Django Form Validators on Comparing One Object Against Another - django

Question

I am creating a Non Disclosure Agreement form that a user fills out after registering and logging in. I am using a custom signup form with AllAuth and pre-populating parts of the form. I pre-populate the first and last name into the top part of the form as shown below in first screen shot, but as a part of the digital signature I am setting up; I need to validate the typed signature field matches the name of the first_name and the last_name concatenated together per the second screen-shot. I know I need to setup a validator based on Django Form & Field Validations and I've tried several things but just can't get my mind rapped around it. Any help putting this together would be huge...thank you.
My Models
class Profile(models.Model):
user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="profile", verbose_name="user")
...
class NonDisclosure(Timestamp):
profile = models.ForeignKey(Profile, on_delete=models.CASCADE, related_name="nda", verbose_name="profile")
user_signature = models.CharField(max_length=250, verbose_name='Signature')
user_street = models.CharField(max_length=250, verbose_name='Street Address')
user_city = models.CharField(max_length=250, verbose_name='City')
user_state = models.CharField(max_length=2, verbose_name='State Initials')
user_zip = models.IntegerField(verbose_name='Zip Code')
phone = models.CharField(max_length=25, verbose_name='Phone Number')
cash_on_hand = models.CharField(max_length=250, verbose_name='Cash on Hand')
value_of_securities = models.CharField(max_length=250, verbose_name='Value of Securities')
equity_in_real_estate = models.CharField(max_length=250, verbose_name='Equity on Real Estate')
other = models.CharField(max_length=250, verbose_name='Other Assets')
#property
def username(self):
return self.profile.username
#property
def first_name(self):
return self.profile.first_name
#property
def last_name(self):
return self.profile.last_name
#property
def email(self):
return self.profile.email
class Meta:
verbose_name = 'Non Disclosure Agreement'
verbose_name_plural = 'Non Disclosure Agreements'
def __str__(self):
return "%s" % self.profile
def get_absolute_url(self):
return reverse('nda_detail', args=[str(self.id)])
My Views:
class NonDisclosureForm(BaseModelForm):
cash_on_hand = forms.CharField(required=False)
value_of_securities = forms.CharField(required=False)
equity_in_real_estate = forms.CharField(required=False)
other = forms.CharField(required=False)
class Meta:
model = NonDisclosure
fields = ['user_signature', 'user_street', 'user_city', 'user_state', 'user_zip', 'phone', 'cash_on_hand', 'value_of_securities', 'equity_in_real_estate', 'other']
class NdaCreate(CreateView):
form_class = NonDisclosureForm
template_name = 'nda/nda_form.html'
def form_valid(self, form):
form.instance.profile = Profile.objects.get(user=self.request.user)
form.instance.created_by = self.request.user
return super(NdaCreate, self).form_valid(form)

Answer 1

Firstly, you should subclass ModelForm, not BaseModelForm. Write a clean_<fieldname> method for your user_signature field, and make sure that the value is as expected. You can access self.instance.created_by to check.
class NonDisclosureForm(ModelForm):
...
class Meta:
model = NonDisclosure
fields = ['user_signature', ...]
def clean_user_signature(self):
user_signature = self.cleaned_data['user_signature']
expected_name = '%s %s' % (self.instance.created_by.first_name, self.instance.created_by.last_name)
if user_signature != expected_name:
raise forms.ValidationError('Signature does not match')
return user_signature
Then you need to update your view so that it sets instance.created_by. You can do this by overriding get_form_kwargs.
class NdaCreate(CreateView):
def get_form_kwargs(self):
kwargs = super(NdaCreate, self).get_form_kwargs()
kwargs['instance'] = NonDisclosure(created_by=self.request.user)
return kwargs