```

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 }

{* ../../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.

            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());
        }
    }

```

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 {

    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);

    #   [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.
    #

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.

     * The default value is empty.
     */
    default Optional<String> module() {
        return Optional.empty();
    }

    /**
     * {@return the version of the platform where the code will be executed}.
     * In a Java environment, this is the value of the {@code --release} compiler option.
     * The default value is empty.
     */
    default Optional<Version> targetVersion() {
        return Optional.empty();