Deserialize a json string to an object in python

Question

I have the following string

{\"action\":\"print\",\"method\":\"onData\",\"data\":\"Madan Mohan\"}

I Want to deserialize to a object of cla

Answer 1

While Alex's answer points us to a good technique, the implementation that he gave runs into a problem when we have nested objects.

class more_info
    string status

class payload
    string action
    string method
    string data
    class more_info

with the below code:

def as_more_info(dct):
    return MoreInfo(dct['status'])

def as_payload(dct):
    return Payload(dct['action'], dct['method'], dct['data'], as_more_info(dct['more_info']))

payload = json.loads(message, object_hook = as_payload)

payload.more_info will also be treated as an instance of payload which will lead to parsing errors.

From the official docs:

object_hook is an optional function that will be called with the result of any object literal decoded (a dict). The return value of object_hook will be used instead of the dict.

Hence, I would prefer to propose the following solution instead:

class MoreInfo(object):
    def __init__(self, status):
        self.status = status

    @staticmethod
    def fromJson(mapping):
        if mapping is None:
            return None

        return MoreInfo(
            mapping.get('status')
        )

class Payload(object):
    def __init__(self, action, method, data, more_info):
        self.action = action
        self.method = method
        self.data = data
        self.more_info = more_info

    @staticmethod
    def fromJson(mapping):
        if mapping is None:
            return None

        return Payload(
            mapping.get('action'),
            mapping.get('method'),
            mapping.get('data'),
            MoreInfo.fromJson(mapping.get('more_info'))
        )

import json
def toJson(obj, **kwargs):
    return json.dumps(obj, default=lambda j: j.__dict__, **kwargs)

def fromJson(msg, cls, **kwargs):
    return cls.fromJson(json.loads(msg, **kwargs))

info = MoreInfo('ok')
payload = Payload('print', 'onData', 'better_solution', info)
pl_json = toJson(payload)
l1 = fromJson(pl_json, Payload)