Python 序列化类并使用 JsonPickle 更改属性大小写

编程问答 2022-05-17

问题描述

使用 Python 和 JsonPickle，如何使用特定大小写（例如 Camel Case、Pascal 等）序列化对象？下面的答案是手动完成的，但是寻找特定的 Jsonpickle 解决方案，因为它可以处理复杂的对象类型。

JSON serialize a class and change property casing with Python

https://stackoverflow.com/a/8614096/15435022

class HardwareSystem:
    def __init__(self,vm_size):
        self.vm_size = vm_size
        self.some_other_thing = 42
        self.a = 'a'

def snake_to_camel(s):
    a = s.split('_')
    a[0] = a[0].lower()
    if len(a) > 1:
        a[1:] = [u.title() for u in a[1:]]
    return ''.join(a)

def serialise(obj):
    return {snake_to_camel(k): v for k,v in obj.__dict__.items()}

hp = HardwareSystem('Large')
print(json.dumps(serialise(hp),indent=4,default=serialise))

解决方法

这是我的尝试。

from importlib import import_module
import inspect
import json
import jsonpickle
import re


def snake_to_camel(s):
    a = s.split('_')
    a[0] = a[0].lower()
    if len(a) > 1:
        a[1:] = [u.title() for u in a[1:]]
    return ''.join(a)

def camel_to_snake(s):
    snake = []
    snake_len = len(s)
    for idx,char in enumerate(s):
        snake.append(char.lower())
        if idx < snake_len - 1:
            if char.islower() and s[idx+1].isupper():
                snake.append('_')
    return ''.join(snake)

def debug_output(obj):
    output = '{}({})'
    attrs = [attr + '=' + repr(getattr(obj,attr)) for attr in vars(obj)]
    return output.format(obj.__class__.__name__,','.join(attrs))


class SoftwareSystem:
    def __init__(self):
        self.software_rating = 'Awesome!'
    
    # Making debug output friendly
    def __repr__(self):
        return debug_output(self)


class HardwareSystem:
    def __init__(self,vm_size):
        self.vm_size = vm_size
        self.some_other_thing = 42
        self.a = 'a'
    
    # Making debug output friendly
    def __repr__(self):
        return debug_output(self)


@jsonpickle.handlers.register(HardwareSystem,base=True)
@jsonpickle.handlers.register(SoftwareSystem,base=True)
class SystemHandler(jsonpickle.handlers.BaseHandler):
    def flatten(self,obj,data):
        for k,v in obj.__dict__.items():
            data[snake_to_camel(k)] = jsonpickle.encode(v)
        return data

    def restore(self,obj):
        # Gets reference to class
        # https://stackoverflow.com/a/55559852/152016
        module_path,class_name = obj['py/object'].rsplit('.',1)
        module = import_module(module_path)
        class_ = getattr(module,class_name)

        # Dealing with __init__ params (except first)
        params = inspect.getargs(class_.__init__.__code__)
        params = params.args[1:]

        # Preparing dict keys
        l_obj = {}
        for k,v in obj.items():
            l_obj[camel_to_snake(k)] = v

        # Instantiating constructor params
        data = {}
        for k,v in l_obj.items():
            if k in params:
                data[k] = v 
        result = class_(**data)

        # Setting other jsonpickled object attributes 
        for k,v in l_obj.items():
            if not k in params:
                setattr(result,k,v)

        return result


hw = HardwareSystem(100)
sw = SoftwareSystem()
hw.software_instance = sw
json_str = jsonpickle.encode(hw)
print(json_str)
decoded = jsonpickle.decode(json_str)
print(hw)

这里有一些假设：

  • 按照您原来的 snake_to_camel 函数，我在解码上放置了一个 camel_to_snake，它假设只有小写字母后的第一个大写字母才会在 _ 字符前面加上 awesomeABC awesome_abc 将翻译为 awesomeAbc，因此，如果您再次将其翻译回来，它将错误地__init__)
  • 以上代码对在 hw.software_instance 之后添加的属性进行编码/解码（参见上面的 debug_output 示例）。
  • 您可以嵌套对象。我只试过一个嵌套的对象。
  • 我添加了辅助 __repr__/import re preposition_lst = ['DE LO','DE LA','DE LAS','DE LES','DEL','DELS','DO','DA','DOS','DAS','DE'] cases = ["DE BLAS ZAPATA","MATIAS DE LA MANO","LOPEZ FERNANDEZ DE VILLAVERDE","DE MIGUEL DEL CORRAL","VIDAL DE LA PENA SOLIS","MONTAVA DEL ARCO","DOS CASAS VALLE"] def split_name(name): f1 = re.compile("(.*)({preps}(.+))".format(preps = "(" + " |".join(preposition_lst) + ")")) m1 = f1.match(case) if m1: if len(m1.group(1)) != 0: return m1.group(1).strip(),m1.group(2).strip() else: return " ".join(name.split()[:-1]),name.split()[-1] else: return " ".join(name.split()[:-1]),name.split()[-1] for case in cases: first,second = split_name(case) print("{} --> name 1 = {},name 2 = {}".format(case,first,second)) # DE BLAS ZAPATA --> name 1 = DE BLAS,name 2 = ZAPATA # MATIAS DE LA MANO --> name 1 = MATIAS,name 2 = DE LA MANO # LOPEZ FERNANDEZ DE VILLAVERDE --> name 1 = LOPEZ FERNANDEZ,name 2 = DE VILLAVERDE # DE MIGUEL DEL CORRAL --> name 1 = DE MIGUEL,name 2 = DEL CORRAL # VIDAL DE LA PENA SOLIS --> name 1 = VIDAL,name 2 = DE LA PENA SOLIS # MONTAVA DEL ARCO --> name 1 = MONTAVA,name 2 = DEL ARCO # DOS CASAS VALLE --> name 1 = DOS CASAS,name 2 = VALLE 函数，你可以把它们扔掉（或自定义 :)）
jsonpicklepythonpython-3.x