python - 使用 PickleProperty 在 GAE 中存储字典

Question

我有一个 python 字典，我试图通过 pickle 属性存储在 GAE Gql 数据存储中。

我试着按照这个问题和答案， Store a list of dictionaries in GAE

但它不适用于我下面的代码。我收到一条错误消息，提示我的列表有问题

我如下设置 pickle 属性和数据模型类，

class PickleProperty(db.Property):
    def get_value_for_datastore(self, model_instance):
        value = getattr(model_instance, self.name, None)
        return pickle.dumps(value)

    def make_value_from_datastore(self, value):
        return pickle.mloads(value)

class MDB(db.Model):
    Name = db.StringProperty(required=True)
    Times = PickleProperty()
    created = db.DateTimeProperty(auto_now_add = True)

我的代码中有一个函数可以插入数据并将其读出

def m_time_manage(m=""):

    if not m:
        r = db.GqlQuery("select * from MDB")
    else:
        #find specific masjid requested
        r = db.GqlQuery("select * from MDB where Name = %s" % (s))

    #if masjid time data doesn't exist in db throw in placeholders...
    if r is None:
        times = {}
        times['a'] = "8:49"
        times['b'] = "10:19"

        times_entry = MDB(Name="abc",Times=times)
        times_entry.put()

    r = db.GqlQuery("select * from MasjidDB")
    return (r[0].Name, r[0].Times)

在我的 get 函数中，我调用 m_time_manage() ftn 如下，

(mName, times) = m_time_manage()
        self.write(times)

我得到这个错误，pickle.loads 和文件结束错误...完整的错误是，但我不确定如何在 python 中存储字典，

 line 31, in make_value_from_datastore
    return pickle.loads(value)
  File "/usr/lib/python2.7/pickle.py", line 1382, in loads
    return Unpickler(file).load()
  File "/usr/lib/python2.7/pickle.py", line 858, in load
    dispatch[key](self)
  File "/usr/lib/python2.7/pickle.py", line 880, in load_eof
    raise EOFError

提前感谢您的帮助

Answer 1

我建议切换到 NDB 并使用其内置的 PickleProperty。参见 https://developers.google.com/appengine/docs/python/ndb/properties