from h11._receivebuffer import ReceiveBuffer

def monkey_patch():
    def _maybe_extract_lines_crlf_insensitive(self):
        if self._data[self._start : self._start + 2] == b"\r\n":
            self._start += 2
            return []
        elif self._data[self._start : self._start + 1] == b"\n":
            self._start += 1
            return []
        else:
            data = self.maybe_extract_until_next(b"\r\n\r\n") \
                    or self.maybe_extract_until_next(b"\n\n")
            if data is None:
                # header not finish 
                return None
            
            lines = []
            lf_lines = data.split(b"\r\n")
            for lf_line in lf_lines:
                lines += lf_line.split(b"\n")
            assert lines[-2] == lines[-1] == b""
            del lines[-2:]
            return lines

    _original_ReceiveBuffer_maybe_extract_lines = ReceiveBuffer.maybe_extract_lines
    ReceiveBuffer.maybe_extract_lines = _maybe_extract_lines_crlf_insensitive
    
    def _recover():
        ReceiveBuffer.maybe_extract_lines = _original_ReceiveBuffer_maybe_extract_lines

    return _recover