class Node(models.Model):
    user = models.ForeignKey(User)
    is_active = models.BooleanField(default=False)
    api_token = models.CharField(max_length=256, blank=True)
    objects = UserNodes()

 class UserNodes(models.Manager):
    def detail(self, request, pk):
        d = self.filter(user=request.user, pk=pk, is_active=True)
        if not d.api_token:
            messages.warning(
                request, 'Для установки сервера следует указать API token')
        return d

 @method_decorator(login_required(redirect_field_name=None), name='dispatch')
class NodeDetail(DetailView):
    def get_queryset(self):
        pk = self.kwargs.get(self.pk_url_kwarg)
        return Node.objects.detail(self.request, pk)