Favoring incoming connection over existing one

Author: tpeczek

Lib.AspNetCore.ServerSentEvents/ServerSentEventsClient.cs

@@ -35,6 +35,8 @@ public sealed class ServerSentEventsClient : IServerSentEventsClient
         public bool IsConnected { get; internal set; }
 
         internal bool PreventReconnect { get; set; } = false;
+
+        internal bool IsRemoved { get; set; } = false;
         #endregion
 
         #region Constructor

Lib.AspNetCore.ServerSentEvents/ServerSentEventsMiddleware.cs

@@ -82,8 +82,7 @@ public async Task Invoke(HttpContext context, IPolicyEvaluator policyEvaluator)
                 Guid clientId = _serverSentEventsClientIdProvider.AcquireClientId(context);
                 if (_serverSentEventsService.IsClientConnected(clientId))
                 {
-                    _logger.LogWarning("The IServerSentEventsClient with identifier {ClientId} is already connected. The request can't have been accepted.", clientId);
-                    return;
+                    _serverSentEventsService.RemoveClient(clientId);
                 }
 
                 if (await PreventReconnectAsync(clientId, context))

Lib.AspNetCore.ServerSentEvents/ServerSentEventsService.cs

@@ -383,15 +383,29 @@ internal void AddClient(ServerSentEventsClient client)
             _clients.TryAdd(client.Id, client);
         }
 
+        internal void RemoveClient(Guid clientId)
+        {
+            IServerSentEventsClient client;
+
+            _clients.TryGetValue(clientId, out client);
+
+            RemoveClient((ServerSentEventsClient)client);
+        }
+
         internal void RemoveClient(ServerSentEventsClient client)
         {
             client.IsConnected = false;
 
-            _clients.TryRemove(client.Id, out _);
-
-            foreach(KeyValuePair<string, ConcurrentDictionary<Guid, IServerSentEventsClient>> group in _groups)
+            if (!client.IsRemoved)
             {
-                group.Value.TryRemove(client.Id, out _);
+                _clients.TryRemove(client.Id, out _);
+
+                client.IsRemoved = true;
+
+                foreach (KeyValuePair<string, ConcurrentDictionary<Guid, IServerSentEventsClient>> group in _groups)
+                {
+                    group.Value.TryRemove(client.Id, out _);
+                }
             }
         }