Pydanic动态别名发电机支持

Question

我需要支持我的Pydantic模型中的动态别名（如果可能的话）。

对于此JSON数据：

{
    "Time Series (5min)": {
        "A": 1,
        "B": 2
    }
}

我在这里有一个pydantic类：

from pydantic import BaseModel, Field
class IntraDayQuote(BaseModel):
     data: Optional[dict] = Field({}, alias='Time Series (5min)')

正确解析，但是我想忽略“（5分钟）”字段名称的“（5分钟）”，例如：

from pydantic import BaseModel, Field
    class IntraDayQuote(BaseModel):
         data: Optional[dict] = Field({}, alias='Time Series .*')

这是可以用Pydantic实现的吗？我尝试了Docs的Alias Alias_generator，但没有运气：

def convert_field_names_for_alias(field_name):
     print(f"field name conversion: {field_name}")
     new_field_name = field_name
     if field_name.startswith("Time Series ("):
         new_field_name = "data"

     return new_field_name

 class IntraDayQuote(BaseModel):
     data: Optional[dict]
     class Config:   
          alias_generator = convert_field_names_for_alias
          allow_population_by_field_name = True

Answer 1

您可以只插入过滤器函数，例如这样：

import json
import pydantic

# I've made some assumptions about the format of your data here,
# since the example you included in your question was invalid.
json_data = """
{
  "Time Series (5 min)": {
    "a": 1,
    "b": 2
  }
}
"""


class IntraDayQuote(pydantic.BaseModel):
    data: dict | None


def normalize_fields(d):
    return {"data" if k.startswith("Time Series (") else k: v for k, v in d.items()}


q = IntraDayQuote(**normalize_fields(json.loads(json_data)))
print(repr(q))

输出：

IntraDayQuote(data={'a': 1, 'b': 2})

---

@scolvin在评论中建议的，我们实际上可以使normalize_fields一个根验证器，看起来像这样：

import json
import pydantic

json_data = """
{
  "Time Series (5 min)": {
    "a": 1,
    "b": 2
  }
}
"""


class IntraDayQuote(pydantic.BaseModel):
    data: dict | None

    @pydantic.root_validator(pre=True)
    def normalize_fields(cls, values):
        return {
            "data" if k.startswith("Time Series (") else k: v for k, v in values.items()
        }


q = IntraDayQuote(**json.loads(json_data))
print(repr(q))

有点清洁。