Adding Django form instance attributes
Sometimes in the
save() methods of a Django
form, you need to have additional form instance attributes available. A
sample case for this is having
user_id available. This is a simple
example of how to do it in Class-Based Views.
Assuming this form:
from django import forms from .models import MyModel class MyForm(forms.ModelForm): class Meta: model = MyModel def __init__(self, user_id, *args, **kwargs): super(MyForm, self).__init__(*args, **kwargs) # set the user_id as an attribute of the form self.user_id = user_id
Now that the form is defined, the view needs to inject the form with the user id:
from django.views.generic import UpdateView # this assumes that django-braces is installed from braces.views import LoginRequiredMixin from .forms import MyForm from .models import MyModel class MyUpdateView(LoginRequiredMixin, UpdateView): model = MyModel form_class = MyForm success_url = "/someplace/" def get_form_kwargs(self): """This method is what injects forms with their keyword arguments.""" # grab the current set of form #kwargs kwargs = super(MyUpdateView, self).get_form_kwargs() # Update the kwargs with the user_id kwargs['user_id'] = self.request.user.pk return kwargs
You can use this technique with:
As always, https://ccbv.co.uk is a great resource for deliving into Django forms.
While this technique is used by
django-braces through the
UserKwargModelFormMixin mixins, it's useful
to know how to do it outside that very useful tool. The reason being
that attaching the
user object or
user_id is just one option out of
This should also work with django-vanilla-views, but I haven't tested it yet.
See you at BarCamp Django SF!
On October 4th and 5th I'll be at BarCamp Django SF if you want to talk about Django, Python, or have me teach you how to do cartwheels.