pydantic结合Union

Pydantic是一个Python库，它用于数据建模，常用于处理请求体、响应体等Web应用程序的数据验证。`Union`是Pydantic中的一个类型提示工具，它允许你指定一个字段可以接受多种数据类型之一。

当你需要在一个字段中支持多种可能的输入类型时，你可以使用`Union`。例如：

from pydantic import BaseModel, Union

class ExampleModel(BaseModel):
    value: Union[int, float, str]

# 这个模型的"value"字段可以接受整数、浮点数或字符串
example = ExampleModel(value=42)  # int
example = ExampleModel(value=3.14)  # float
example = ExampleModel(value="hello")  # str

`Union`在数据验证时非常有用，如果提交的数据类型匹配其中的任何一个，Pydantic会接受并继续执行。如果不匹配，则会引发验证错误。

相关问题

A Response Pydantic onjext

A `Response` Pydantic BaseModel in the context of FastAPI or a similar Python web framework is a model that represents an HTTP response object. Pydantic is a powerful library for data validation and setting up structured data models. In this case, you'd use it to define the structure and expected fields for a successful or error-prone response returned by your API endpoints.

When creating a `Response` with Pydantic, you might include attributes like:

1. **status_code**: The HTTP status code (e.g., 200 for success, 400 for bad request).
2. **content**: The actual response body, which could be any serializable data type.
3. **headers**: Additional headers to send along with the response.
4. **model**: Optionally, if the response contains a specific data structure, you can specify a Pydantic model to validate the content.

Here's a simple example:

from fastapi import HTTPException
from pydantic import BaseModel

class ErrorResponse(BaseModel):
    detail: str
    status_code: int = 400

class SuccessResponse(BaseModel):
    message: str
    data: Any = None

class CustomResponse:
    def __init__(self, *, ok: bool, status_code: int, content: Union[SuccessResponse, ErrorResponse]):
        self.ok = ok
        self.status_code = status_code
        self.content = content

    @classmethod
    async def http_exception_handler(cls, exc: HTTPException) -> CustomResponse:
        return cls(
            ok=False,
            status_code=exc.status_code,
            content=ErrorResponse(detail=str(exc.detail))
        )

    @classmethod
    async def success_response(cls, data: Any = None) -> CustomResponse:
        return cls(
            ok=True,
            status_code=200,
            content=SuccessResponse(message="Success", data=data)
        )