**FastAPI** **extraerá** los datos para **cada campo** de los **headers** en el request y te dará el modelo Pydantic que definiste.

## Revisa la Documentación { #check-the-docs }

Puedes ver los headers requeridos en la interfaz de documentación en `/docs`:

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">
</div>

## Prohibir Headers Extra { #forbid-extra-headers }

    * Ein Python-`datetime.timedelta`.
    * Wird in Requests und Responses als `float` der Gesamtsekunden dargestellt.
    * Pydantic ermöglicht auch die Darstellung als „ISO 8601 Zeitdifferenz-Kodierung“, <a href="https://docs.pydantic.dev/latest/concepts/serialization/#custom-serializers" class="external-link" target="_blank">siehe die Dokumentation für weitere Informationen</a>.
* `frozenset`:
    * Wird in Requests und Responses wie ein `set` behandelt:

class BackgroundTasks(StarletteBackgroundTasks):
    """
    A collection of background tasks that will be called after a response has been
    sent to the client.

    Read more about it in the
    [FastAPI docs for Background Tasks](https://fastapi.tiangolo.com/tutorial/background-tasks/).

    ## Example

    ```python
    from fastapi import BackgroundTasks, FastAPI

    app = FastAPI()

### Target language

Translate to Simplified Chinese (简体中文).

Language code: zh.

### Grammar and tone

1) Use clear, concise technical Chinese consistent with existing docs.
2) Address the reader naturally (commonly using “你/你的”).

### Headings

1) Follow existing Simplified Chinese heading style (short and descriptive).
2) Do not add trailing punctuation to headings.

    * 在请求和响应中将表示为 ISO 8601 格式的 `str` ，比如:  `14:23:55.003`.
* `datetime.timedelta`:
    * 一个 Python `datetime.timedelta`.
    * 在请求和响应中将表示为 `float` 代表总秒数。
    * Pydantic 也允许将其表示为 "ISO 8601 时间差异编码", <a href="https://docs.pydantic.dev/latest/concepts/serialization/#json_encoders" class="external-link" target="_blank">查看文档了解更多信息</a>。
* `frozenset`:
    * 在请求和响应中，作为 `set` 对待：
        * 在请求中，列表将被读取，消除重复，并将其转换为一个 `set`。

{* ../../docs_src/middleware/tutorial001.py hl[8:9,11,14] *}

/// tip | Порада

Не забувайте, що власні заголовки можна додавати, використовуючи <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">префікс 'X-'</a>.

bucket). ## mcImage: repository: quay.io/minio/mc tag: RELEASE.2021-10-07T04-19-58Z pullPolicy: IfNotPresent ## minio mode, i.e. standalone or distributed or gateway (nas) ## Distributed MinIO ref: https://docs.minio.io/docs/distributed-minio-quickstart-guide ## NAS Gateway MinIO ref: https://docs.min.io/docs/minio-gateway-for-nas.html mode: distributed ## NOTE: currently only "nas" gateway is supported. ## Additional labels to include with deployment or statefulset additionalLabels: [] ## Additional annotations...

updateStrategy: RollingUpdate ## Pod priority settings ## ref: https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/ ## priorityClassName: "" ## Pod runtime class name ## ref https://kubernetes.io/docs/concepts/containers/runtime-class/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html...

updateStrategy: RollingUpdate ## Pod priority settings ## ref: https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/ ## priorityClassName: "" ## Pod runtime class name ## ref https://kubernetes.io/docs/concepts/containers/runtime-class/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html...

updateStrategy: RollingUpdate ## Pod priority settings ## ref: https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/ ## priorityClassName: "" ## Pod runtime class name ## ref https://kubernetes.io/docs/concepts/containers/runtime-class/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## AccessKey and secretKey is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html...