Fastapi报错RuntimeError: no validator found for ＜class ‘typing._UnionGenericAlias‘＞, see `arbitrary_ty

Fastapi报错RuntimeError: no validator found for <class ‘typing._UnionGenericAlias’>, see `arbitrary_ty

问题描述

使用FastAPI 请求体 - 嵌套模型的时候报错, 不嵌套的时候是可以的

不嵌套校验

class PredictGas(BaseModel):
    predict_level: str
    predict_day_is_heating_season: bool
    predict_type: str = Field(default="area", description="预测类型")
    heating_start_date: Union[datetime, date]
    heating_end_date: Union[datetime, date]
    # Optional可选类型  Optional[X]等价于Union[X, None]    int=1等价于Optional[int] = 2   Union[int, float]只能传int  float
    model: Optional[int] = Field(default=1, title="算法模型id", description="可选不同模型调用", le=2, ge=1)
    data: List[dict] = []  # List[dict] = [] 等价于 list = []  # 前者可验证list内部第一层数据结构

其中 Optional可选类型 Optional[X]等价于Union[X, None] int=1等价于Optional[int] = 2 Union[int, float]只能传int float

使用嵌套模型 (其中data是第一层列表字典数据)

其中验证流程是 从外到内层 PredictGas —>>> DataBody ----->>> (PredictParams, PastParams)

class PredictParams(BaseModel):
    # is_heating = Optional[bool]
    # ts: Union[datetime, date]
    # low_temp = Union[int, float]
    # low_temp = float
    # high_temp = float
    # is_heating = bool

    ts = date
    low_temp: float = 1.0
    high_temp: float = 10.0
    is_heating: bool = False

    # class Config:
    #     arbitrary_types_allowed = True


class PastParams(BaseModel):
    # ts: Union[datetime, date]
    # gas_value: float
    # low_temp = float
    # high_temp = float
    # is_heating = bool

    ts: date
    gas_value: float
    low_temp: float = 1.0
    high_temp: float = 10.0
    is_heating: bool = False


class DataBody(BaseModel):
    code: str
    # predict_params: Union[List[PredictParams], None] =None
    # predict_params: List  # 不进行内层验证
    predict_params: List[PredictParams]
    past_params: List[PastParams]

class PredictGas(BaseModel):
    predict_level: str
    predict_day_is_heating_season: bool
    predict_type: str = Field(default="area", description="预测类型")
    heating_start_date: Union[datetime, date]
    heating_end_date: Union[datetime, date]
    # Optional可选类型  Optional[X]等价于Union[X, None]    int=1等价于Optional[int] = 2   Union[int, float]只能传int  float
    model: Optional[int] = Field(default=1, title="算法模型id", description="可选不同模型调用", le=2, ge=1)
    # data: List[dict] = []  # List[dict] = [] 等价于 list = []  # 前者可验证list内部第一层数据结构
    # 嵌套模型校验
    # data: Union[List[Image], None] = None
    data: List[DataBody]

我的检验数据格式

{
    "predict_level": "day",
    "predict_day_is_heating_season": False,
    "predict_type": "area",
    "heating_start_date": "2023-10-10",
    "heating_end_date": "2024-3-10",
    "model": 1,
    "data": [
        {
            "code": "1",
            "predict_params": [
                {
                    "ts": "2023-10-12",
                    "low_temp": -1,
                    "high_temp": 2,
                    "is_heating": True
                },
                {
                    "ts": "2023-10-13",
                    "low_temp": -1,
                    "high_temp": 2,
                    "is_heating": True
                }
            ],
            "past_params": [
                {
                    "ts": "2023-10-05",
                    "gas_value": 1555,
                    "low_temp": -1,
                    "high_temp": 2,
                    "is_heating": True
                },
                {
                    "ts": "2023-10-06",
                    "gas_value": 2000,
                    "low_temp": -1,
                    "high_temp": 2,
                    "is_heating": True
                },
                {
                    "ts": "2023-10-07",
                    "gas_value": 2000,
                    "low_temp": -1,
                    "high_temp": 2,
                    "is_heating": True
                },
                {
                    "ts": "2023-10-08",
                    "gas_value": 1555,
                    "low_temp": -1,
                    "high_temp": 2,
                    "is_heating": True
                },
                {
                    "ts": "2023-10-09",
                    "gas_value": 1555,
                    "low_temp": -1,
                    "high_temp": 2,
                    "is_heating": True
                },
                {
                    "ts": "2023-10-10",
                    "gas_value": 1555,
                    "low_temp": -1,
                    "high_temp": 2,
                    "is_heating": True
                },
                {
                    "ts": "2023-10-11",
                    "gas_value": 1555,
                    "low_temp": -1,
                    "high_temp": 2,
                    "is_heating": True
                }

            ]
        }
        ]
        }

报错情况

当我最内层嵌套的class使用 Union的时候会报错RuntimeError: no validator found for <class ‘typing._UnionGenericAlias’>, see `arbitrary_ty

github提供的解决方案

用了上面的解决方式后fastapi启动不报错,但是接口测试报错

最终定位发现,使用python3.10版本 将Union[int, float]的使用方式换位low_temp = int, | float这种就好了
如果python3.10一下版本的话 使用单种类型验证才可以例如:

class PredictParams(BaseModel):
	ts = date
	low_temp: float = 1.0
	high_temp: float = 10.0
	is_heating: bool = False

github错误参考地址