migration
迁移 v2
HttpUrl
背景
在从 v1 迁移到 v2 的时候, 使用 HttpUrl 的模型遇到了异常
PydanticSerializationUnexpectedValue(Expected `<class 'pydantic.networks.HttpUrl'>` but got `<class 'str'>` with value `'https://github.com/NSRingo/WeatherKit/releases/tag/v1.8.6-rc3'` - serialized value may not be as expected.)
TypeError: Object of type HttpUrl is not JSON serializable
分析
In pydantic v1 urls inherited from str, so it can be easily passed to library codes, where they usually expects string representation of urls.
在某个版本, pydantic 对于 HttpUrl 的实现发生了改变。
原来 HttpUrl 是基于 str 的实现, 后续变成了一个自定义的 Class, 所以在传参和反序列化的时候都遇到了问题
解决方案
HttpUrl
from typing import Annotated
from pydantic import TypeAdapter, HttpUrl as _HttpUrl, BeforeValidator
HttpUrlTypeAdapter = TypeAdapter(_HttpUrl)
HttpUrl = Annotated[
str,
BeforeValidator(lambda value: HttpUrlTypeAdapter.validate_python(value) and value),
]
定义一个类型，作为 str 存储前以 HttpUrl 进行验证