MultiValueDictKeyError hen adding lines with inlineformset - django

Question

I am trying to add more lines on the inline formset factory using the same methodology that I used before on a formset factory but is getting an error:
MultiValueDictKeyError form-TOTAL_FORMS'
models.py:
class ttransactions(models.Model):
transaction_type = models.CharField(max_length=10, choices=tx_choices)
description = models.CharField(max_length=50, null=False, blank=False, default='Description')
transaction_date = models.DateField(default=datetime.today, db_index=True)
company = models.ForeignKey(tcompany, on_delete=models.PROTECT, db_index=True)
def __str__(self):
return self.description
class ttransaction_lines(models.Model):
transaction = models.ForeignKey(ttransactions, on_delete=models.PROTECT, db_index=True)
sequence = models.IntegerField()
transaction_type = models.CharField(max_length=6, choices=debit_credit)
ledger_account = models.ForeignKey(tledger_account, on_delete=models.PROTECT, db_index=True)
amount = models.DecimalField(max_digits=14, decimal_places=2, default=0.0)
vat_amount = models.DecimalField(max_digits=14, decimal_places=2, default=0.0)
vat_code = models.ForeignKey(tvat, on_delete=models.PROTECT, blank=True, null=True)
quantity = models.IntegerField(blank=True, null=True)
posted = models.BooleanField(default=True)
forms.py:
class TransactionsForm(forms.ModelForm):
transaction_date = forms.DateField(widget=forms.SelectDateWidget(years=year_range), initial=datetime.today)
def __init__(self, *args, **kwargs):
self.request = kwargs.pop('request')
super(TransactionsForm, self).__init__(*args, **kwargs)
class Meta:
model = ttransactions
fields = ['description',
'transaction_date']
class TransactionLinesForm(forms.ModelForm):
class Meta:
model = ttransaction_lines
fields = ['transaction_type', 'ledger_account', 'amount']
class BaseTransactionLinesFormSet(BaseModelFormSet):
def clean(self):
super(BaseTransactionLinesFormSet, self).clean()
# Check errors dictionary first, if there are any error, no point in validating further
if any(self.errors):
return
balance = 0
for form in self.forms:
if form.cleaned_data['DELETE'] == True or form.cleaned_data['DELETE'] == '':
continue
if form.cleaned_data['transaction_type']=='Debit':
balance = balance + form.cleaned_data['amount']
else:
balance = balance - form.cleaned_data['amount']
if balance != 0:
message = 'Transactions not balanced (excluding deleting lines)'
raise forms.ValidationError(message)
TransactionLineFormset = inlineformset_factory(ttransactions,
ttransaction_lines,
form=TransactionLinesForm,
can_order=True, can_delete=True)
views.py
class JournalCreateView(LoginRequiredMixin, CreateView):
template_name = 'accounting/journal.html'
model = ttransactions
formset = TransactionLineFormset
form_class = TransactionsForm
success_url = '/accounting/transaction_list'
def get_form_kwargs(self):
kwargs = super(JournalCreateView, self).get_form_kwargs()
kwargs['request'] = self.request
return kwargs
def get(self, request, *args, **kwargs):
self.object = None
form_class = self.get_form_class()
form = self.get_form(form_class)
formset = TransactionLineFormset(queryset=ttransaction_lines.objects.none())
formset.form.base_fields['ledger_account'].queryset = \
tledger_account.objects.filter(company=request.user.current_company)
return self.render_to_response(
self.get_context_data(form=form, formset=formset))
def post(self, request, *args, **kwargs):
extra_forms = 1
if 'additems' in request.POST and request.POST['additems'] == 'true':
formset_dictionary_copy = self.request.POST.copy()
formset_dictionary_copy['form-TOTAL_FORMS'] = \
int(formset_dictionary_copy['form-TOTAL_FORMS']) + extra_forms
formset = TransactionLineFormSet(formset_dictionary_copy)
return self.render_to_response(
self.get_context_data(form=form,
formset=formset))
self.object = None
form_class = self.get_form_class()
form = self.get_form(form_class)
formset = TransactionLineFormset(self.request.POST)
if (form.is_valid() and formset.is_valid()):
return self.form_valid(form, formset)
else:
return self.form_invalid(form, formset)
def form_valid(self, form, formset):
form.instance.company = self.request.user.current_company
self.object = form.save()
sequence = 1
for line in formset:
line.instance.sequence = sequence
sequence += 1
formset.instance = self.object
formset.save()
return super().form_valid(form)
def form_invalid(self, form, formset):
return self.render_to_response(
self.get_context_data(form=form,
formset=formset))
I get the error on the line that dictionary copy line. The code for adding the line is added in the post function. I am not sure if that is the correct place to add this code. Help will be appreciated.

Answer 1

This error occurs if the form submitted is missing the key.
The .get() method allows for a default when accessing a missing key in a dict.
formset_dictionary_copy['form-TOTAL_FORMS'] = \
int(formset_dictionary_copy.get('form-TOTAL_FORMS', 1)) + extra_forms
It appears that, the formset is not getting all it's hidden values or a different form is submitted.
I would consider a frontend solution or sending a single initial formset with the add button values.
A frontend / js example:
https://www.brennantymrak.com/articles/django-dynamic-formsets-javascript