change a form value before validation in Django form

Question

I have a django form and on my view function I do this :

search_packages_form = SearchPackagesForm( data = request.POST )

I would like to overwrite a form field called price which is decleared as such :

price = forms.ChoiceField( choices = PRICE_CHOICES, required = False,widget = forms.RadioSelect )

I would like to overwrite the form field before calling search_packages_form.is_valid()

I thought of doing :

search_packages_form.data['price'] = NEW_PRICE

But it does not work. Any ideas ?

Answer 1

Probably not the Django way but based on https://stackoverflow.com/a/17304350/2730032 I'm guessing the easiest way to change your form value before validation is to do something like the following:

def search_packages_view(request):
    if request.method == 'POST'
        updated_request = request.POST.copy()
        updated_request.update({'price': NEW_PRICE})
        search_packages_form = SearchPackagesForm(updated_request)
        if search_packages_form.is_valid():
             # You're all good

This works but I'd be interested if anyone has another way that seems more in line with Django, or if there isn't: then an explanation about why.

Answer 2

one trick for what you want is to do it like this:

changed_data = dict(request.POST)
changed_data['price'] = NEW_PRICE
search_packages_form = SearchPackagesForm(data = changed_data)