## Technical Details { #technical-details }

The class `BackgroundTasks` comes directly from <a href="https://www.starlette.io/background/" class="external-link" target="_blank">`starlette.background`</a>.

La principale chose dont vous avez besoin pour exécuter une application **FastAPI** sur une machine serveur distante est un programme serveur ASGI tel que **Uvicorn**.

Il existe 3 principales alternatives :

* <a href="https://www.uvicorn.org/" class="external-link" target="_blank">Uvicorn</a> : un serveur ASGI haute performance.
* <a href="https://hypercorn.readthedocs.io/" class="external-link" target="_blank">Hypercorn</a> : un serveur

No HTTP Basic Auth, a aplicação espera um cabeçalho que contém um usuário e uma senha.

Caso ela não receba, ela retorna um erro HTTP 401 "Unauthorized" (*Não Autorizado*).

E retorna um cabeçalho `WWW-Authenticate` com o valor `Basic`, e um parâmetro opcional `realm`.

Isso sinaliza ao navegador para mostrar o prompt integrado para um usuário e senha.

///

## Дополнительная информация

Для более глубокого изучения темы воспользуйтесь документацией Starlette:

* <a href="https://www.starlette.io/websockets/" class="external-link" target="_blank">The `WebSocket` class</a>.

{* ../../docs_src/security/tutorial003_an_py310.py hl[58:66,69:74,94] *}

/// info

The additional header `WWW-Authenticate` with value `Bearer` we are returning here is also part of the spec.

Any HTTP (error) status code 401 "UNAUTHORIZED" is supposed to also return a `WWW-Authenticate` header.

In the case of bearer tokens (our case), the value of that header should be `Bearer`.

For this, you use the `TestClient` in a `with` statement, connecting to the WebSocket:

{* ../../docs_src/app_testing/tutorial002.py hl[27:31] *}

/// note

For more details, check Starlette's documentation for <a href="https://www.starlette.io/testclient/#testing-websocket-sessions" class="external-link" target="_blank">testing WebSockets</a>.

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