Esto no es una limitación de **FastAPI**, es parte del protocolo HTTP.

///

## Subida de Archivos Opcional { #optional-file-upload }

Puedes hacer un archivo opcional utilizando anotaciones de tipos estándar y estableciendo un valor por defecto de `None`:

	public final fun getProtocolNegotiationEnabled ()Z
	public final fun getRequestCount ()I
	public final fun getServerSocketFactory ()Ljavax/net/ServerSocketFactory;
	public final fun noClientAuth ()V
	public final fun protocols ()Ljava/util/List;
	public final fun requestClientAuth ()V
	public final fun requireClientAuth ()V
	public final fun setBodyLimit (J)V
	public final fun setDispatcher (Lokhttp3/mockwebserver/Dispatcher;)V

Solo un detalle técnico para los nerds curiosos. 🤓

Por debajo, en la especificación técnica ASGI, esto es parte del <a href="https://asgi.readthedocs.io/en/latest/specs/lifespan.html" class="external-link" target="_blank">Protocolo de Lifespan</a>, y define eventos llamados `startup` y `shutdown`.

/// info | Información

			// client sent this as part of signed headers we need to
			// handle otherwise we would see a signature mismatch.
			// `aws-cli` sets this as part of signed headers.
			//
			// According to
			// http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.20
			// Expect header is always of form:
			//
			//   Expect       =  "Expect" ":" 1#expectation
			//   expectation  =  "100-continue" | expectation-extension
			//

    * Introduce Alpha field `AllowWatchBookmarks` in ListOptions for requesting watch bookmarks from apiserver. The implementation in apiserver is hidden behind feature gate `WatchBookmark` (currently in Alpha stage).
* Override protocol between etcd server and kube-apiserver on master with HTTPS instead HTTP when mTLS is enabled in GCE ([#74690](https://github.com/kubernetes/kubernetes/pull/74690), [@wenjiaswe](https://github.com/wenjiaswe))

## Origin { #origin }

Ein <abbr title="Ursprung">Origin</abbr> ist die Kombination aus Protokoll (`http`, `https`), Domain (`myapp.com`, `localhost`, `localhost.tiangolo.com`) und Port (`80`, `443`, `8080`).

Alle folgenden sind also unterschiedliche Origins:

* `http://localhost`
* `https://localhost`

pkg syscall (linux-arm-cgo), type RawSockaddrLinklayer struct, Ifindex int32
pkg syscall (linux-arm-cgo), type RawSockaddrLinklayer struct, Pkttype uint8
pkg syscall (linux-arm-cgo), type RawSockaddrLinklayer struct, Protocol uint16
pkg syscall (linux-arm-cgo), type RawSockaddrNetlink struct
pkg syscall (linux-arm-cgo), type RawSockaddrNetlink struct, Family uint16
pkg syscall (linux-arm-cgo), type RawSockaddrNetlink struct, Groups uint32

### Sécurité et authentification

La sécurité et l'authentification sont intégrées. Sans aucun compromis avec les bases de données ou les modèles de données.

Tous les protocoles de sécurités sont définis dans OpenAPI, incluant:

* HTTP Basic.
* **OAuth2** (aussi avec **JWT tokens**). Jetez un oeil au tutoriel [OAuth2 avec JWT](tutorial/security/oauth2-jwt.md){.internal-link target=_blank}.

Esses headers preservam informações sobre a requisição original que, de outra forma, seriam perdidas:

* X-Forwarded-For: o endereço IP original do cliente
* X-Forwarded-Proto: o protocolo original (`https`)
* X-Forwarded-Host: o host original (`mysuperapp.com`)

But it provides you the tools to simplify the process as much as possible without compromising flexibility, robustness, or security.

And you can use and implement secure, standard protocols, like OAuth2 in a relatively simple way.