Raising ValidationError from django model's save method?

Question

I need to raise an exception in a model's save method. I'm hoping that an exception exists that will be caught by any django ModelForm that uses this model including the admin forms.

I tried raising django.forms.ValidationError, but this seems to be uncaught by the admin forms. The model makes a remote procedure call at save time, and it's not known until this call if the input is valid.

Thanks, Pete

Answer 1

Since Django 1.2, this is what I've been doing:

class MyModel(models.Model):

    <...model fields...>

    def clean(self, *args, **kwargs):
        if <some constraint not met>:
            raise ValidationError('You have not met a constraint!')
        super(MyModel, self).clean(*args, **kwargs)

    def full_clean(self, *args, **kwargs):
        return self.clean(*args, **kwargs)

    def save(self, *args, **kwargs):
        self.full_clean()
        super(MyModel, self).save(*args, **kwargs)

This has the benefit of working both inside and outside of admin.