appengine.py 文件源码

def __init__(self, model, key_name, property_name, cache=None, user=None):
        """Constructor for Storage.

        Args:
            model: db.Model or ndb.Model, model class
            key_name: string, key name for the entity that has the credentials
            property_name: string, name of the property that is a
                           CredentialsProperty or CredentialsNDBProperty.
            cache: memcache, a write-through cache to put in front of the
                   datastore. If the model you are using is an NDB model, using
                   a cache will be redundant since the model uses an instance
                   cache and memcache for you.
            user: users.User object, optional. Can be used to grab user ID as a
                  key_name if no key name is specified.
        """
        if key_name is None:
            if user is None:
                raise ValueError('StorageByKeyName called with no '
                                 'key name or user.')
            key_name = user.user_id()

        self._model = model
        self._key_name = key_name
        self._property_name = property_name
        self._cache = cache