```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">

Der Callback-*Pfad* kann einen <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.1.0.md#key-expression" class="external-link" target="_blank">OpenAPI-3-Ausdruck</a> enthalten, welcher Teile des ursprünglichen Requests enthalten kann, der an *Ihre API* gesendet wurde.

In diesem Fall ist es der `str`:

```Python
"{$callback_url}/invoices/{$request.body.id}"
```

	z.conns.addConn(conn)
	defer z.conns.deleteConn(conn)

	// get hello message from ztunnel
	m, _, err := readProto[zdsapi.ZdsHello](conn.u, readWriteDeadline, nil)
	if err != nil {
		return err
	}
	log.WithLabels("version", m.Version).Infof("received hello from ztunnel")
	log.Debug("sending snapshot to ztunnel")
	if err := z.sendSnapshot(ctx, conn); err != nil {
		return err

## 예제

### 만들기

* `main.py` 파일을 만드십시오:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">

			[]byte("foo"),
		}, {
			&Header{Name: "world", Mode: 0640, Size: int64(5)},
			[]byte("hello"),
		}},
	}, {
		"GNU",
		[]file{{
			&Header{Name: "bar", Mode: 0640, Size: int64(3), Devmajor: -1},
			[]byte("foo"),
		}, {
			&Header{Name: "world", Mode: 0640, Size: int64(5), Devmajor: -1},
			[]byte("hello"),
		}},
	}, {
		"PAX",
		[]file{{

### Create it

* Create a file `main.py` with:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">

```Python hl_lines="9-14  17"
{!../../docs_src/custom_response/tutorial009c.py!}
```

Agora em vez de retornar:

```json
{"message": "Hello World"}
```

...essa resposta retornará:

```json
{
  "message": "Hello World"
}
```

Obviamente, você provavelmente vai encontrar maneiras muito melhores de se aproveitar disso do que a formatação de JSON. 😉

func TestCopyAligned(t *testing.T) {
	f, err := os.CreateTemp("", "")
	if err != nil {
		t.Errorf("Error creating tmp file: %v", err)
	}
	defer f.Close()
	defer os.Remove(f.Name())

	r := strings.NewReader("hello world")

	bufp := ODirectPoolSmall.Get().(*[]byte)
	defer ODirectPoolSmall.Put(bufp)

	written, err := CopyAligned(f, io.LimitReader(r, 5), *bufp, r.Size(), f)
	if !errors.Is(err, io.ErrUnexpectedEOF) {

from .main import app

client = TestClient(app)


@pytest.mark.parametrize(
    "path,expected_status,expected_response",
    [
        ("/api_route", 200, {"message": "Hello World"}),
        ("/non_decorated_route", 200, {"message": "Hello World"}),
        ("/nonexistent", 404, {"detail": "Not Found"}),
    ],
)
def test_get_path(path, expected_status, expected_response):
    response = client.get(path)

* Ṣẹ̀dá fáìlì `main.py (èyí tíí ṣe, akọkọ.py)` pẹ̀lú:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">