Discovers if a request is from a knwon spam bot and denies access.

def process_request(self, request):
        """Discovers if a request is from a knwon spam bot and denies access."""
        
        if COOKIE_KEY in request.COOKIES and \
            request.COOKIES[COOKIE_KEY] == COOKIE_SPAM:
                # Is a known spammer.
                response = HttpResponse("")
                # We do not reveal why it has been forbbiden:
                response.status_code = 404
                if DJANGOSPAM_LOG:
                    logger.log("SPAM REQUEST", request.method,
                       request.path_info,
                       request.META.get("HTTP_USER_AGENT", "undefined"))
                return response
        if DJANGOSPAM_LOG:
            logger.log("PASS REQUEST", request.method, request.path_info,
                       request.META.get("HTTP_USER_AGENT", "undefined"))
        return None