In a Django form, how do I make a field readonly (or disabled) so that it cannot be edited?

Question

In a Django form, how do I make a field read-only (or disabled)?

When the form is being used to create a new entry, all fields should be enabled - but when the recor

Answer 1

For Django 1.2+, you can override the field like so:

sku = forms.CharField(widget = forms.TextInput(attrs={'readonly':'readonly'}))

Answer 2

As a useful addition to Humphrey's post, I had some issues with django-reversion, because it still registered disabled fields as 'changed'. The following code fixes the problem.

class ItemForm(ModelForm):

    def __init__(self, *args, **kwargs):
        super(ItemForm, self).__init__(*args, **kwargs)
        instance = getattr(self, 'instance', None)
        if instance and instance.id:
            self.fields['sku'].required = False
            self.fields['sku'].widget.attrs['disabled'] = 'disabled'

    def clean_sku(self):
        # As shown in the above answer.
        instance = getattr(self, 'instance', None)
        if instance:
            try:
                self.changed_data.remove('sku')
            except ValueError, e:
                pass
            return instance.sku
        else:
            return self.cleaned_data.get('sku', None)

Answer 3

How I do it with Django 1.11 :

class ItemForm(ModelForm):
    disabled_fields = ('added_by',)

    class Meta:
        model = Item
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        super(ItemForm, self).__init__(*args, **kwargs)
        for field in self.disabled_fields:
            self.fields[field].disabled = True

Answer 4

I was going into the same problem so I created a Mixin that seems to work for my use cases.

class ReadOnlyFieldsMixin(object):
    readonly_fields =()

    def __init__(self, *args, **kwargs):
        super(ReadOnlyFieldsMixin, self).__init__(*args, **kwargs)
        for field in (field for name, field in self.fields.iteritems() if name in self.readonly_fields):
            field.widget.attrs['disabled'] = 'true'
            field.required = False

    def clean(self):
        cleaned_data = super(ReadOnlyFieldsMixin,self).clean()
        for field in self.readonly_fields:
           cleaned_data[field] = getattr(self.instance, field)

        return cleaned_data

Usage, just define which ones must be read only:

class MyFormWithReadOnlyFields(ReadOnlyFieldsMixin, MyForm):
    readonly_fields = ('field1', 'field2', 'fieldx')

Answer 5

Two more (similar) approaches with one generalized example:

1) first approach - removing field in save() method, e.g. (not tested ;) ):

def save(self, *args, **kwargs):
    for fname in self.readonly_fields:
        if fname in self.cleaned_data:
            del self.cleaned_data[fname]
    return super(<form-name>, self).save(*args,**kwargs)

2) second approach - reset field to initial value in clean method:

def clean_<fieldname>(self):
    return self.initial[<fieldname>] # or getattr(self.instance, fieldname)

Based on second approach I generalized it like this:

from functools                 import partial

class <Form-name>(...):

    def __init__(self, ...):
        ...
        super(<Form-name>, self).__init__(*args, **kwargs)
        ...
        for i, (fname, field) in enumerate(self.fields.iteritems()):
            if fname in self.readonly_fields:
                field.widget.attrs['readonly'] = "readonly"
                field.required = False
                # set clean method to reset value back
                clean_method_name = "clean_%s" % fname
                assert clean_method_name not in dir(self)
                setattr(self, clean_method_name, partial(self._clean_for_readonly_field, fname=fname))

    def _clean_for_readonly_field(self, fname):
        """ will reset value to initial - nothing will be changed 
            needs to be added dynamically - partial, see init_fields
        """
        return self.initial[fname] # or getattr(self.instance, fieldname)

Answer 6

Here is a slightly more involved version, based on christophe31's answer. It does not rely on the "readonly" attribute. This makes its problems, like select boxes still being changeable and datapickers still popping up, go away.

Instead, it wraps the form fields widget in a readonly widget, thus making the form still validate. The content of the original widget is displayed inside <span class="hidden"></span> tags. If the widget has a render_readonly() method it uses that as the visible text, otherwise it parses the HTML of the original widget and tries to guess the best representation.

import django.forms.widgets as f
import xml.etree.ElementTree as etree
from django.utils.safestring import mark_safe

def make_readonly(form):
    """
    Makes all fields on the form readonly and prevents it from POST hacks.
    """

    def _get_cleaner(_form, field):
        def clean_field():
            return getattr(_form.instance, field, None)
        return clean_field

    for field_name in form.fields.keys():
        form.fields[field_name].widget = ReadOnlyWidget(
            initial_widget=form.fields[field_name].widget)
        setattr(form, "clean_" + field_name, 
                _get_cleaner(form, field_name))

    form.is_readonly = True

class ReadOnlyWidget(f.Select):
    """
    Renders the content of the initial widget in a hidden <span>. If the
    initial widget has a ``render_readonly()`` method it uses that as display
    text, otherwise it tries to guess by parsing the html of the initial widget.
    """

    def __init__(self, initial_widget, *args, **kwargs):
        self.initial_widget = initial_widget
        super(ReadOnlyWidget, self).__init__(*args, **kwargs)

    def render(self, *args, **kwargs):
        def guess_readonly_text(original_content):
            root = etree.fromstring("<span>%s</span>" % original_content)

            for element in root:
                if element.tag == 'input':
                    return element.get('value')

                if element.tag == 'select':
                    for option in element:
                        if option.get('selected'):
                            return option.text

                if element.tag == 'textarea':
                    return element.text

            return "N/A"

        original_content = self.initial_widget.render(*args, **kwargs)
        try:
            readonly_text = self.initial_widget.render_readonly(*args, **kwargs)
        except AttributeError:
            readonly_text = guess_readonly_text(original_content)

        return mark_safe("""<span class="hidden">%s</span>%s""" % (
            original_content, readonly_text))

# Usage example 1.
self.fields['my_field'].widget = ReadOnlyWidget(self.fields['my_field'].widget)

# Usage example 2.
form = MyForm()
make_readonly(form)