},
              "changes-requested": {
                "delay": 2628000,
                "message": "As this PR had requested changes to be applied but has been inactive for a while, it's now going to be closed. But if there's anyone interested, feel free to create a new PR."
              }

For this reason it's common to provide them in environment variables that are read by the application.

## Environment Variables

!!! tip
    If you already know what "environment variables" are and how to use them, feel free to skip to the next section below.

)

_T = TypeVar("_T")


@asynccontextmanager
async def contextmanager_in_threadpool(
    cm: ContextManager[_T],
) -> AsyncGenerator[_T, None]:
    # blocking __exit__ from running waiting on a free thread
    # can create race conditions/deadlocks if the context manager itself
    # has its own internal pool (e.g. a database connection pool)
    # to avoid this we let __exit__ run without a capacity limit

```

## Description avancée de docstring

Vous pouvez limiter le texte utilisé de la docstring d'une *fonction de chemin* qui sera affiché sur OpenAPI.

L'ajout d'un `\f` (un caractère d'échappement "form feed") va permettre à **FastAPI** de tronquer la sortie utilisée pour OpenAPI à ce stade.

Il n'apparaîtra pas dans la documentation, mais d'autres outils (tel que Sphinx) pourront utiliser le reste.

```Python hl_lines="19-29"

!!! warning
    If you are just starting, the tutorial [SQL (Relational) Databases](../tutorial/sql-databases.md){.internal-link target=_blank} that uses SQLAlchemy should be enough.

    Feel free to skip this.

    Peewee is not recommended with FastAPI as it doesn't play well with anything async Python. There are several better alternatives.

!!! info
    These docs assume Pydantic v1.

```Python hl_lines="6"
{!../../../docs_src/path_operation_advanced_configuration/tutorial003.py!}
```

## docstringによる説明の高度な設定

*path operation関数* のdocstringからOpenAPIに使用する行を制限することができます。

`\f` (「書式送り (Form Feed)」のエスケープ文字) を付与することで、**FastAPI** はOpenAPIに使用される出力をその箇所までに制限します。

ドキュメントには表示されませんが、他のツール (例えばSphinx) では残りの部分を利用できるでしょう。

```Python hl_lines="19-29"
{!../../../docs_src/path_operation_advanced_configuration/tutorial004.py!}

OAuth2 doesn't specify how to encrypt the communication, it expects you to have your application served with HTTPS.

!!! tip
    In the section about **deployment** you will see how to set up HTTPS for free, using Traefik and Let's Encrypt.


## OpenID Connect

OpenID Connect is another specification, based on **OAuth2**.

!!! note
    `PATCH` is less commonly used and known than `PUT`.

    And many teams use only `PUT`, even for partial updates.

    You are **free** to use them however you want, **FastAPI** doesn't impose any restrictions.

    But this guide shows you, more or less, how they are intended to be used.

### Using Pydantic's `exclude_unset` parameter

```

## Advanced description from docstring

You can limit the lines used from the docstring of a *path operation function* for OpenAPI.

Adding an `\f` (an escaped "form feed" character) causes **FastAPI** to truncate the output used for OpenAPI at this point.

It won't show up in the documentation, but other tools (such as Sphinx) will be able to use the rest.

```Python hl_lines="19-29"

## Fortgeschrittene Beschreibung mittels Docstring

Sie können die verwendeten Zeilen aus dem Docstring einer *Pfadoperation-Funktion* einschränken, die für OpenAPI verwendet werden.

Das Hinzufügen eines `\f` (ein maskiertes „Form Feed“-Zeichen) führt dazu, dass **FastAPI** die für OpenAPI verwendete Ausgabe an dieser Stelle abschneidet.

Sie wird nicht in der Dokumentation angezeigt, aber andere Tools (z. B. Sphinx) können den Rest verwenden.