class VersionedDocument(Document):
my_metaclass = TopLevelDocumentMetaclass
_rev = ObjectIdField(required=True)
_parent = ObjectIdField()
_ts = DateTimeField(default=datetime.now)
_meta = {'abstract': True}
def save(self, *args, **kwargs):
Document.save.__doc__
#generate a new revision
if not self.id:
self.id = ObjectId()
# self._created is an internal attribute used by MongoEngine to determine
# what to do when saving the document. When we assign a value to self.id
# this attribute gets set to False. We want to reset it to True so ME will
# do its usual business when saving this new document.
self._created = True
self._parent = None
else:
self._parent = self._rev
self._ts = datetime.now()
self._rev = ObjectId()
#save it in the versioning collection
nv = self.to_mongo()
if issubclass(type(self.id), EmbeddedDocument):
nv['_id'] = {'id': self.id.to_mongo(), 'rev': self._rev}
else:
nv['_id'] = {'id': self.id, 'rev': self._rev}
db = self._get_db()
db['versioned_'+self._meta['collection']].insert(nv, safe=True)
return super(VersionedDocument, self).save(*args, **kwargs)
