Question

Searching on the documentation provided by google and browsing SO I haven’t found a way to retrieve the choices set on a db.Property object (I want to retrieve it in order to create forms based on the model).

I’m using the following recipe to do what I need, Is this correct? Is there any other way of doing it? (simpler, more elegant, more pythonic, etc.)

For a model like this:

class PhoneNumber(db.Model):
    contact = db.ReferenceProperty(Contact,
                               collection_name='phone_numbers')
    phone_type = db.StringProperty(choices=('home', 'work'))
    number = db.PhoneNumberProperty()

I do the following modification:

class PhoneNumber(db.Model):
    _phone_types = ('home', 'work')
    contact = db.ReferenceProperty(Contact,
                               collection_name='phone_numbers')
    phone_type = db.StringProperty(choices=_phone_types)
    number = db.PhoneNumberProperty()

    @classmethod
    def get_phone_types(self):
        return self._phone_types

Answer 1

You should be able to use PhoneNumber.phone_type.choices. If you want you could make that into a class method too:

@classmethod
def get_phone_types(class_):
    return class_.phone_type.choices

You can decide if you prefer the class method approach or not.

Don’t forget about Python’s dir built-in! It is very useful when exploring objects.