from typing import Optional, Union

from bson import ObjectId
from pydantic import BaseModel, Field


# mongodb  _id 类型
class OId(ObjectId):
    @classmethod
    def __get_validators__(cls):
        yield cls.validate

    @classmethod
    def validate(cls, v):
        try:
            return ObjectId(v)
        except:
            raise ValueError('无效的格式')


class DBBase(BaseModel):
    id: Union[OId, str] = Field(None, alias='_id')