```

This results in the following execution order:

* **Request**: MiddlewareB → MiddlewareA → route

* **Response**: route → MiddlewareA → MiddlewareB

This stacking behavior ensures that middlewares are executed in a predictable and controllable order.

## Other middlewares { #other-middlewares }

```

Quando você cria um gerenciador de contexto ou um gerenciador de contexto assíncrono como mencionado acima, o que ele faz é que, antes de entrar no bloco `with`, ele irá executar o código anterior ao `yield`, e depois de sair do bloco `with`, ele irá executar o código depois do `yield`.

No nosso exemplo de código acima, nós não usamos ele diretamente, mas nós passamos para o FastAPI para ele usá-lo.

     *
     * @param charset the character encoding to set
     */
    public void setCharset(final String charset) {
        this.charset = charset;
    }

    /**
     * Executes a HEAD request for the given URL.
     * @param url The URL to request.
     * @return The ResponseData.
     */
    @Override
    public ResponseData doHead(final String url) {
        try {

            DfFinalTimeZoneProvider provider = getDBFluteSystemTimeZoneProvider();
            // Provider might be null due to reflection limitations, which is ok
            assertTrue("processDBFluteSystem executed without exception", true);
        } catch (Exception e) {
            fail("processDBFluteSystem should handle unlock/lock properly: " + e.getMessage());
        }
    }

{* ../../docs_src/websockets/tutorial001.py hl[48:52] *}

Puedes recibir y enviar datos binarios, de texto y JSON.

## Pruébalo

Si tu archivo se llama `main.py`, ejecuta tu aplicación con:

<div class="termy">

```console
$ fastapi dev main.py

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

Calls are executed in one of two ways:

 * **Synchronous:** your thread blocks until the response is readable.

    #   [true]
    #     The customize entities for procedure's out-parameter
    #     and not-param-result are auto-generated.
    #     And also not-param-result's properties are auto-generated.
    #     Target procedures are executed actually at Sql2Entity task.
    #     (because of getting from execution meta data (result set meta data))
    #     This property is valid only when isGenerateProcedureParameterBean is true.
    #

    protected String filterPathEncoding;

    /** An array of supported language codes. */
    protected String[] supportedLanguages;

    /** A list of shutdown hooks to be executed on system shutdown. */
    protected List<Runnable> shutdownHookList = new ArrayList<>();

    /** The previous state of the cluster. */
    protected AtomicInteger previousClusterState = new AtomicInteger(0);

You don't even have to check if the token exists to return an error. You can be sure that if your function is executed, it will have a `str` in that token.

You can try it already in the interactive docs:

<img src="/img/tutorial/security/image03.png">

We are not verifying the validity of the token yet, but that's a start already.

This was designed this way mainly to allow using the same objects "yielded" by dependencies inside of background tasks, because the exit code would be executed after the background tasks were finished.