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. [`msgpack`](https://msgpack.org/index.html)).
* Decompressing gzip-compressed request bodies.

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) :

<blockquote markdown="1">

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

Tienden a requerir configuraciones más complejas, un gestor de cola de mensajes/trabajos, como RabbitMQ o Redis, pero te permiten ejecutar tareas en segundo plano en múltiples procesos, y especialmente, en múltiples servidores.

 *  New: Build with Kotlin 1.3.41, BouncyCastle 1.62, and Conscrypt 2.2.1.
 *  Fix: Recover gracefully when a coalesced connection immediately goes unhealthy.
 *  Fix: Defer the `SecurityException` when looking up the default proxy selector.
 *  Fix: Don't use brackets formatting IPv6 host names in MockWebServer.
 *  Fix: Don't permit cache iterators to remove entries that are being written.


## Version 4.0.1

_2019-07-10_

Оскільки це WebSocket, не має сенсу піднімати `HTTPException`, натомість ми піднімаємо `WebSocketException`.

Ви можете використати код закриття з [чинних кодів, визначених у специфікації](https://tools.ietf.org/html/rfc6455#section-7.4.1).

///

### Спробуйте WebSockets із залежностями { #try-the-websockets-with-dependencies }

Запустіть ваш застосунок:

<div class="termy">

```console
$ fastapi dev

from annotated_doc import Doc
from pydantic import AfterValidator, BaseModel, Field, model_validator
from starlette.responses import StreamingResponse

# Canonical SSE event schema matching the OpenAPI 3.2 spec
# (Section 4.14.4 "Special Considerations for Server-Sent Events")
_SSE_EVENT_SCHEMA: dict[str, Any] = {
    "type": "object",
    "properties": {
        "data": {"type": "string"},
        "event": {"type": "string"},

également avoir ses propres sous‑applications montées et tout fonctionnera correctement, car FastAPI gère automatiquement tous ces `root_path`.

Vous en apprendrez davantage sur `root_path` et sur la façon de l'utiliser explicitement dans la section [Derrière un proxy](behind-a-proxy.md)....

		{"TEXT", "$:0:(SB, 0, $1", "expected '(', found 0"},          // Issue 12468.
		{"TEXT", "@B(SB),0,$0", "expected '(', found B"},             // Issue 23580.
		{"TEXT", "foo<ABIInternal>(SB),0", "ABI selector only permitted when compiling runtime, reference was to \"foo\""},
		{"FUNCDATA", "", "expect two operands for FUNCDATA"},
		{"FUNCDATA", "(SB ", "expect two operands for FUNCDATA"},
		{"DATA", "", "expect two operands for DATA"},

            Map<String, Artifact> map = new HashMap<>();
            for (Artifact artifact : resolvedArtifacts) {
                /**
                 * MNG-6300: resolvedArtifacts can be cache result; this ensures reactor files are always up-to-date
                 * During lifecycle the Artifact.getFile() can change from target/classes to the actual jar.

	if s3Error := checkRequestAuthType(ctx, r, policy.GetObjectAction, bucket, zipPath); s3Error != ErrNone {
		if getRequestAuthType(r) == authTypeAnonymous {
			// As per "Permission" section in
			// https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectGET.html
			// If the object you request does not exist,
			// the error Amazon S3 returns depends on
			// whether you also have the s3:ListBucket