You might notice that to create an instance of a Python class, you use that same syntax.

For example:

```Python
class Cat:
    def __init__(self, name: str):
        self.name = name


fluffy = Cat(name="Mr Fluffy")
```

In this case, `fluffy` is an instance of the class `Cat`.

And to create `fluffy`, you are "calling" `Cat`.

So, a Python class is also a **callable**.

from fastapi.routing import APIRoute


class GzipRequest(Request):
    async def body(self) -> bytes:
        if not hasattr(self, "_body"):
            body = await super().body()
            if "gzip" in self.headers.getlist("Content-Encoding"):
                body = gzip.decompress(body)
            self._body = body
        return self._body


class GzipRoute(APIRoute):
    def get_route_handler(self) -> Callable:

## Custom response class

You can create your own custom response class, inheriting from `Response` and using it.

For example, let's say that you want to use <a href="https://github.com/ijl/orjson" class="external-link" target="_blank">`orjson`</a>, but with some custom settings not used in the included `ORJSONResponse` class.

import jakarta.annotation.Resource;

/**
 * @author shinsuke
 * @author Keiichi Watanabe
 */
public class AdminFileauthAction extends FessAdminAction {

    public static final String ROLE = "admin-fileauth";

    private static final Logger logger = LogManager.getLogger(AdminFileauthAction.class);

    // ===================================================================================

/**
 * @author shinsuke
 * @author Shunji Makino
 * @author Keiichi Watanabe
 */
public class AdminReqheaderAction extends FessAdminAction {

    public static final String ROLE = "admin-reqheader";

    private static final Logger logger = LogManager.getLogger(AdminReqheaderAction.class);

    // ===================================================================================

* <a href="https://cdn.jsdelivr.net/npm/swagger-ui-dist@5/swagger-ui-bundle.js" class="external-link" target="_blank">`swagger-ui-bundle.js`</a>
* <a href="https://cdn.jsdelivr.net/npm/swagger-ui-dist@5/swagger-ui.css" class="external-link" target="_blank">`swagger-ui.css`</a>

And **ReDoc** uses the file:

* <a href="https://cdn.jsdelivr.net/npm/redoc@next/bundles/redoc.standalone.js" class="external-link" target="_blank">`redoc.standalone.js`</a>

  /**
   * A trust manager for Android applications that customize the trust manager.
   *
   * This class exploits knowledge of Android implementation details. This class is potentially
   * much faster to initialize than [BasicTrustRootIndex] because it doesn't need to load and
   * index trusted CA certificates.
   */
  internal data class CustomTrustRootIndex(
    private val trustManager: X509TrustManager,

# WebSockets

Sie können <a href="https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API" class="external-link" target="_blank">WebSockets</a> mit **FastAPI** verwenden.

## `WebSockets` installieren

Zuerst müssen Sie `WebSockets` installieren:

<div class="termy">

```console
$ pip install websockets

---> 100%
```

</div>

## WebSockets-Client

### In Produktion

import javax.net.ssl.SSLSocket
import javax.net.ssl.SSLSocketFactory
import javax.net.ssl.X509TrustManager
import okhttp3.Protocol
import okhttp3.internal.SuppressSignatureCheck

/** OpenJDK 9+. */
open class Jdk9Platform : Platform() {
  @SuppressSignatureCheck
  override fun configureTlsExtensions(
    sslSocket: SSLSocket,
    hostname: String?,
    protocols: List<@JvmSuppressWildcards Protocol>,
  ) {

import jakarta.annotation.Resource;

/**
 * @author shinsuke
 * @author Keiichi Watanabe
 */
public class AdminSchedulerAction extends FessAdminAction {

    public static final String ROLE = "admin-scheduler";

    private static final Logger logger = LogManager.getLogger(AdminSchedulerAction.class);

    // ===================================================================================