Server file which need to run on laptop for screen-latency-testing

server.go

package main

import (
	"bufio"
	"bytes"
	"fmt"
	"net"
	"os/exec"
	"strconv"
	"time"

	"github.com/go-vgo/robotgo"
)

func main() {
	fmt.Println("Start server...")

	ln, _ := net.Listen("tcp", "127.0.0.1:")
	_, serverPort, _ := net.SplitHostPort(ln.Addr().String())
	fmt.Println("Listening on address:")
	fmt.Println(ln.Addr())

	cmd := exec.Command("adb", "shell", "am", "start", "-n",
		"com.android.example.camera2.slowmo/com.example.android.camera2.slowmo.CameraActivity",
		"--es", "port "+serverPort)
	// error logging and execution for cmd
	var out bytes.Buffer
	var stderr bytes.Buffer
	cmd.Stdout = &out
	cmd.Stderr = &stderr
	err := cmd.Run()
	if err != nil {
		fmt.Println(fmt.Sprint(err) + ": " + stderr.String())
		return
	}
	fmt.Println("Result: " + out.String())

	cmd2 := exec.Command("adb", "reverse", "tcp:"+serverPort, "tcp:"+serverPort)
	// error logging and execution for cmd2
	var out2 bytes.Buffer
	var stderr2 bytes.Buffer
	cmd2.Stdout = &out2
	cmd2.Stderr = &stderr2
	err2 := cmd2.Run()
	if err2 != nil {
		fmt.Println(fmt.Sprint(err2) + ": " + stderr2.String())
		return
	}
	fmt.Println("Result: " + out2.String())

	// accept connection
	conn, _ := ln.Accept()
	fmt.Println("Got connection from:")
	fmt.Println(conn.LocalAddr().String())

	// serverReader := bufio.NewReader(os.Stdin)
	hostReader := bufio.NewReader(conn)
	var cache [12]string
	counter := 0

	// fmt.Print("Text to send: ")
	// text, _ := serverReader.ReadString('\n')
	// // send to server
	// fmt.Fprintf(conn, text)
	message, _ := hostReader.ReadString('*') // using * as delim and hardcoded in app to append * at end of message
	fmt.Println(message)
	if message == "started capture*" {
		cache[counter] = strconv.Itoa(int(time.Now().UnixNano() / 1000000))
		counter++
		time.Sleep(1 * time.Second)
		for i := 0; i < 10; i++ {
			robotgo.TypeStr("m")
			cache[counter] = strconv.Itoa(int(time.Now().UnixNano() / 1000000))
			counter++
			time.Sleep(100 * time.Millisecond)
		}
	}
	fmt.Println("Key simulation ended")
	message, _ = hostReader.ReadString('*') // using * as delim and hardcoded in app to append * at end of message
	fmt.Println(message)
	if message == "send cache*" {
		//time.Sleep(1 * time.Second)
		for i := 0; i < counter; i++ {
			fmt.Fprint(conn, cache[i]+"\n")
		}
	}
}