Improve: 카메라 프리뷰 모바일 대응 + WebSocket 안정성 강화

- iOS/iPadOS 감지 → base64 텍스트 JSON 프리뷰 전송 (바이너리 WS 회피)
- Android/PC는 기존 바이너리 패킷 유지 (클라이언트별 포맷 분기)
- 양방향 WebSocket keepalive (클라이언트 ping 3초 + 서버 keepalive 5초)
- websocket-sharp KeepClean + WaitTime 설정
- 하트비트 타임아웃 완화 (12초) + 재연결 지수 백오프
- 재연결 후 프리뷰 구독 딜레이 (iOS 1.5초)
- SendMessage/SendBinary에 연결 상태 체크 추가
- 모바일 CSS 반응형 (태블릿/폰 터치 타겟, 그리드, 풀스크린 safe-area)
- 대시보드 Cache-Control 강화 (no-store)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Assets/Scripts/Streamdeck/StreamDeckServerManager.cs

@@ -43,6 +43,10 @@ public class StreamDeckServerManager : MonoBehaviour
     private readonly Queue<System.Action> mainThreadActions = new Queue<System.Action>();
     private readonly object lockObject = new object();
 
+    // WebSocket keep-alive
+    private float lastPingTime = 0f;
+    private const float WsPingInterval = 5f;
+
     // 카메라 프리뷰 내부 상태
     private readonly List<Camera> previewCameraPool = new List<Camera>();
     private RenderTexture previewRT;
@@ -108,6 +112,13 @@ public class StreamDeckServerManager : MonoBehaviour
                 }
             }
         }
+
+        // WebSocket 프로토콜 레벨 ping — WiFi 라우터의 유휴 연결 드롭 방지
+        if (Time.time - lastPingTime >= WsPingInterval)
+        {
+            lastPingTime = Time.time;
+            BroadcastWsPing();
+        }
     }
 
     void LateUpdate()
@@ -133,6 +144,8 @@ public class StreamDeckServerManager : MonoBehaviour
         {
             // 0.0.0.0 으로 바인딩하여 LAN 내 다른 기기에서도 접속 가능
             server = new WebSocketServer(port);
+            server.KeepClean = true;                          // 비활성 세션 자동 정리
+            server.WaitTime = TimeSpan.FromSeconds(3);        // ping-pong 응답 대기 시간
             server.AddWebSocketService<StreamDeckService>("/");
             server.Start();
             Debug.Log($"[StreamDeckServerManager] WebSocket 서버 시작됨, 포트: {port} (모든 인터페이스)");
@@ -143,6 +156,12 @@ public class StreamDeckServerManager : MonoBehaviour
         }
     }
 
+    private void BroadcastWsPing()
+    {
+        if (server == null || !server.IsListening) return;
+        BroadcastMessage("{\"type\":\"keepalive\"}");
+    }
+
     private void StopServer()
     {
         if (server != null)
@@ -404,7 +423,6 @@ public class StreamDeckServerManager : MonoBehaviour
             case "ping":
                 SendJson(service, new { type = "pong", timestamp = DateTime.UtcNow.ToString("o") });
                 break;
-
             // SystemController 명령어들
             case "toggle_optitrack_markers":
             case "show_optitrack_markers":
@@ -433,7 +451,17 @@ public class StreamDeckServerManager : MonoBehaviour
 
             // 카메라 프리뷰
             case "subscribe_preview":
-                PreviewSubscribe(service);
+                {
+                    bool useBase64 = false;
+                    if (message.ContainsKey("data"))
+                    {
+                        if (message["data"] is Newtonsoft.Json.Linq.JObject jData && jData.ContainsKey("format"))
+                            useBase64 = jData["format"]?.ToString() == "base64";
+                        else if (message["data"] is Dictionary<string, object> dData && dData.ContainsKey("format"))
+                            useBase64 = dData["format"]?.ToString() == "base64";
+                    }
+                    PreviewSubscribe(service, useBase64);
+                }
                 break;
             case "unsubscribe_preview":
                 PreviewUnsubscribe(service);
@@ -868,22 +896,18 @@ public class StreamDeckServerManager : MonoBehaviour
         });
     }
 
+    private const int PreviewMaxFailCount = 5;
+
     private void BroadcastPreviewBinary(int index, string name, byte[] jpegData)
     {
         int currentIndex = cameraManager.GetCameraListData().current_index;
         bool isActive = (currentIndex == index);
         int totalCameras = cameraManager.cameraPresets.Count;
 
-        byte[] nameBytes = System.Text.Encoding.UTF8.GetBytes(name);
+        // 바이너리 패킷 (필요 시 생성)
-        byte nameLen = (byte)Math.Min(nameBytes.Length, 255);
+        byte[] binaryPacket = null;
-
+        // Base64 텍스트 JSON (필요 시 생성)
-        byte[] packet = new byte[4 + nameLen + jpegData.Length];
+        string base64Json = null;
-        packet[0] = (byte)index;
-        packet[1] = (byte)totalCameras;
-        packet[2] = (byte)(isActive ? 1 : 0);
-        packet[3] = nameLen;
-        Buffer.BlockCopy(nameBytes, 0, packet, 4, nameLen);
-        Buffer.BlockCopy(jpegData, 0, packet, 4 + nameLen, jpegData.Length);
 
         StreamDeckService[] clients;
         lock (previewSubscriberLock)
@@ -893,22 +917,61 @@ public class StreamDeckServerManager : MonoBehaviour
 
         foreach (var client in clients)
         {
-            try
+            if (client.previewFailCount >= PreviewMaxFailCount)
-            {
-                client.SendBinary(packet);
-            }
-            catch (Exception)
             {
                 lock (previewSubscriberLock)
                 {
                     previewSubscribers.Remove(client);
                 }
+                Debug.Log($"[StreamDeckServerManager] 프리뷰 구독 제거 (연속 {PreviewMaxFailCount}회 전송 실패)");
+                continue;
+            }
+
+            if (client.previewUseBase64)
+            {
+                // iOS 등: base64 텍스트 JSON으로 전송 (WebSocket 바이너리 프레임 불안정 기기용)
+                if (base64Json == null)
+                {
+                    base64Json = JsonConvert.SerializeObject(new
+                    {
+                        type = "camera_preview_frame",
+                        data = new
+                        {
+                            camera_index = index,
+                            camera_name = name,
+                            image = Convert.ToBase64String(jpegData),
+                            total_cameras = totalCameras,
+                            is_active = isActive
+                        }
+                    });
+                }
+                client.SendPreviewTextAsync(base64Json);
+            }
+            else
+            {
+                // Android/PC: 바이너리 패킷 (효율적)
+                if (binaryPacket == null)
+                {
+                    byte[] nameBytes = System.Text.Encoding.UTF8.GetBytes(name);
+                    byte nameLen = (byte)Math.Min(nameBytes.Length, 255);
+                    binaryPacket = new byte[4 + nameLen + jpegData.Length];
+                    binaryPacket[0] = (byte)index;
+                    binaryPacket[1] = (byte)totalCameras;
+                    binaryPacket[2] = (byte)(isActive ? 1 : 0);
+                    binaryPacket[3] = nameLen;
+                    Buffer.BlockCopy(nameBytes, 0, binaryPacket, 4, nameLen);
+                    Buffer.BlockCopy(jpegData, 0, binaryPacket, 4 + nameLen, jpegData.Length);
+                }
+                client.SendPreviewAsync(binaryPacket);
             }
         }
     }
 
-    private void PreviewSubscribe(StreamDeckService client)
+    private void PreviewSubscribe(StreamDeckService client, bool useBase64 = false)
     {
+        client.previewSendBusy = false;
+        client.previewFailCount = 0;
+        client.previewUseBase64 = useBase64;
         lock (previewSubscriberLock)
         {
             previewSubscribers.Add(client);
@@ -1042,6 +1105,11 @@ public class StreamDeckService : WebSocketBehavior
 {
     private StreamDeckServerManager serverManager;
 
+    // 프리뷰 비동기 전송 상태
+    public volatile bool previewSendBusy;
+    public int previewFailCount;
+    public bool previewUseBase64;  // iOS 등 바이너리 WS 불안정 기기용 텍스트 모드
+
     protected override void OnOpen()
     {
         serverManager = StreamDeckServerManager.Instance;
@@ -1054,14 +1122,24 @@ public class StreamDeckService : WebSocketBehavior
 
     protected override void OnMessage(WebSocketSharp.MessageEventArgs e)
     {
+        // client_ping은 메인 스레드를 거치지 않고 즉시 응답 (iOS WiFi keepalive용)
+        if (e.Data != null && e.Data.Contains("\"client_ping\""))
+        {
+            try { Send("{\"type\":\"client_pong\"}"); } catch { }
+            return;
+        }
+
         if (serverManager != null)
         {
             serverManager.ProcessMessageOnMainThread(e.Data, this);
         }
     }
 
+    public bool IsConnected => ReadyState == WebSocketSharp.WebSocketState.Open;
+
     public void SendMessage(string message)
     {
+        if (!IsConnected) return;
         try
         {
             Send(message);
@@ -1074,6 +1152,7 @@ public class StreamDeckService : WebSocketBehavior
 
     public void SendBinary(byte[] data)
     {
+        if (!IsConnected) return;
         try
         {
             Send(data);
@@ -1084,6 +1163,58 @@ public class StreamDeckService : WebSocketBehavior
         }
     }
 
+    /// <summary>
+    /// 프리뷰 프레임 비동기 전송 (바이너리). 이전 프레임 전송 중이면 스킵 (backpressure 방지).
+    /// </summary>
+    public void SendPreviewAsync(byte[] data)
+    {
+        if (previewSendBusy || !IsConnected) return;
+        previewSendBusy = true;
+
+        try
+        {
+            SendAsync(data, completed =>
+            {
+                previewSendBusy = false;
+                if (completed)
+                    previewFailCount = 0;
+                else
+                    previewFailCount++;
+            });
+        }
+        catch (Exception)
+        {
+            previewSendBusy = false;
+            previewFailCount++;
+        }
+    }
+
+    /// <summary>
+    /// 프리뷰 프레임 비동기 전송 (텍스트/Base64). iOS 등 바이너리 WS 불안정 기기용.
+    /// </summary>
+    public void SendPreviewTextAsync(string json)
+    {
+        if (previewSendBusy || !IsConnected) return;
+        previewSendBusy = true;
+
+        try
+        {
+            SendAsync(json, completed =>
+            {
+                previewSendBusy = false;
+                if (completed)
+                    previewFailCount = 0;
+                else
+                    previewFailCount++;
+            });
+        }
+        catch (Exception)
+        {
+            previewSendBusy = false;
+            previewFailCount++;
+        }
+    }
+
     protected override void OnClose(WebSocketSharp.CloseEventArgs e)
     {
         if (serverManager != null)

Assets/Scripts/Streamdeck/StreamingleDashboardServer.cs

@@ -211,7 +211,7 @@ public class StreamingleDashboardServer
             byte[] buffer = Encoding.UTF8.GetBytes(responseContent);
             context.Response.ContentType = contentType;
             context.Response.ContentLength64 = buffer.Length;
-            context.Response.AddHeader("Cache-Control", "no-cache");
+            context.Response.AddHeader("Cache-Control", "no-store, no-cache, must-revalidate, max-age=0");
             context.Response.OutputStream.Write(buffer, 0, buffer.Length);
             context.Response.Close();
         }