{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[7:11,34:51] *}

/// tip

The `callback_url` query parameter uses a Pydantic [Url](https://docs.pydantic.dev/latest/api/networks/) type.

///

The only new thing is the `callbacks=invoices_callback_router.routes` as an argument to the *path operation decorator*. We'll see what that is next.

		}
	}
	return extractedSignedHeaders, ErrNone
}

// Trim leading and trailing spaces and replace sequential spaces with one space, following Trimall()
// in http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
func signV4TrimAll(input string) string {
	// Compress adjacent spaces (a space is determined by
	// unicode.IsSpace() internally here) to one space and return

	// Content-Md5 is required should be set
	// http://docs.aws.amazon.com/AmazonS3/latest/API/multiobjectdeleteapi.html
	if !validateLengthAndChecksum(r) {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrMissingContentMD5), r.URL)
		return
	}

	// Content-Length is required and should be non-zero
	// http://docs.aws.amazon.com/AmazonS3/latest/API/multiobjectdeleteapi.html
	if r.ContentLength <= 0 {

* MinIO doesn't currently support PFX certificates.

### 3.1 Use `certgen` to Generate a Certificate

Download [`certgen`](https://github.com/minio/certgen/releases/latest) for your specific operating system and platform.

`certgen` is a simple *Go* tool to generate self-signed certificates, and provides SAN certificates with DNS and IP entries:

```sh

}

// S3 docs: "Each form field that you specify in a form (except x-amz-signature, file, policy, and field names
// that have an x-ignore- prefix) must appear in the list of conditions."
// https://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-HTTPPOSTConstructPolicy.html
// keyInPolicyExceptions - list of keys that, when present in the form, can be missing in the conditions of the policy.
var keyInPolicyExceptions = map[string]bool{
	xhttp.AmzSignature: true,

</p>
<p align="center">
<a href="https://github.com/fastapi/fastapi/actions?query=workflow%3ATest+event%3Apush+branch%3Amaster">
    <img src="https://github.com/fastapi/fastapi/actions/workflows/test.yml/badge.svg?event=push&branch=master" alt="Test">
</a>
<a href="https://coverage-badge.samuelcolvin.workers.dev/redirect/fastapi/fastapi">

</p>
<p align="center">
<a href="https://github.com/fastapi/fastapi/actions?query=workflow%3ATest+event%3Apush+branch%3Amaster">
    <img src="https://github.com/fastapi/fastapi/actions/workflows/test.yml/badge.svg?event=push&branch=master" alt="Test">
</a>
<a href="https://coverage-badge.samuelcolvin.workers.dev/redirect/fastapi/fastapi">

</p>
<p align="center">
<a href="https://github.com/fastapi/fastapi/actions?query=workflow%3ATest+event%3Apush+branch%3Amaster">
    <img src="https://github.com/fastapi/fastapi/actions/workflows/test.yml/badge.svg?event=push&branch=master" alt="Test">
</a>
<a href="https://coverage-badge.samuelcolvin.workers.dev/redirect/fastapi/fastapi">

sleep 10

./mc stat --no-list sitea/bucket/new-test-encrypted-object
./mc stat --no-list siteb/bucket/new-test-encrypted-object
./mc stat --no-list sitec/bucket/new-test-encrypted-object

./mc ls -r sitea/bucket/
./mc ls -r siteb/bucket/
./mc ls -r sitec/bucket/

你可以將回應宣告為多個型別的 `Union`，表示回應可能是其中任一型別。

在 OpenAPI 中會以 `anyOf` 定義。

要達成這點，使用標準的 Python 型別提示 [`typing.Union`](https://docs.python.org/3/library/typing.html#typing.Union)：

/// note

在定義 [`Union`](https://docs.pydantic.dev/latest/concepts/types/#unions) 時，請先放置「更具體」的型別，再放「較不具體」的型別。以下範例中，較具體的 `PlaneItem` 置於 `CarItem` 之前：`Union[PlaneItem, CarItem]`。

///

{* ../../docs_src/extra_models/tutorial003_py310.py hl[1,14:15,18:20,33] *}