You can configure the two documentation user interfaces included:

* **Swagger UI**: served at `/docs`.
    * You can set its URL with the parameter `docs_url`.
    * You can disable it by setting `docs_url=None`.
* **ReDoc**: served at `/redoc`.
    * You can set its URL with the parameter `redoc_url`.
    * You can disable it by setting `redoc_url=None`.

## Use a `Response` parameter { #use-a-response-parameter }

You can declare a parameter of type `Response` in your *path operation function* (as you can do for cookies).

And then you can set headers in that *temporal* response object.

{* ../../docs_src/response_headers/tutorial002.py hl[1, 7:8] *}

And then you can return any object you need, as you normally would (a `dict`, a database model, etc).

    /**
     * Check if directory can cache enumeration results
     * @param state lease state
     * @return true if directory enumeration can be cached
     */
    public static boolean canCacheEnumeration(int state) {
        return Smb2LeaseState.hasReadCaching(state);
    }

    /**
     * Check if directory can keep handles open
     * @param state lease state

When defining WebSockets, you normally declare a parameter of type `WebSocket` and with it you can read data from the client and send data to it.

It is provided directly by Starlette, but you can import it from `fastapi`:

```python
from fastapi import WebSocket
```

/// tip

For those cases, you can use a `Response` parameter.

## Use a `Response` parameter { #use-a-response-parameter }

You can declare a parameter of type `Response` in your *path operation function* (as you can do for cookies and headers).

And then you can set the `status_code` in that *temporal* response object.

}
```

## Recap { #recap }

You can add multiple body parameters to your *path operation function*, even though a request can only have a single body.

But **FastAPI** will handle it, give you the correct data in your function, and validate and document the correct schema in the *path operation*.

You can also declare singular values to be received as part of the body.

///

## Await for messages and send messages { #await-for-messages-and-send-messages }

In your WebSocket route you can `await` for messages and send messages.

{* ../../docs_src/websockets/tutorial001.py hl[48:52] *}

You can receive and send binary, text, and JSON data.

## Try it { #try-it }

If your file is named `main.py`, run your application with:

<div class="termy">

* Processing data:
    * For example, let's say you receive a file that must go through a slow process, you can return a response of "Accepted" (HTTP 202) and process the file in the background.

## Using `BackgroundTasks` { #using-backgroundtasks }

         the new CRI + CNI code path.
      * If you are using plugins other than `bridge`, make sure you have
        updated custom plugins to the latest version that is compatible.
* **CNI plugins now affect node readiness**
  * Kubelet will now block node readiness until a CNI configuration file is
    present in `/etc/cni/net.d` or a given custom CNI configuration path.

It is possible to receive duplicate headers. That means, the same header with multiple values.

You can define those cases using a list in the type declaration.

You will receive all the values from the duplicate header as a Python `list`.

For example, to declare a header of `X-Token` that can appear more than once, you can write:

{* ../../docs_src/header_params/tutorial003_an_py310.py hl[9] *}