Making inlines conditional in the Django admin

Question

I have a model that I want staff to be able to edit up to the date for the event. Like this:

class ThingAdmin(admin.ModelAdmin):
    model = Thing

    if obj.date < today: #Something like that
        inlines = [MyInline,]

The problem is, I don't have access to the obj instance at this level. I've tried overriding get_formset(), but didn't get anywhere.

Please advise?

Answer 1

I had a complex case where the solutions I tried failed in unexpected ways (problems with readonly fields in inlines). This is the most clear and failsafe way I've found:

class MyAdmin(admin.ModelAdmin):

    def add_view(self, request, form_url='', extra_context=None):
        self.inlines = [InlineA, InlineC]
        return super(MyAdmin, self).add_view(request, form_url, extra_context)

    def change_view(self, request, object_id, form_url='', extra_context=None):
        self.inlines = [InlineB, InlineC, InlineD]
        return super(MyAdmin, self).change_view(request, object_id, form_url, extra_context)

This is working in Django 1.4.x.

Answer 2

In recent version of Django, you'll need to override ModelAdmin.get_formsets. e.g.

class MyAdmin(admin.ModelAdmin):

    def get_formsets(self, request, obj=None):
        if obj:
            for _ in super(MyAdmin, self).get_formsets(request, obj):
                yield _
        else:
            for inline in self.get_specific_inlines(request):
                yield inline.get_formset(request, obj)

Answer 3

Thanks to the comments for a change in 1.4. My implementation here wasn't thread safe either, so it really should have been deleted.

Since get_formsets is passed the object and calls get_inline_instances, we can modify both functions to act on the object.

This should work:

class ThingAdmin(admin.ModelAdmin):
    model = Thing

    inlines = [inline]
    other_set_of_inlines = [other_inline]

    def get_inline_instances(self, request, obj=None):
        #                                    ^^^ this is new
        inline_instances = []

        if obj.date > datetime.date(2012, 1, 1):
            inlines = self.inlines
        else:
            inlines = self.other_set_of_inlines

        for inline_class in inlines:
            inline = inline_class(self.model, self.admin_site)
            if request:
                if not (inline.has_add_permission(request) or
                        inline.has_change_permission(request) or
                        inline.has_delete_permission(request)):
                    continue
                if not inline.has_add_permission(request):
                    inline.max_num = 0
            inline_instances.append(inline)
        return inline_instances

    def get_formsets(self, request, obj=None):
        for inline in self.get_inline_instances(request, obj):
            #                                           ^^^^^ this is new
            yield inline.get_formset(request, obj)

Answer 4

I had a situation where I needed to show an Inline based on the admin site that you were on for a given story.

I was able to get dynamic inlines working for Django 1.3 using the following code:

In highlights/admin.py

class HighlightInline(generic.GenericTabularInline):
    model = Highlight
    extra = 1
    max_num = 4
    fields = ('order', 'highlight')
    template = 'admin/highlights/inline.html'

class HighlightAdmin(admin.ModelAdmin):
    def regulate_highlight_inlines(self):
        highlights_enabled = Setting.objects.get_or_default('highlights_enabled', default='')
        highlight_inline_instance = HighlightInline(self.model, self.admin_site)
        highlight_found = any(isinstance(x, HighlightInline) for x in self.inline_instances)
        if highlights_enabled.strip().lower() == 'true':
            if not highlight_found:
                self.inline_instances.insert(0, highlight_inline_instance)
        else:
            if highlight_found:
                self.inline_instances.pop(0)
        print self.inline_instances

    def change_view(self, request, object_id, form_url='', extra_context=None):
        self.regulate_highlight_inlines()
        return super(HighlightAdmin, self).change_view(request, object_id)

    def add_view(self, request, form_url='', extra_context=None):
        self.regulate_highlight_inlines()   
        return super(HighlightAdmin, self).add_view(request, form_url, extra_context)

In story/admin.py

class StoryAdmin(HighlightAdmin):

One thing to note is that I'm not merely manipulating inline classes(HighlightInline) but rather, I'm changing inline instances(HighlightInline(self.model, self.admin_site)). This is because django has already constructed a list of inline instances based on a list of inline classes during the initial construction of the admin class.

Answer 5

I think the best answer is in the django documentation: https://docs.djangoproject.com/en/1.9/ref/contrib/admin/

Search for "get_inline_instances" The example provided is very good and the nuances of the call are described in detail.

Answer 6

I think the easiest way to hack this is to call your custom funciton in get_fields, or get_fieldsets and so on, just set self.inlines in a custom function.

class XXXAdmin(admin.ModelAdmin):
    def set_inlines(self, request, obj):
        """ hack inlines models according current request.user or obj """
        self.inlines = []
        if request.user.is_superuser or request.user is obj.recorder:
            self.inlines = [AbcInline, ]

    def get_fields(self, request, obj=None):
        self.set_inlines(request, obj)  # NOTICE this line
        super(XXXAdmin, self).get_fields(request, obj)