Pour cela, importez d'abord `Query` depuis `fastapi` :

{* ../../docs_src/query_params_str_validations/tutorial002.py hl[3] *}

## Utiliser `Query` comme valeur par défaut

Construisez ensuite la valeur par défaut de votre paramètre avec `Query`, en choisissant 50 comme `max_length` :

{* ../../docs_src/query_params_str_validations/tutorial002.py hl[9] *}

    └── swagger-ui.css
```

### Serve the static files

* Import `StaticFiles`.
* "Mount" a `StaticFiles()` instance in a specific path.

{* ../../docs_src/custom_docs_ui/tutorial002.py hl[7,11] *}

### Test the static files

# 응답 쿠키

## `Response` 매개변수 사용하기

*경로 작동 함수*에서 `Response` 타입의 매개변수를 선언할 수 있습니다.

그런 다음 해당 *임시* 응답 객체에서 쿠키를 설정할 수 있습니다.

```Python hl_lines="1  8-9"
{!../../docs_src/response_cookies/tutorial002.py!}
```

그런 다음 필요한 객체(`dict`, 데이터베이스 모델 등)를 반환할 수 있습니다.

그리고 `response_model`을 선언했다면 반환한 객체를 거르고 변환하는 데 여전히 사용됩니다.

**FastAPI**는 그 *임시* 응답에서 쿠키(또한 헤더 및 상태 코드)를 추출하고, 반환된 값이 포함된 최종 응답에 이를 넣습니다. 이 값은 `response_model`로 걸러지게 됩니다.

All we need to do is handle the request inside a `try`/`except` block:

{* ../../docs_src/custom_request_and_route/tutorial002.py hl[13,15] *}

If an exception occurs, the`Request` instance will still be in scope, so we can read and make use of the request body when handling the error:

{* ../../docs_src/custom_request_and_route/tutorial002.py hl[16:18] *}

## Custom `APIRoute` class in a router

{* ../../docs_src/configure_swagger_ui/tutorial001.py hl[3] *}

...and then Swagger UI won't show the syntax highlighting anymore:

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

## Change the Theme

The same way you could set the syntax highlighting theme with the key `"syntaxHighlight.theme"` (notice that it has a dot in the middle):

{* ../../docs_src/configure_swagger_ui/tutorial002.py hl[3] *}

```Python hl_lines="1  18"
{!../../docs_src/response_directly/tutorial002.py!}
```

### `HTMLResponse`

Usa algum texto ou sequência de bytes e retorna uma resposta HTML. Como você leu acima.

### `PlainTextResponse`

Usa algum texto ou sequência de bytes para retornar uma resposta de texto não formatado.

```Python hl_lines="2  7  9"
{!../../docs_src/custom_response/tutorial005.py!}
```

### `JSONResponse`

## Paramètres optionnels

De la même façon, vous pouvez définir des paramètres de requête comme optionnels, en leur donnant comme valeur par défaut `None` :

{* ../../docs_src/query_params/tutorial002.py hl[9] *}

Ici, le paramètre `q` sera optionnel, et aura `None` comme valeur par défaut.

/// check | "Remarque"

Let's see the previous example again:

{* ../../docs_src/response_status_code/tutorial001.py hl[6] *}

`201` is the status code for "Created".

But you don't have to memorize what each of these codes mean.

You can use the convenience variables from `fastapi.status`.

{* ../../docs_src/response_status_code/tutorial002.py hl[1,6] *}

{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## Ajouter une tâche d'arrière-plan

Dans votre *fonction de chemin*, passez votre fonction de tâche à l'objet de type `BackgroundTasks` (`background_tasks` ici) grâce à la méthode `.add_task()` :


{* ../../docs_src/background_tasks/tutorial001.py hl[14] *}

`.add_task()` reçoit comme arguments :

{* ../../docs_src/advanced_middleware/tutorial001.py hl[2,6] *}

## `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.py hl[2,6:8] *}

The following arguments are supported: