{* ../../docs_src/first_steps/tutorial001.py hl[7] *}

C'est une fonction Python.

Elle sera appelée par **FastAPI** quand une requête sur l'URL `/` sera reçue via une opération `GET`.

Ici, c'est une fonction asynchrone (définie avec `async def`).

---

Vous pourriez aussi la définir comme une fonction classique plutôt qu'avec `async def` :

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

/// note

 * ListenableFuture}</a>.
 *
 * <p>This class is GWT-compatible.
 *
 * <h3>Purpose</h3>
 *
 * <p>The main purpose of {@code ListenableFuture} is to help you chain together a graph of
 * asynchronous operations. You can chain them together manually with calls to methods like {@link
 * Futures#transform(ListenableFuture, com.google.common.base.Function, Executor) Futures.transform}

            }

            return response;

        } catch (Exception e) {
            throw new IOException("Witness heartbeat RPC failed", e);
        }
    }

    /**
     * Requests asynchronous notifications from the witness service.
     *
     * @param contextHandle the context handle from registration
     * @return the async notify response containing notifications

   */
  fun cancel()

  fun interface Factory {
    /**
     * Creates a new web socket and immediately returns it. Creating a web socket initiates an
     * asynchronous process to connect the socket. Once that succeeds or fails, `listener` will be
     * notified. The caller must either close or cancel the returned web socket when it is no longer
     * in use.
     */

In this section we'll see how to use other middlewares.

## Adding ASGI middlewares { #adding-asgi-middlewares }

As **FastAPI** is based on Starlette and implements the <abbr title="Asynchronous Server Gateway Interface">ASGI</abbr> specification, you can use any ASGI middleware.

A middleware doesn't have to be made for FastAPI or Starlette to work, as long as it follows the ASGI spec.

dökümantasyon için Pydantic gibi bir üçüncü parti kütüphane kullanmıyor, kendi içerisinde bunlara sahip. Yani bu veri tipi tanımlarını tekrar kullanmak pek de kolay değil.

Biraz daha detaylı ayarlamalara gerek duyuyor. Ayrıca <abbr title="ASGI (Asynchronous Server Gateway Interface): Asenkron Sunucu Ağ Geçidi Arabirimi, asenkron Python web uygulamaları geliştirmek için yeni standart.">ASGI</abbr> yerine <abbr title="WSGI (Web Server Gateway Interface): Web Sunucusu Ağ Geçidi Arabirimi, Pythonda senkron...

import com.google.errorprone.annotations.DoNotMock;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

/**
 * An object with an operational state, plus asynchronous {@link #startAsync()} and {@link
 * #stopAsync()} lifecycle methods to transition between states. Example services include
 * webservers, RPC servers and timers.
 *
 * <p>The normal lifecycle of a service is:
 *

   dropped in 2.0.

## Version 1.5.4

_2014-04-14_

 * Drop ALPN support in Android. There's a concurrency bug in all
   currently-shipping versions.
 * Support asynchronous disconnects by breaking the socket only. This should
   prevent flakiness from multiple threads concurrently accessing a stream.

## Version 1.5.3

_2014-03-29_

///

/// tip

If you want to call `async` functions in your tests apart from sending requests to your FastAPI application (e.g. asynchronous database functions), have a look at the [Async Tests](../advanced/async-tests.md){.internal-link target=_blank} in the advanced tutorial.

///

## Separating tests { #separating-tests }

그리고 [CORS with the `CORSMiddleware`](){.internal-link target=_blank}하는 방법도 보셨습니다.

이 섹션에서는 다른 미들웨어들을 사용하는 방법을 알아보겠습니다.

## ASGI 미들웨어 추가하기

**FastAPI**는 Starlette을 기반으로 하고 있으며, <abbr title="Asynchronous Server Gateway Interface">ASGI</abbr> 사양을 구현하므로 ASGI 미들웨어를 사용할 수 있습니다.

미들웨어가 FastAPI나 Starlette용으로 만들어지지 않아도 ASGI 사양을 준수하는 한 동작할 수 있습니다.

일반적으로 ASGI 미들웨어는 첫 번째 인수로 ASGI 앱을 받는 클래스들입니다.