From 534b00aeb8e31f7e5180e548023511c0784d8edd Mon Sep 17 00:00:00 2001
From: Yinyin Liu <liu@innov.energy>
Date: Thu, 5 Mar 2026 09:17:06 +0100
Subject: [PATCH] removed accumulating duplicate/stale WebSocket entries over
 time

---
 .../Backend/Websockets/WebsockerManager.cs    | 47 +++++++++++--------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/csharp/App/Backend/Websockets/WebsockerManager.cs b/csharp/App/Backend/Websockets/WebsockerManager.cs
index 9a6a7dc40..0a8533f94 100644
--- a/csharp/App/Backend/Websockets/WebsockerManager.cs
+++ b/csharp/App/Backend/Websockets/WebsockerManager.cs
@@ -69,6 +69,9 @@ public static class WebsocketManager
             var installationConnection = InstallationConnections[installationId];
             Console.WriteLine("Update all the connected websockets for installation " + installation.Name);
 
+            // Prune dead/closed connections before sending
+            installationConnection.Connections.RemoveAll(c => c.State != WebSocketState.Open);
+
             var jsonObject = new
             {
                 id = installationId,
@@ -82,20 +85,18 @@ public static class WebsocketManager
 
         // Send to all connections concurrently (preserves original fire-and-forget intent),
         // but isolate failures so one closed socket doesn't affect others or crash the caller.
-        await Task.WhenAll(connections
-            .Where(c => c.State == WebSocketState.Open)
-            .Select(async c =>
+        await Task.WhenAll(connections.Select(async c =>
+        {
+            try
             {
-                try
-                {
-                    await c.SendAsync(new ArraySegment<byte>(dataToSend, 0, dataToSend.Length),
-                        WebSocketMessageType.Text, true, CancellationToken.None);
-                }
-                catch (Exception ex)
-                {
-                    Console.WriteLine($"WebSocket send failed for installation {installationId}: {ex.Message}");
-                }
-            }));
+                await c.SendAsync(new ArraySegment<byte>(dataToSend, 0, dataToSend.Length),
+                    WebSocketMessageType.Text, true, CancellationToken.None);
+            }
+            catch (Exception ex)
+            {
+                Console.WriteLine($"WebSocket send failed for installation {installationId}: {ex.Message}");
+            }
+        }));
     }
 
 
@@ -163,7 +164,10 @@ public static class WebsocketManager
                             };
                         }
 
-                        InstallationConnections[installationId].Connections.Add(currentWebSocket);
+                        if (!InstallationConnections[installationId].Connections.Contains(currentWebSocket))
+                        {
+                            InstallationConnections[installationId].Connections.Add(currentWebSocket);
+                        }
 
                         var jsonObject = new WebsocketMessage
                         {
@@ -197,13 +201,9 @@ public static class WebsocketManager
             lock (InstallationConnections)
             {
                 //When the front-end terminates the connection, the following code will be executed
-                //Console.WriteLine("The connection has been terminated");
                 foreach (var installationConnection in InstallationConnections)
                 {
-                    if (installationConnection.Value.Connections.Contains(currentWebSocket))
-                    {
-                        installationConnection.Value.Connections.Remove(currentWebSocket);
-                    }
+                    installationConnection.Value.Connections.RemoveAll(ws => ws == currentWebSocket);
                 }
             }
 
@@ -224,6 +224,15 @@ public static class WebsocketManager
         catch (Exception ex)
         {
             Console.WriteLine("WebSocket error: " + ex.Message);
+
+            // Ensure stale socket is removed even on unexpected errors
+            lock (InstallationConnections)
+            {
+                foreach (var installationConnection in InstallationConnections)
+                {
+                    installationConnection.Value.Connections.RemoveAll(ws => ws == currentWebSocket);
+                }
+            }
         }
     }