CODEWITHSUNDEEP
djangodjango-forms
Rob L
Rob L

Reputation: 3734

Django field to_python() method on ModelForm

The to_python method of my custom field seems to not get called.

I have:

models.py

class FooURLField(models.URLField):
    def to_python(self, value):
        if value == u'http://':
            return u''
        return value


class Foo(models.Model):
    slug = models.SlugField(unique=True, max_length=128)
    url = FooURLField(blank=True)

forms.py

class FooForm(ModelForm):

    class Meta:
        model = Foo
        exclude = ['slug',]

I want the form to clear out the (default) value 'http://' if the url is left blank. But the to_python() method never gets called. On a POST, it just goes straight to the foo_form.is_valid().

I was under the impression that to_python() happens before the form gets cleaned. I realize I could do it with javascript, but I'd rather do it this way.

Upvotes: 0

Views: 3260

Answers (1)

Daniel Roseman
Daniel Roseman

Reputation: 599778

This is explained in the documentation for custom model fields; you need to add the SubfieldBase metaclass declaration.

However, this isn't really an appropriate use of a custom field. You should really do this in the form: either via a specific clean_url method or by providing a custom form field with its own clean method.

Upvotes: 2

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