* そして、**レスポンス**を返します。

/// note | 技術詳細

`yield` を使った依存関係をもつ場合は、終了コードはミドルウェアの *後に* 実行されます。

バックグラウンドタスク (後述) がある場合は、それらは全てのミドルウェアの *後に* 実行されます。

///

## ミドルウェアの作成

ミドルウェアを作成するには、関数の上部でデコレータ `@app.middleware("http")` を使用します。

ミドルウェア関数は以下を受け取ります:

* `request`。
* パラメータとして `request` を受け取る関数 `call_next`。
    * この関数は、対応する*path operation*に `request` を渡します。
    * 次に、対応する*path operation*によって生成された `response` を返します。

    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.body_nested_models.{request.param}")

    client = TestClient(mod.app)
    return client


def test_put_all(client: TestClient):
    response = client.put(
        "/items/123",
        json={
            "name": "Foo",
            "description": "A very nice Item",

        pytest.param("tutorial012_an_py39"),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.dependencies.{request.param}")

    client = TestClient(mod.app)
    return client


def test_get_no_headers_items(client: TestClient):
    response = client.get("/items/")
    assert response.status_code == 422, response.text
    assert response.json() == {
        "detail": [

        pytest.param("tutorial003_an_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.security.{request.param}")

    client = TestClient(mod.app)
    return client


def test_login(client: TestClient):
    response = client.post("/token", data={"username": "johndoe", "password": "secret"})
    assert response.status_code == 200, response.text

* «the response» (what the server sends back to the client): «die Response»
* «the return type»: «der Rückgabetyp»
* «the return value»: «der Rückgabewert»
* «the startup» (the event of the app): «der Startup»
* «the shutdown» (the event of the app): «der Shutdown»
* «the startup event»: «das Startup-Event»
* «the shutdown event»: «das Shutdown-Event»
* «the startup» (of the server): «das Hochfahren»

        importlib.reload(mod)
    mod.sqlite_url = "sqlite://"
    mod.engine = create_engine(
        mod.sqlite_url, connect_args={"check_same_thread": False}, poolclass=StaticPool
    )

    with TestClient(mod.app) as c:
        yield c
    # Clean up connection explicitly to avoid resource warning
    mod.engine.dispose()


def test_crud_app(client: TestClient):

    callbacks=callback_router1.routes,
)

app.include_router(router2_override)

app.include_router(router2_default)

client = TestClient(app)


def test_level1_override():
    response = client.get("/override1?level1=foo")
    assert response.json() == "foo"
    assert response.headers["content-type"] == "application/x-level-1"
    assert "x-level0" in response.headers

* `description`: A descrição da sua API, que pode incluir markdown e será exibida na documentação.
* `routes`: Uma lista de rotas, que são cada uma das *operações de rota* registradas. Elas são obtidas de `app.routes`.

/// info | Informação

O parâmetro `summary` está disponível no OpenAPI 3.1.0 e superior, suportado pelo FastAPI 0.99.0 e superior.

///

## Sobrescrevendo os padrões { #overriding-the-defaults }

Supongamos que tienes una excepción personalizada `UnicornException` que tú (o un paquete que usas) podrías lanzar.

Y quieres manejar esta excepción globalmente con FastAPI.

Podrías agregar un manejador de excepciones personalizado con `@app.exception_handler()`:

{* ../../docs_src/handling_errors/tutorial003_py39.py hl[5:7,13:18,24] *}

Aquí, si solicitas `/unicorns/yolo`, la *path operation* lanzará un `UnicornException`.

```Python
results = await some_library()
```

Then, declare your *path operation functions* with `async def` like:

```Python hl_lines="2"
@app.get('/')
async def read_results():
    results = await some_library()
    return results
```

/// note

You can only use `await` inside of functions created with `async def`.

///

---