运行示例并访问 <a href="http://127.0.0.1:8000/items/3" class="external-link" target="_blank">http://127.0.0.1:8000/items/3</a>，返回的响应如下：

```JSON
{"item_id":3}
```

/// check | 检查

注意，函数接收并返回的值是 `3`（ `int`），不是 `"3"`（`str`）。

**FastAPI** 通过类型声明自动<abbr title="将来自 HTTP 请求中的字符串转换为 Python 数据类型">**解析**请求中的数据</abbr>。

///

## 数据校验

///

## Validação de dados { #data-validation }

Mas se você for no navegador para <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>, verá um bom erro HTTP:

```JSON
{
  "detail": [
    {
      "type": "int_parsing",

# Test Client - `TestClient`

You can use the `TestClient` class to test FastAPI applications without creating an actual HTTP and socket connection, just communicating directly with the FastAPI code.

Read more about it in the [FastAPI docs for Testing](https://fastapi.tiangolo.com/tutorial/testing/).

You can import it directly from `fastapi.testclient`:

```python
from fastapi.testclient import TestClient
```

 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

Wenn Sie mehr über Formularfelder und ihre Kodierungen lesen möchten, besuchen Sie die <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/POST" class="external-link" target="_blank"><abbr title="Mozilla Developer Network – Mozilla-Entwicklernetzwerk">MDN</abbr>-Webdokumentation für <code>POST</code></a>.

///

/// warning | Achtung

Якщо були заплановані фонові задачі (background tasks - розглянуто далі), вони виконаються *після* всіх middleware.

///

## Створення middleware

Щоб створити middleware, Ви використовуєте декоратор `@app.middleware("http")` на функції.

Функція middleware отримує:

* `Запит`.
* Функцію `call_next`, яка приймає `запит` як параметр.
    * Ця функція передає `запит` відповідній *операції шляху*.

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package subnet

import (
	"net/http"
	"net/url"
	"os"
	"strings"
	"sync"

	"github.com/minio/minio/internal/config"
	"github.com/minio/pkg/v3/env"
	xnet "github.com/minio/pkg/v3/net"
)

const (
	baseURL    = "https://subnet.min.io"
	baseURLDev = "http://localhost:9000"
)

 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY