django-eav2/eav/fields.py

63 lines
2 KiB
Python

import re
from django.core.exceptions import ValidationError
from django.db import models
from django.utils.translation import gettext_lazy as _
class EavSlugField(models.SlugField):
"""
The slug field used by :class:`~eav.models.Attribute`
"""
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 in
variables we don't want to be saved in the database.
"""
super(EavSlugField, self).validate(value, instance)
slug_regex = r'[a-z][a-z0-9_]*'
if not re.match(slug_regex, value):
raise ValidationError(_(
'Must be all lower case, start with a letter, and contain '
'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):
"""
The datatype field used by :class:`~eav.models.Attribute`.
"""
def validate(self, value, instance):
"""
Raise ``ValidationError`` if they try to change the datatype of an
:class:`~eav.models.Attribute` that is already used by
:class:`~eav.models.Value` objects.
"""
super(EavDatatypeField, self).validate(value, instance)
if not instance.pk:
return
if type(instance).objects.get(pk=instance.pk).datatype == instance.datatype:
return
if instance.value_set.count():
raise ValidationError(_(
'You cannot change the datatype of an attribute that is already in use.'
))