,'utf-8');
  if (sftp.LastMethodSuccess = False) then
    begin
      WriteLn(sftp.LastErrorText);
      Exit;
    end;
  WriteLn(text);

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

  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.