function HTTPEncode(const AStr: String): String;
const
  NoConversion = ['A'..'Z','a'..'z','*','@','.','_','-','0'..'9','$','!','''','(',')'];
var
  Sp, Rp: PAnsiChar;
begin
  SetLength(Result, Length(AStr) * 3);
  Sp:= PAnsiChar(AStr);
  Rp:= PAnsiChar(Result);
  while Sp^ <> #0 do
  begin
    if Sp^ in NoConversion then
      Rp^ := Sp^
    else
      if Sp^ = ' ' then
        Rp^ := '+'
      else
      begin
        FormatBuf(Rp^, 3, '%%%.2x', 6, [Ord(Sp^)]);
        Inc(Rp,2);
      end;
    Inc(Rp);
    Inc(Sp);
  end;
  SetLength(Result, Rp - PAnsiChar(Result));
end;
function URLEncode(const Url: String): String;
begin
  Result:= HttpEncode(UTF8Encode(Url));
end;