Django creating a form field that's read only using widgets

You should use a form field and not a model field:

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

replaced with

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

Should fix it.

Note that the readonly attribute does not keep Django from processing any value sent by the client. If it is important to you that the value doesn't change, no matter how creative your users are with FireBug, you need to use a more involved method, e.g. a ReadOnlyField/ReadOnlyWidget like demonstrated in a blog entry by Alex Gaynor.

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')