Crea una variable `ALGORITHM` con el algoritmo usado para firmar el token JWT y configúralo a `"HS256"`.

Crea una variable para la expiración del token.

Define un Modelo de Pydantic que se usará en el endpoint de token para el response.

Crea una función de utilidad para generar un nuevo token de acceso.

{* ../../docs_src/security/tutorial004_an_py310.py hl[4,7,13:15,29:31,82:90] *}

## Actualizar las dependencias { #update-the-dependencies }

它設計為函式接收兩個參數，一個是「request」，一個是「response」。然後你從 request「讀取」資料、往 response「寫入」資料。由於這種設計，無法使用標準的 Python 型別提示，直接以函式參數宣告請求參數與主體。

因此，資料驗證、序列化與文件必須以程式碼手動完成，無法自動化。或者需在 Falcon 之上實作另一層框架（如 Hug）。其他受 Falcon 設計啟發的框架也有同樣的區別：將 request 與 response 物件作為參數。

/// check | 啟發 **FastAPI**

設法取得優秀的效能。

連同 Hug（Hug 建立於 Falcon 之上）一起，也啟發 **FastAPI** 在函式中宣告一個 `response` 參數。

不過在 FastAPI 中它是可選的，主要用來設定標頭、Cookie 與替代狀態碼。

///

   * a response from a remote station. It may be used as a "Who Are You" (WRU) to obtain
   * identification, or may be used to obtain station status, or both.
   *
   * @since 8.0
   */
  public static final byte ENQ = 5;

  /**
   * Acknowledge: A communication control character transmitted by a receiver as an affirmative
   * response to a sender.
   *
   * @since 8.0
   */

### Documentation de l’API { #api-docs }

Si vous allez sur `/docs`, vous verrez qu’elle contient les **schémas** pour les données à envoyer dans les requêtes et reçues dans les réponses :

<img src="/img/tutorial/generate-clients/image01.png">

Vous voyez ces schémas parce qu’ils ont été déclarés avec les modèles dans l’application.

     * @param file the file object
     */
    public void setFile(Object file) {
        this.file = file;
    }

    /**
     * Update the file ID after successful create response
     * @param newFileId the new 16-byte file ID
     */
    public void updateFileId(byte[] newFileId) {
        if (newFileId.length != 16) {
            throw new IllegalArgumentException("File ID must be 16 bytes");

Então podemos criar um `AsyncClient` com a aplicação, e enviar requisições assíncronas para ela utilizando `await`.

{* ../../docs_src/async_tests/app_a_py310/test_main.py hl[9:12] *}

Isso é equivalente a:

```Python
response = client.get('/')
```

...que nós utilizamos para fazer as nossas requisições utilizando o `TestClient`.

/// tip | Dica

Mas se você tem um monte de dataclasses por aí, este é um truque legal para usá-las para alimentar uma API web usando FastAPI. 🤓

///

## Dataclasses em `response_model` { #dataclasses-in-response-model }

Você também pode usar `dataclasses` no parâmetro `response_model`:

{* ../../docs_src/dataclasses_/tutorial002_py310.py hl[1,6:12,18] *}

A dataclass será automaticamente convertida para uma dataclass Pydantic.

Також можна використовувати `BackgroundTask` окремо в FastAPI, але для цього вам доведеться створити об'єкт у коді та повернути Starlette `Response`, включаючи його.

Детальніше можна почитати в [офіційній документації Starlette про Background Tasks](https://www.starlette.dev/background/).

## Застереження { #caveat }

            question=None,
            yes_reply=None,
            no_reply=None):
  """Get boolean input from user.

  If var_name is not set in env, ask user to enable query_item or not. If the
  response is empty, use the default.

  Args:
    environ_cp: copy of the os.environ.
    var_name: string for name of environment variable, e.g. "TF_NEED_CUDA".

   * HTTP/2 only. Send a push promise header block.
   *
   * A push promise contains all the headers that pertain to a server-initiated request, and a
   * `promisedStreamId` to which response frames will be delivered. Push promise frames are sent as
   * a part of the response to `streamId`. The `promisedStreamId` has a priority of one greater than
   * `streamId`.
   *
   * @param streamId client-initiated stream ID.  Must be an odd number.