credential := fmt.Sprintf("%s/%s", accessKeyID, scope)

	// Set URL query.
	query := req.URL.Query()
	query.Set("X-Amz-Algorithm", signV4Algorithm)
	query.Set("X-Amz-Date", date.Format(iso8601Format))
	query.Set("X-Amz-Expires", strconv.FormatInt(expires, 10))
	query.Set("X-Amz-SignedHeaders", "host")
	query.Set("X-Amz-Credential", credential)
	query.Set("X-Amz-Content-Sha256", unsignedPayload)

from .param_functions import File as File
from .param_functions import Form as Form
from .param_functions import Header as Header
from .param_functions import Path as Path
from .param_functions import Query as Query
from .param_functions import Security as Security
from .requests import Request as Request
from .responses import Response as Response
from .routing import APIRouter as APIRouter

</p>
<p align="center">
    FastAPI framework, high performance, easy to learn, fast to code, ready for production
</p>
<p align="center">
<a href="https://github.com/tiangolo/fastapi/actions?query=workflow%3ATest+event%3Apush+branch%3Amaster" target="_blank">
    <img src="https://github.com/tiangolo/fastapi/workflows/Test/badge.svg?event=push&branch=master" alt="Test">
</a>

}

// ServeHTTP - implements http.Handler interface.
//
// When the `list` query parameter is provided (its value is ignored), the
// server lists all metrics that could be returned for the requested path.
//
// The (repeatable) `buckets` query parameter is a list of bucket names (or it
// could be a comma separated value) to return metrics with a bucket label.

"docs_src/dependencies/tutorial008_an.py" = ["F821"]
"docs_src/dependencies/tutorial008_an_py39.py" = ["F821"]
"docs_src/query_params_str_validations/tutorial012_an.py" = ["B006"]
"docs_src/query_params_str_validations/tutorial012_an_py39.py" = ["B006"]
"docs_src/query_params_str_validations/tutorial013_an.py" = ["B006"]
"docs_src/query_params_str_validations/tutorial013_an_py39.py" = ["B006"]
"docs_src/security/tutorial004.py" = ["B904"]

example to query API metrics for buckets `test1` and `test2`, make a scrape request to `/minio/metrics/v3/api/bucket?buckets=test1,test2`. 

Instead of a metrics scrape, it is also possible to list the metrics that would be returned by a path. This is done by adding a `?list` query parameter. The MinIO server will then list all possible metrics that could be returned. During an actual metrics scrape, only available metrics are returned - not all of them. With the `list` query parameter, the...

There you can set:

* The "Item ID", used in the path.
* The "Token" used as a query parameter.

!!! tip
    Notice that the query `token` will be handled by a dependency.

With that you can connect the WebSocket and then send and receive messages:

<img src="/img/tutorial/websockets/image05.png">

It will have a *path operation* that will receive an `Invoice` body, and a query parameter `callback_url` that will contain the URL for the callback.

This part is pretty normal, most of the code is probably already familiar to you:

```Python hl_lines="9-13  36-53"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

!!! tip

    * Large refactor, improvement, and simplification of param extraction from *path operations*.
    * Fix/add support for list *query parameters* with list defaults. New documentation: [Query parameter list / multiple values with defaults](https://fastapi.tiangolo.com/tutorial/query-params-str-validations/#query-parameter-list-multiple-values-with-defaults).

</p>
<p align="center">
    FastAPI framework, high performance, easy to learn, fast to code, ready for production
</p>
<p align="center">
<a href="https://github.com/tiangolo/fastapi/actions?query=workflow%3ATest+event%3Apush+branch%3Amaster" target="_blank">
    <img src="https://github.com/tiangolo/fastapi/workflows/Test/badge.svg?event=push&branch=master" alt="Test">
</a>