Question

I am trying to filter a m-2-m based on some 3 way relational logic. I have the following models (example only… but the more I write it, it looks like a game I’d like to play…) Forgive my over use of the spam and eggs metavariables…

Models:

class SuperProfile(models.Model):
    user = models.ForgeignKey('User')
    eggs_unlocked = models.ManyToMany('Egg')
    my_kitchen = models.ForeignKey('SuperKitchen')

class SuperKitchen(models.Model):
    name = models.CharField(max_length=20)

class Egg(models.Model):
    eggyness = models.PostiveIntegerField(help_text=_("how Eggy it is. eg." 
                                                      "Spam'n'Eggs is over 9000")
    kitchens = models.ForeignKey(help_text=_('What kitchen carries this')

Question: As an administrator, in someone else’s SuperProfileAdmin:

• I want to list what eggs they can use based on what kitchen they are part of
• A person’s Kitchen doesn’t change, ever.
• Eggs only appear in one kitchen.
• How do you get an instance of the SuperProfile or SuperKitchen to filter the Egg list for said other user

I’m not sure if this is clear, please comment on what needs clarification.

Answer 1

In your EggAdmin, you must override queryset method

class EggAdmin(admin.ModelAdmin):
    ...
    def queryset(self, request):
        kitchen = request.user.superprofile_set.get().my_kitchen #get related users kitchen
        qs = super(EggAdmin, self).queryset(request) #call original queryset method that you are overriding
        return qs.filter(kitchens=kitchen) #apply your filter

UPDATE: Ok, that change everything… On SuperPrifile admin, when you open a SuperProfile record, you wish eggs_unlocked to be filtered according to that user… So:

import re
# grab the superprofile id from the url
sup_pro_rgx=re.compile(r'(\d+)')
sup_pro = sup_pro_rgx.findall(request.META['REQUEST_URI'])[0]
# I know this is really the ugliest way to do this, but there is no other way (at least as far as i know) to do this


class SuperProfileAdmin(admin.ModelAdmin):
...
def formfield_for_manytomany(self, db_field, request, **kwargs):
    if db_field.name == "eggs_unlocked":
        my_kitchen = self.get_object(request, object_id=sup_pro).my_kitchen
        kwargs["queryset"] = Egg.objects.filter(kitchen=my_kitchen)
    return super(SuperProfileAdmin, self).formfield_for_manytomany(db_field, request, **kwargs)

I know, using regex to grab the object id is a really bad practise, but as i mention, that is the only way to do this as i know.

And here is the doc for formfield_for_manytomany