]

app = FastAPI()


@app.websocket("/function-scope")
async def function_scope(websocket: WebSocket, session: SessionFuncDep) -> Any:
    await websocket.accept()
    await websocket.send_json({"is_open": session.open})


@app.websocket("/request-scope")
async def request_scope(websocket: WebSocket, session: SessionRequestDep) -> Any:
    await websocket.accept()
    await websocket.send_json({"is_open": session.open})

          text: String,
        ) {
          webSocket.send(text)
        }

        override fun onClosing(
          webSocket: WebSocket,
          code: Int,
          reason: String,
        ) {
          webSocket.close(1000, null)
          latch.countDown()
        }

        override fun onFailure(
          webSocket: WebSocket,
          t: Throwable,
          response: Response?,

        .Builder()
        .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(

當然，這並不理想，你不會在生產環境這樣做。

在生產環境你通常會用上述其中一種方式。

但這是能讓我們專注於 WebSocket 伺服端並跑起一個可運作範例的最簡單方式：

{* ../../docs_src/websockets_/tutorial001_py310.py hl[2,6:38,41:43] *}

## 建立一個 `websocket` { #create-a-websocket }

在你的 **FastAPI** 應用中，建立一個 `websocket`：

{* ../../docs_src/websockets_/tutorial001_py310.py hl[1,46:47] *}

/// note | 技術細節

你也可以使用 `from starlette.websockets import WebSocket`。

  @Override public void onMessage(WebSocket webSocket, String text) {
    System.out.println("onMessage: " + text);
  }

  @Override public void onClosing(WebSocket webSocket, int code, String reason) {
    webSocket.close(1000, null);
    System.out.println("onClose (" + code + "): " + reason);
  }

  @Override public void onFailure(WebSocket webSocket, Throwable t, Response response) {

    client.dispatcher().executorService().shutdown();
  }

  @Override public void onOpen(WebSocket webSocket, Response response) {
    webSocket.send("Hello...");
    webSocket.send("...World!");
    webSocket.send(ByteString.decodeHex("deadbeef"));
    webSocket.close(1000, "Goodbye, World!");
  }

  @Override public void onMessage(WebSocket webSocket, String text) {
    System.out.println("MESSAGE: " + text);
  }

   * messages.
   */
  open fun onOpen(
    webSocket: WebSocket,
    response: Response,
  ) {
  }

  /** Invoked when a text (type `0x1`) message has been received. */
  open fun onMessage(
    webSocket: WebSocket,
    text: String,
  ) {
  }

  /** Invoked when a binary (type `0x2`) message has been received. */
  open fun onMessage(
    webSocket: WebSocket,
    bytes: ByteString,
  ) {
  }

  /**

 * Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits=15
 * Sec-WebSocket-Extensions: permessage-deflate; client_no_context_takeover
 * Sec-WebSocket-Extensions: permessage-deflate; server_max_window_bits="15"
 * Sec-WebSocket-Extensions: permessage-deflate; server_max_window_bits=15
 * Sec-WebSocket-Extensions: permessage-deflate; server_no_context_takeover
 * Sec-WebSocket-Extensions: permessage-deflate; server_no_context_takeover;

async def get_cookie_or_token(
    websocket: WebSocket,
    session: str | None = Cookie(default=None),
    token: str | None = Query(default=None),
):
    if session is None and token is None:
        raise WebSocketException(code=status.WS_1008_POLICY_VIOLATION)
    return session or token


@app.websocket("/items/{item_id}/ws")
async def websocket_endpoint(
    websocket: WebSocket,
    item_id: str,

{* ../../docs_src/websockets_/tutorial001_py310.py hl[2,6:38,41:43] *}

## 创建 `websocket` { #create-a-websocket }

在您的 **FastAPI** 应用程序中，创建一个 `websocket`：

{* ../../docs_src/websockets_/tutorial001_py310.py hl[1,46:47] *}

/// note | 技术细节

您也可以使用 `from starlette.websockets import WebSocket`。

**FastAPI** 直接提供了相同的 `WebSocket`，只是为了方便开发人员。但它直接来自 Starlette。

///