Making some fields on a form read only

forms.py

from django import forms
from readonly_form import ReadOnly

class MyForm(ReadOnly):
    """
    This form may now add fields as readonly
    """
    
    class Meta:
        model = auth.User
        exclude = ('password', )
        readonly = ('modified_by', 'last_login')

readonly_form.py

from django.utils.encoding import force_text
import types


def render(self, name, value, attrs=None):
    attrs['disabled'] = 'disabled'
    return super(self.__class__, self).render(name, value, attrs)


def value_from_datadict(self, data, files, name):
    return self.original_value


def disable_widget(field):
    widget = field.widget
    widget.render = types.MethodType(render, widget)
    widget.value_from_datadict = types.MethodType(value_from_datadict, widget)
    return widget


class Readonly(object):
    """Base class for ReadonlyForm and ReadonlyModelForm which provides
    the meat of the features described in the docstings for those classes.
    """

    def __init__(self, *args, **kwargs):
        super(Readonly, self).__init__(*args, **kwargs)
        readonly = getattr(self.Meta, 'readonly', tuple())
        if not readonly:
            return
        for name in readonly:
            field = self.fields[name]
            disable_widget(field)
            field.widget.original_value = force_text(field.widget._format_value(getattr(self.instance, name)))