def slug_exists(self, request):
        """Check if given url slug exists.

        Check if slug given in query parameter ``name`` exists. Return
        ``True`` if slug already exists and ``False`` otherwise.

        """
        if not request.user.is_authenticated:
            return Response(status=status.HTTP_401_UNAUTHORIZED)

        if 'name' not in request.query_params:
            return Response({'error': 'Query parameter `name` must be given.'},
                            status=status.HTTP_400_BAD_REQUEST)

        queryset = self.get_queryset()
        slug_name = request.query_params['name']
        return Response(queryset.filter(slug__iexact=slug_name).exists())
Check if given url slug exists.

        Check if slug given in query parameter ``name`` exists. Return
        ``True`` if slug already exists and ``False`` otherwise.