Django custom Form and GenericView - django

Question

The following code is working but I wonder if there is a more elegant way of doing. I have to pass the specie_id so I can filter the breeds to the corresponding specie. I can pass the specie_id to the view but I also have the information in the Resident model ("specie").
both get() and post() have nearly the same code, passing the specie_id.
The View
class ResidentUpdate(UpdateView):
model = Resident
template_name = "administration/resident_form.html"
form_class = ResidentCreateForm
def get(self, request, pk):
initial = self.model.objects.get(id=pk)
form = self.form_class(instance=initial, specie_id=initial.specie.id)
return render(request, self.template_name, {"form": form})
def post(self, request, pk):
initial = self.model.objects.get(id=pk)
form = self.form_class(request.POST, specie_id=initial.specie.id, instance=initial)
if form.is_valid():
form.save()
return redirect("resident_detail", pk)
return render(request, self.template_name, {"form", form})
The Form
class ResidentCreateForm(ModelForm):
class Meta:
model = Resident
fields = [
"name",
"specie",
"breed",
"gender",
"gender_status",
"birth_date",
"organization",
"social_behaviors",
"notes",
]
widgets = {
"birth_date": DateInput(attrs={"class": "flatpickr"}),
"specie": HiddenInput(),
}
def __init__(self, *args, **kwargs):
self.specie_id = kwargs.pop("specie_id", None)
super(ResidentCreateForm, self).__init__(*args, **kwargs)
self.fields["specie"].initial = self.specie_id
self.fields["breed"].queryset = Breed.objects.for_specie(self.specie_id)
EDIT :
#Alasdair's answer is good and I think I perfected it a little more. My form is used for the create view too. So I added a check to see if I have the specie_id in kwargs (create) or if I have to use the specie_id from the instance (update)
def __init__(self, *args, **kwargs):
self.specie_id = kwargs.pop("specie_id", None)
super(ResidentForm, self).__init__(*args, **kwargs)
if not self.specie_id:
self.specie_id = self.instance.specie.id
self.fields["specie"].initial = self.specie_id
self.fields["breed"].queryset = Breed.objects.for_specie(self.specie_id)

Answer 1

It looks like you can do self.fields["breed"].queryset = Breed.objects.for_specie(self.initial.specie_id), then you don't need to pass in specie_id to the form.
class ResidentCreateForm(ModelForm):
class Meta:
model = Resident
fields = [
"name",
"specie",
"breed",
"gender",
"gender_status",
"birth_date",
"organization",
"social_behaviors",
"notes",
]
widgets = {
"birth_date": DateInput(attrs={"class": "flatpickr"}),
}
def __init__(self, *args, **kwargs):
super(ResidentCreateForm, self).__init__(*args, **kwargs)
self.fields["breed"].queryset = Breed.objects.for_specie(self.instance.specie_id)
Note I've removed the specie hidden input above, I don't think it's necessary.
The UpdateView takes care of passing instance to the form, so you can simplify the view.
from django.urls import reverse
class ResidentUpdate(UpdateView):
model = Resident
template_name = "administration/resident_form.html"
form_class = ResidentCreateForm
def get_success_url(self):
"""Redirect to resident_detail view after a successful update"""
return reverse('resident_detail', args=[self.kwargs['pk']]

Answer 2

I think a better approach would be overriding the get_form_kwargs method in your views.
def get_form_kwargs(self):
form_kwargs = super().get_form_kwargs()
form_kwargs.update({'specie_id': self.kwargs.get('specie_id')})
return form_kwargs