Validating a formset using data from another form - django

Question

I'm having to do some validation across both a form and formset. The £££ amount in the form must equal the sum of the amounts in the formset.
After a lot of Googling I found a solution where I add a custom init to the baseformset as follows:
class BaseSplitPaymentLineItemFormSet(BaseFormSet):
def __init__(self, cr=None, *args, **kwargs):
self._cr = cr
super().__init__(*args, **kwargs)
def clean(self):
if any(self.errors):
return
sum_dr = 0
for form in self.forms:
sum_dr += form.cleaned_data.get('dr')
if sum_dr != float(self._cr):
raise forms.ValidationError('The amount entered needs to equal the sum of the split payments.')
I then pass the amount value from the form when the formset is instantiated, so that the value can be used in the formset validation:
lineitem_formset = LineItemFormSet(form.data['amount'], request.POST)
This worked great for the create_new view which uses formset_factory(). This morning I wrote the update view using inline_formsetfactory(), but I now get an error:
__init__() got an unexpected keyword argument 'instance'
I only have a basic understanding of how the custom init works, so I can't find a solution to this error.
Forms.py:
class SplitPaymentForm(forms.Form):
date = forms.DateField(widget=DateTypeInput())
account = GroupedModelChoiceField(queryset=Ledger.objects.filter(coa_sub_group__type='a').order_by('coa_sub_group__name','name'), choices_groupby = 'coa_sub_group')
store = forms.CharField(required=True)
amount = forms.DecimalField(decimal_places=2)
class SplitPaymentLineItemForm(ModelForm):
ledger = GroupedModelChoiceField(queryset=Ledger.objects.all().order_by('coa_sub_group__name', 'name'), choices_groupby = 'coa_sub_group', empty_label="Ledger", required=True)
project = forms.ModelChoiceField(queryset=Project.objects.filter(status=0), empty_label="Project", required=False)
class Meta:
model = LineItem
fields = ['description','project', 'ledger','dr',]
# This init disallows empty formsets
def __init__(self, *arg, **kwarg):
super(SplitPaymentLineItemForm, self).__init__(*arg, **kwarg)
self.empty_permitted = False
class BaseSplitPaymentLineItemFormSet(BaseFormSet):
def __init__(self, cr=None, *args, **kwargs):
self._cr = cr
super().__init__(*args, **kwargs)
def clean(self):
if any(self.errors):
return
sum_dr = 0
for form in self.forms:
sum_dr += form.cleaned_data.get('dr')
if sum_dr != float(self._cr):
raise forms.ValidationError('The amount entered needs to equal the sum of the split payments.')
Views.py:
def split_payments_new(request):
LineItemFormSet = formset_factory(SplitPaymentLineItemForm, formset=BaseSplitPaymentLineItemFormSet, extra=2)
if request.method == 'POST':
form = SplitPaymentForm(request.POST)
lineitem_formset = LineItemFormSet(form.data['amount'], request.POST)
if form.is_valid() and lineitem_formset.is_valid():
q0 = JournalEntry(user=request.user, date=form.cleaned_data['date'], type="SP",)
q1 = LineItem(journal_entry=q0, description=form.cleaned_data['store'], ledger=form.cleaned_data['account'], cr=form.cleaned_data['amount'])
q0.save()
q1.save()
for lineitem in lineitem_formset:
q2 = LineItem(journal_entry=q0,description=lineitem.cleaned_data.get('description'),ledger=lineitem.cleaned_data.get('ledger'),project=lineitem.cleaned_data.get('project'),dr=lineitem.cleaned_data.get('dr'))
q2.save()
messages.success(request, "Split payment successfully created.")
return HttpResponseRedirect(reverse('journal:split_payments_show_detail', kwargs={'pk': q0.id}) )
else:
form = SplitPaymentForm(initial = {'date': datetime.date.today().strftime('%Y-%m-%d')})
lineitem_formset = LineItemFormSet()
return render(request, 'journal/split_payments_new.html', {'form': form, 'formset': lineitem_formset})
def split_payments_update(request, pk):
journal_entry = get_object_or_404(JournalEntry, pk=pk, type="SP")
lineitem = LineItem.objects.get(journal_entry=journal_entry.id, dr__isnull=True)
initial = {
'date': journal_entry.date.strftime('%Y-%m-%d'),
'account': lineitem.ledger,
'store': lineitem.description,
'amount': lineitem.cr,
}
form = SplitPaymentForm(initial=initial)
LineItemFormSet = inlineformset_factory(JournalEntry, LineItem, form=SplitPaymentLineItemForm, formset=BaseSplitPaymentLineItemFormSet, extra=0)
lineitem_formset = LineItemFormSet(instance=journal_entry)
if request.method == 'POST':
lineitem_formset = LineItemFormSet(form.data['amount'], request.POST, instance=journal_entry)
form = SplitPaymentForm(request.POST)
if lineitem_formset.is_valid() and form.is_valid():
lineitem_formset.save()
journal_entry.date = form.cleaned_data['date']
lineitem.ledger = form.cleaned_data['account']
lineitem.description = form.cleaned_data['store']
lineitem.cr = form.cleaned_data['amount']
journal_entry.save()
lineitem.save()
messages.success(request, "Split payment successfully updated.")
return HttpResponseRedirect(reverse('journal:split_payments_show_detail', kwargs={'pk': journal_entry.id}) )
return render(request, 'journal/split_payments_update.html',{'form': form, 'formset': lineitem_formset, 'journal_entry': journal_entry})

Answer 1

Solved. Just had to use BaseInlineFormSet.