python - How can I disable a model field in a django form

Question

I have a model like this:

class MyModel(models.Model):
    REGULAR = 1
    PREMIUM = 2
    STATUS_CHOICES = ((REGULAR, "regular"), (PREMIUM, "premium"))
    name = models.CharField(max_length=30)
    status = models.IntegerField(choices = STATUS_CHOICES, default = REGULAR)

class MyForm(forms.ModelForm):
    class Meta:
        model = models.MyModel

In a view I initialize one field and try to make it non-editable:

myform = MyForm(initial = {'status': requested_status})
myform.fields['status'].editable = False

But the user can still change that field.

What's the real way to accomplish what I'm after?

Answer 1

Step 1: Disable the frontend widget

Use the HTML readonly attribute:
http://www.w3schools.com/tags/att_input_readonly.asp

Or disabled attribute:
http://www.w3.org/TR/html401/interact/forms.html#adef-disabled

You can inject arbitrary HTML key value pairs via the widget attrs property:

myform.fields['status'].widget.attrs['readonly'] = True # text input
myform.fields['status'].widget.attrs['disabled'] = True # radio / checkbox

Step 2: Ensure the field is effectively disabled on backend

Override your clean method for your field so that regardless of POST input (somebody can fake a POST, edit the raw HTML, etc.) you get the field value that already exists.

def clean_status(self):
    # when field is cleaned, we always return the existing model field.
    return self.instance.status