# Keepalive ping tests


keepalive_app = FastAPI()


@keepalive_app.get("/slow-async", response_class=EventSourceResponse)
async def slow_async_stream():
    yield {"n": 1}
    # Sleep longer than the (monkeypatched) ping interval so a keepalive
    # comment is emitted before the next item.
    await asyncio.sleep(0.3)
    yield {"n": 2}


@keepalive_app.get("/slow-sync", response_class=EventSourceResponse)

{* ../../docs_src/stream_data/tutorial002_py310.py ln[30:34] hl[31] *}

/// tip

If you need to call blocking code from inside of an async function, or an async function from inside of a blocking function, you could use [Asyncer](https://asyncer.tiangolo.com), a sibling library to FastAPI.

///

{* ../../docs_src/stream_data/tutorial002_py310.py ln[30:34] hl[31] *}

/// tip | Astuce

### 文件与异步 { #files-and-async }

大多数情况下，类文件对象默认与 async 和 await 不兼容。

例如，它们没有 `await file.read()`，也不支持 `async for chunk in file`。

而且很多情况下，读取它们是一个阻塞操作（可能会阻塞事件循环），因为数据来自磁盘或网络。

/// info | 信息

上面的示例其实是个例外，因为 `io.BytesIO` 对象已经在内存中，所以读取它不会阻塞。

但在许多情况下，读取文件或类文件对象会发生阻塞。

///

为避免阻塞事件循环，你可以简单地把*路径操作函数*声明为常规的 `def`（而不是 `async def`），这样 FastAPI 会在一个线程池工作线程上运行它，从而避免阻塞主事件循环。

        "/async-wrapped-dependency-async-wrapper/",
        "/async-wrapped-gen-dependency-async-wrapper/",
        "/wrapped-class-instance-dependency-async-wrapper/",
        "/wrapped-class-instance-async-dependency-async-wrapper/",
        "/wrapped-class-dependency-async-wrapper/",
        "/wrapped-endpoint-async-wrapper/",
        "/async-wrapped-endpoint-async-wrapper/",
    ],
)

///

イベントループのブロッキングを避けるには、path operation 関数を `async def` ではなく通常の `def` で宣言してください。そうすると FastAPI はその関数をスレッドプールワーカー上で実行し、メインループのブロッキングを避けます。

{* ../../docs_src/stream_data/tutorial002_py310.py ln[30:34] hl[31] *}

/// tip | 豆知識

async 関数内からブロッキングなコードを呼び出す必要がある場合、あるいはブロッキングな関数内から async 関数を呼び出す必要がある場合は、FastAPI の兄弟ライブラリである [Asyncer](https://asyncer.tiangolo.com) を利用できます。

///

### `yield from` { #yield-from }

/// tip | 팁

Pydantic이 **Rust** 쪽에서 직렬화하므로, 반환 타입을 선언하지 않았을 때보다 훨씬 더 높은 **성능**을 얻을 수 있습니다.

///

### 비 async *경로 처리 함수* { #non-async-path-operation-functions }

`async`가 없는 일반 `def` 함수도 사용할 수 있으며, 동일하게 `yield`를 사용할 수 있습니다.

FastAPI가 이벤트 루프를 막지 않도록 올바르게 실행을 보장합니다.

이 경우 함수가 async가 아니므로 적절한 반환 타입은 `Iterable[Item]`입니다:

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[28:31] hl[29] *}

`GET/HEAD` operations if object or object version requested qualifies for replication and is missing on one site, but present on the other. This allows the applications to take full advantage of two-way replication even before the two sites get fully synced.

In the case of multi destination replication, the replication status shows `COMPLETED` only after the replication operation succeeds on each of the targets specified in the replication configuration. If multiple targets are configured to...

@app.get("/callable-gen-dependency")
async def get_callable_gen_dependency(value: str = Depends(callable_gen_dependency)):
    return value


@app.get("/async-callable-dependency")
async def get_async_callable_dependency(
    value: str = Depends(async_callable_dependency),
):
    return value


@app.get("/async-callable-gen-dependency")
async def get_async_callable_gen_dependency(
    value: str = Depends(async_callable_gen_dependency),
):

objects or object prefixes that satisfy the replication rules and were created prior to adding replication configuration OR while replication rules were disabled will be synced to the target cluster. Depending on the number of previously existing objects, the existing objects that are now eligible to be replicated will eventually be synced to the target cluster as the scanner schedules them. This may be slower depending on the load on the cluster, latency and size of the namespace.

In the rare...