使用msgpack-python和嵌套的namedtuples

我的数据结构是这样的：

user = UserTuple(
    name=u'Anakin', surname=u'Skywalker', birthdate=datetime.date(1981, 7, 25),
    profile=ProfileTuple(avatar=u'http://localhost/profile.jpg')
)

我想用msgpack-python模块打包这些数据.但是msgpack将namedtuples转换为列表.有可能用msgpack打包这样的数据并保留namedtuples,就像pickle / cpickle一样？

解决方法:

你需要有最新的msgpack-python版本. v0.4.7不起作用. (目前必须从master分支安装).

import msgpack
from collections import namedtuple

User = namedtuple('User', ['name', 'profile'])
Profile = namedtuple('Profile', ['avatar'])

def ext_pack(x):
    if isinstance(x, User):
        return msgpack.ExtType(1, msgpack.packb([x[0], x[1]], default=ext_pack, strict_types=True))
    elif isinstance(x, Profile):
        return msgpack.ExtType(2, msgpack.packb(x[0], default=ext_pack, strict_types=True))
    return x

def ext_unpack(code, data):
    if code == 1:
        name, profile = msgpack.unpackb(data, ext_hook=ext_unpack)
        return User(name, profile)
    elif code == 2:
        avatar = msgpack.unpackb(data, ext_hook=ext_unpack)
        return Profile(avatar)
    return msgpack.ExtType(code, data)

x = User("me", Profile(234))
s = msgpack.packb([x, [1, x]], default=ext_pack, strict_types=True)
msgpack.unpackb(s, ext_hook=ext_unpack)
>>> [User(name='me', profile=Profile(avatar=234)),
 [1, User(name='me', profile=Profile(avatar=234))]]

这里我们将User,Profile分别标记为类型代码1,2.或者,您可以将所有namedtuple视为相同的类型代码,并将实际类型存储在数据字段中.

标签：python,msgpack
来源： https://codeday.me/bug/20190829/1759706.html