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Three-level inline formsets in the frontend

I'm trying to accomplish a three-level stacked inline form in Django. Suppose these models:
class Anuncio(models.Model):
title = models.CharField(max_length=200)
delivery = models.CharField(max_length=100)
class Product(models.Model):
anuncio = models.ForeignKey(Anuncio, on_delete=models.CASCADE)
name = models.CharField(max_length=200)
quantity = models.PositiveIntegerField(default=1)
price = models.PositiveIntegerField()
class Image(models.Model):
product = models.ForeignKey(Product, on_delete=models.CASCADE)
image = models.ImageField()
There is a relation Anuncio-Product and another relation Product-Image. With this Django package, I accomplished exactly what I want in the Django admin: when creating an Anuncio object, I can add as many Products as I want, and those products can have as many Images as I want. I'm trying to accomplish this in the front end.
I think the way to go is with Django formsets, but I'm facing some problems. All the resources I've been able to find online are only 'two-level' formsets or in 'three-level' cases all the foreign keys point to the same parent model.
With this forms.py file:
class ProductForm(ModelForm):
class Meta:
model = Product
fields = ['name', 'quantity', 'price']
class ImageForm(ModelForm):
class Meta:
model = Imagen
fields = ['image']
class AnuncioForm(ModelForm):
class Meta:
model = Anuncio
fields = ['title', 'delivery']
And this views.py function:
def anunciocreateview(request):
form = AnuncioForm(request.POST or None)
ProductFormSet = inlineformset_factory(Anuncio, Product, form=ProductForm)
ImageFormSet = inlineformset_factory(Product, Image, form=ImageForm)
if all([form.is_valid(), ProductFormSet.is_valid(), ImageFormSet.is_valid()]):
parent = form.save(commit=False)
parent.anunciante = request.user
parent.save()
for form in ProductoFormSet:
child = form.save(commit=False)
child.anuncio = parent
child.save()
for form in ImagenFormSet:
imagen = form.save(commit=False)
imagen.product = form.product
imagen.save()
context = {
'form_1' : form,
'form_2' : ProductFormSet,
'form_3' : ImageFormSet,
}
But I think I'm missing important points when it comes to add the proper relations between models. This set-up gives an AttributeError of: 'ProductForm' object has no attribute '__name__'
The, for example, 'add (extra) Product' that appears in AdminStackedInLine I guess it can be accomplished with JavaScript, playing with hidden forms and changing attributes on click events.
Anyone has experience doing something similar or can guide me through the correct direction? Also on how to manage the data and the relations of the submitted forms?

I think your problem is you have tried to validate a class Form instead of instanciate your formset and validate them.
Your code would be look like to something like that :
def anunciocreateview(request):
ProductFormSet = inlineformset_factory(Anuncio, Product, form=ProductForm)
ImageFormSet = inlineformset_factory(Product, Image, form=ImageForm)
anuncio_form = AnuncioForm(request.POST or None)
product_formset = ProductFormSet(request.POST or None)
image_formset = ImageFormSet(request.POST or None)
if all([form.is_valid(), product_formset.is_valid(), image_formset.is_valid()]):
...
The function inlineformset_factory just create a Form class, not a instance of form.
More information and example on the documentation : https://docs.djangoproject.com/fr/4.1/topics/forms/formsets/

Django modelformset with customized model initialization

I have the following models in django:
class tag(models.Model):
...
user = models.ForeignKey(user)
shop = models.ForeignKey(shop)
name = models.CharField()
...
class user(models.Model):
...
name = models.CharField()
...
class shop(models.Model):
...
user = models.ForeignKey(user)
name = models.CharField()
...
Now I need to create a modelformset of tag model that will allow me to store bunch of different tags per user. What I am looking for is a way to initialize such formset with a shop field filtered out for a given user.
This way my forms would have a selection of shops that are assigned to the user.
Any ideas are very welcome!
Thanks

You can use inlineformset_factory to create a formset for related models. To create a formset for your tag and user model you can do the following:
tag_formset = inlineformset_factory(user, tag, fields=['shop', 'name'])
formset = tag_formset(instance=request.user)
To filter the queryset for the shop field you can either create a form dynamically or pass formfield_callback to the factory function.
If you use formfield_callback, this callback can be used to return a custom field for your form
def cb(field, **kwargs):
if field.name == 'shop':
kwargs['queryset'] = shop.objects.filter(user=request.user)
return field.formfield(**kwargs)
tag_formset = inlineformset_factory(user, tag, fields=['shop', 'name'], formfield_callback=cb)
formset = tag_formset(instance=request.user)
Or you can define a form class dynamically in your view
class TagForm(forms.ModelForm):
shop = forms.ModelChoiceField(shop.objects.filter(user=request.user))
class Meta:
fields = ['shop', 'name']
tag_formset = forms.inlineformset_factory(user, tag, form=TagForm)
formset = tag_formset(instance=request.user)

How to take form string value from CharField and convert into object instance in Django?

I keep running into this error:
Cannot assign "u'Foo Group'": "Team.membership_group" must be a "Group" instance.
In my Django application, I give the user an option to create a Team. The team has a memebership_group ForeignKey attribute which maps to 'Group' (django.contrib.auth.models.Group). In the form, I've changed the widget to be a CharField so that if a group that the user types isn't actually a group, my code should create it. Here is my form:
class TeamForm(ModelForm):
"""Form to create and modify systems"""
membership_group = CharField()
manager = ModelChoiceField(queryset=Manager.objects.all(), required=True)
class Meta:
model = Team
fields = ['name', 'manager', 'membership_group']
In my views (or possibly I need to write the code elsewhere?), I want to take the string value and run a get_or_create to either return the existing group or create a new one. Here is the code in my views that isn't working:
class TeamCreateView(AutoEventLogMixin, SuccessMessageMixin, PermissionRequiredMixin, CreateView):
"""View to create Teams"""
form_class = TeamForm
model = Team
permission_required = 'teams.add_team'
success_message = "Team '%(name)s' created successfully."
template_name = 'teams/team_form.html'
def form_valid(self, form):
team_created = super(TeamCreateView, self).form_valid(form)
team = self.object
group_name = form.instance.membership_group
group_name.encode('utf-8')
membership_group = Group.objects.get_or_create(name=group_name)[0]
team.membership_group = membership_group
team.save()
return team_created
What am I doing wrong? What code do I need to add (and where) to be able to serialize/deserialize the membership group value from string to group and vice versa

I think in anyway it is not a good idea to do type translation in form_valid. If you use django1.9, then consider to create a customized FormField:
from django import forms
class MyGroupField(forms.Field):
def to_python(self, group_name):
return Group.objects.get_or_create(name=group_name)[0]
class TeamForm(ModelForm):
membership_group = MyGroupField()

Dynamic Fields ModelForms Django

I am trying to figure out how to dynamically change a ModelForm field based on the input from a previous field.
For example, if I have these kinds of models:
class Phone(models.Model):
name = models.CharField(max_length=10)
class Series(models.Model):
name = models.CharField(max_length=10)
class Manufacturer(models.Model):
phone = models.ForeignKey('Phone')
series = models.ForeignKey('Series')
class ManufacturerForm(ModelForm):
class Meta:
model = Manufacturer
Which would generate a form (ManufacturerForm) with dropdown options for the phone and series entries in the database. Is it possible to a different set of series entries based on the phone entered by the user, for example?
I have read about using the __init__ method to accomplish this, based on what I have read on this blog post, but I am not sure how to execute this given my scenario. Or maybe there is a better way to go about achieving this that you have taken? Thanks for any advice!
EDIT: Added the form's view.
def make_ad(request):
if request.method == 'POST':
form = ManufacturerForm(request.POST, request.FILES)
if form.is_valid():
a = form.save()
a.user = request.user
a.save()
else:
form = ManufacturerForm()
variables = RequestContext(request, {
'form': form
})
return render_to_response('place.html', variables)
#super9 mentioned using ajax request to change these elements. I need to check if request.is_ajax(), but at what point should I check this in my view? And how do I add or change the queryset based on the ajax request?
Thanks for your advice.
EDIT: Trying to use django-smart-selects
Not sure how to setup my models to utilize django-smart-selects to accomplish what I am trying. Here is how I have structured my models:
from smart_selects.db_fields import ChainedForeignKey
class Phone(models.Model):
phone = models.CharField(max_length=10)
class Series(models.Model):
series = models.CharField(max_length=10)
phone = models.ForeignKey(Phone)
class SeriesModel(models.Model):
model = models.CharField(max_length=10)
series = models.ForeignKey(Series)
class Manufacturer(models.Model):
phone = models.ForeignKey(Phone)
series = ChainedForeignKey (Series, chained_field = "phone", chained_model_field = "phone")
series_model = ChainedForeignKey (SeriesModel, chained_field = "series", chained_model_field = "series")
But when I view my form (ModelForm) the fields for series_model are not chained properly to series. Am I missing something to make smart-selects work on the second layer of abstraction?
EDIT: Above code now works.

Copying over the fields from a ModelForm into a Form

I have a dummy Form that looks like:
class MyForm(forms.Form):
class __init__(self, *args, **kwargs):
pass
Here's are the ModelForms and their respective Models:
class Person(models.Model):
fname = models.CharField(max_length = 255)
lname = models.CharField(max_length = 255)
class Address(models.Model):
address = models.CharField(max_length = 255)
person = models.ForeignKey(Person)
class PersonForm(ModelForm):
class Meta:
model = Person
class AddressForm(ModelForm):
class Meta:
model = Address
I would like to initiate MyForm like this myfrm = MyForm(PersonForm, AddressForm).
How can I dynamically add the fields of each of the Forms to MyForm excluding AutoFields and ForeignKey fields i.e. MyForm when initiated would have three fields in the end — fname, lname and address. It's a simple copying of the fields from one form to another but I'm a little lost with it.
Thanks

Just adding a field is not correct, considering the models above.
Address has a ManyToOne relation to Person - A user can have multiple addresses. In that case better take a look at django's inline form sets:
https://docs.djangoproject.com/en/dev/topics/forms/modelforms/#using-an-inline-formset-in-a-view
Cumbersome, but You can also manually add a CharField to to Person's ModelForm, override it's save and handle saving the content of that field to Address (ugly, I don't like it).

You can put both forms inside one html <form> tag, using the prefix argument. You then do a bit of work in the view to link the address to the person.
def my_view(request):
if request.method == "POST":
person_form = PersonForm(data=request.POST, prefix="person")
address_form = AddressForm(data=request.POST, prefix="address")
if person_form.is_valid() and address_form.is_valid():
person = person.save()
address = address.save(commit=False)
address.person = person
address.save()
return HttpResponseRedirect('/success-url/')
...