### `startup` event { #startup-event }

To add a function that should be run before the application starts, declare it with the event `"startup"`:

{* ../../docs_src/events/tutorial001_py39.py hl[8] *}

In this case, the `startup` event handler function will initialize the items "database" (just a `dict`) with some values.

You can add more than one event handler function.

### Evento `startup` { #startup-event }

Para adicionar uma função que deve rodar antes de a aplicação iniciar, declare-a com o evento `"startup"`:

{* ../../docs_src/events/tutorial001_py39.py hl[8] *}

Nesse caso, a função de manipulador do evento `startup` inicializará os itens do "banco de dados" (apenas um `dict`) com alguns valores.

Você pode adicionar mais de uma função de manipulador de eventos.

## Create a TypeScript SDK { #create-a-typescript-sdk }

Let's start with a simple FastAPI application:

{* ../../docs_src/generate_clients/tutorial001_py39.py hl[7:9,12:13,16:17,21] *}

Notice that the *path operations* define the models they use for request payload and response payload, using the models `Item` and `ResponseMessage`.

### API Docs { #api-docs }

from ...utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial002_py39"),
        pytest.param("tutorial002_py310", marks=needs_py310),
        pytest.param("tutorial002_an_py39"),
        pytest.param("tutorial002_an_py310", marks=needs_py310),
        pytest.param("tutorial003_py39"),
        pytest.param("tutorial003_py310", marks=needs_py310),
        pytest.param("tutorial003_an_py39"),

<img src="/img/tutorial/extending-openapi/image02.png">

Mas você pode desabilitá-lo definindo `syntaxHighlight` como `False`:

{* ../../docs_src/configure_swagger_ui/tutorial001_py39.py hl[3] *}

...e então o Swagger UI não mostrará mais o destaque de sintaxe:

<img src="/img/tutorial/extending-openapi/image03.png">

## Alterar o tema { #change-the-theme }

{* ../../docs_src/advanced_middleware/tutorial001_py39.py hl[2,6] *}

## `TrustedHostMiddleware` { #trustedhostmiddleware }

Enforces that all incoming requests have a correctly set `Host` header, in order to guard against HTTP Host Header attacks.

{* ../../docs_src/advanced_middleware/tutorial002_py39.py hl[2,6:8] *}

The following arguments are supported:

{* ../../docs_src/advanced_middleware/tutorial001_py39.py hl[2,6] *}

## `TrustedHostMiddleware` { #trustedhostmiddleware }

Гарантирует, что во всех входящих запросах корректно установлен `Host`‑заголовок, чтобы защититься от атак на HTTP‑заголовок Host.

{* ../../docs_src/advanced_middleware/tutorial002_py39.py hl[2,6:8] *}

Поддерживаются следующие аргументы:

Nesse caso, o path original `/app` seria servido em `/api/v1/app`.

Embora todo o seu código esteja escrito assumindo que existe apenas `/app`.

{* ../../docs_src/behind_a_proxy/tutorial001_py39.py hl[6] *}

### `startup`-Event { #startup-event }

Um eine Funktion hinzuzufügen, die vor dem Start der Anwendung ausgeführt werden soll, deklarieren Sie diese mit dem Event `startup`:

{* ../../docs_src/events/tutorial001_py39.py hl[8] *}

In diesem Fall initialisiert die Eventhandler-Funktion `startup` die „Datenbank“ der Items (nur ein `dict`) mit einigen Werten.

Sie können mehr als eine Eventhandler-Funktion hinzufügen.

@pytest.fixture(
    name="mod_name",
    params=[
        pytest.param("tutorial001_py39"),
        pytest.param("tutorial001_py310", marks=needs_py310),
        pytest.param("tutorial002_py39"),
        pytest.param("tutorial002_py310", marks=needs_py310),
        pytest.param("tutorial003_py39"),
        pytest.param("tutorial003_py310", marks=needs_py310),
    ],
)