Ela será chamada pelo **FastAPI** sempre que receber uma requisição para a URL "`/`" usando uma operação `GET`.

Neste caso, é uma função `async`.

---

Você também pode defini-la como uma função normal em vez de `async def`:

{* ../../docs_src/first_steps/tutorial003_py310.py hl[7] *}

/// note | Nota

Se você não sabe a diferença, verifique o [Async: *"Com pressa?"*](../async.md#in-a-hurry).

///

 * <li>{@literal file}</li>
 * <li>{@literal jar}</li>
 * <li>{@literal wsjar} (WebSphere proprietary protocol, alias for {@literal jar})</li>
 * <li>{@literal zip} (WebLogic proprietary protocol, use {@literal jar} protocol for normal zip files)</li>
 * <li>{@literal code-source} (Oracle AS(OC4J) proprietary protocol)</li>
 * <li>{@literal vfsfile} (JBossAS5 proprietary protocol, alias for {@literal file})</li>

/* encdec - encode and decode integers, times, and
 * internationalized strings to and from popular binary formats
 * http://www.ioplex.com/~miallen/encdec/
 * Copyright (c) 2003 Michael B. Allen <******@****.***>
 *
 * The GNU Library General Public License
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either

 * limitations under the License.
 */
```

### Submitting Your Change

After you submit your pull request, a Gradle developer will review it. It is normal for this to take several iterations, so don't get discouraged by change requests. They ensure the high quality that we all enjoy.

}

@Override
protected void doConnect() throws IOException {
    // Request directory lease for directories
    if (isDirectory()) {
        requestDirectoryLease();
    }
    
    // Continue with normal connection logic
    super.doConnect();
}

@Override
public void close() throws IOException {
    try {
        super.close();
    } finally {

    * The router dependencies are executed first, then the [`dependencies` in the decorator](dependencies/dependencies-in-path-operation-decorators.md), and then the normal parameter dependencies.
    * You can also add [`Security` dependencies with `scopes`](../advanced/security/oauth2-scopes.md).

/// tip

	// Do not change this order, x-amz-date value should be
	// validated first.
	"x-amz-date",
	"date",
}

// parseAmzDateHeader - parses supported amz date headers, in
// supported amz date formats.
func parseAmzDateHeader(req *http.Request) (time.Time, APIErrorCode) {
	for _, amzDateHeader := range amzDateHeaders {
		amzDateStr := req.Header.Get(amzDateHeader)
		if amzDateStr != "" {

    public static final int ACB_PWNOTREQ = 4;
    /** Account control bit flag: Temporary duplicate account */
    public static final int ACB_TEMPDUP = 8;
    /** Account control bit flag: Normal user account */
    public static final int ACB_NORMAL = 16;
    /** Account control bit flag: MNS logon user account */
    public static final int ACB_MNS = 32;
    /** Account control bit flag: Interdomain trust account */

    public static final int ACB_PWNOTREQ = 4;
    /** Account control bit flag: Temporary duplicate account */
    public static final int ACB_TEMPDUP = 8;
    /** Account control bit flag: Normal user account */
    public static final int ACB_NORMAL = 16;
    /** Account control bit flag: MNS logon user account */
    public static final int ACB_MNS = 32;
    /** Account control bit flag: Interdomain trust account */

その後、あなたの API は（仮にこうしましょう）:

* 外部開発者の顧客に請求書を送ります。
* 代金を回収します。
* API 利用者（外部開発者）に通知を送り返します。
    * これは（あなたの API から）外部開発者が提供する *外部 API* に POST リクエストを送ることで行われます（これが「コールバック」です）。

## 通常の FastAPI アプリ { #the-normal-fastapi-app }

まず、コールバックを追加する前の通常の API アプリがどうなるか見てみましょう。

`Invoice` ボディを受け取り、クエリパラメータ `callback_url` にコールバック用の URL を含める *path operation* を持ちます。

この部分はとても普通で、ほとんどのコードはすでに見覚えがあるはずです: