"""
mixins used by other openwisp components to implement multi-tenancy
"""
from django.core.exceptions import ValidationError
from django.db import models
from django.utils.translation import ugettext_lazy as _
from swapper import get_model_name
class ValidateOrgMixin(object):
"""
- implements ``_validate_org_relation`` method
"""
def _validate_org_relation(self, rel, field_error='organization'):
"""
if the relation is owned by a specific organization
this object must be related to the same organization
"""
# avoid exceptions caused by the relation not being set
if not hasattr(self, rel):
return
rel = getattr(self, rel)
if (
rel
and rel.organization_id
and str(self.organization_id) != str(rel.organization_id)
):
message = _(
'Please ensure that the organization of this {object_label} '
'and the organization of the related {related_object_label} match.'
)
message = message.format(
object_label=self._meta.verbose_name,
related_object_label=rel._meta.verbose_name,
)
raise ValidationError({field_error: message})
def _validate_org_reverse_relation(self, rel_name, field_error='organization'):
"""
prevents changing organization for existing objects
which have relations specified by ``rel_name`` pointing to them,
in order to prevent inconsistencies
(relations belonging to different organizations)
"""
# do nothing on new objects, because they
# cannot have relations pointing to them
if self._state.adding:
return
old_self = self.__class__.objects.get(pk=self.pk)
old_org = old_self.organization
# org hasn't been changed, everything ok
if old_org == self.organization:
return
rel = getattr(self, rel_name)
count = rel.count()
if count:
rel_meta = rel.model._meta
related_label = (
rel_meta.verbose_name if count == 1 else rel_meta.verbose_name_plural
)
verb = _('is') if count == 1 else _('are')
message = _(
'The organization of this {object_label} cannot be changed '
'because {0} {related_object_label} {verb} still '
'related to it'.format(
count,
object_label=self._meta.verbose_name,
related_object_label=related_label,
verb=verb,
)
)
raise ValidationError({field_error: message})
class OrgMixin(ValidateOrgMixin, models.Model):
"""
- adds a ``ForeignKey`` field to the ``Organization`` model
(the relation cannot be NULL)
- implements ``_validate_org_relation`` method
"""
organization = models.ForeignKey(
get_model_name('openwisp_users', 'Organization'),
verbose_name=_('organization'),
on_delete=models.CASCADE,
)
class Meta:
abstract = True
class ShareableOrgMixin(OrgMixin):
"""
like ``OrgMixin``, but the relation can be NULL, in which
case it means that the object can be shared between multiple organizations
"""
class Meta:
abstract = True
_org_field = ShareableOrgMixin._meta.get_field('organization')
_org_field.blank = True
_org_field.null = True
