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|
package main
import (
"encoding/json"
"flag"
"fmt"
"log"
"net/http"
"sync"
"sync/atomic"
"time"
"github.com/gorilla/websocket"
)
type playerState struct {
ID string `json:"id"`
X float64 `json:"x"`
Y float64 `json:"y"`
VX float64 `json:"vx"`
VY float64 `json:"vy"`
Height float64 `json:"height"`
Layer string `json:"layer"`
Cycle int `json:"cycle"`
UpdatedAt int64 `json:"updatedAt"`
}
type stateMessage struct {
Type string `json:"type"`
X float64 `json:"x"`
Y float64 `json:"y"`
VX float64 `json:"vx"`
VY float64 `json:"vy"`
Height float64 `json:"height"`
Layer string `json:"layer"`
Cycle int `json:"cycle"`
}
type welcomeMessage struct {
Type string `json:"type"`
ID string `json:"id"`
}
type snapshotMessage struct {
Type string `json:"type"`
Players []playerState `json:"players"`
}
type client struct {
id string
conn *websocket.Conn
hub *hub
mu sync.Mutex
}
type hub struct {
mu sync.RWMutex
clients map[string]*client
states map[string]playerState
ids atomic.Uint64
}
var upgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
CheckOrigin: func(r *http.Request) bool {
return true
},
}
func newHub() *hub {
return &hub{
clients: make(map[string]*client),
states: make(map[string]playerState),
}
}
func (h *hub) addClient(conn *websocket.Conn) *client {
id := fmt.Sprintf("ghost-%04d", h.ids.Add(1))
client := &client{id: id, conn: conn, hub: h}
h.mu.Lock()
h.clients[id] = client
h.mu.Unlock()
return client
}
func (h *hub) removeClient(id string) {
h.mu.Lock()
delete(h.clients, id)
delete(h.states, id)
h.mu.Unlock()
h.broadcastSnapshot()
}
func (h *hub) updateState(id string, message stateMessage) {
h.mu.Lock()
h.states[id] = playerState{
ID: id,
X: message.X,
Y: message.Y,
VX: message.VX,
VY: message.VY,
Height: message.Height,
Layer: message.Layer,
Cycle: message.Cycle,
UpdatedAt: time.Now().UnixMilli(),
}
h.mu.Unlock()
h.broadcastSnapshot()
}
func (h *hub) snapshot() []playerState {
h.mu.RLock()
defer h.mu.RUnlock()
players := make([]playerState, 0, len(h.states))
for _, state := range h.states {
players = append(players, state)
}
return players
}
func (h *hub) clientCount() int {
h.mu.RLock()
defer h.mu.RUnlock()
return len(h.clients)
}
func (h *hub) broadcastSnapshot() {
payload, err := json.Marshal(snapshotMessage{Type: "snapshot", Players: h.snapshot()})
if err != nil {
log.Printf("snapshot marshal error: %v", err)
return
}
h.mu.RLock()
clients := make([]*client, 0, len(h.clients))
for _, connected := range h.clients {
clients = append(clients, connected)
}
h.mu.RUnlock()
for _, connected := range clients {
connected.writeJSON(payload)
}
}
func (c *client) writeJSON(payload []byte) {
c.mu.Lock()
defer c.mu.Unlock()
if err := c.conn.WriteMessage(websocket.TextMessage, payload); err != nil {
log.Printf("write error for %s: %v", c.id, err)
}
}
func (c *client) sendWelcome() error {
payload, err := json.Marshal(welcomeMessage{Type: "welcome", ID: c.id})
if err != nil {
return err
}
c.writeJSON(payload)
return nil
}
func (c *client) readLoop() {
defer func() {
c.hub.removeClient(c.id)
_ = c.conn.Close()
}()
if err := c.sendWelcome(); err != nil {
log.Printf("welcome error for %s: %v", c.id, err)
return
}
for {
_, payload, err := c.conn.ReadMessage()
if err != nil {
if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
log.Printf("read error for %s: %v", c.id, err)
}
return
}
var message stateMessage
if err := json.Unmarshal(payload, &message); err != nil {
continue
}
if message.Type != "state" {
continue
}
c.hub.updateState(c.id, message)
}
}
func main() {
addr := flag.String("addr", ":8080", "HTTP service address")
flag.Parse()
h := newHub()
mux := http.NewServeMux()
mux.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
conn, err := upgrader.Upgrade(w, r, nil)
if err != nil {
log.Printf("websocket upgrade error: %v", err)
return
}
client := h.addClient(conn)
go client.readLoop()
})
mux.HandleFunc("/ping", func(w http.ResponseWriter, _ *http.Request) {
withCORS(w)
w.WriteHeader(http.StatusOK)
_, _ = w.Write([]byte("pong"))
})
mux.HandleFunc("/status", func(w http.ResponseWriter, _ *http.Request) {
withCORS(w)
w.Header().Set("Content-Type", "application/json")
_ = json.NewEncoder(w).Encode(map[string]any{
"status": "online",
"players": h.clientCount(),
})
})
mux.HandleFunc("/servers", func(w http.ResponseWriter, r *http.Request) {
withCORS(w)
w.Header().Set("Content-Type", "application/json")
host := r.Host
if host == "" {
host = "localhost:8080"
}
scheme := "ws"
if r.TLS != nil {
scheme = "wss"
}
_ = json.NewEncoder(w).Encode(map[string]any{
"servers": []map[string]string{{
"url": fmt.Sprintf("%s://%s/ws", scheme, host),
"region": "local",
}},
})
})
log.Printf("CyberJump relay listening on %s", *addr)
if err := http.ListenAndServe(*addr, mux); err != nil {
log.Fatal(err)
}
}
func withCORS(w http.ResponseWriter) {
w.Header().Set("Access-Control-Allow-Origin", "*")
}
|
