django-eav2/fields.py
2010-09-22 16:41:07 +03:00

75 lines
2.7 KiB
Python

#!/usr/bin/env python
# vim: ai ts=4 sts=4 et sw=4 coding=utf-8
#
# This software is derived from EAV-Django originally written and
# copyrighted by Andrey Mikhaylenko <http://pypi.python.org/pypi/eav-django>
#
# This is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This software is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with EAV-Django. If not, see <http://gnu.org/licenses/>.
import uuid
import re
from django.db import models
from django.utils.translation import ugettext_lazy as _
from django.core.exceptions import ValidationError
class EavSlugField(models.SlugField):
def validate(self, value, instance):
"""
Slugs are used to convert the Python attribute name to a database
lookup and vice versa. We need it to be a valid Python identifier.
We don't want it to start with a '_', underscore will be used
var variables we don't want to be saved in db.
"""
super(EavSlugField, self).validate(value, instance)
slug_regex = r'[a-z][a-z0-9_]*'
if not re.match(slug_regex, value):
raise ValidationError(_(u"Must be all lower case, "\
u"start with a letter, and contain "\
u"only letters, numbers, or underscores."))
@staticmethod
def create_slug_from_name(name):
'''
Creates a slug based on the name
'''
name = name.strip().lower()
# Change spaces to underscores
name = '_'.join(name.split())
# Remove non alphanumeric characters
return re.sub('[^\w]', '', name)
class EavDatatypeField(models.CharField):
"""
This holds checks for the attributes datatypes.
"""
def validate(self, value, instance):
"""
We don't want them to be able to change the attribute type
once it have been created.
"""
super(EavDatatypeField, self).validate(value, instance)
from .models import Attribute
if not instance.pk:
return
if instance.value_set.count():
raise ValidationError(_(u"You cannot change the datatype of an "
u"attribute that is already in use."))