(Delphi ActiveX) Socket Receive String Until Specific Byte Value is Received

Demonstrates the Chilkat Socket ReceiveStringUntilByte method.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
sock: TChilkatSocket;
useTls: Integer;
port: Integer;
maxWaitMs: Integer;
success: Integer;
lookForByte: Integer;
s1: WideString;
s2: WideString;

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

sock := TChilkatSocket.Create(Self);

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

useTls := 0;
port := 4242;
maxWaitMs := 5000;
success := sock.Connect('tcpbin.com',port,useTls,maxWaitMs);
if (success = 0) then
  begin
    Memo1.Lines.Add(sock.LastErrorText);
    Exit;
  end;

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

// Send some strings, each terminated by a 0 byte.
sock.SendString('This is the 1st string');
sock.SendByte(0);
sock.SendString('This is string number 2');
sock.SendByte(0);

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

// Now let's receive what is echoed back....
// Receive each string and the NULL byte.
// The call to ReceiveStringUntilByte will receive incoming data until the lookForByte is encountered.
// The lookForByte is receive and discarded (it is not returned in the string)
lookForByte := 0;
s1 := sock.ReceiveStringUntilByte(lookForByte);
if (sock.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(sock.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add(s1);

s2 := sock.ReceiveStringUntilByte(lookForByte);
if (sock.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(sock.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add(s2);

// The echo server will also echo back the final LF
sock.ReceiveByte(1);
maxWaitMs := 100;
sock.Close(100);

// Output:
// This is the 1st string
// This is string number 2
end;