Delphi — TClientSocket ReceiveText MaxLen?

Question

I've been trying to set the length of the amount of characters you recover from the ReceiveText TClientSocket function and nothing seems to be working. E.g., Receiving the first leftmost character(s) from the recovered data or otherwise data stream. Is there a way to accomplish this in Delphi using this specific object?

Help would be much appreciated. Thanks in advance.

Answer 1

ReceiveText doesn't have any means to control the maximum length of the received text.

The easiest way in ClientType := ctBlocking mode is to use a TWinSocketStream as the documentation states:

http://docwiki.embarcadero.com/VCL/XE2/en/ScktComp.TClientSocket.ClientType

When ClientType is ctBlocking, use a TWinSocketStream object for reading and writing. TWinSocketStream prevents the application from hanging indefinitely if a problem occurs while reading or writing. It also can wait for the socket connection to indicate its readiness for reading.

Example code:

var
  Stream : TWinSocketStream;
  Buffer : TBytes;
  S      : string;
begin
  SetLength(Buffer, 100); // 100 bytes buffer size
  Stream := TWinSocketStream.Create(Socket, 5000); // 5 seconds or 5000 milliseconds
  try
    Stream.ReadBuffer(Buffer[0], Length(Buffer)); // raises an Exception if it couldn't read the number of bytes requested
    S := TEncoding.Default.GetString(Buffer); // Works in Delphi 2009+
  finally
    Stream.Free;
  end;
end;

Answer 2

here is a little tipp for sending and receiving text

first you must send the length of yout text too

Socket.SendText(IntToStr(Length(text)) + seperator + text);

then you can check at your server socket on receiving data streams, if your incoming text is complete

procedure TMyServer.OnClientRead(Sender: TObject; Socket: TCustomWinSocket);
begin
  if (xRecLength = 0) then begin
    if Length(Socket.ReceiveText) <= 0 then EXIT;
    xRecLength:= StrToIntDef(GetFirstFromSplitted(Socket.ReceiveText, seperator), -1);
    if xRecLength = -1 then EXIT;
  end;
  xActLength:= xActLength + Length(Socket.ReceiveText);
  xRecPuffer:= xRecPuffer + Socket.ReceiveText;

  isComplete:= xActLength = xRecLength;
  if isComplete then begin
    // complete text received
  end;
end;

hope that helps you...

Answer 3

I'm not at home with Delphi, but a quick Google search turned up this page that indicates that ReceiveText does not accept any parameters, but instead returns a string of as much as it can read.

What you might need is might be ReceiveBuf instead.