```Python hl_lines="2  7  9"
{!../../docs_src/custom_response/tutorial006c.py!}
```

### `StreamingResponse`

Nimmt einen asynchronen Generator oder einen normalen Generator/Iterator und streamt den Responsebody.

```Python hl_lines="2  14"
{!../../docs_src/custom_response/tutorial007.py!}
```

Articles: English: - author: Balthazar Rouberol author_link: https://balthazar-rouberol.com link: https://blog.balthazar-rouberol.com/how-to-profile-a-fastapi-asynchronous-request title: How to profile a FastAPI asynchronous request - author: Stephen Siegert - Neon link: https://neon.tech/blog/deploy-a-serverless-fastapi-app-with-neon-postgres-and-aws-app-runner-at-any-scale title: Deploy a Serverless FastAPI App with Neon Postgres and AWS App Runner at any scale - author: Kurtis Pykes - NVIDIA...

   */
  fun cancel()

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

Hier ist ein wenig über diese Geschichte.

## Alternativen

Ich habe seit mehreren Jahren APIs mit komplexen Anforderungen (maschinelles Lernen, verteilte Systeme, asynchrone Jobs, NoSQL-Datenbanken, usw.) erstellt und leitete mehrere Entwicklerteams.

Dabei musste ich viele Alternativen untersuchen, testen und nutzen.

  /**
   * Returns an output {@code Future} to use in place of the given {@code input}. The output {@code
   * Future} need not be {@linkplain Future#isDone done}, making {@code AsyncFunction} suitable for
   * asynchronous derivations.
   *
   * <p>Throwing an exception from this method is equivalent to returning a failing {@code Future}.
   */
  ListenableFuture<O> apply(@ParametricNullness I input) throws Exception;

Calls are executed in one of two ways:

 * **Synchronous:** your thread blocks until the response is readable.
 * **Asynchronous:** you enqueue the request on any thread, and get [called back](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-callback/) on another thread when the response is readable.

& ⤴️ 👆 ✍ ❔ 🍵 [⚜ ⏮️ `CORSMiddleware`](../tutorial/cors.md){.internal-link target=_blank}.

👉 📄 👥 🔜 👀 ❔ ⚙️ 🎏 🛠️.

## ❎ 🔫 🛠️

**FastAPI** ⚓️ 🔛 💃 &amp; 🛠️ <abbr title="Asynchronous Server Gateway Interface">🔫</abbr> 🔧, 👆 💪 ⚙️ 🙆 🔫 🛠️.

🛠️ 🚫 ✔️ ⚒ FastAPI ⚖️ 💃 👷, 📏 ⚫️ ⏩ 🔫 🔌.

🏢, 🔫 🛠️ 🎓 👈 ⌛ 📨 🔫 📱 🥇 ❌.

, 🧾 🥉-🥳 🔫 🛠️ 👫 🔜 🎲 💬 👆 🕳 💖:

```Python

## Créer une fonction de tâche

Une fonction à exécuter comme tâche d'arrière-plan est juste une fonction standard qui peut recevoir des paramètres.

Elle peut être une fonction asynchrone (`async def`) ou une fonction normale (`def`), **FastAPI** saura la gérer correctement.

Dans cet exemple, la fonction de tâche écrira dans un fichier (afin de simuler un envoi d'email).

   * calls returns to zero).
   *
   * Note: The time at which a [call][Call] is considered idle is different depending on whether it
   * was run [asynchronously][Call.enqueue] or [synchronously][Call.execute]. Asynchronous calls
   * become idle after the [onResponse][Callback.onResponse] or [onFailure][Callback.onFailure]
   * callback has returned. Synchronous calls become idle once [execute()][Call.execute] returns.

 *
 * Other exception types cancel the current call:
 *
 *  * For synchronous calls made with [Call.execute], the exception is propagated to the caller.
 *
 *  * For asynchronous calls made with [Call.enqueue], an [IOException] is propagated to the caller
 *    indicating that the call was canceled. The interceptor's exception is delivered to the current