Class Based View, add data to the Form - django

Question

I'm trying to achieve something that I tought would be pretty basic, but can't seem to find the solution for it.
I'm creating a pretty generic view for creating and updating users in a django app. I have a 'provider' model with associated permissions. I would like to add rights management in a very checkboxy simple way. When I show the form the checkbox should be check if user have permissions to add / delete / modify, and on the other hand, when the checkbox is checked, the permissions should be set in the database.
It goes like this :
class UserUpdate(UpdateView):
form_class = UserForm
model = User
def get_initial(self):
user = self.get_object()
if user is not None and user.has_perm('core.add_provider'):
return { 'right_provider' : True }
def form_valid(self, form):
user = form.save(commit=False)
if form.right_provider:
user.user_permissions.add('core.add_provider', 'core.change_provider', 'core.delete_provider')
else:
user.user_permissions.remove('core.add_provider', 'core.change_provider', 'core.delete_provider')
return super().form_valid(form)
Then a form :
class UserForm(ModelForm):
right_provider = BooleanField(label='Right Provider', required=False)
class Meta:
model = User
fields = ['username', 'email', 'first_name', 'last_name']
Apparently it's not the way to do it, since 'UserForm' object has no attribute 'right_provider'
Am i doing it right, and if so, what is the issue with this code?
Is there litterature on how to pass data back and forth between the ModelForm and the Model?

Answer 1

You can get the value from the form's cleaned_data.
def form_valid(self, form):
if form.cleaned_data['right_provider']:
...
else:
...
return super().form_valid(form)
def form_valid(self, form):
if form.cleaned_data['right_provider']:
...
else:
...
return super().form_valid(form)
Note I have removed the save() call - the form will be saved automatically when you call super().
If you do need to call save in your view, I would avoid calling super(). I think it's clearer, and it avoids a potential problem of save_m2m not being called. See the docs for the save method form more information.
def form_valid(self, form):
user = form.save(commit=False)
...
user.save() # save the user to the db
form.save_m2m() # required if the form has m2m fields
return HttpResponseRedirect(self.get_success_url())
Another option is to call super() first without returning, then access self.object, and finally return the response.
def form_valid(self, form):
response = super().form_valid(form)
user = self.object
if form.cleaned_data['right_provider']:
...
else:
...
return response

Answer 2

Model forms expect the form fields to match the model fields. So you could add it as a field to your model.
If you only want the field on the form, you want to add it in the innit method of the form.
class UserFrom(ModelForm)
def __init__(self, **kwargs)
super(UserForm, self).__init__(**kwargs)
# probably some code here to work out the initial state of the checkbox,
self.fields['right_provider'] = forms.BooleanField(label='Right Provider', required=False)