{* ../../docs_src/request_forms/tutorial001_an_py39.py hl[9] *}

Por exemplo, em uma das maneiras que a especificação OAuth2 pode ser usada (chamada "fluxo de senha"), é necessário enviar um `username` e uma `password` como campos do formulário.

# Özelikler

## FastAPI özellikleri

**FastAPI** sana bunları sağlıyor

### Açık standartları temel alır

        end
        handler -->> client: HTTP error response
    end

    operation ->> client: Return response to client
    Note over client,operation: Response is already sent, can't change it anymore
    opt Tasks
        operation -->> tasks: Send background tasks
    end
    opt Raise other exception
        tasks -->> tasks: Handle exceptions in the background task code
    end
```

/// info | 정보

begins. Communication blocks until the send can proceed.
A send on an unbuffered channel can proceed if a receiver is ready.
A send on a buffered channel can proceed if there is room in the buffer.
A send on a closed channel proceeds by causing a <a href="#Run_time_panics">run-time panic</a>.
A send on a <code>nil</code> channel blocks forever.
</p>

<pre>
ch &lt;- 3  // send value 3 to channel ch
</pre>

<p>

El beneficio de lanzar una excepción en lugar de `return`ar un valor será más evidente en la sección sobre Dependencias y Seguridad.

En este ejemplo, cuando el cliente solicita un ítem por un ID que no existe, lanza una excepción con un código de estado de `404`:

De manera similar, no puedes redefinir una path operation:

{* ../../docs_src/path_params/tutorial003b_py39.py hl[6,11] *}

La primera siempre será utilizada ya que el path coincide primero.

## Valores predefinidos { #predefined-values }

	}

	var checksumCombined []byte

	// However, in case of encryption, the persisted part ETags don't match
	// what we have sent to the client during PutObjectPart. The reason is
	// that ETags are encrypted. Hence, the client will send a list of complete
	// part ETags of which may not match the ETag of any part. For example
	//   ETag (client):          30902184f4e62dd8f98f0aaff810c626

    const val DEFAULT_INITIAL_WINDOW_SIZE = 65535

    /** HTTP/2: Size in bytes of the table used to decode the sender's header blocks. */
    const val HEADER_TABLE_SIZE = 1

    /** HTTP/2: The peer must not send a PUSH_PROMISE frame when this is 0. */
    const val ENABLE_PUSH = 2

    /** Sender's maximum number of concurrent streams. */
    const val MAX_CONCURRENT_STREAMS = 3

    /** Window size in bytes. */

### Use cases: external service { #use-cases-external-service }

An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

This provider might be charging you per request, and calling it might take some extra time than if you had a fixed mock user for tests.

}

var httpTimeFormats = []string{
	// Do not change this order, http time format dates
	// are usually in http.TimeFormat however there are
	// situations where for example aws-sdk-java doesn't
	// send the correct format.
	http.TimeFormat,
	"Mon, 2 Jan 2006 15:04:05 GMT",
}

// ParseHeader parses http.TimeFormat with an acceptable
// extension for http.TimeFormat - return time might be zero