Dans ce cadre, j'ai dû étudier, tester et utiliser de nombreuses alternatives.

L'histoire de **FastAPI** est en grande partie l'histoire de ses prédécesseurs.

Comme dit dans la section [Alternatives](alternatives.md){.internal-link target=\_blank} :

<blockquote markdown="1">

**FastAPI** n'existerait pas sans le travail antérieur d'autres personnes.

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.

///

## Use cases { #use-cases }

Some use cases include:

* Converting non-JSON request bodies to JSON (e.g. <a href="https://msgpack.org/index.html" class="external-link" target="_blank">`msgpack`</a>).

        websocket: WebSocket,
        session: Annotated[str | None, Cookie()] = None,
        item_id: str,
    ):
        if session is None:
            raise WebSocketException(code=status.WS_1008_POLICY_VIOLATION)
        await websocket.accept()
        while True:
            data = await websocket.receive_text()
            await websocket.send_text(f"Session cookie is: {session}")

      #   - regex: (server|pod)
      #     action: labeldrop
    namespace: ~
    # Scrape interval, for example `interval: 30s`
    interval: ~
    # Scrape timeout, for example `scrapeTimeout: 10s`
    scrapeTimeout: ~

## ETCD settings: https://github.com/minio/minio/blob/master/docs/sts/etcd.md
## Define endpoints to enable this section.
etcd:
  endpoints: []
  pathPrefix: ""

<img src="/img/tutorial/body-fields/image01.png">

## 技术细节

关于 `example` 和 `examples`...

JSON Schema在最新的一个版本中定义了一个字段 <a href="https://json-schema.org/draft/2019-09/json-schema-validation.html#rfc.section.9.5" class="external-link" target="_blank">`examples`</a> ，但是 OpenAPI 基于之前的一个旧版JSON Schema，并没有 `examples`.

   *
   * <p><i>Notes:</i> This is an implementation of the algorithm for Lexicographical Permutations
   * Generation, described in Knuth's "The Art of Computer Programming", Volume 4, Chapter 7,
   * Section 7.2.1.2. The iteration order follows the lexicographical order. This means that the
   * first permutation will be in ascending order, and the last will be in descending order.
   *

    }

    /**
     * Test multiple initializations with different session IDs
     */
    public void test_multipleInit_differentSessionIds() {
        // First session
        urlFilter.init("session-001");
        urlFilter.addInclude("https://first.com/.*");

        // Second session
        urlFilter.init("session-002");
        urlFilter.addInclude("https://second.com/.*");

    As always, in FastAPI you can combine `def` and `async def` as needed.

    If you need a refresher about when to use which, check out the section _"In a hurry?"_ in the docs about [`async` and `await`](../async.md#in-a-hurry){.internal-link target=_blank}.

And then you also read how to handle [CORS with the `CORSMiddleware`](../tutorial/cors.md){.internal-link target=_blank}.

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

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

   *
   * <p>If you are designing a new system that needs HMAC, prefer {@link #hmacSha256} or other
   * future-proof algorithms <a
   * href="https://datatracker.ietf.org/doc/html/rfc6151#section-2.3">over {@code hmacMd5}</a>.
   *
   * @param key the secret key
   * @throws IllegalArgumentException if the given key is inappropriate for initializing this MAC
   * @since 20.0
   */