How to know whether or not the client has closed the HTTP connection?

[ShigeruOta]

Hi.

Please teach me.

How to detect HTTP connection closed by the client before sending a response?
If I detect it, I want to notify it to subsequent application that work with the echo server.

I want to check the status of the HTTP connection from middleware function code, but ican't do it well.

Thank you.

[choyri]

https://golang.org/pkg/net/http/#Request.Context

func main() {
	e := echo.New()
	e.GET("/", func(c echo.Context) error {
		select {
		case <-time.After(2 * time.Second):
			return c.String(http.StatusOK, "Hello, World!")
		case <-c.Request().Context().Done():
			_, _ = fmt.Fprint(os.Stderr, "Request canceled.\n")
		}
		return nil
	})
	e.Logger.Fatal(e.Start(":1323"))
}

[ShigeruOta]

Thank you.
I was able to solve this issue the way described above.