⚡ Optimize typing indicator

DysonNetwork.Sphere/Chat/ChatRoomService.cs

@@ -193,7 +193,18 @@ public class ChatRoomService(
     public async Task<List<Guid>> GetSubscribedMembers(Guid roomId)
     {
         var group = $"chatroom:subscribers:{roomId}";
-        var keys = await cache.GetGroupKeysAsync(group);
-        return keys.Select(k => Guid.Parse(k.Split(':').Last())).ToList();
+        var keys = (await cache.GetGroupKeysAsync(group)).ToList();
+        
+        var memberIds = new List<Guid>(keys.Count);
+        foreach (var key in keys)
+        {
+            var lastColonIndex = key.LastIndexOf(':');
+            if (lastColonIndex >= 0 && Guid.TryParse(key.AsSpan(lastColonIndex + 1), out var memberId))
+            {
+                memberIds.Add(memberId);
+            }
+        }
+        
+        return memberIds;
     }
 }

DysonNetwork.Sphere/Startup/BroadcastEventHandler.cs

@@ -266,20 +266,26 @@ public class BroadcastEventHandler(
             {
                 room_id = sender.ChatRoomId,
                 sender_id = sender.Id,
-                sender = sender
+                sender
             }
         };
 
-        // Broadcast typing indicator to other room members
-        var otherMembers = (await crs.ListRoomMembers(requestData.ChatRoomId))
-            .Where(m => m.AccountId != evt.AccountId)
+        // Broadcast typing indicator to subscribed room members only
+        var subscribedMemberIds = await crs.GetSubscribedMembers(requestData.ChatRoomId);
+        var roomMembers = await crs.ListRoomMembers(requestData.ChatRoomId);
+        
+        // Filter to subscribed members excluding the current user
+        var subscribedMembers = roomMembers
+            .Where(m => subscribedMemberIds.Contains(m.Id) && m.AccountId != evt.AccountId)
             .Select(m => m.AccountId.ToString())
             .ToList();
 
-        var respRequest = new PushWebSocketPacketToUsersRequest() { Packet = responsePacket.ToProtoValue() };
-        respRequest.UserIds.AddRange(otherMembers);
-
-        await pusher.PushWebSocketPacketToUsersAsync(respRequest);
+        if (subscribedMembers.Count > 0)
+        {
+            var respRequest = new PushWebSocketPacketToUsersRequest { Packet = responsePacket.ToProtoValue() };
+            respRequest.UserIds.AddRange(subscribedMembers);
+            await pusher.PushWebSocketPacketToUsersAsync(respRequest);
+        }
     }
 
     private async Task HandleMessageSubscribe(WebSocketPacketEvent evt, WebSocketPacket packet)