from django.core.exceptions import ValidationError
from django.db import models
from django.utils.translation import gettext_lazy as _
from eav.forms import CSVFormField
[docs]class EavDatatypeField(models.CharField):
"""
The datatype field used by :class:`~eav.models.Attribute`.
"""
[docs] 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
# added
if not type(instance).objects.filter(pk=instance.pk).exists():
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.'
)
)
[docs]class CSVField(models.TextField): # (models.Field):
description = _("A Comma-Separated-Value field.")
default_separator = ";"
def __init__(self, separator=";", *args, **kwargs):
self.separator = separator
kwargs.setdefault('default', "")
super().__init__(*args, **kwargs)
[docs] def deconstruct(self):
name, path, args, kwargs = super().deconstruct()
if self.separator != self.default_separator:
kwargs['separator'] = self.separator
return name, path, args, kwargs
def from_db_value(self, value, expression, connection, context=None):
if value is None:
return []
return value.split(self.separator)
[docs] def to_python(self, value):
if value is None:
return []
if isinstance(value, list):
return value
return value.split(self.separator)
[docs] def get_prep_value(self, value):
if not value:
return ""
if isinstance(value, str):
return value
elif isinstance(value, list):
return self.separator.join(value)
[docs] def value_to_string(self, obj):
value = self.value_from_object(obj)
return self.get_prep_value(value)