Django form blank=False - django

Question

Currently, if a field is required, this can be enforced via the blank = False argument, such as:
models.py
address1 = models.CharField(max_length=255,null=False,blank=False)
However, the validation is performed prior to the POST action, yielding something like this when trying to submit the form containing an empty field:
I would prefer the validation to be done during the post step, like this:
models.py
address1 = models.CharField(max_length=255,null=False,blank=true)
forms.py
class AddressForm(forms.ModelForm):
def __init__(self,*args,**kwargs):
super(AddressForm,self).__init__(*args,**kwargs)
self.fields['address1'].required = True
And this yields the following result when trying to submit the form containing an empty field:
But the problem with this, (as far as I can tell) is that I need to explicitly state the required attribute for each field on a case-by-case basis.
Is there any way that I can associate blank=False as being representative of the required=True attribute, suppressing the first form validation (above), in favour of the second?

Answer 1

ModelForm runs form validation, then model validation:
There are two main steps involved in validating a ModelForm:
Validating the form
Validating the model instance
So you have to manually add the extra form validation that you want before the inherited model validations.
However, default ModelForm field for blank field is already required:
If the model field has blank=True, then required is set to False on
the form field. Otherwise, required=True
You can change the error message. If you use this additional validations a lot, you can use a Mixin:
class BlankToRequiredMixin(object):
def set_required(self):
model = self._meta.model
for field_name,form_field in self.fields.iteritems():
if not model._meta.get_field(field_name).blank:
form_field.error_messages={'required': 'This field is required'} # to make it required in addtion to non-blank set .required=True
Then, to set required=True for all fields that are non-blank in the model:
class AddressForm(forms.ModelForm,BlankToRequiredMixin):
def __init__(self,*args,**kwargs):
super(AddressForm,self).__init__(*args,**kwargs)
self.set_required()
In a similar way you can add other validations to the form fields, based on the model validation attributes. For the appearance, change the widget and set the field widget in the mixin.