from fastapi import Body, FastAPI, Request, Response
from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):

        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

@app.websocket("/ws")
async def websocket_endpoint(websocket: WebSocket, session: SessionDep):
    await websocket.accept()
    for item in session:
        await websocket.send_text(f"{item}")


@app.websocket("/ws-broken")
async def websocket_endpoint_broken(websocket: WebSocket, session: BrokenSessionDep):
    await websocket.accept()
    for item in session:
        await websocket.send_text(f"{item}")  # pragma no cover


client = TestClient(app)

    exit_limiter = CapacityLimiter(1)
    try:
        yield await run_in_threadpool(cm.__enter__)
    except Exception as e:
        ok = bool(
            await anyio.to_thread.run_sync(
                cm.__exit__, type(e), e, e.__traceback__, limiter=exit_limiter
            )
        )
        if not ok:
            raise e
    else:
        await anyio.to_thread.run_sync(

    assertFalse(service.startUpCalled);

    service.startAsync().awaitRunning();
    assertTrue(service.startUpCalled);
    assertEquals(Service.State.RUNNING, service.state());

    enterRun.await(); // to avoid stopping the service until run() is invoked

    service.stopAsync().awaitTerminated();
    assertTrue(service.shutDownCalled);
    assertEquals(Service.State.TERMINATED, service.state());

    val entryTime = System.nanoTime()

    for (queue in TaskRunner.INSTANCE.activeQueues()) {
      // We wait at most 1 second, so we don't ever turn multiple lost threads into
      // a test timeout failure.
      val waitTime = (entryTime + 1_000_000_000L - System.nanoTime())
      if (!queue.idleLatch().await(waitTime, TimeUnit.NANOSECONDS)) {
        TaskRunner.INSTANCE.withLock {
          TaskRunner.INSTANCE.cancelAll()

            ready.countDown()
            try {
              proceed.await(5, TimeUnit.SECONDS)
            } catch (e: InterruptedException) {
              throw RuntimeException(e)
            }
            chain.proceed(chain.request())
          },
        ).build()
    val t1 = makeSynchronousCall(client.newCall(newRequest("http://a/3")))
    ready.await(5, TimeUnit.SECONDS)
    executor.finishJob("http://a/2")

    ):
        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}")
            await websocket.send_text(f"Message text was: {data}, for item ID: {item_id}")
    ```
    """

    def __init__(
        self,

# Nebenläufigkeit und async / await { #concurrency-and-async-await }

Details zur `async def`-Syntax für *Pfadoperation-Funktionen* und Hintergrundinformationen zu asynchronem Code, Nebenläufigkeit und Parallelität.

## In Eile? { #in-a-hurry }

<abbr title="too long; didn't read – Zu lang; nicht gelesen"><strong>TL;DR:</strong></abbr>

Wenn Sie Bibliotheken von Dritten verwenden, die mit `await` aufgerufen werden müssen, wie zum Beispiel:

```Python