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# GNU MediaGoblin -- federated, autonomous media hosting
# Copyright (C) 2011, 2012 MediaGoblin contributors. See AUTHORS.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import inspect
from mediagoblin.tools.transition import DISABLE_GLOBALS
if not DISABLE_GLOBALS:
from sqlalchemy.orm import scoped_session, sessionmaker
Session = scoped_session(sessionmaker())
class GMGTableBase(object):
# Deletion types
HARD_DELETE = "hard-deletion"
SOFT_DELETE = "soft-deletion"
deletion_mode = HARD_DELETE
@property
def _session(self):
return inspect(self).session
@property
def _app(self):
return self._session.bind.app
if not DISABLE_GLOBALS:
query = Session.query_property()
def get(self, key):
return getattr(self, key)
def setdefault(self, key, defaultvalue):
# The key *has* to exist on sql.
return getattr(self, key)
def save(self, commit=True):
sess = self._session
if sess is None and not DISABLE_GLOBALS:
sess = Session()
assert sess is not None, "Can't save, %r has a detached session" % self
sess.add(self)
if commit:
sess.commit()
else:
sess.flush()
def delete(self, commit=True, deletion=None):
""" Delete the object either using soft or hard deletion """
# Get the setting in the model args if none has been specified.
if deletion is None:
deletion = self.deletion_mode
# Hand off to the correct deletion function.
if deletion == self.HARD_DELETE:
return self.hard_delete(commit=commit)
elif deletion == self.SOFT_DELETE:
return self.soft_delete(commit=commit)
else:
raise ValueError(
"Invalid deletion mode {mode!r}".format(
mode=deletion
)
)
def soft_delete(self, commit):
# Create the graveyard version of this model
# Importing this here due to cyclic imports
from mediagoblin.db.models import User, Graveyard, GenericModelReference
tombstone = Graveyard()
if getattr(self, "public_id", None) is not None:
tombstone.public_id = self.public_id
# This is a special case, we don't want to save any actor if the thing
# being soft deleted is a User model as this would create circular
# ForeignKeys
if not isinstance(self, User):
tombstone.actor = User.query.filter_by(
id=self.actor
).first()
tombstone.object_type = self.object_type
tombstone.save()
# There will be a lot of places where the GenericForeignKey will point
# to the model, we want to remap those to our tombstone.
gmrs = GenericModelReference.query.filter_by(
obj_pk=self.id,
model_type=self.__tablename__
).update({
"obj_pk": tombstone.id,
"model_type": tombstone.__tablename__,
})
# Now we can go ahead and actually delete the model.
return self.hard_delete(commit=commit)
def hard_delete(self, commit):
"""Delete the object and commit the change immediately by default"""
sess = self._session
assert sess is not None, "Not going to delete detached %r" % self
sess.delete(self)
if commit:
sess.commit()
Base = declarative_base(cls=GMGTableBase)
class DictReadAttrProxy(object):
"""
Maps read accesses to obj['key'] to obj.key
and hides all the rest of the obj
"""
def __init__(self, proxied_obj):
self.proxied_obj = proxied_obj
def __getitem__(self, key):
try:
return getattr(self.proxied_obj, key)
except AttributeError:
raise KeyError("%r is not an attribute on %r"
% (key, self.proxied_obj))
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