Я реализовал это сам и делюсь своими выводами.
Архив
Первое архивирование довольно просто, так как я ослабил ограничения внешнего ключа для архивных таблиц.
Вы не можете сохранить все ограничения в архивном мире, как в живом мире, потому что то, на что ссылается ваш подлежащий удалению объект, не будет в архивном мире. (потому что он не будет удален)
Это можно сделать через миксин (систематически)
По сути, вы создаете архивные объекты с помощью каскада, а затем удаляете оригинал.
Разархивировать
С другой стороны, разархивировать сложнее, потому что вам нужно подтвердить ограничения внешнего ключа.
Это нельзя делать систематически.
По той же причине сериализаторы, такие как Django rest framework, не могут волшебным образом создавать связанные объекты. Вы должны знать граф объекта и ограничения.
Вот почему нет библиотеки или миксина для поддержки этого.
В любом случае, я делюсь своим кодом миксина ниже.
class DeleteModelQuerySet(object):
'''
take a look at django.db.models.deletion
'''
def hard_delete(self):
super().delete()
def delete(self):
if not self.is_archivable():
super().delete()
return
archive_object_ids = []
seen = []
collector = NestedObjects(using='default') # or specific database
collector.collect(list(self))
collector.sort()
with transaction.atomic():
for model, instances in six.iteritems(collector.data):
if model in self.model.exclude_models_from_archive():
continue
assert hasattr(model, "is_archivable"), {
"model {} doesn't know about archive".format(model)
}
if not model.is_archivable():
# just delete
continue
for instance in instances:
if instance in seen:
continue
seen.append(instance)
for ptr in six.itervalues(instance._meta.parents):
# add parents to seen
if ptr:
seen.append(getattr(instance, ptr.name))
archive_object = model.create_archive_object(instance)
archive_object_ids.append(archive_object.id)
# real delete
super().delete()
archive_objects = self.model.get_archive_model().objects.filter(id__in=archive_object_ids)
return archive_objects
def undelete(self):
with transaction.atomic():
self.unarchive()
super().delete()
def is_archivable(self):
# if false, we hard delete instead of archive
return self.model.is_archivable()
def unarchive(self):
for obj_archive in self:
self.model.create_live_object(obj_archive)
class DeleteModelMixin(models.Model):
@classmethod
def is_archivable(cls):
# override if you don't want to archive and just delete
return True
def get_deletable_objects(self):
collector = NestedObjects(using='default') # or specific database
collector.collect(list(self))
collector.sort()
deletable_data = collector.data
return deletable_data
@classmethod
def create_archive_object(cls, obj):
# http://stackoverflow.com/q/21925671/433570
# d = cls.objects.filter(id=obj.id).values()[0]
d = obj.__dict__.copy()
remove_fields = []
for field_name, value in six.iteritems(d):
try:
obj._meta.get_field(field_name)
except FieldDoesNotExist:
remove_fields.append(field_name)
for remove_field in remove_fields:
d.pop(remove_field)
cls.convert_to_archive_dictionary(d)
# print(d)
archive_object = cls.get_archive_model().objects.create(**d)
return archive_object
@classmethod
def create_live_object(cls, obj):
# index error, dont know why..
# d = cls.objects.filter(id=obj.id).values()[0]
d = obj.__dict__.copy()
remove_fields = [cls.convert_to_archive_field_name(field_name) + '_id' for field_name in cls.get_twostep_field_names()]
for field_name, value in six.iteritems(d):
try:
obj._meta.get_field(field_name)
except FieldDoesNotExist:
remove_fields.append(field_name)
for remove_field in remove_fields:
d.pop(remove_field)
cls.convert_to_live_dictionary(d)
live_object = cls.get_live_model().objects.create(**d)
return live_object
@classmethod
def get_archive_model_name(cls):
return '{}Archive'.format(cls._meta.model_name)
@classmethod
def get_live_model_name(cls):
if cls._meta.model_name.endswith("archive"):
length = len("Archive")
return cls._meta.model_name[:-length]
return cls._meta.model_name
@classmethod
def get_archive_model(cls):
# http://stackoverflow.com/a/26126935/433570
return apps.get_model(app_label=cls._meta.app_label, model_name=cls.get_archive_model_name())
@classmethod
def get_live_model(cls):
return apps.get_model(app_label=cls._meta.app_label, model_name=cls.get_live_model_name())
@classmethod
def is_archive_model(cls):
if cls._meta.model_name.endswith("Archive"):
return True
return False
@classmethod
def is_live_model(cls):
if cls.is_archive_model():
return False
return True
def make_referers_point_to_archive(self, archive_object, seen):
instance = self
for related in get_candidate_relations_to_delete(instance._meta):
accessor_name = related.get_accessor_name()
if accessor_name.endswith('+') or accessor_name.lower().endswith("archive"):
continue
referers = None
if related.one_to_one:
referer = getattr(instance, accessor_name, None)
if referer:
referers = type(referer).objects.filter(id=referer.id)
else:
referers = getattr(instance, accessor_name).all()
refering_field_name = '{}_archive'.format(related.field.name)
if referers:
assert hasattr(referers, 'is_archivable'), {
"referers is not archivable: {referer_cls}".format(
referer_cls=referers.model
)
}
archive_referers = referers.delete(seen=seen)
if referers.is_archivable():
archive_referers.update(**{refering_field_name: archive_object})
def hard_delete(self):
super().delete()
def delete(self, *args, **kwargs):
self._meta.model.objects.filter(id=self.id).delete()
def undelete(self, commit=True):
self._meta.model.objects.filter(id=self.id).undelete()
def unarchive(self, commit=True):
self._meta.model.objects.filter(id=self.id).unarchive()
@classmethod
def get_archive_field_names(cls):
raise NotImplementedError('get_archive_field_names() must be implemented')
@classmethod
def convert_to_archive_dictionary(cls, d):
field_names = cls.get_archive_field_names()
for field_name in field_names:
field_name = '{}_id'.format(field_name)
archive_field_name = cls.convert_to_archive_field_name(field_name)
d[archive_field_name] = d.pop(field_name)
@classmethod
def convert_to_live_dictionary(cls, d):
field_names = list(set(cls.get_archive_field_names()) - set(cls.get_twostep_field_names()))
for field_name in field_names:
field_name = '{}_id'.format(field_name)
archive_field_name = cls.convert_to_archive_field_name(field_name)
d[field_name] = d.pop(archive_field_name)
@classmethod
def convert_to_archive_field_name(cls, field_name):
if field_name.endswith('_id'):
length = len('_id')
return '{}_archive_id'.format(field_name[:-length])
return '{}_archive'.format(field_name)
@classmethod
def convert_to_live_field_name(cls, field_name):
if field_name.endswith('_archive_id'):
length = len('_archive_id')
return '{}_id'.format(field_name[:-length])
if field_name.endswith('archive'):
length = len('_archive')
return '{}'.format(field_name[:-length])
return None
@classmethod
def get_twostep_field_names(cls):
return []
@classmethod
def exclude_models_from_archive(cls):
# excluded model can be deleted if referencing to me
# or just lives if I reference him
return []
class Meta:
abstract = True
person
eugene
schedule
24.12.2015
put-on-hold
статуса? - person eugene   schedule 21.12.2015