.webSocketUpgrade(serverListener)
        .build(),
    )
    val webSocket: WebSocket = newWebSocket()
    clientListener.assertOpen()
    val server = serverListener.assertOpen()
    webSocket.send("Hello, WebSockets!")
    serverListener.assertTextMessage("Hello, WebSockets!")
    closeWebSockets(webSocket, server)
  }

  @Test
  fun binaryMessage() {
    webServer.enqueue(

    taskFaker.runTasks()
    server.webSocket!!.tearDown()
    client.webSocket!!.tearDown()
    taskFaker.close()
  }

  @Test
  fun close() {
    client.webSocket!!.close(1000, "Hello!")
    // This will trigger a close response.
    assertThat(server.processNextFrame()).isFalse()
    server.listener.assertClosing(1000, "Hello!")
    server.webSocket!!.finishReader()
    server.webSocket!!.close(1000, "Goodbye!")

# WebSockets

Bei der Definition von WebSockets deklarieren Sie normalerweise einen Parameter vom Typ `WebSocket` und können damit Daten vom Client lesen und an ihn senden. Er wird direkt von Starlette bereitgestellt, Sie können ihn aber von `fastapi` importieren:

```python
from fastapi import WebSocket
```

!!! tip "Tipp"

{!../../../docs_src/websockets/tutorial001.py!}
```

## Einen `websocket` erstellen

Erstellen Sie in Ihrer **FastAPI**-Anwendung einen `websocket`:

```Python hl_lines="1  46-47"
{!../../../docs_src/websockets/tutorial001.py!}
```

!!! note "Technische Details"
    Sie können auch `from starlette.websockets import WebSocket` verwenden.

# WebSockets

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

{!../../../docs_src/websockets/tutorial001.py!}
```

## Create a `websocket`

In your **FastAPI** application, create a `websocket`:

```Python hl_lines="1  46-47"
{!../../../docs_src/websockets/tutorial001.py!}
```

!!! note "Technical Details"
    You could also use `from starlette.websockets import WebSocket`.

        .build()
    val request =
      originalRequest.newBuilder()
        .header("Upgrade", "websocket")
        .header("Connection", "Upgrade")
        .header("Sec-WebSocket-Key", key)
        .header("Sec-WebSocket-Version", "13")
        .header("Sec-WebSocket-Extensions", "permessage-deflate")
        .build()
    call = RealCall(webSocketClient, request, forWebSocket = true)
    call!!.enqueue(

Dazu verwenden Sie den `TestClient` in einer `with`-Anweisung, eine Verbindung zum WebSocket herstellend:

```Python hl_lines="27-31"
{!../../../docs_src/app_testing/tutorial002.py!}
```

!!! note "Hinweis"

      object : WebSocketListener() {
        override fun onOpen(
          webSocket: WebSocket,
          response: Response,
        ) = TODO()

        override fun onMessage(
          webSocket: WebSocket,
          text: String,
        ) = TODO()

        override fun onMessage(
          webSocket: WebSocket,
          bytes: ByteString,
        ) = TODO()

```python
from fastapi import Request
```

!!! tip
    When you want to define dependencies that should be compatible with both HTTP and WebSockets, you can define a parameter that takes an `HTTPConnection` instead of a `Request` or a `WebSocket`.