Inklusive externer Bibliotheken, die auf Pydantic basieren, wie <abbr title="Object-Relational Mapper (Abbildung von Objekten auf relationale Strukturen)">ORM</abbr>s, <abbr title="Object-Document Mapper (Abbildung von Objekten auf nicht-relationale Strukturen)">ODM</abbr>s für Datenbanken.

```Python hl_lines="13  15  22  25"
{!../../../docs_src/background_tasks/tutorial002.py!}
```

Neste exemplo, as mensagens serão gravadas no arquivo `log.txt` _após_ o envio da resposta.

Se houver uma consulta na solicitação, ela será gravada no log em uma tarefa em segundo plano.

E então outra tarefa em segundo plano gerada na _função de operação de caminho_ escreverá uma mensagem usando o parâmetro de caminho `email`.

        with client.websocket_connect("/no-router/"):
            pass  # pragma: no cover
    assert e.value.code == status.WS_1000_NORMAL_CLOSURE


def websocket_middleware(middleware_func):
    """
    Helper to create a Starlette pure websocket middleware
    """

    def middleware_constructor(app):
        @functools.wraps(app)
        async def wrapped_app(scope, receive, send):

**FastAPI**は<a href="https://docs.pydantic.dev/" class="external-link" target="_blank"><strong>Pydantic </strong></a>と完全に互換性があります（そしてベースになっています）。したがって、追加のPydanticコードがあれば、それも機能します。

データベースのために<abbr title = "Object-Relational Mapper">ORM</abbr>sや、<abbr title = "Object-Document Mapper">ODM</abbr>sなどの、Pydanticに基づく外部ライブラリを備えています。

これは、すべてが自動的に検証されるため、多くの場合、リクエストから取得したオブジェクトを**データベースに直接**渡すことができるということを意味しています。

同じことがその逆にも当てはまり、多くの場合、データベースから取得したオブジェクトを**クライアントに直接**渡すことができます。

    * The information about the **specific domain** requested goes in the **HTTP data**.
* The **HTTPS certificates** "certify" a **certain domain**, but the protocol and encryption happen at the TCP level, **before knowing** which domain is being dealt with.
* **By default**, that would mean that you can only have **one HTTPS certificate per IP address**.

    So, behind the scenes, it will actually work as if everything was the same single app.

!!! check
    You don't have to worry about performance when including routers.

    This will take microseconds and will only happen at startup.

    So it won't affect performance. ⚡

### Include an `APIRouter` with a custom `prefix`, `tags`, `responses`, and `dependencies`

At some point you would have started the definition of the function, you had the parameters ready...

But then you have to call "that method that converts the first letter to upper case".

Was it `upper`? Was it `uppercase`? `first_uppercase`? `capitalize`?

Then, you try with the old programmer's friend, editor autocompletion.

```Python
async def do_something():
    try:
        yield something
    finally:
        some_cleanup()
```

...that way the `finally` block is run regardless of any exception that might happen.

### Features

* The same PR [#4575](https://github.com/tiangolo/fastapi/pull/4575) from above also fixes the `contextvars` context for the code before and after `yield`. This was the main objective of that PR.

!!! tip
    The *path operation* for `swagger_ui_redirect` is a helper for when you use OAuth2.

    If you integrate your API with an OAuth2 provider, you will be able to authenticate and come back to the API docs with the acquired credentials. And interact with it using the real OAuth2 authentication.

    Swagger UI will handle it behind the scenes for you, but it needs this "redirect" helper.

### Create a *path operation* to test it

Bunlara Pydantic üzerine kurulu <abbr title="Object-Relational Mapper">ORM</abbr> databaseler ve , <abbr title="Object-Document Mapper">ODM</abbr> kütüphaneler de dahil olmak üzere.