fix stream

management/src/components/ExamGridProctor.tsx

@@ -96,7 +96,7 @@ export const ExamGridProctor: React.FC<ExamGridProctorProps> = ({
     });
     currentVisibleIds.forEach((id) => {
       if (!prev.has(id)) {
-        ws.send(JSON.stringify({ event: 'teacher:subscribe', data: { studentId: id } }));
+        ws.send(JSON.stringify({ event: 'teacher:subscribe', data: { studentId: id, mode: 'grid' } }));
         prev.add(id);
       }
     });

management/src/components/ProctorStreamPanels.tsx

@@ -70,7 +70,7 @@ export const ProctorStreamPanels: React.FC<ProctorStreamPanelsProps> = ({
         hasOpened.current = true;
         setStreaming(true);
         setErrorMessage(null);
-        ws.send(JSON.stringify({ event: 'teacher:subscribe', data: { studentId } }));
+        ws.send(JSON.stringify({ event: 'teacher:subscribe', data: { studentId, mode: 'focus' } }));
         clearPing();
         pingTimer = setInterval(() => {
           if (ws.readyState === WebSocket.OPEN) {

server/internal/websocket/websocket.go

@@ -60,6 +60,8 @@ type WsHub struct {
 	subscribers     map[int64][]string // studentId -> list of teacher connection addresses
 	grace           map[int64]offlineGrace
 	graceTimers     map[int64]*time.Timer
+	subscriberModes map[string]string  // "teacherAddr_studentId" -> "grid"|"focus"
+	lastRelayed     map[string]time.Time // "teacherAddr_studentId_event" -> time
 }
 
 var Hub = &WsHub{
@@ -69,6 +71,8 @@ var Hub = &WsHub{
 	subscribers:     make(map[int64][]string),
 	grace:           make(map[int64]offlineGrace),
 	graceTimers:     make(map[int64]*time.Timer),
+	subscriberModes: make(map[string]string),
+	lastRelayed:     make(map[string]time.Time),
 }
 
 func (h *WsHub) IsStudentOnline(studentRkID int64) bool {
@@ -317,6 +321,12 @@ func (h *WsHub) Unregister(c *SocketClient) {
 					newList = append(newList, addr)
 				}
 			}
+			// Clean up mode map for this student and teacher
+			key := c.Addr + "_" + strconv.FormatInt(sID, 10)
+			delete(h.subscriberModes, key)
+			delete(h.lastRelayed, key+"_screenshot_stream_frame")
+			delete(h.lastRelayed, key+"_webcam_stream_frame")
+
 			if len(newList) == 0 {
 				delete(h.subscribers, sID)
 				if student, exists := h.students[sID]; exists {
@@ -330,7 +340,7 @@ func (h *WsHub) Unregister(c *SocketClient) {
 	}
 }
 
-func (h *WsHub) Subscribe(teacherAddr string, studentID int64) {
+func (h *WsHub) Subscribe(teacherAddr string, studentID int64, mode string) {
 	h.mu.Lock()
 	defer h.mu.Unlock()
 
@@ -344,9 +354,12 @@ func (h *WsHub) Subscribe(teacherAddr string, studentID int64) {
 	}
 	if !alreadySubscribed {
 		h.subscribers[studentID] = append(teachersList, teacherAddr)
-		log.Printf("[WS] Teacher %s subscribed to student %d stream", teacherAddr, studentID)
+		log.Printf("[WS] Teacher %s subscribed to student %d stream in %s mode", teacherAddr, studentID, mode)
 	}
 
+	key := teacherAddr + "_" + strconv.FormatInt(studentID, 10)
+	h.subscriberModes[key] = mode
+
 	if student, exists := h.students[studentID]; exists {
 		_ = student.WriteJSON(SocketMsg{Event: "start_screenshot_stream"})
 		_ = student.WriteJSON(SocketMsg{Event: "start_webcam_stream"})
@@ -357,6 +370,11 @@ func (h *WsHub) Unsubscribe(teacherAddr string, studentID int64) {
 	h.mu.Lock()
 	defer h.mu.Unlock()
 
+	key := teacherAddr + "_" + strconv.FormatInt(studentID, 10)
+	delete(h.subscriberModes, key)
+	delete(h.lastRelayed, key+"_screenshot_stream_frame")
+	delete(h.lastRelayed, key+"_webcam_stream_frame")
+
 	teachersList, exists := h.subscribers[studentID]
 	if !exists {
 		return
@@ -382,15 +400,13 @@ func (h *WsHub) Unsubscribe(teacherAddr string, studentID int64) {
 }
 
 func (h *WsHub) RelayFrameRaw(studentID int64, event string, rawImageBuffer json.RawMessage) {
-	h.mu.RLock()
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
 	teachersList, exists := h.subscribers[studentID]
 	if !exists || len(teachersList) == 0 {
-		h.mu.RUnlock()
 		return
 	}
-	addrs := make([]string, len(teachersList))
-	copy(addrs, teachersList)
-	h.mu.RUnlock()
 
 	relayEvent := "teacher:screenshot-stream-frame"
 	if event == "webcam_stream_frame" {
@@ -416,27 +432,33 @@ func (h *WsHub) RelayFrameRaw(studentID int64, event string, rawImageBuffer json
 		return
 	}
 
-	var dead []string
-	h.mu.RLock()
-	for _, addr := range addrs {
-		if t, found := h.teachers[addr]; found {
-			if err := t.WriteRaw(msgBytes); err != nil {
-				log.Printf("[WS] Relay to teacher %s failed: %v", addr, err)
-				dead = append(dead, addr)
-			}
+	now := time.Now()
+	for _, addr := range teachersList {
+		t, found := h.teachers[addr]
+		if !found || t == nil {
+			continue
 		}
-	}
-	h.mu.RUnlock()
 
-	for _, addr := range dead {
-		if t, ok := func() (*SocketClient, bool) {
-			h.mu.RLock()
-			defer h.mu.RUnlock()
-			t, ok := h.teachers[addr]
-			return t, ok
-		}(); ok && t != nil {
-			_ = t.Conn.Close()
+		subKey := addr + "_" + strconv.FormatInt(studentID, 10)
+		mode := h.subscriberModes[subKey]
+
+		if mode == "grid" {
+			// In grid mode, rate limit to max 1 frame per 3 seconds per stream type
+			relayKey := subKey + "_" + event
+			lastTime, ok := h.lastRelayed[relayKey]
+			if ok && now.Sub(lastTime) < 3*time.Second {
+				continue
+			}
+			h.lastRelayed[relayKey] = now
 		}
+
+		// Send asynchronously to avoid head-of-line blocking on slower clients
+		go func(client *SocketClient, data []byte) {
+			if err := client.WriteRaw(data); err != nil {
+				log.Printf("[WS] Relay to teacher %s failed: %v", client.Addr, err)
+				_ = client.Conn.Close()
+			}
+		}(t, msgBytes)
 	}
 }
 
@@ -546,8 +568,15 @@ func WebSocketHandler(db *gorm.DB) func(*websocket.Conn) {
 						case string:
 							sID, _ = strconv.ParseInt(v, 10, 64)
 						}
+						
+						// Nhận chế độ subscription (mặc định là "focus")
+						mode := "focus"
+						if mVal, ok := msg.Data["mode"].(string); ok && mVal != "" {
+							mode = mVal
+						}
+
 						if sID > 0 {
-							Hub.Subscribe(client.Addr, sID)
+							Hub.Subscribe(client.Addr, sID, mode)
 						}
 					}
 				}