### Requests simples { #simple-requests }

Cualquier request con un header `Origin`. En este caso, el middleware pasará el request a través de lo normal, pero incluirá los headers CORS adecuados en el response.

## Más info { #more-info }

* Editor support (completion, etc.), even for nested models
* Data conversion
* Data validation
* Automatic documentation

## Special types and validation { #special-types-and-validation }

Apart from normal singular types like `str`, `int`, `float`, etc. you can use more complex singular types that inherit from `str`.

   * Response and normal event sequences will not be received.
   *
   * This event will only be received when a Cache is configured for the client.
   */
  open fun cacheHit(
    call: Call,
    response: Response,
  ) {
  }

  /**
   * Invoked when a response will be served from the network. The Response will be
   * available from normal event sequences.
   *

You can define event handlers (functions) that need to be executed before the application starts up, or when the application is shutting down.

These functions can be declared with `async def` or normal `def`.

### `startup` event { #startup-event }

To add a function that should be run before the application starts, declare it with the event `"startup"`:

{* ../../docs_src/events/tutorial001_py39.py hl[8] *}

Você provavelmente pode pular esta parte.

///

Existe uma forma alternativa de definir essa lógica para ser executada durante a *inicialização* e durante o *encerramento*.

Você pode definir manipuladores de eventos (funções) que precisam ser executados antes de a aplicação iniciar ou quando a aplicação estiver encerrando.

Essas funções podem ser declaradas com `async def` ou `def` normal.

### Evento `startup` { #startup-event }

// Tests extracting bucket and objectname from various types of paths.
func TestPath2BucketObjectName(t *testing.T) {
	testCases := []struct {
		path           string
		bucket, object string
	}{
		// Test case 1 normal case.
		{
			path:   "/bucket/object",
			bucket: "bucket",
			object: "object",
		},
		// Test case 2 where url only has separator.
		{
			path:   SlashSeparator,
			bucket: "",
			object: "",

Bu fonksiyon bir `GET` işlemi kullanılarak "`/`" bağlantısına bir istek geldiğinde **FastAPI** tarafından çağrılır.

Bu durumda bu fonksiyon bir `async` fonksiyondur.

---

Bu fonksiyonu `async def` yerine normal bir fonksiyon olarak da tanımlayabilirsiniz.

{* ../../docs_src/first_steps/tutorial003.py hl[7] *}

/// note | Not

Por ejemplo, dentro de una *path operation function* `async` puedes obtener los contenidos con:

```Python
contents = await myfile.read()
```

Si estás dentro de una *path operation function* normal `def`, puedes acceder al `UploadFile.file` directamente, por ejemplo:

```Python
contents = myfile.file.read()
```

/// note | Detalles Técnicos de `async`

	// path cannot be so long that you cannot append an 8.3 file
	// name (that is, the directory name cannot exceed MAX_PATH
	// minus 12)." Since MAX_PATH is 260, 260 - 12 = 248.
	//
	// The MSDN docs appear to say that a normal path that is 248 bytes long
	// will work; empirically the path must be less then 248 bytes long.
	if len(path) < 248 {
		// Don't fix. (This is how Go 1.7 and earlier worked,
		// not automatically generating the \\?\ form)

Pero si vas con tu navegador a <a href="http://127.0.0.1:8000/app" class="external-link" target="_blank">http://127.0.0.1:8000/app</a> verás el response normal:

```JSON
{
    "message": "Hello World",
    "root_path": "/api/v1"
}
```

Así que no se esperará que sea accedido en `http://127.0.0.1:8000/api/v1/app`.