add setting for mouse polling interval

main.go

@@ -43,6 +43,7 @@ const (
 	authenticationRateLimit time.Duration = time.Second / 10
 	authenticationRateBurst int           = 10
 	challengeLength         int           = 8
+	defaultUpdateInterval   int           = 50
 	defaultBind             string        = ":0"
 	version                 string        = "0.0.3"
 )
@@ -127,12 +128,15 @@ func secureRandBase64(length int) string {
 func main() {
 	var bind, certFile, keyFile, secret string
 	var showVersion, invert bool
+	var updateInterval int
 	flag.BoolVar(&showVersion, "version", false, "show program's version number and exit")
 	flag.StringVar(&bind, "bind", defaultBind, "bind server to [IP]:PORT")
 	flag.StringVar(&secret, "secret", "", "shared secret for client authentication")
 	flag.StringVar(&certFile, "cert", "", "file containing TLS certificate")
 	flag.StringVar(&keyFile, "key", "", "file containing TLS private key")
 	flag.BoolVar(&invert, "invert", false, "use inverse colors for QR code")
+	flag.IntVar(&updateInterval, "interval", defaultUpdateInterval,
+		"mouse polling interval in milliseconds")
 	flag.Parse()
 	if showVersion {
 		fmt.Println(version)
@@ -148,6 +152,9 @@ func main() {
 	if secret == "" {
 		secret = secureRandBase64(defaultSecretLength)
 	}
+	if updateInterval < 0 {
+		log.Fatal("interval must be greater or equal to zero")
+	}
 	var plugin Plugin
 	platformErrors := ""
 	for _, f := range Plugins {
@@ -199,6 +206,7 @@ func main() {
 		if !challenge.verify(message) {
 			return
 		}
+		websocket.Message.Send(ws, fmt.Sprintf("i%d", updateInterval))
 		for {
 			if err := websocket.Message.Receive(ws, &message); err != nil {
 				return

webdata/fn.js

@@ -24,7 +24,6 @@ const MOVE_MULT = 1;
 const SCROLL_MULT = 0.05;
 // [[px/s, mult], ...]
 const POINTER_ACCELERATION = [[0, 0], [87, 1], [173, 1], [553, 2]];
-const UPDATE_INTERVAL = 50;
 const MAX_IDLE_UPDATES = 10;
 
 var ws;
@@ -43,6 +42,7 @@ var scrollYSum = 0;
 var dragging = false;
 var draggingTimeout = null;
 var updateTimer = null;
+var updateInterval = 0;
 var idleUpdates = 0;
 
 function fullscreenEnabled() {
@@ -147,8 +147,8 @@ function onDraggingTimeout() {
 function updateMoveAndScroll() {
     if (updateTimer == null) {
         onUpdateTimeout();
-        if (UPDATE_INTERVAL > 0 && idleUpdates == 0) {
-            updateTimer = setInterval(onUpdateTimeout, UPDATE_INTERVAL);
+        if (updateInterval > 0 && idleUpdates == 0) {
+            updateTimer = setInterval(onUpdateTimeout, updateInterval);
         }
     }
 }
@@ -298,6 +298,20 @@ function challengeResponse(message) {
     return btoa(shaObj.getHMAC("BYTES"));
 }
 
+function processCommand(message) {
+    if (message.charAt(0) == "i") {
+        var x = parseInt(message.substr(1));
+        if (isNaN(x) || x.toString() != message.substr(1) || x < 0) {
+            return false;
+        }
+        updateInterval = x;
+        clearInterval(updateTimer);
+        updateTimer = null;
+        return true;
+    }
+    return false;
+}
+
 window.addEventListener("load", function() {
     var authenticated = false;
     var opening = document.getElementById("opening");
@@ -322,7 +336,9 @@ window.addEventListener("load", function() {
 
     ws.onmessage = function(event) {
         if (authenticated) {
+            if (!processCommand(event.data)) {
                 ws.close();
+            }
             return;
         }
         authenticated = true;