Replace common module with validate module. Move validation function from feed module to validate module and remove feed.py. Correct any usage of validation functions from common and feed modules into validate module.
Patch by: Pawel Solyga
Review by: to-be-reviewed
"""
Convenience routines for creating non-trivial Field subclasses.
Add SubfieldBase as the __metaclass__ for your Field subclass, implement
to_python() and the other necessary methods and everything will work seamlessly.
"""
from django.utils.maxlength import LegacyMaxlength
class SubfieldBase(LegacyMaxlength):
"""
A metaclass for custom Field subclasses. This ensures the model's attribute
has the descriptor protocol attached to it.
"""
def __new__(cls, base, name, attrs):
new_class = super(SubfieldBase, cls).__new__(cls, base, name, attrs)
new_class.contribute_to_class = make_contrib(
attrs.get('contribute_to_class'))
return new_class
class Creator(object):
"""
A placeholder class that provides a way to set the attribute on the model.
"""
def __init__(self, field):
self.field = field
def __get__(self, obj, type=None):
if obj is None:
raise AttributeError('Can only be accessed via an instance.')
return obj.__dict__[self.field.name]
def __set__(self, obj, value):
obj.__dict__[self.field.name] = self.field.to_python(value)
def make_contrib(func=None):
"""
Returns a suitable contribute_to_class() method for the Field subclass.
If 'func' is passed in, it is the existing contribute_to_class() method on
the subclass and it is called before anything else. It is assumed in this
case that the existing contribute_to_class() calls all the necessary
superclass methods.
"""
def contribute_to_class(self, cls, name):
if func:
func(self, cls, name)
else:
super(self.__class__, self).contribute_to_class(cls, name)
setattr(cls, self.name, Creator(self))
return contribute_to_class