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
			//

* AWS: Avoid spurious ELB listener recreation - ignore case when matching protocol ([#47391](https://github.com/kubernetes/kubernetes/pull/47391), [@justinsb](https://github.com/justinsb))

* Add FastAPI with Swagger UI cheatsheet to external links. PR [#671](https://github.com/tiangolo/fastapi/pull/671) by [@euri10](https://github.com/euri10).
* Fix typo in HTTP protocol in CORS example. PR [#647](https://github.com/tiangolo/fastapi/pull/647) by [@forestmonster](https://github.com/forestmonster).

    * If you are using docker manifests there are not visible changes.

### Other notable changes

* Use HTTPS as etcd-apiserver protocol when mTLS between etcd and kube-apiserver on master is enabled, change etcd metrics/health port to 2382. ([#77561](https://github.com/kubernetes/kubernetes/pull/77561), [@wenjiaswe](https://github.com/wenjiaswe))

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.

        assertTrue(urlFilter.match("https://example.com/日本/page"));
        assertFalse(urlFilter.match("https://example.com/china/page"));
    }

    /**
     * Test URL with special protocols
     */
    public void test_specialProtocols() {
        String sessionId = "test-session-022";
        urlFilter.init(sessionId);

        urlFilter.addInclude("(http|https|ftp|file)://.*");