How to use c.Request().Context().Done() to cancel response

[usermodi]

Im using Pocketbase, which uses echo v5. So my problem is that c.Request().Context().Done() is not signaling/working when the frontend/client closes the browser window/tab or refreshes the page. I'm streaming contents of a txt file line bye line with a delay between every written line. It works fine, but I want to stop/cancel the streaming of the txt file when the user leaves or closes the page.
Here the go code:

func main() {
	app := pocketbase.New()//pocketbase stuff
	app.OnBeforeServe().Add(func(e *core.ServeEvent) error {
		e.Router.AddRoute(echo.Route{
			Method:  http.MethodGet,
			Path:    "/api/stream",
			Handler: stream,
		})
		return nil
	})
	if err := app.Start(); err != nil {
		log.Fatal(err)
	}
}

func stream(c echo.Context) error {
	byto := glob_txtFileContent
	ch := make(chan bool)
	workers[cookie.Value] = ch

	w.Header().Set(echo.HeaderContentType, echo.MIMETextHTML)
	w.WriteHeader(http.StatusOK)

	for i := 0; i < len(byto); i++ {
		select {
		case <-c.Request().Context().Done(): // case request canceled!!
			fmt.Println("---------closing----------- ") //this doesnt get fired when the
			return nil		// user leaves the page or close tab
		case msg := <-ch: 
			//... some bool channel action
		default:
		}

		w.Write(byto[i])
		if f, ok := w.(http.Flusher); ok {
			f.Flush()
		}
		fmt.Println("--flushing: ", w.Write(byto[i]))
		time.Sleep(1 * time.Millisecond)
	}
	return nil
}

and the js code with svelte, where i just trigger the fn with a button:

async function getStream() {
  const response = await fetch("http://localhost:5173/api/stream");
  // @ts-ignore
  const reader = response.body.pipeThrough(new TextDecoderStream()).getReader();
  while (true) {
    const { value, done } = await reader.read();
    if (done) break;
    result += value;
  }
}

If something isn't clear, just ask.
I appreciate any help!

[opfsun]

解决了吗？

[aldas]

Have you tried it with some other client?

When I use this example and curl - it seems that it works

func main() {
	e := echo.New()
	e.Use(middleware.Logger())

	e.GET("/stream", func(c echo.Context) error {
		i := 0
		for {
			select {
			case <-c.Request().Context().Done(): // case request canceled!!
				fmt.Println("---------closing----------- ") //this doesnt get fired when the
				return nil                                  // user leaves the page or close tab
			default:
			}

			c.Response().Write([]byte(fmt.Sprintf("%d\n", i)))
			c.Response().Flush()
			time.Sleep(250 * time.Millisecond)
			i++
		}
	})

	if err := e.Start(":8080"); err != nil && !errors.Is(err, http.ErrServerClosed) {
		log.Fatal(err)
	}
}

Output from command line

x@x:~/code/$ curl http://localhost:8080/stream -N
0
1
2
3
4
5
6
7
8
9
10
11
^C

output from server:

   ____    __
  / __/___/ /  ___
 / _// __/ _ \/ _ \
/___/\__/_//_/\___/ v4.10.2
High performance, minimalist Go web framework
https://echo.labstack.com
____________________________________O/_______
                                    O\
⇨ http server started on [::]:8080
---------closing----------- 
{"time":"2023-05-12T19:58:47.444903658+03:00","id":"","remote_ip":"127.0.0.1","host":"localhost:8080","method":"GET","uri":"/stream","user_agent":"curl/7.85.0","status":200,"error":"","latency":3007786147,"latency_human":"3.007786147s","bytes_in":0,"bytes_out":26}