## Бути `async` чи не бути `async` { #to-async-or-not-to-async }

Оскільки залежності також викликатимуться **FastAPI** (так само, як і ваші *функції операцій шляху*), під час визначення ваших функцій діють ті самі правила.

Ви можете використовувати `async def` або звичайний `def`.

    async def broadcast(self, message: str):
        for connection in self.active_connections:
            await connection.send_text(message)


manager = ConnectionManager()


@app.get("/")
async def get():
    return HTMLResponse(html)


@app.websocket("/ws/{client_id}")
async def websocket_endpoint(websocket: WebSocket, client_id: int):
    await manager.connect(websocket)
    try:
        while True:

            )
    return user


async def get_current_active_user(
    current_user: Annotated[User, Security(get_current_user, scopes=["me"])],
):
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user


@app.post("/token")
async def login_for_access_token(

                } catch (InterruptedException e) {
                    log.debug("Async notification monitoring interrupted for {}", registrationId);
                    Thread.currentThread().interrupt();
                    break;
                } catch (Exception e) {
                    log.debug("Error in async notification monitoring for {}: {}", registrationId, e.getMessage());

from starlette.websockets import WebSocket

app = FastAPI()
app.state.value = 42


async def extract_value_from_http_connection(conn: HTTPConnection):
    return conn.app.state.value


@app.get("/http")
async def get_value_by_http(value: int = Depends(extract_value_from_http_connection)):
    return value


@app.websocket("/ws")
async def get_value_by_ws(

app = FastAPI()

router = APIRouter()


async def common_parameters(q: str, skip: int = 0, limit: int = 100):
    return {"q": q, "skip": skip, "limit": limit}


@app.get("/main-depends/")
async def main_depends(commons: dict = Depends(common_parameters)):
    return {"in": "main-depends", "params": commons}


@app.get("/decorator-depends/", dependencies=[Depends(common_parameters)])
async def decorator_depends():

echo 1 > /proc/sys/kernel/perf_event_paranoid
exit
```

Grab the async profiler from https://github.com/jvm-profiling-tools/async-profiler
and run `prof async` like so:
```
gradlew -p benchmarks/ run --args 'LongKeyedBucketOrdsBenchmark.multiBucket -prof "async:libPath=/home/nik9000/Downloads/tmp/async-profiler-1.8.3-linux-x64/build/libasyncProfiler.so;dir=/tmp/prof;output=flamegraph"'
```

@app.get("/items/stream", response_class=EventSourceResponse)
async def sse_items() -> AsyncIterable[Item]:
    for item in items:
        yield item


@app.get("/items/stream-no-async", response_class=EventSourceResponse)
def sse_items_no_async() -> Iterable[Item]:
    for item in items:
        yield item


@app.get("/items/stream-no-annotation", response_class=EventSourceResponse)
async def sse_items_no_annotation():
    for item in items:

    responses={404: {"description": "Not found"}},
)


fake_items_db = {"plumbus": {"name": "Plumbus"}, "gun": {"name": "Portal Gun"}}


@router.get("/")
async def read_items():
    return fake_items_db


@router.get("/{item_id}")
async def read_item(item_id: str):
    if item_id not in fake_items_db:
        raise HTTPException(status_code=404, detail="Item not found")

            return response

        return custom_route_handler


app = FastAPI()
router = APIRouter(route_class=TimedRoute)


@app.get("/")
async def not_timed():
    return {"message": "Not timed"}


@router.get("/timed")
async def timed():
    return {"message": "It's the time of my life"}