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

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 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 . 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("%s" % 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("""%s%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)