Starlette (y **FastAPI**) están basados en <a href="https://anyio.readthedocs.io/en/stable/" class="external-link" target="_blank">AnyIO</a>, lo que lo hace compatible tanto con el <a href="https://docs.python.org/3/library/asyncio-task.html" class="external-link" target="_blank">asyncio</a> del paquete estándar de Python como con <a href="https://trio.readthedocs.io/en/stable/" class="external-link" target="_blank">Trio</a>.

href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">mittels des Präfix `X-`</a> hinzugefügt werden können.

Wenn Sie jedoch benutzerdefinierte Header haben, die ein Client in einem Browser sehen können soll, müssen Sie diese zu Ihrer CORS-Konfiguration hinzufügen (weitere Informationen finden Sie unter [CORS (Cross-Origin Resource Sharing)](../tutorial/cors.md){.internal-link target=_blank}), unter Verwendung des Parameters `expose_headers`,...

proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the `X-` prefix</a>.

But if you have custom headers that you want a client in a browser to be able to see, you need to add them to your CORS configurations (read more in [CORS (Cross-Origin Resource Sharing)](../tutorial/cors.md){.internal-link target=_blank}), using the parameter `expose_headers` documented in <a href="https://www.starlette.dev...

# CORS (Cross-Origin Resource Sharing) { #cors-cross-origin-resource-sharing }

<a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS" class="external-link" target="_blank">CORS ou "Cross-Origin Resource Sharing"</a> refere-se às situações em que um frontend rodando em um navegador possui um código JavaScript que se comunica com um backend, e o backend está em uma "origem" diferente do frontend.

## Origem { #origin }

### Instalar `pydantic-settings` { #install-pydantic-settings }

Primeiro, certifique-se de criar seu [ambiente virtual](../virtual-environments.md){.internal-link target=_blank}, ativá-lo e então instalar o pacote `pydantic-settings`:

<div class="termy">

```console

## Technische Details { #technical-details }

Die Klasse `BackgroundTasks` stammt direkt von <a href="https://www.starlette.dev/background/" class="external-link" target="_blank">`starlette.background`</a>.

	@(env bash $(PWD)/buildscripts/race.sh)

test-iam: install-race ## verify IAM (external IDP, etcd backends)
	@echo "Running tests for IAM (external IDP, etcd backends)"
	@MINIO_API_REQUESTS_MAX=10000 CGO_ENABLED=0 go test -timeout 15m -tags kqueue,dev -v -run TestIAM* ./cmd
	@echo "Running tests for IAM (external IDP, etcd backends) with -race"

## Détails techniques

La classe `BackgroundTasks` provient directement de <a href="https://www.starlette.dev/background/" class="external-link" target="_blank">`starlette.background`</a>.

# FastAPI Cloud { #fastapi-cloud }

Você pode implantar sua aplicação FastAPI no <a href="https://fastapicloud.com" class="external-link" target="_blank">FastAPI Cloud</a> com um **único comando**; entre na lista de espera, caso ainda não tenha feito isso. 🚀

## Login { #login }

Certifique-se de que você já tem uma conta no **FastAPI Cloud** (nós convidamos você a partir da lista de espera 😉).

Depois, faça login:

<div class="termy">

```console

{* ../../docs_src/dataclasses_/tutorial001_py310.py hl[1,6:11,18:19] *}

This is still supported thanks to **Pydantic**, as it has <a href="https://docs.pydantic.dev/latest/concepts/dataclasses/#use-of-stdlib-dataclasses-with-basemodel" class="external-link" target="_blank">internal support for `dataclasses`</a>.