Pascal (Lazarus/Delphi)

Socket Send and Receive BinData

Demonstrates the Chilkat Socket ReceiveBdN and SendBd methods. 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.BinData,
  Chilkat.Socket;

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

procedure RunDemo;
var
  success: Boolean;
  sock: TSocket;
  useTls: Boolean;
  port: Integer;
  maxWaitMs: Integer;
  bdToSend: TBinData;
  i: Integer;
  byteVal: Integer;
  bdRecv: TBinData;

begin
  success := False;

  //  This example requires the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  sock := TSocket.Create;

  //  --------------------------------------------------------------------
  //  This example uses the public TCP echo service at https://tcpbin.com/
  //  --------------------------------------------------------------------

  useTls := False;
  port := 4242;
  maxWaitMs := 5000;
  success := sock.Connect('tcpbin.com',port,useTls,maxWaitMs);
  if (success = False) then
    begin
      WriteLn(sock.LastErrorText);
      Exit;
    end;

  //  Wait a max of 2 seconds for a response..
  sock.MaxReadIdleMs := 2000;

  //  Send 26 bytes contained in a Chilkat BinData
  bdToSend := TBinData.Create;
  i := 0;
  byteVal := 65;
  while i < 26 do
    begin
      bdToSend.AppendByte(byteVal);
      byteVal := byteVal + 1;
      i := i + 1;
    end;

  //  Send the contents of the BinData
  //  Pass zero's in the 2nd and 3rd arguments to send the entire contents of the BinData.
  sock.SendBd(bdToSend,0,0);

  //  The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
  sock.SendByte(10);

  //  The echo server will echo back whatever is sent to it.
  //  We should be able to read the same bytes back..
  bdRecv := TBinData.Create;
  //  Receive the 26 bytes previously sent, plus the LF char.
  success := sock.ReceiveBdN(27,bdRecv);
  if (success = False) then
    begin
      WriteLn(sock.LastErrorText);
      Exit;
    end;

  //  Show the contents of bdRecv in hex format
  WriteLn(bdRecv.GetEncoded('hex'));

  //  Output:  4142434445464748494A4B4C4D4E4F505152535455565758595A0A


  sock.Free;
  bdToSend.Free;
  bdRecv.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.