* **Editor support**.
* **Type checks**.

...and **FastAPI** uses the same declarations to:

* **Define requirements**: from request path parameters, query parameters, headers, bodies, dependencies, etc.
* **Convert data**: from the request to the required type.
* **Validate data**: coming from each request:
    * Generating **automatic errors** returned to the client when the data is invalid.

按规范的要求，应像本示例一样，返回带有 `access_token` 和 `token_type` 的 JSON 对象。

这是开发者必须在代码中自行完成的工作，并且要确保使用这些 JSON 的键。

这几乎是唯一需要开发者牢记在心，并按规范要求正确执行的事。

**FastAPI** 则负责处理其它的工作。

///

## 更新依赖项 { #update-the-dependencies }

接下来，更新依赖项。

使之仅在当前用户为激活状态时，才能获取 `current_user`。

为此，要再创建一个依赖项 `get_current_active_user`，此依赖项以 `get_current_user` 依赖项为基础。

如果用户不存在，或状态为未激活，这两个依赖项都会返回 HTTP 错误。

        "//tensorflow/cc:scope",
        "//tensorflow/core:tensorflow",
        "//tensorflow/core/data:standalone",
        # Exports for pywrap_tensorflow_internal. Many of these are transitive
        # dependencies of the above, but must be explicitly listed for
        # cc_shared_library to work.
        "//tensorflow/c/eager:c_api_experimental",
        "//tensorflow/c/eager:c_api_internal",

The benefit of raising an exception over returning a value will be more evident in the section about Dependencies and Security.

In this example, when the client requests an item by an ID that doesn't exist, raise an exception with a status code of `404`:

{* ../../docs_src/handling_errors/tutorial001_py310.py hl[11] *}

   */
  ConcurrentMap<K, V> asMap();

  /**
   * Performs any pending maintenance operations needed by the cache. Exactly which activities are
   * performed -- if any -- is implementation-dependent.
   */
  void cleanUp();

* el header
* los headers
* el header de autorización
* el header `Authorization`
* el header forwarded

* el sistema de inyección de dependencias
* la dependencia
* el dependable
* el dependiente

* limitado por I/O
* limitado por CPU
* concurrencia
* paralelismo
* multiprocesamiento

* la env var
* la variable de entorno
* el `PATH`
* la variable `PATH`

Crie uma função utilitária para gerar um novo token de acesso.

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

## Atualize as dependências { #update-the-dependencies }

Atualize `get_current_user` para receber o mesmo token de antes, mas desta vez, usando tokens JWT.

Decodifique o token recebido, verifique-o e retorne o usuário atual.

==== Refactor code to make it easier to test

Unfortunately, a large part of our code base is still hard to unit test.
Sometimes because some classes have lots of dependencies that make them hard to
instantiate. Sometimes because API contracts make tests hard to write. Code
refactors that make functionality easier to unit test are encouraged. If this
sounds very abstract to you, you can have a look at

É quase a única coisa que você deve se lembrar de fazer corretamente, para estar em conformidade com as especificações.

De resto, **FastAPI** cuida disso para você.

///

## Atualize as dependências { #update-the-dependencies }

Agora vamos atualizar nossas dependências.

Queremos obter o `current_user` *somente* se este usuário estiver ativo.

Створіть утилітарну функцію для генерації нового токена доступу.

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

## Оновіть залежності { #update-the-dependencies }

Оновіть `get_current_user`, щоб отримувати той самий токен, що й раніше, але цього разу - токен JWT.

Декодуйте отриманий токен, перевірте його та поверніть поточного користувача.