Sample code for 30+ languages & platforms
Pascal (Lazarus/Delphi)

Read Text at a String Offset from a Remote SFTP File

See more SFTP Examples

Demonstrates the Chilkat SFtp.ReadFileText64s method, which is like ReadFileText64 but takes the byte offset as a decimal string. The arguments are the handle, the offset string, the maximum number of bytes, and the charset.

Background: The string-offset read exists for the same reason as its write counterpart: it lets code in languages without convenient 64-bit integers still address positions in very large files by supplying the offset as text. Functionally it is identical to the int64 version.

Chilkat Pascal (Lazarus/Delphi) Downloads

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;
  offset: string;
  numBytes: Integer;
  text: string;

begin
  success := False;

  //  Demonstrates the SFtp.ReadFileText64s method, which is like ReadFileText64 but takes the byte
  //  offset as a decimal string.  The 1st argument is the handle, the 2nd is the offset string, the
  //  3rd is the maximum number of bytes, and the 4th is the charset.

  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;

  //  Supplying the offset as a string is convenient in languages without a native 64-bit integer.
  offset := '5000000000';
  numBytes := 6;
  text := sftp.ReadFileText64s(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.