例如，上述模型声明如下 JSON **对象**（即 Python **字典**）：

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

……由于 `description` 和 `tax` 是可选的（默认值为 `None`），下面的 JSON **对象**也有效：

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## 声明请求体参数

使用与声明路径和查询参数相同的方式声明请求体，把请求体添加至*路径操作*：

//// tab | Python 3.10+

```Python hl_lines="16"

{!../../docs_src/body_nested_models/tutorial004.py!}
```

Isso significa que o **FastAPI** vai esperar um corpo similar à:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

 * attributes for business methods.
 * <p>
 * For example:
 *
 * <pre>
 * &#064;Secured({ &quot;ROLE_USER&quot; })
 * public void create(Contact contact);
 *
 * &#064;Secured({ &quot;ROLE_USER&quot;, &quot;ROLE_ADMIN&quot; })
 * public void update(Contact contact);
 *
 * &#064;Secured({ &quot;ROLE_ADMIN&quot; })
 * public void delete(Contact contact);
 * </pre>
 * @author Mark St.Godard
 */

 * <p>
 * Consider the following output of <tt>examples/SidLookup.java</tt>:
 * 
 * <pre>
 *        toString: S-1-5-21-4133388617-793952518-2001621813-512
 * toDisplayString: WNET\Domain Admins
 *         getType: 2
 *     getTypeText: Domain group
 *   getDomainName: WNET
 *  getAccountName: Domain Admins
 * </pre>
 */
public interface SID {

    /**
     * 
     */

var includeConfigType bool

func SetPrintConfigTypeInSummary(p bool) {
	includeConfigType = p
}

// Prime loads the config dump into the writer ready for printing
func (c *ConfigWriter) Prime(b []byte) error {
	w := &configdump.Wrapper{}
	err := w.UnmarshalJSON(b)
	if err != nil {
		return fmt.Errorf("error unmarshalling config dump response from Envoy: %v", err)
	}

from fastapi.testclient import TestClient

from docs_src.cors.tutorial001 import app


def test_cors():
    client = TestClient(app)
    # Test pre-flight response
    headers = {
        "Origin": "https://localhost.tiangolo.com",
        "Access-Control-Request-Method": "GET",
        "Access-Control-Request-Headers": "X-Example",
    }
    response = client.options("/", headers=headers)
    assert response.status_code == 200, response.text

```

////

Это означает, что **FastAPI** будет ожидать тело запроса, аналогичное этому:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

```Python hl_lines="20"
{!../../docs_src/body_nested_models/tutorial004.py!}
```

이는 **FastAPI**가 다음과 유사한 본문을 기대한다는 것을 의미합니다:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

```

////

This would mean that **FastAPI** would expect a body similar to:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],
    "image": {
        "url": "http://example.com/baz.jpg",
        "name": "The Foo live"
    }
}
```

///

### Criar um `APIRouter` para o callback

Primeiramente crie um novo `APIRouter` que conterá um ou mais callbacks.

```Python hl_lines="3  25"
{!../../docs_src/openapi_callbacks/tutorial001.py!}
```

### Crie a *operação de rota* do callback

Para criar a *operação de rota* do callback, use o mesmo `APIRouter` que você criou acima.