This is a very fast how-to encode and decode python objects to json.
- For decoding we will use the parameter object_hook. With it, we can pass a function to the json.loads function.
- For encoding we will use a Custom JSON encoder.
Mapping incoming object with standard library
import json my_json_str = '{"name":"John", "age":31, "city":"New York"}' my_dict_json = json.loads(my_json_str) print(my_json_str) # output: {"name":"John", "age":31, "city":"New York"} Now, with a dictionary we have different approaches for making the object mapping
Mapping approach with dict and constructor´s parameters
class MyObject(object): def __init__(self, age:int, city:str, name:str): self.name = name self.age = age self.city = city def __repr__(self): return f"{self.name} {self.age} {self.city}" my_obj = json.loads(my_json_str, object_hook=lambda data: MyObject(**data)) print(my_obj) # output: John 31 New York Decode class with a Custom encoder
class CustomJSONEncoder(json.JSONEncoder): def default(self, obj): if issubclass(type(obj), MyObject): return json.dumps(obj.__dict__, default=lambda _: None) return json.JSONEncoder.default(self, obj) obj_str = json.dumps(my_obj, default=CustomJSONEncoder().default) print(obj_str) #output: "{\"name\": \"John\", \"age\": 31, \"city\": \"New York\"}" Mapping approach with NamedTuple
from typing import NamedTuple class MyObjectTuple(NamedTuple): name:str city:str age:int my_obj = json.loads(my_json_str, object_hook=lambda data: MyObjectTuple(**data)) print(my_obj) # output: MyObjectTuple(name='John', city='New York', age=31) print((my_obj)._asdict()) # output: {'name': 'John', 'city': 'New York', 'age': 31} Decode class without custom encoder
obj_str = json.dumps(my_obj._asdict()) print(obj_str) # output: {"name": "John", "city": "New York", "age": 31} Do you any other method to object decode/encode? Do you think that it can be done better?. Leave your thoughts below, feedback is always welcomed :)
Top comments (2)
I think you are great! i just want to discuss tech with Python developer.
I built a display machine state using Python3 with Flask!
Flask State Github：github.com/yoobool/flask-state
Should i can get some improvement suggestions from you? Thanks~
That's great. Would you give me a star on GitHub Flask State?
because my project isn't active. ^.^