.isEqualTo(bytes)
    assertThat(CertificateAdapters.extension.fromDer(bytes))
      .isEqualTo(extension)
  }

  @Test fun `extension with type hint for subject alternative names`() {
    val extension =
      Extension(
        SUBJECT_ALTERNATIVE_NAME,
        false,
        listOf(
          generalNameDnsName to "cash.app",
          generalNameDnsName to "www.cash.app",
        ),
      )

![Swagger UI](https://fastapi.tiangolo.com/img/index/index-01-swagger-ui-simple.png)

### Alternative API docs

And now, go to <a href="http://127.0.0.1:8000/redoc" class="external-link" target="_blank">http://127.0.0.1:8000/redoc</a>.

You will see the alternative automatic documentation (provided by <a href="https://github.com/Rebilly/ReDoc" class="external-link" target="_blank">ReDoc</a>):

It is imported/included directly into FastAPI so that you can import it from `fastapi` and avoid accidentally importing the alternative `BackgroundTask` (without the `s` at the end) from `starlette.background`.

⚠️ **ATTENTION** ⚠️

Si vous démarrez un nouveau projet de zéro, allez voir les alternatives au début de cette page.

Par exemple, le générateur de projet <a href="https://github.com/tiangolo/full-stack-fastapi-postgresql" class="external-link" target="_blank">Full Stack FastAPI PostgreSQL</a>  peut être une meilleure alternative, étant activement maintenu et utilisé et comprenant toutes les nouvelles fonctionnalités et améliorations.

        Cell a = as[i];
        if (a != null) sum += a.value;
      }
    }
    return sum;
  }

  /**
   * Resets variables maintaining the sum to zero. This method may be a useful alternative to
   * creating a new adder, but is only effective if there are no concurrent updates. Because this
   * method is intrinsically racy, it should only be used when it is known that no threads are
   * concurrently updating.

import java.nio.charset.CodingErrorAction;
import java.util.Arrays;

/**
 * An {@link InputStream} that converts characters from a {@link Reader} into bytes using an
 * arbitrary Charset.
 *
 * <p>This is an alternative to copying the data to an {@code OutputStream} via a {@code Writer},
 * which is necessarily blocking. By implementing an {@code InputStream} it allows consumers to

    builder.setUnsafeReplacement("\uFFFD");

    /*
     * Except for \n, \t, and \r, all ASCII control characters are replaced with the Unicode
     * replacement character.
     *
     * Implementation note: An alternative to the following would be to make a map that simply
     * replaces the allowed ASCII whitespace characters with themselves and to set the minimum safe

# Custom Request and APIRoute class

In some cases, you may want to override the logic used by the `Request` and `APIRoute` classes.

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

!!! danger
    This is an "advanced" feature.

    If you are just starting with **FastAPI** you might want to skip this section.

 * might be absent" as two distinct types in your program, which can aid clarity.
 *
 * <p>Some uses of this class include
 *
 * <ul>
 *   <li>As a method return type, as an alternative to returning {@code null} to indicate that no
 *       value was available
 *   <li>To distinguish between "unknown" (for example, not present in a map) and "known to have no

# Benutzerdefinierte Request- und APIRoute-Klasse

In einigen Fällen möchten Sie möglicherweise die von den Klassen `Request` und `APIRoute` verwendete Logik überschreiben.

Das kann insbesondere eine gute Alternative zur Logik in einer Middleware sein.

Wenn Sie beispielsweise den Requestbody lesen oder manipulieren möchten, bevor er von Ihrer Anwendung verarbeitet wird.

!!! danger "Gefahr"
    Dies ist eine „fortgeschrittene“ Funktion.