Copying over the fields from a ModelForm into a Form - python

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/')
...

Related

Django Admin - How to prefill add inline forms values sent through the querystring?

I am able to prefill a form using query-string parameters in Django Admin.
Let's say I have the following models:
class Book(models.Model):
id = models.Autofield(primary_key=True)
author = models.ForeignKey(Author, on_delete=models.CASCADE)
name = models.Charfield(max_length=200)
class Author(models.Model):
id = models.Autofield(primary_key=True)
name = models.Charfield(max_length=200)
If I go to /admin/library/author/add/?name=J.+K.+Rowling the author's name will be properly prefilled.
However if I add InlineForms like that:
class BookInline(StackedInline):
model = Book
extra = 0
class AuthorAdmin(ModelAdmin):
inlines = [BookInline]
admin.site.register(Author, AuthorAdmin)
I don't seem to be able to prefill books.
I tried: /admin/library/author/add/?name=J.+K.+Rowling&books-TOTAL_FORMS=1&books-0-name=Harry+Potter+and+the+Philosopher's+Stone
The author form is prefilled, but the first book form is not prefilled. Do you know how one manages that?
If you override get_formset_kwargs, you can prefill forms with some initial values:
class AuthorAdmin(ModelAdmin):
inlines = [BookInline]
def get_formset_kwargs(self, request, obj, inline, prefix):
formset_params = super().get_formset_kwargs(request, obj, inline, prefix)
if request.method == "GET":
# Mind you, this will prefill all form of the formset with the same values.
# But for our usecase it is sufficient.
prefix_length = len(prefix) + 3
initial_values = [{key[prefix_length:]: value for key, value in request.GET.items() if key.startswith(prefix)}]
formset_params.update(initial=initial_values)
return formset_params
However, all extra form will contain the same values.
If you know how we can manage to use the index there, it would improve this answer.

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 Models design: many-to-many relationship with specific needs

I am in the process of designing a couple of new models for my django app and this is what I need:
class Bookmaker(models.Model):
name = models.CharField(max_length=50)
accepted_countries = ?
restricted_countries = ?
class Country(models.Model):
name = models.CharField(max_length=50)
bookmakers = ?
So I need a model Bookmaker and a model Country and they need to be related, BUT every bookmaker should have a list of countries that are accepted and a list of countries that are excluded.
The question marks are both in the Country and in the Bookmaker models as I'm not sure which way the relation should go.
Not sure if I'm on the right path, but I'm thinking that I need a couple of many-to-many relationships.. And, which is the right way (if any) to use the same Country model (those will be different instances) in both accepted_countries and restricted_countries?
Thanks.
You should use two many to many relations with related_name to separate them:
class Bookmaker(models.Model):
name = models.CharField(max_length=50)
accepted_countries = models.ManyToManyField(Country, related_name="accepted_for")
restricted_countries = models.ManyToManyField(Country, related_name="restricted_for")
You can then use the reverse relation as:
bookmakers_for_which_county_is_accepted = Country.objects.values('accepted_for').distinct()
bookmakers_for_which_county_is_restricted = Country.objects.values('restricted_for').distinct()
docs
You need indeed some many to many:
class Bookmaker(models.Model):
name = models.CharField(max_length=50)
accepted_countries = models.ManyToMany('Country',related_name='accepted')
restricted_countries = models.ManyToMany('Country', related_name= 'restricted')
class Country(models.Model):
name = models.CharField(max_length=50)
bookmakers = models.ManyToMany(Bookmaker)
Then if you create a form to edit a bookmaker you will be abble to add the name, the accepted and restricted countries:
forms.py
class BookmakerForm(models.ModelForm):
class Meta:
model = Bookmaker
fields = ['name', 'accepted_countries', 'restricted_countries']
#for having a better default display you can change the widget:
self __init__(self, *args, **kwargs):
super(BookmakerForm, self).__init__(*args, **kwargs)
self.fields['accepted_countries'].widget = CheckboxSelectMultiple()
self.fields['restricted_countries'].widget = CheckboxSelectMultiple()
In the view by default if you just need to check if form.is_valid() and save. django modelform will manage the intermediary step for you.
The bookmakers field in Country allows you to retrieve all the bookmaker associated to a country without having to check in both accepted and restricted (it's more for convenience).
But you will need to add the bookmaker to that list on you view like:
class CreateBookmakerView(CreateView):
model = Bookmaker
form_class = BookmakerForm
success_url = reverse_lazy('your success url name here')
def form_valid(self,form):
bookmaker = form.save()
bookmaker.country_set.add(bookmaker)
bookmaker.save()
return HttpResponseRedirect(self.get_success_url())

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.

how can I save a form with ModelMultipleChoiceField?

I have a model Calendar and in a form I want to be able to create multiple instances of it.
Here are my models:
class Event(models.Model):
user = models.ForeignKey(User)
class Group(models.Model):
name = models.CharField(_('Name'), max_length=80)
events = models.ManyToManyField(Event, through='Calendar')
class Calendar(models.Model):
event = models.ForeignKey(Event)
group = models.ForeignKey(Group)
class CalendarInline(admin.TabularInline):
model = Calendar
extra = 1
class GroupAdmin(admin.ModelAdmin):
inlines = (CalendarInline,)
Here is how I try to code my form:
class AddEventToGroupForm(ModelForm):
group = ModelMultipleChoiceField(queryset=Group.objects.all(), widget=SelectMultiple())
def save(self):
for g in self:
g.save()
class Meta:
model = Calendar
fields = ('group',)
And here is a part of my view:
e = Event.objects.get(id=event_id)
calentry = Calendar(event=e)
if request.POST:
f = AddEventToGroupForm(data=request.POST, instance=calentry)
if f.is_valid():
f.save()
If I try to submit that form, I get:
AttributeError at /groups/add_event/7/
'BoundField' object has no attribute 'save'
What is the proper way to create multiple instances of Calendar in this
situation?
That's not how to deal with many-to-many relationships in forms. You can't iterate through fields in a form and save them, it really doesn't work that way.
In this form, there's only one field, which happens to have multiple values. The thing to do here is to iterate through the values of this field, which you'll find in the cleaned_data dictionary (when the form is valid).
So, in your view, you do something like:
if f.is_valid():
for group in f.cleaned_data['group']:
calentry.groups.add(group)
Note you're not 'saving' the AddEventToGroupForm form at all. I would make it a standard forms.Form, rather than a ModelForm, as you're not really depending on any of the ModelForm functionality.

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