django-mptt filter without breaking the tree

Question

I'm using django-mptt for a Article model in my Django application. If I want to get all Articles which are set to for example hidden, I could do

Article.objects.filter(hidden=False)

but that would break the mptt-tree. How can I filter on my queryset in such a way that not only does it exclude all hidden articles, but also the childs of those nodes and that way maintain the integrity of the tree so that I still can use the tree_info template tag?

In what way does that query "break" the tree? – Daniel Roseman Sep 11 '12 at 14:13 — Daniel Roseman, Sep 11 '12 at 14:13
Well by doing that a node might lose it's parent. :o – Sep 11 '12 at 14:20 — , Sep 11 '12 at 14:20

score 1 · Answer 1 · answered Sep 06 '13 at 07:29

I am having a similar issue. I would like to remove a node and all of its children.

Here is how I manage to do that:

class FolderForm(forms.ModelForm):
    class Meta:
        model = Folder
        fields = ('name', 'parent')

    def __init__(self, *args, **kwargs)
        super(FolderForm, self).__init__(*args, **kwargs)

        if self.instance is not None:
            exclude_ids = [f.id for f in self.instance.get_descendants(
                include_self=True)]

            self.fields['parent'].queryset = self.fields['parent'].queryset \
                .exclude(pk__in=exclude_ids)

score 0 · Answer 2 · answered Mar 18 '15 at 21:23

0

There is a simpler solution: just set all the children to hidden as well.

answered Mar 18 '15 at 21:23

quantum

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django-mptt filter without breaking the tree

2 Answers2