Django - ForeignKey field initial value definition in Admin - django

Question

I have a Person model, which has a ForeignKey field to itself, called mother.
When the user goes to the 'add' admin form, I want to define an initial value for mother, in case there is a GET('mother') parameter, or leave it blank, in case there is not.
I have actually 2 questions:
How to access request inside ModelAdmin?
How to define initial value for a ForeignKey field?
In models.py:
class Person(models.Model):
name=models.CharField()
mother=models.ForeignKey('self')
In admin.py:
class PersonAdminForm(forms.ModelForm):
class Meta:
model = Person
class PersonAdmin(admin.ModelAdmin):
mother = request.GET.get('mother','') #don`t know how to access request
if mother != '':
form = PersonAdminForm
form.initial={'mother':Person.objects.get(id=mother)}
Well, this ain't working. Even if I only try to define a hardcoded initial value, it doesn`t work.
What am I doing wrong?
PS.: Of course, I may be asking the wrong questions, so I appreciate any help that solves the problem.

Answer 1

My solution:
class PersonAdmin(admin.ModelAdmin):
form = PersonAdminForm
# ...
def get_form(self, request, obj=None, *args, **kwargs):
form = super(PersonAdmin, self).get_form(request, *args, **kwargs)
# Initial values
form.base_fields['mother'].initial = None
if obj and obj.mother:
form.base_fields['mother'].initial = obj.mother
return form

Answer 2

Oh, it happens to be a lot easier than I thought.
If you pass a GET parameter with the name of the field as key to a Django`s add form, the GET parameters value will be set as initial value for that field.
In my case, I just needed to redirect to
localhost/admin/my_app/person/add/?&mother=< id >
There was no need for manipulating admin or anything.

Answer 3

Try overriding the get_form() method on ModelAdmin:
class PersonAdmin(admin.ModelAdmin):
form = PersonAdminForm
def get_form(self, request, *args, **kwargs):
form = super(PersonAdmin, self).get_form(request, *args, **kwargs)
mother = request.GET.get('mother', None)
if mother:
form.initial = {'mother': Person.objects.get(id=mother)}
return form