)

    return StreamingResponse(iter_data())


app.include_router(
    prefix="/router-scope-function",
    router=router,
    dependencies=[Depends(raise_after_yield, scope="function")],
)

app.include_router(
    prefix="/router-scope-request",
    router=router,
    dependencies=[Depends(raise_after_yield, scope="request")],
)

client = TestClient(app)

from ..dependencies import get_token_header

router = APIRouter(
    prefix="/items",
    tags=["items"],
    dependencies=[Depends(get_token_header)],
    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):

## Eine **FastAPI**-Anwendung mounten { #mounting-a-fastapi-application }

import pytest
from fastapi import APIRouter


def test_router_circular_import():
    router = APIRouter()

    with pytest.raises(
        AssertionError,
        match="Cannot include the same APIRouter instance into itself. Did you mean to include a different router?",
    ):

from fastapi import APIRouter

router = APIRouter()


@router.get("/users/", tags=["users"])
async def read_users():
    return [{"username": "Rick"}, {"username": "Morty"}]


@router.get("/users/me", tags=["users"])
async def read_user_me():
    return {"username": "fakecurrentuser"}


@router.get("/users/{username}", tags=["users"])
async def read_user(username: str):

from fastapi.responses import JSONResponse
from fastapi.testclient import TestClient

app = FastAPI()
router = APIRouter()


@router.route("/items/")
def read_items(request: Request):
    return JSONResponse({"hello": "world"})


app.include_router(router)

client = TestClient(app)


def test_sub_router():
    response = client.get("/items/")

* <abbr title="Mozilla Developer Network – Mozilla-Entwicklernetzwerk: Dokumentation für Entwickler, geschrieben von den Firefox-Leuten">MDN</abbr>
* <abbr title="Input/Output – Eingabe/Ausgabe: Lesen oder Schreiben auf der Festplatte, Netzwerkkommunikation.">I/O</abbr>.

////

//// tab | Info

We are importing the submodule `items` directly, instead of importing just its variable `router`.

This is because we also have another variable named `router` in the submodule `users`.

If we had imported one after the other, like:

```Python
from .routers.items import router
from .routers.users import router
```

///

### 避免名稱衝突 { #avoid-name-collisions }

我們直接匯入子模組 `items`，而不是只匯入它的變數 `router`。

這是因為在子模組 `users` 中也有另一個名為 `router` 的變數。

如果我們像下面這樣一個接一個匯入：

```Python
from .routers.items import router
from .routers.users import router
```

來自 `users` 的 `router` 會覆蓋掉 `items` 的 `router`，我們就無法同時使用兩者。

因此，為了能在同一個檔案中同時使用它們，我們直接匯入子模組：

            response.headers["X-Response-Time"] = str(duration)
            print(f"route duration: {duration}")
            print(f"route response: {response}")
            print(f"route response headers: {response.headers}")
            return response

        return custom_route_handler


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


@app.get("/")
async def not_timed():