Broadcast player posistion to websocket clients this could be high traffic.

cmd/mtwebmapper/forwardupdates.go

@@ -17,7 +17,7 @@ type websocketForwarder struct {
 	upgrader    *websocket.Upgrader
 	register    chan *connection
 	unregister  chan *connection
-	broadcast   chan map[xz]bool
+	broadcast   chan msg
 	connections map[*connection]bool
 }
 
@@ -26,13 +26,18 @@ type connection struct {
 	send chan []byte
 }
 
+type msg struct {
+	tiles map[xz]bool
+	pls   []*player
+}
+
 func newWebsocketForwarder() *websocketForwarder {
 	upgrader := &websocket.Upgrader{ReadBufferSize: 512, WriteBufferSize: 2048}
 	return &websocketForwarder{
 		upgrader:    upgrader,
 		register:    make(chan *connection),
 		unregister:  make(chan *connection),
-		broadcast:   make(chan map[xz]bool),
+		broadcast:   make(chan msg),
 		connections: make(map[*connection]bool)}
 }
 
@@ -46,26 +51,34 @@ func (wsf *websocketForwarder) run() {
 				delete(wsf.connections, c)
 				close(c.send)
 			}
-		case changes := <-wsf.broadcast:
+		case message := <-wsf.broadcast:
 			if len(wsf.connections) == 0 {
 				continue
 			}
-			// Do the JSON encoding this late to save
+			encMsg := map[string]interface{}{}
-			// some CPU cyles if no client is connected.
+
-			xzs := make([]xz, 0, len(changes))
+			if tiles := message.tiles; tiles != nil {
-			for xz := range changes {
+				xzs := make([]xz, 0, len(tiles))
+				for xz := range tiles {
 					xzs = append(xzs, xz)
 				}
+				encMsg["tiles"] = xzs
+			}
+
+			if message.pls != nil {
+				encMsg["players"] = message.pls
+			}
+
 			var buf bytes.Buffer
 			encoder := json.NewEncoder(&buf)
-			if err := encoder.Encode(xzs); err != nil {
+			if err := encoder.Encode(encMsg); err != nil {
 				log.Printf("encoding changes failed: %s\n", err)
 				continue
 			}
-			msg := buf.Bytes()
+			m := buf.Bytes()
 			for c := range wsf.connections {
 				select {
-				case c.send <- msg:
+				case c.send <- m:
 				default:
 					delete(wsf.connections, c)
 					close(c.send)
@@ -89,7 +102,11 @@ func (wsf *websocketForwarder) ServeHTTP(rw http.ResponseWriter, r *http.Request
 }
 
 func (wsf *websocketForwarder) BaseTilesUpdated(changes map[xz]bool) {
-	wsf.broadcast <- changes
+	wsf.broadcast <- msg{tiles: changes}
+}
+
+func (wsf *websocketForwarder) BroadcastPlayers(pls []*player) {
+	wsf.broadcast <- msg{pls: pls}
 }
 
 func (c *connection) writer() {

cmd/mtwebmapper/players.go

@@ -77,7 +77,10 @@ func (ps *players) run() {
 		ps.mu.Lock()
 		ps.pls = pls
 		ps.mu.Unlock()
-		// TODO: Implement websocket broadcast.
+		if ps.wsf != nil {
+			// TODO: Throttle this!
+			ps.wsf.BroadcastPlayers(pls)
+		}
 	}
 }
 

cmd/mtwebmapper/web/js/auto-update.js

@@ -47,13 +47,18 @@ L.Control.AutoUpdate = L.Control.extend({
                 if (!(typeof json === "string")) {
                     return invalidateAll;
                 }
-                var tiles;
+                var msg;
                 try {
-                    tiles = JSON.parse(json);
+                    msg = JSON.parse(json);
                 } catch (err) {
                     return invalidateAll;
                 }
 
+                var tiles = msg.tiles;
+                if !tiles {
+                    continue;
+                }
+
                 var pyramid = new Array(9);
                 var last = new Object();
                 pyramid[8] = last;