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Lazarus Pascal

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 Lazarus Pascal Downloads

Lazarus Pascal
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.