[英]Serialize/Deserialize simple but nested object to/from JSON
I'm trying to transmit a Config from client to server.我正在尝试将配置从客户端传输到服务器。
password
key I must NOT transmitpassword
密钥 This code works:此代码有效:
class Empty:
pass
class Config:
def __init__(self):
# don't want to transmit this over the internet
self.secret = 'P@ssw0rd'
def create(self, foo):
self.foo = foo # property passed in
self.bar = f'Hello {foo}' # calculated property
# A couple of custom objects, but they are simple
# (only containing key/value pairs where value is basic primitive)
self.v = Empty()
self.v.a = 1
self.w = Empty()
self.w.b = 2
def export_json(self):
J = {}
for k, v in vars(self).items():
if k == 'secret':
continue
J[k] = vars(v) if isinstance(v, Empty) else v
return J
def construct_from_json(self, J_str):
J = json.loads(J_str)
for k, v in J.items():
if isinstance(v, dict):
_ = Empty()
for k_, v_ in v.items():
setattr(_, k_, v_)
v = _
setattr(self, k, v)
Test:
```python
c = Config()
c.create('123')
J = c.export_json()
print('Serialized:')
print(json.dumps(J, indent=4))
d = Config()
d.construct_from_json(J)
print('Reconstructed: w.b = ', d.w.b)
Output: Output:
Serialized:
{
"foo": "123",
"bar": "Hello 123",
"v": {
"b": 2
},
"w": {
"b": 2
}
}
Reconstructed: w.b = 2
However, is there a preferred/pythonic way to do this?但是,是否有首选/pythonic 方式来执行此操作?
As someone mentioned in the comments, you might just want to use the pickle
library here to avoid having to serialize/deserialize yourself, and to avoid having to make major modifications to the serialization code in the future if you add nested structures / etc or want to ignore other attributes.正如评论中提到的那样,您可能只想在这里使用
pickle
库来避免自己序列化/反序列化,并避免将来如果添加嵌套结构 / 等或想要对序列化代码进行重大修改忽略其他属性。 Here's a version of your code that works with pickle
, while not serializing the secret
attribute.这是与
pickle
一起使用的代码版本,但不序列化secret
属性。
class Empty:
pass
class Config:
def __init__(self):
# don't want to transmit this over the internet
self.secret = 'P@ssw0rd'
def create(self, foo):
self.foo = foo # property passed in
self.bar = f'Hello {foo}' # calculated property
# A couple of custom objects, but they are simple
# (only containing key/value pairs where value is basic primitive)
self.v = Empty()
self.v.a = 1
self.w = Empty()
self.w.b = 2
# This gets the state for pickling. Note how we are explicitly removing
# the `secret` attribute from the internal dictionary. You don't need to
# do anything else
def __getstate__(self):
state = self.__dict__.copy()
del state['secret']
return state
Testing it out:测试一下:
import pickle
c = Config()
c.create('123')
J = pickle.dumps(c)
print("Serialized: ", J)
d = pickle.loads(J)
print("Reconstructed w.b:", d.w.b)
print("Reconstructed secret:", d.secret)
And this is the output it produces (as wanted):这是它产生的 output(根据需要):
Serialized: b'\x80\x04\x95m\x00...(truncated)'
Reconstructed w.b: 2
Traceback (most recent call last):
File "/Users/mustafa/scratch/test.py", line 36, in <module>
print("Reconstructed secret:", d.secret)
AttributeError: 'Config' object has no attribute 'secret'
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