空指针导致程序出错

handler/tool.go

@@ -166,16 +166,20 @@ func subscribeAndHandleMessagesV3(ws *websocket.Conn, device_id int) {
 		img, c := service.GetDeviceCurrentFrame(device_id)
 		if c != count {
 			//将img转[]byte
-			buf, _ := gocv.IMEncode(".jpg", img)
-			buf1 := buf.GetBytes()
+			if img.Empty() {
+				fmt.Println("device:%d img is empty!", device_id)
+			} else {
+				buf, _ := gocv.IMEncode(".jpg", img)
+				buf1 := buf.GetBytes()
 
-			err2 := ws.WriteMessage(websocket.BinaryMessage, buf1)
-			if err2 != nil {
-				fmt.Println("send message to client err:", err2)
-				worker.SetRedisSetRemove(online_conn_key, con_id)
-				goto end
+				err2 := ws.WriteMessage(websocket.BinaryMessage, buf1)
+				if err2 != nil {
+					fmt.Println("send message to client err:", err2)
+					worker.SetRedisSetRemove(online_conn_key, con_id)
+					goto end
+				}
+				c = count
 			}
-			c = count
 		} else {
 			//每秒发送一次心跳检测
 			if t_count%10 == 0 {