Question

在Flask-PyMongo中，他们使用self._Collection__database来表示此Collection对象所属的数据库对象：

class Collection(collection.Collection):
    """Custom sub-class of :class:`pymongo.collection.Collection` which
    adds Flask-specific helper methods.
    """

    def __getattr__(self, name):
        attr = super(Collection, self).__getattr__(name)
        if isinstance(attr, collection.Collection):
            db = self._Collection__database
            return Collection(db, attr.name)
        return attr

工作正常。虽然我想定义另一个

class CollectionV（collection.Collection）

类由于某种原因（原因：我想让'remove'操作只将字段值从“visible”更改为“removed”），类定义为：

class CollectionV(collection.Collection):
    """Custom sub-class of :class:`pymongo.collection.Collection` which
    adds Flask-specific helper methods.
    """

    def __getattr__(self, name):
        attr = super(CollectionV, self).__getattr__(name)
        if isinstance(attr, collection.Collection):
            db = self._CollectionV__database
            return CollectionV(db, attr.name)
        return attr

然后我收到'RuntimeError: maximum recursion depth exceeded'错误，错误日志显示"self._CollectionV__database"被视为一个集合，它会继续以递归方式调用__getattr__()。

为什么在"self._Collection__database"中使用class Collection(collection.Collection)是正常的，而CollectionV会导致问题？

像Flask-PyMongo这样的Flask扩展：为什么我不能改变Collection的名字？

0 个答案: