我想为我的应用引擎应用程序实现一个简单的 VersionedModel 基模型类。我正在寻找一种不涉及明确选择要复制的字段的模式。
我正在尝试这样的东西,但它对我的口味来说太老套了,还没有在生产环境中测试它。
class VersionedModel(BaseModel):
is_history_copy = db.BooleanProperty(default=False)
version = db.IntegerProperty()
created = db.DateTimeProperty(auto_now_add=True)
edited = db.DateTimeProperty()
user = db.UserProperty(auto_current_user=True)
def put(self, **kwargs):
if self.is_history_copy:
if self.is_saved():
raise Exception, "History copies of %s are not allowed to change" % type(self).__name__
return super(VersionedModel, self).put(**kwargs)
if self.version is None:
self.version = 1
else:
self.version = self.version +1
self.edited = datetime.now() # auto_now would also affect copies making them out of sync
history_copy = copy.copy(self)
history_copy.is_history_copy = True
history_copy._key = None
history_copy._key_name = None
history_copy._entity = None
history_copy._parent = self
def tx():
result = super(VersionedModel, self).put(**kwargs)
history_copy._parent_key = self.key()
history_copy.put()
return result
return db.run_in_transaction(tx)
有没有人有更简单的清洁解决方案来保存应用引擎模型的版本历史?
编辑:搬出copy
tx。感谢@Adam Crossland 的建议。