From a3b986674e3c07f096a22520dfe5dfd52cd0b951 Mon Sep 17 00:00:00 2001
From: Phuoc NTB <phuocntb@mieusoft.com>
Date: Wed, 1 Jul 2026 13:42:13 +0700
Subject: [PATCH] fix: resolve concurrent write crash on gorilla/websocket by
 adding wsWriteMu mutex

---
 client/.DS_Store       | Bin 10244 -> 10244 bytes
 client/app.go          |  76 +++++++++++++++++++----------------------
 client/build/.DS_Store | Bin 12292 -> 12292 bytes
 3 files changed, 36 insertions(+), 40 deletions(-)

diff --git a/client/.DS_Store b/client/.DS_Store
index 74cf6a76dc494e600b522d6768ff388867390a98..d1cf0765ddae3d822e986caddd517f9df605aae9 100644
GIT binary patch
delta 51
zcmZn(XbIR*Ex@>Aa*aSCmqc~7iII+iv61oQ9|AIrU6Vxx<r%v-n+jgy+svl$n`JYT
HC^Itvx7QE0

delta 100
zcmZn(XbIR*Ex@>Qa*aTthh%lNv4NqEf{}?)t&T#qp`p2vj)Iw?L2WH3hp4i?bx?eE
kPHtX)Hv<?jGD2tuUMLNtdN!K~UgF!#uJDUxlPEJY0NTkF5dZ)H

diff --git a/client/app.go b/client/app.go
index 6128344..5aebbf4 100644
--- a/client/app.go
+++ b/client/app.go
@@ -140,6 +140,7 @@ type App struct {
 	chatUnread        int
 	replyStaffID      uint
 	fetchAppsMu       sync.Mutex
+	wsWriteMu         sync.Mutex
 }
 
 type LocalStats struct {
@@ -608,23 +609,32 @@ func (a *App) GetStats() map[string]any {
 	}
 }
 
+// safeWriteWS writes a message to the WebSocket connection thread-safely
+func (a *App) safeWriteWS(msg any) error {
+	a.mu.Lock()
+	conn := a.wsConn
+	a.mu.Unlock()
+
+	if conn == nil {
+		return errors.New("websocket connection is nil")
+	}
+
+	a.wsWriteMu.Lock()
+	defer a.wsWriteMu.Unlock()
+	return conn.WriteJSON(msg)
+}
+
 // SendWebcamFrame truyền webcam frame từ JS frontend lên máy chủ qua WS
 func (a *App) SendWebcamFrame(frameBase64 string) {
 	if !a.isMonitoringActive() {
 		return
 	}
-	a.mu.Lock()
-	conn := a.wsConn
-	a.mu.Unlock()
-
-	if conn != nil {
-		_ = conn.WriteJSON(map[string]any{
-			"event": "webcam_stream_frame",
-			"data": map[string]any{
-				"imageBuffer": frameBase64,
-			},
-		})
-	}
+	_ = a.safeWriteWS(map[string]any{
+		"event": "webcam_stream_frame",
+		"data": map[string]any{
+			"imageBuffer": frameBase64,
+		},
+	})
 }
 
 // authStorageScanner chỉ quét localStorage khi người dùng chủ động mở trang đăng nhập
@@ -1225,18 +1235,12 @@ func (a *App) startScreenshotStream() {
 					continue
 				}
 
-				a.mu.Lock()
-				conn := a.wsConn
-				a.mu.Unlock()
-
-				if conn != nil {
-					_ = conn.WriteJSON(map[string]any{
-						"event": "screenshot_stream_frame",
-						"data": map[string]any{
-							"imageBuffer": frame,
-						},
-					})
-				}
+				_ = a.safeWriteWS(map[string]any{
+					"event": "screenshot_stream_frame",
+					"data": map[string]any{
+						"imageBuffer": frame,
+					},
+				})
 			case <-a.streamScStop:
 				return
 			}
@@ -1301,22 +1305,14 @@ func (a *App) startWebcamStream() {
 				emptyCount = 0
 				sentCount++
 
-				a.mu.Lock()
-				conn := a.wsConn
-				a.mu.Unlock()
-
-				if conn != nil {
-					err := conn.WriteJSON(map[string]any{
-						"event": "webcam_stream_frame",
-						"data": map[string]any{
-							"imageBuffer": frame,
-						},
-					})
-					if sentCount <= 5 {
-						log.Printf("[WS] Webcam frame #%d sent (len=%d, err=%v)", sentCount, len(frame), err)
-					}
-				} else if sentCount <= 5 {
-					log.Printf("[WS] Webcam frame #%d: no WS connection", sentCount)
+				err := a.safeWriteWS(map[string]any{
+					"event": "webcam_stream_frame",
+					"data": map[string]any{
+						"imageBuffer": frame,
+					},
+				})
+				if sentCount <= 5 {
+					log.Printf("[WS] Webcam frame #%d sent (len=%d, err=%v)", sentCount, len(frame), err)
 				}
 			case <-a.streamCamStop:
 				return
diff --git a/client/build/.DS_Store b/client/build/.DS_Store
index ce2646935de6d20ca643124f504ab5737eab6fec..811af543e1ad52edaf1e9df3de27f218aeb22cbb 100644
GIT binary patch
delta 91
zcmZokXi3;`g>CayB?Cqt1_lO3AO->s?#+T6Vl120c)~>(cTBERDCCl;t~NB%Q7|&G
rocv2chOujMzl1zv_hxfNAJ)mgSZ{BRRiDGU`Iky3BZxOSR(v@Ca9$jh

delta 68
zcmZokXi3;`g^iJ6^A$FIMji$R21XzT0uJuYf*fKjo7H&2MJ8to?A>gs=*c?yH|x#K
UG3s+!H**MgF@kuLW5ibg0AaZlLI3~&