initial go implementation

game.go

@@ -0,0 +1,39 @@
+package main
+
+type game struct {
+	players    map[*player]bool
+	broadcast  chan *player
+	register   chan *player
+	unregister chan *player
+}
+
+var g = game{
+	broadcast:  make(chan *player),
+	register:   make(chan *player),
+	unregister: make(chan *player),
+	players:    make(map[*player]bool),
+}
+
+func (g *game) run() {
+	for {
+		select {
+		case c := <-g.register:
+			g.players[c] = true
+		case c := <-g.unregister:
+			delete(g.players, c)
+			close(c.send)
+		case p := <-g.broadcast:
+			for c := range g.players {
+				if p != c {
+					select {
+					case c.send <- p:
+					default:
+						delete(g.players, c)
+						close(c.send)
+						go c.ws.Close()
+					}
+				}
+			}
+		}
+	}
+}

main.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"code.google.com/p/go.net/websocket"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+)
+
+var addr = flag.String("addr", ":8666", "http service address")
+var static_files = flag.String("static", "./static", "location of static files")
+
+func main() {
+	flag.Parse()
+
+	http.Handle("/", http.FileServer(http.Dir(
+		fmt.Sprintf("%s/html", *static_files))))
+	http.Handle("/static/", http.StripPrefix("/static/",
+		http.FileServer(http.Dir(*static_files))))
+
+	http.Handle("/ws/game/", websocket.Handler(addPlayer))
+
+	go g.run()
+
+	err := http.ListenAndServe(*addr, nil)
+	if err != nil {
+		log.Fatal("unable to start server")
+	}
+}

player.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"code.google.com/p/go.net/websocket"
+	"encoding/json"
+	"fmt"
+	"log"
+    "math"
+)
+
+type Position struct {
+	X, Y int
+}
+
+type player struct {
+	Position Position `json:"position"`
+	Name     string   `json:"name"`
+	ws       *websocket.Conn
+	send     chan *player
+}
+
+func (p *player) validMove(next Position) (r bool) {
+    r = true
+    if math.Abs(float64(p.Position.X - next.X)) > 1 {
+        r = false
+    }
+    if math.Abs(float64(p.Position.Y - next.Y)) > 1 {
+        r = false
+    }
+    return
+}
+
+func (p *player) sender() {
+	for pinfo := range p.send {
+		err := websocket.JSON.Send(p.ws, pinfo)
+		if err != nil {
+			break
+		}
+	}
+	p.ws.Close()
+}
+
+func (p *player) recv() {
+	for {
+		var msg string
+		err := websocket.Message.Receive(p.ws, &msg)
+		if err != nil {
+			break
+		}
+		// XXX: the danger!
+        var pos Position
+		err = json.Unmarshal([]byte(msg), &pos)
+		if err != nil {
+			break
+		}
+        if !p.validMove(pos) {
+            break
+        }
+        p.Position = pos
+		g.broadcast <- p
+	}
+	p.ws.Close()
+}
+
+func addPlayer(ws *websocket.Conn) {
+	var name string
+	err := websocket.Message.Receive(ws, &name)
+	if err != nil {
+		log.Fatal("trouble parsing username")
+	}
+	p := &player{
+		Name: name,
+		send: make(chan *player, 256),
+		ws:   ws,
+	}
+	g.register <- p
+	defer func() {
+		g.unregister <- p
+	}()
+	go p.sender()
+	p.recv()
+	fmt.Printf("%v has been disconnect from this game\n", p)
+}