fix groutine leak (#86)

handlers.go

@@ -54,6 +54,7 @@ func (s *Server) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 	defer s.clientsMu.Unlock()
 	s.clients[conn] = struct{}{}
 	ticker := time.NewTicker(pingPeriod)
+	stop := make(chan struct{})
 
 	// NIP-42 challenge
 	challenge := make([]byte, 8)
@@ -75,6 +76,8 @@ func (s *Server) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 	go func() {
 		defer func() {
 			ticker.Stop()
+			stop <- struct{}{}
+			close(stop)
 			s.clientsMu.Lock()
 			if _, ok := s.clients[conn]; ok {
 				conn.Close()
@@ -113,7 +116,7 @@ func (s *Server) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 			if ws.limiter != nil {
 				// NOTE: Wait will throttle the requests.
 				// To reject requests exceeding the limit, use if !ws.limiter.Allow()
-				if err := ws.limiter.Wait(context.Background()); err != nil {
+				if err := ws.limiter.Wait(context.TODO()); err != nil {
 					s.Log.Warningf("unexpected limiter error %v", err)
 					continue
 				}
@@ -125,7 +128,8 @@ func (s *Server) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 			}
 
 			go func(message []byte) {
-				ctx = context.Background()
+				ctx = context.TODO()
+
 				var notice string
 				defer func() {
 					if notice != "" {
@@ -377,11 +381,14 @@ func (s *Server) HandleWebsocket(w http.ResponseWriter, r *http.Request) {
 		for {
 			select {
 			case <-ticker.C:
+				conn.SetWriteDeadline(time.Now().Add(writeWait))
 				err := ws.WriteMessage(websocket.PingMessage, nil)
 				if err != nil {
 					s.Log.Errorf("error writing ping: %v; closing websocket", err)
 					return
 				}
+			case <-stop:
+				return
 			}
 		}
 	}()