Function serveWs

examples/command/main.go:103–166

(w http.ResponseWriter, r *http.Request)

var upgrader = websocket.Upgrader{}

func serveWs(w http.ResponseWriter, r *http.Request) {
	ws, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Println("upgrade:", err)
		return
	}

	defer ws.Close()

	outr, outw, err := os.Pipe()
	if err != nil {
		internalError(ws, "stdout:", err)
		return
	}
	defer outr.Close()
	defer outw.Close()

	inr, inw, err := os.Pipe()
	if err != nil {
		internalError(ws, "stdin:", err)
		return
	}
	defer inr.Close()
	defer inw.Close()

	proc, err := os.StartProcess(cmdPath, flag.Args(), &os.ProcAttr{
		Files: []*os.File{inr, outw, outw},
	})
	if err != nil {
		internalError(ws, "start:", err)
		return
	}

	inr.Close()
	outw.Close()

	stdoutDone := make(chan struct{})
	go pumpStdout(ws, outr, stdoutDone)
	go ping(ws, stdoutDone)

	pumpStdin(ws, inw)

	// Some commands will exit when stdin is closed.
	inw.Close()

	// Other commands need a bonk on the head.
	if err := proc.Signal(os.Interrupt); err != nil {
		log.Println("inter:", err)
	}

	select {
	case <-stdoutDone:
	case <-time.After(time.Second):
		// A bigger bonk on the head.
		if err := proc.Signal(os.Kill); err != nil {
			log.Println("term:", err)
		}
		<-stdoutDone