return new ParamMap<>(new HashMap<>(getDataMap(params)));
    }

    /**
     * Extracts the underlying data map from a parameter map.
     * If the provided map is a ParamMap instance, returns its parent map.
     * Otherwise, returns the map as-is.
     *
     * @param params the parameter map to extract data from
     * @return the underlying data map
     */

例えば、クライアントが次のフォームフィールドを送ろうとした場合:

- `username`: `Rick`
- `password`: `Portal Gun`
- `extra`: `Mr. Poopybutthole`

フィールド `extra` は許可されていない旨のエラーレスポンスが返されます:

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["body", "extra"],
            "msg": "Extra inputs are not permitted",
            "input": "Mr. Poopybutthole"
        }
    ]
}
```

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["body", "extra"],
            "msg": "Extra inputs are not permitted",
            "input": "Mr. Poopybutthole"
        }
    ]
}
```

## Підсумок { #summary }

from fastapi import Cookie, FastAPI, Header, Query
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Model(BaseModel):
    param: str

    model_config = {"extra": "allow"}


@app.get("/query")
async def query_model_with_extra(data: Model = Query()):
    return data


@app.get("/header")
async def header_model_with_extra(data: Model = Header()):
    return data

例如，用戶端若送出以下表單欄位：

* `username`: `Rick`
* `password`: `Portal Gun`
* `extra`: `Mr. Poopybutthole`

他們會收到一個錯誤回應，告知欄位 `extra` 不被允許：

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["body", "extra"],
            "msg": "Extra inputs are not permitted",
            "input": "Mr. Poopybutthole"
        }
    ]
}
```

## 摘要 { #summary }

例如，客户端尝试发送如下表单字段：

* `username`: `Rick`
* `password`: `Portal Gun`
* `extra`: `Mr. Poopybutthole`

他们将收到一条错误响应，表明字段 `extra` 不被允许：

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["body", "extra"],
            "msg": "Extra inputs are not permitted",
            "input": "Mr. Poopybutthole"
        }
    ]
}
```

## 总结 { #summary }

    alias_with: str = Field(alias="with", default="nothing")


class FormModelExtraAllow(BaseModel):
    param: str

    model_config = {"extra": "allow"}


@app.post("/form/")
def post_form(user: Annotated[FormModel, Form()]):
    return user


@app.post("/form-extra-allow/")
def post_form_extra_allow(params: Annotated[FormModelExtraAllow, Form()]):
    return params


client = TestClient(app)

</div>

## Как запретить дополнительные заголовки { #forbid-extra-headers }

В некоторых случаях (не особо часто встречающихся) вам может понадобиться **ограничить** заголовки, которые вы хотите получать.

Вы можете использовать возможности конфигурации Pydantic-модели для того, чтобы запретить (`forbid`) любые дополнительные (`extra`) поля:

{* ../../docs_src/header_param_models/tutorial002_an_py310.py hl[10] *}

* `username`: `Rick`
* `password`: `Portal Gun`
* `extra`: `Mr. Poopybutthole`

erhält er eine Error-Response, die ihm mitteilt, dass das Feld `extra` nicht erlaubt ist:

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["body", "extra"],
            "msg": "Extra inputs are not permitted",
            "input": "Mr. Poopybutthole"
        }
    ]

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["body", "extra"],
            "msg": "Extra inputs are not permitted",
            "input": "Mr. Poopybutthole"
        }
    ]
}
```

## Résumer { #summary }