I am using the formfield_for_manytomany given in django documentation.
But inside that function I need to get the current parent object being edited.
def formfield_for_manytomany(self, db_field, request, **kwargs):
if db_field.name == "car":
kwargs["queryset"] = Cars.objects.filter(owner=person)
return super(myModel, self).formfield_for_manytomany(db_field, request, **kwargs)
How can I get the person being edited?
If the person cannot be easily got from request, you may need to manually pass it by overriding ModelAdmin.get_form() or InlineModelAdmin.get_formset():
from functools import partial
class MyModelAdmin(admin.ModelAdmin):
def get_form(self, request, obj=None, **kwargs):
kwargs['formfield_callback'] = partial(self.formfield_for_dbfield, request=request, obj=obj)
return super(MyModelAdmin, self).get_form(request, obj, **kwargs)
def formfield_for_dbfield(self, db_field, **kwargs):
person = kwargs.pop('obj', None)
formfield = super(MyModelAdmin, self).formfield_for_dbfield(db_field, **kwargs)
if db_field.name == "car" and person:
formfield.queryset = Cars.objects.filter(owner=person)
return formfield
# or its inline
class MyInlineModelAdmin(admin.StackedInline):
def get_formset(self, request, obj=None, **kwargs):
kwargs['formfield_callback'] = partial(self.formfield_for_dbfield, request=request, obj=obj)
return super(MyInlineModelAdmin, self).get_formset(request, obj, **kwargs)
def formfield_for_dbfield(self, db_field, **kwargs):
person = kwargs.pop('obj', None)
formfield = super(MyInlineModelAdmin, self).formfield_for_dbfield(db_field, **kwargs)
if db_field.name == "car" and person:
formfield.queryset = Cars.objects.filter(owner=person)
return formfield
Or
class MyModelAdmin(admin.ModelAdmin):
def get_form(self, request, obj=None, **kwargs):
kwargs['formfield_callback'] = partial(self.formfield_for_dbfield, request=request, obj=obj)
return super(MyModelAdmin, self).get_form(request, obj, **kwargs)
def formfield_for_dbfield(self, db_field, **kwargs):
if db_field.name != "car":
kwargs.pop('obj', None)
return super(MyModelAdmin, self).formfield_for_dbfield(db_field, **kwargs)
def formfield_for_manytomany(self, db_field, request=None, **kwargs):
person = kwargs.pop('obj', None)
if db_field.name == "car" and person:
kwargs['queryset'] = Cars.objects.filter(owner=person)
return super(MyModelAdmin, self).formfield_for_manytomany(db_field, request, **kwargs)
formfield_callback and what is partial
formfield_for_manytomany, we need to manually pass it the obj, in order to get obj from kwargs inside formfield_for_manytomany. The partial part makes a high-order function which, when being called as formfield_callback(some_more_arguments), behaves like self.formfield_for_dbfield(request, some_more_arguments), you could check the doc and the postformfield_callback . is that build in django or its custom 2. how cna i know what are the things or fields or functions avaiable inside kwargs. i how do you know that obj is in kwargsobj, but we could customize it easily, check the code. 2. kwargs is filled by Django form to generate form field, thus it could contain possible things that the field accepts: widget and queryset for example. Here we do mix the arguments having different targets, thus remember to name it unique (obj here`).__init__() got an unexpected keyword argument objI discovered a cleaner way without all of the hacking around in get_formset() / get_formsets() / formfield_for_dbfield(). Use Django's Request object (which you have access to) to retrieve the request.path_info, then retrieve the PK from the args in the resolve match. Example:
from django.contrib import admin
from django.core.urlresolvers import resolve
from app.models import YourParentModel, YourInlineModel
class YourInlineModelInline(admin.StackedInline):
model = YourInlineModel
def get_parent_object_from_request(self, request):
"""
Returns the parent object from the request or None.
Note that this only works for Inlines, because the `parent_model`
is not available in the regular admin.ModelAdmin as an attribute.
"""
resolved = resolve(request.path_info)
if resolved.args:
return self.parent_model.objects.get(pk=resolved.args[0])
return None
def has_add_permission(self, request):
parent = self.get_parent_object_from_request(request)
if parent and parent.is_active is True:
return False
return super(YourInlineModelInline, self).has_add_permission(request)
def get_formset(self, request, *args, **kwargs):
"""
Using the get_formset example from above to override the QuerySet.
"""
def formfield_callback(field, **kwargs):
formfield = field.formfield(**kwargs)
if field.name == 'car':
formfield.queryset = self.parent_model.objects.filter(
owner=self.get_parent_object_from_request(request)
)
return formfield
if self.get_parent_object_from_request(request) is not None:
kwargs['formfield_callback'] = formfield_callback
return super(YourInlineModelInline, self).get_formset(*args, **kwargs)
@admin.register(YourParentModel)
class YourParentModelAdmin(admin.ModelAdmin):
inlines = [YourInlineModelInline]
from django.urls import resolve, pk=resolved.kwargs['object_id'], for ModelAdmin self.parent_model -> self.model
object_id = request.path.split("/")[4] knowing that the ID would always be the 4th parameter in the request URL.To access the model instance of the InlineModelAdmin's parent ModelAdmin, I have used this hack in the past:
class PersonAdmin(ModelAdmin):
def get_formsets(self, request, obj=None, *args, **kwargs):
for inline in self.inline_instances:
inline._parent_instance = obj
yield inline.get_formset(request, obj)
class CarInline(TabularInline):
_parent_instance = None
def get_formset(self, *args, **kwargs):
def formfield_callback(field, **kwargs):
formfield = field.formfield(**kwargs)
if field.name == 'car':
formfield.queryset = Cars.objects.filter(owner=self._parent_instance)
return formfield
if self._parent_instance is not None:
kwargs['formfield_callback'] = formfield_callback
return super(CarInline, self).get_formset(*args,
**kwargs)
