如何在快速 API Python 中阅读 URL 参数和正文输入

Question

我想在 Fast API Python 中创建一个通用端点定义，它读取 URL 路径参数，然后调用一个特定的方法来进行去实现。但我总是得到

422 Unprocessable Entity

所以我希望它能像这样工作：

/answer/aaa -> handle_generic_answer -> read_item_aaa，将 body 键入 ModelAAA

/answer/bbb -> handle_generic_answer -> read_item_bbb，将 body 键入 ModelBBB 等等

这是通用端点代码：

@app.post("/answer/{type}")
def handle_generic_answer(type: str, item):
# I also tried 
# def handle_generic_answer(type: str, item: Any):
# or
# def handle_generic_answer(type: str, item: Optional):
    switcher = {
        'aaaa': read_item_aaa,
        'bbb': read_item_bbb,
        'nothing': unrecognised_answer
    }
    func = switcher.get(type, unrecognised_answer)
    print('answer >> ' + type)
    func(item)

然后我根据 type 值调用单独的方法：

def read_item_aaa(item: ModelAAA):
    update_aaa(item)
    return {"type": "aaa", "result": "success"}

def read_item_bbb(item: ModelBBB):
    update_bbb(item)
    return {"type": "bbb", "result": "success"}

和一个默认值 -

def unrecognised_answer(type):
    print("unrecognised_answer")
    raise HTTPException(status_code=400, detail="answer type not found")
    return {}

模型定义如下：

from pydantic import BaseModel, Field

class ModelAAA(BaseModel):
    field1: str
    field2: list = []

但我是否打电话

http://localhost:8000/answer/aaa

或http://localhost:8000/answer/some-other-url

我总是得到 422:

{
    "detail": [
        {
            "loc": [
                "query",
                "item"
            ],
            "msg": "field required",
            "type": "value_error.missing"
        }
    ]
}

Answer 1

您忘记注释正文参数 item。

没有这个 item 被视为查询 str 参数。例如：

@app.post("/answer/{type}")
def handle_generic_answer(type: str, item: Union[ModelAAA, ModelBBB]):

如何在快速 API Python 中阅读 URL 参数和正文输入

How to Read URL param and body typing in Fast API Python

python

rest

python-typing

fastapi