'Return operation log format.'

def _get_log_format(self, request):

    user = getattr(request, 'user', None)
    if (not user):
        return
    if (not request.user.is_authenticated()):
        return
    method = request.method.upper()
    if (not (method in self.target_methods)):
        return
    request_url = urlparse.unquote(request.path)
    for rule in self._ignored_urls:
        if rule.search(request_url):
            return
    return self.format
