"میان‌افزار" یک تابع است که با هر درخواست(request) قبل از پردازش توسط هر path operation (عملیات مسیر) خاص کار می‌کند. همچنین با هر پاسخ(response) قبل از بازگشت آن نیز کار می‌کند.

* هر **درخواستی (request)** که به برنامه شما می آید را می گیرد.
* سپس می تواند کاری برای آن **درخواست** انجام دهید یا هر کد مورد نیازتان را اجرا کنید.
* سپس **درخواست** را به بخش دیگری از برنامه (توسط یک path operation مشخص) برای پردازش ارسال می کند.

                            * `security_scopes.scopes` contendrá `["me"]` para la *path operation* `read_users_me`, porque está declarado en la dependencia `get_current_active_user`.

  ) = throw CertificateException("Unsupported operation")

  override fun checkClientTrusted(
    chain: Array<out X509Certificate>,
    authType: String?,
  ) = throw CertificateException("Unsupported operation")

  override fun checkClientTrusted(
    chain: Array<out X509Certificate>,
    authType: String,
    engine: SSLEngine?,
  ) = throw CertificateException("Unsupported operation")

  override fun checkClientTrusted(

* It takes each **request** that comes to your application.
* It can then do something to that **request** or run any needed code.
* Then it passes the **request** to be processed by the rest of the application (by some *path operation*).

{* ../../docs_src/security/tutorial002_an_py310.py hl[30:32] *}

## Recap { #recap }

You can now get the current user directly in your *path operation function*.

We are already halfway there.

We just need to add a *path operation* for the user/client to actually send the `username` and `password`.

     */
    SuggestWriterResult write(Client client, SuggestSettings settings, String index, SuggestItem[] items, boolean update);

    /**
     * Deletes a suggestion from the specified index.
     *
     * @param client   the client to use for the operation
     * @param settings the settings to use for the operation

But you can also declare the `Response` that you want to be used (e.g. any `Response` subclass), in the *path operation decorator* using the `response_class` parameter.

The contents that you return from your *path operation function* will be put inside of that `Response`.

## Usando `BackgroundTasks`

Primero, importa `BackgroundTasks` y define un parámetro en tu *path operation function* con una declaración de tipo de `BackgroundTasks`:

{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}

**FastAPI** creará el objeto de tipo `BackgroundTasks` por ti y lo pasará como ese parámetro.

/// tip

Note that, much like [dependencies in *path operation decorators*](dependencies/dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, no value will be passed to your *path operation function*.

///

The end result is that the item paths are now:

* `/items/`
* `/items/{item_id}`

...as we intended.

{* ../../docs_src/security/tutorial002_an_py310.py hl[30:32] *}

## Resumen

Ahora puedes obtener el usuario actual directamente en tu *path operation function*.

Ya estamos a mitad de camino.

Solo necesitamos agregar una *path operation* para que el usuario/cliente envíe realmente el `username` y `password`.