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