python - 任何用于序列化属性的 cattrs 解决方案都使用不同的名称？

Question

我试图找到类似于 java Jackson ObjectMapper 的解决方案可以将 python 对象序列化/反序列化为 json。并发现

• cattrs最接近我需要的。但它不能像在 json 中使用 firstName 但在反序列化对象中使用 first_name 那样进行属性映射。

• attrs-serde可以做属性映射，不能做递归反序列化。

这个问题可以用这个例子来说明，

import attr
import cattr
from attrs_serde import serde

name_path = ["contact", "personal", "Name"]
phone_path = ["contact", "Phone"]


@serde
@attr.s(auto_attribs=True, frozen=True)
class Name:
    first: str
    last: str


@serde
@attr.s(auto_attribs=True, frozen=True)
class Person:
    name: Name = attr.ib(metadata={"to": name_path, "from": name_path})
    phone: str = attr.ib(metadata={"to": phone_path, "from": phone_path})


person_json = {"contact": {"personal": {"Name": {"first": "John", "last": "Smith"}}, "Phone": "555-112233"}}

# XXX: to/from only works on serde
p = Person(name=Name(first="John", last="Smith"), phone="555-112233")
print(p.to_dict())
# {'contact': {'personal': {'Name': {'first': 'John', 'last': 'Smith'}}, 'Phone': '555-112233'}}
p1 = Person.from_dict(person_json)
print(f"p1={p1}")
# p1=Person(name={'first': 'John', 'last': 'Smith'}, phone='555-112233')

# XXX: nested only works on cttrs
person = {"Name": {"First": "John", "Last": "Smith"}, "Phone": "555-112233"}
converter = cattr.Converter()
converter.register_structure_hook(
    Person, lambda d, _: Person(name=converter.structure(d["Name"], Name), phone=d.get("Phone"))
)
converter.register_structure_hook(Name, lambda d, _: Name(first=d["First"], last=d.get("Last")))

p2 = converter.structure(person, Person)
print(p2)
assert p == p2

print(converter.unstructure(p2))
# {'name': {'first': 'John', 'last': 'Smith'}, 'phone': '555-112233'}
# {"contact": {"personal": {"name": "John"}, "phone": "555-112233"}}

使用 cattr 的任何更优雅的解决方案？

Answer 1

你可以使用驼峰来进行大小写转换

import humps

import cattr

class CAttrConverter:

    converter = cattr.Converter()

    def __init__(self):
        """
        structure hook for load
        unstructure hook for dump
        """

    def load(self, params, data_cls, camel_to_snake=True):
        """
        :param params: params, mostly from front end
        :param data_cls:
        :param camel_to_snake: need to convert from camel style to snake style
        """
        if camel_to_snake:
            params = humps.depascalize(params)
        return self.converter.structure(params, data_cls)

    def dump(self, data, snake_to_camel=False):
        """
        :param data:
        :param snake_to_camel: dump as camel case
        """
        result: dict = self.converter.unstructure(data)
        if snake_to_camel:
            result = humps.camelize(result)

        return result