django-formfield 0.4 documentation

Getting Started

django-formfield is a form field that accepts a django form as its first argument, and validates as well as render’s each form field as expected. Yes a form within a form, within a dream? There are two types of fields available, FormField and ModelFormField. For ModelFormField the data is stored in json. For FormField data is simply returned as a python dictionary (form.cleaned_data)


from django.db import models
from django import forms

from formfield import ModelFormField

class PersonMetaForm(forms.Form):
    age = forms.IntegerField()
    sex = forms.ChoiceField(choices=((1, 'male'), (2, 'female')), required=False)

class Person(models.Model):
    name = CharField(max_length=200)

    meta_info = ModelFormField(form=PersonMetaForm)


Changed in 0.3: You must supply the kwarg argument form to ModelFormField

Which will result in something like this (using the admin)


The ModelFormField is automatically set to null=True, blank=True, this is because validation is done on the inner form. As a result you will see something like the following if we hit save on the change form:


If we supply the change for valid data you should get a python dictionary when retrieving the data:

>>> person = Person.objects.get(pk=1)
>>> person.meta_info
{u'age': 12, u'sex': u'1'}

The form is the only thing forcing valid input, behind the scenes the data is being serialized into json. Therefore on the python level we can supply meta_info any valid json::

>>> from sample_app.models import Person
>>> data = {'some': 'thing', 'is': 'wrong', 'here': 'help!'}
>>> p = Person.objects.create(name="Joan", meta_info=data)
>>> p.meta_info
{'is': 'wrong', 'some': 'thing', 'here': 'help!'}


If the form field is being made available via a change form, such as the admin, any unexpected value will be overridden by what the form returns . For example, the PersonMetaForm above only expects age and sex, so none of the values above (‘is’, ‘some’ and ‘here’) match and will be overridden when the form submitted.

We can however, make the field hidden or readonly and use it to supply any valid json, but its not really the intension of this app.