Come ottenere l'istanza del modello corrente da inlineadmin in Django

Question

Sto usando il formfield_for_manytomany dato in django documentation. Ma all'interno di quella funzione ho bisogno di ottenere l'oggetto genitore corrente in fase di modifica.

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) 

Come posso ottenere la persona che si modifica?

Answer 1

Se il person non può essere facilmente ottenuto da request, potrebbe essere necessario passare manualmente sovrascrivendo ModelAdmin.get_form() o 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 

O

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) 

Answer 2

per accedere all'istanza modello del InlineModelAdmin del genitore ModelAdmin, ho usato questo hack in passato:

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) 

Answer 3

Ho scoperto un modo più pulito senza tutto l'hacking in get_formset()/get_formsets()/formfield_for_dbfield(). Usa l'oggetto Request di Django (a cui hai accesso) per recuperare lo request.path_info, quindi recupera il PK dagli args nella partita resolve. Esempio:

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]