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Django formset for validating a minimum number of filled out forms.
from django import forms
class MinimumRequiredFormSet(forms.models.BaseInlineFormSet):
"""
Inline formset that enforces a minimum number of non-deleted forms
that are not empty
"""
default_minimum_forms_message = "At least %s set%s of data is required"
def __init__(self, *args, **kwargs):
self.minimum_forms = kwargs.pop('minimum_forms', 0)
minimum_forms_message = kwargs.pop('minimum_forms_message', None)
if minimum_forms_message:
self.minimum_forms_message = minimum_forms_message
else:
self.minimum_forms_message = \
self.default_minimum_forms_message % (
self.minimum_forms,
'' if self.minimum_forms == 1 else 's'
)
super(MinimumRequiredFormSet, self).__init__(*args, **kwargs)
def clean(self):
non_deleted_forms = self.total_form_count()
non_empty_forms = 0
for i in xrange(0, self.total_form_count()):
form = self.forms[i]
if self.can_delete and self._should_delete_form(form):
non_deleted_forms -= 1
if not (form.instance.id is None and not form.has_changed()):
non_empty_forms += 1
if (
non_deleted_forms < self.minimum_forms
or non_empty_forms < self.minimum_forms
):
raise forms.ValidationError(self.minimum_forms_message)
class SamuraiForm(forms.ModelForm):
class Meta:
model = Samuari
###
from django.forms.models import inlineformset_factory
SamuraiFormset = inlineformset_factory(
Kurosawa,
Samurai,
formset=MinimumRequiredFormSet,
form=SamuraiForm,
)
formset = SamuraiFormset(
request.POST,
instance=instance,
minimum_forms=7,
minimum_forms_message="At least seven samurai are required.",
)
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