func ExerciseKernelWebsockets()

in jupytertestutil/jupytertestutil.go [736:797]
59 lines of code
10 McCabe index (conditional complexity)

func ExerciseKernelWebsockets(serverURL, jupyterBasePath, kernelID string, requestHeader http.Header) error {
	wsURL, err := url.Parse(serverURL)
	if err != nil {
		return fmt.Errorf("failure parsing the server URL: %v", err)
	}
	wsURL.Scheme = "ws"
	wsURL.Path = path.Join(wsURL.Path, jupyterBasePath, "/api/kernels/", kernelID, "/channels")
	q := wsURL.Query()
	q.Set("session_id", kernelID)
	wsURL.RawQuery = q.Encode()
	log.Printf("Creating a websocket connection to %q", wsURL.String())
	conn, _, err := websocket.DefaultDialer.Dial(wsURL.String(), requestHeader)
	if err != nil {
		return err
	}
	defer conn.Close()
	if conn.Subprotocol() != "" {
		// Neither this client code nor the mock Jupyter server implement the V1 kernel protocol, so if
		// the test method requested (and somehow got accepted) anything but the default (empty)
		// subprotocol then report that as an error.
		return fmt.Errorf("Unsupported websocket protocol %q", conn.Subprotocol())
	}
	kernelMsgHeader := &KernelMessageHeader{
		Date:     time.Now().Format(time.RFC3339),
		MsgID:    uuid.NewString(),
		MsgType:  "execute_request",
		Session:  kernelID,
		Username: "user",
		Version:  "5.4",
	}
	kernelMsg := &KernelMessage{
		Header:  kernelMsgHeader,
		Channel: "shell",
		MsgID:   kernelMsgHeader.MsgID,
		MsgType: kernelMsgHeader.MsgType,
		Content: map[string]any{
			"code": "!true",
		},
	}
	msgBytes, err := json.Marshal(kernelMsg)
	if err != nil {
		return err
	}
	if err := conn.WriteMessage(websocket.TextMessage, msgBytes); err != nil {
		return err
	}
	_, respBytes, err := conn.ReadMessage()
	if err != nil {
		return err
	}
	var resp KernelMessage
	if err := json.Unmarshal(respBytes, &resp); err != nil {
		return err
	}
	if got, want := resp.ParentHeadder.MsgID, kernelMsgHeader.MsgID; got != want {
		return fmt.Errorf("unexpected message parent ID: got %q, want %q", got, want)
	}
	if got, want := resp.Content["status"], "ok"; got != want {
		return fmt.Errorf("unexpected message status: got %q, want %q", got, want)
	}
	return nil
}