Aspect based locking to prevent parallel model operations. Spelling f…

…ixes.

PalmHill.BlazorChat/Client/Components/Chat/ChatMessageList.razor

@@ -7,7 +7,7 @@
 
 <div class="chat-messages">
     @* Display each prompt in a card. Display each response in a card. *@
-    @foreach (var promptWithResponse in Controller!.WebsocketChatMessages)
+    @foreach (var promptWithResponse in Controller!.WebSocketChatMessages)
     {
         <FluentCard>
             <FluentStack>

PalmHill.BlazorChat/Client/Services/ChatService.cs

@@ -65,7 +65,7 @@ ILogger<ChatService> logger
         /// <summary>
         /// The list of chat messages. Containing a prompt and its response.
         /// </summary>
-        public List<WebSocketChatMessage> WebsocketChatMessages { get; private set; } = new List<WebSocketChatMessage>();
+        public List<WebSocketChatMessage> WebSocketChatMessages { get; private set; } = new List<WebSocketChatMessage>();
 
         /// <summary>
         /// The WebSocketChatService that handles the WebSocket connection.
@@ -142,7 +142,7 @@ public async Task SendToWebSocketChat()
             var prompt = new WebSocketChatMessage();
             prompt.ConversationId = ConversationId;
             prompt.Prompt = UserInput;
-            WebsocketChatMessages.Add(prompt);
+            WebSocketChatMessages.Add(prompt);
             UserInput = string.Empty;
             StateHasChanged();
             await SendInferenceRequest();
@@ -160,7 +160,7 @@ public async Task AskDocumentApi()
             var prompt = new WebSocketChatMessage();
             prompt.Prompt = UserInput;
             prompt.ConversationId = ConversationId;
-            WebsocketChatMessages.Add(prompt);
+            WebSocketChatMessages.Add(prompt);
             UserInput = string.Empty;
             StateHasChanged();
 
@@ -258,7 +258,7 @@ private void setupWebSocketChatConnection()
             WebSocketChatConnection = new WebSocketChatService(
                     ConversationId,
                     _navigationManager.ToAbsoluteUri("/chathub?customUserId=user1"),
-                    WebsocketChatMessages,
+                    WebSocketChatMessages,
                     _localStorageService
                     );
 

PalmHill.BlazorChat/Server/ChatCancelation.cs → PalmHill.BlazorChat/Server/ChatCancellation.cs

@@ -2,8 +2,8 @@
 
 namespace PalmHill.BlazorChat.Server
 {
-    public static class ChatCancelation
+    public static class ChatCancellation
     {
-        public static ConcurrentDictionary<Guid, CancellationTokenSource> CancelationTokens { get; private set; } = new ConcurrentDictionary<Guid, CancellationTokenSource>();
+        public static ConcurrentDictionary<Guid, CancellationTokenSource> CancellationTokens { get; private set; } = new ConcurrentDictionary<Guid, CancellationTokenSource>();
     }
 }

PalmHill.BlazorChat/Server/PalmHill.BlazorChat.Server.csproj

@@ -7,6 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="AspectInjector" Version="2.8.2" />
     <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.Server" Version="8.0.6" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="6.6.2" />
   </ItemGroup>

PalmHill.BlazorChat/Server/SerialExecutionAspect.cs

@@ -0,0 +1,44 @@
+namespace PalmHill.BlazorChat.Server
+{
+    using AspectInjector.Broker;
+    using System;
+    using System.Collections.Concurrent;
+    using System.Reflection;
+    using System.Threading;
+    using System.Threading.Tasks;
+
+    [Aspect(Scope.Global)]
+    public class SerialExecutionAspect
+    {
+        private static readonly ConcurrentDictionary<string, SemaphoreSlim> _semaphores = new ConcurrentDictionary<string, SemaphoreSlim>();
+
+        [Advice(Kind.Around, Targets = Target.Method)]
+        public object? Handle(
+            [Argument(Source.Name)] string methodName,
+            [Argument(Source.Target)] Func<object[], object> method,
+            [Argument(Source.Arguments)] object[] args,
+            [Argument(Source.Metadata)] MethodBase methodBase)
+        {
+            var attribute = methodBase.GetCustomAttribute<SerialExecutionAttribute>();
+            var key = attribute?.Key ?? string.Empty;
+            var semaphore = _semaphores.GetOrAdd(key, _ => new SemaphoreSlim(1, 1));
+
+            semaphore.Wait();
+            try
+            {
+                var result = method(args);
+                if (result is Task task)
+                {
+                    task.GetAwaiter().GetResult(); // Ensure the task completes
+                    return task;
+                }
+                return result;
+            }
+            finally
+            {
+                semaphore.Release();
+            }
+        }
+    }
+
+}

PalmHill.BlazorChat/Server/SerialExecutionAttribute.cs

@@ -0,0 +1,18 @@
+namespace PalmHill.BlazorChat.Server
+{
+    using AspectInjector.Broker;
+
+    [AttributeUsage(AttributeTargets.Method)]
+    [Injection(typeof(SerialExecutionAspect))]
+    public class SerialExecutionAttribute : Attribute
+    {
+        public string Key { get; }
+
+        public SerialExecutionAttribute(string key)
+        {
+            Key = key;
+        }
+    }
+
+
+}

PalmHill.BlazorChat/Server/SignalR/WebSocketChat.cs

@@ -1,5 +1,6 @@
 using Azure.AI.OpenAI;
 using LLama;
+using Microsoft.AspNetCore.Components;
 using Microsoft.AspNetCore.SignalR;
 using Microsoft.SemanticKernel.ChatCompletion;
 using PalmHill.BlazorChat.Server.WebApi;
@@ -39,7 +40,7 @@ public async Task InferenceRequest(InferenceRequest chatConversation)
         {
             var conversationId = chatConversation.Id;
             var cancellationTokenSource = new CancellationTokenSource();
-            ChatCancelation.CancelationTokens[conversationId] = cancellationTokenSource;
+            ChatCancellation.CancellationTokens[conversationId] = cancellationTokenSource;
 
             try
             {
@@ -70,7 +71,7 @@ public async Task InferenceRequest(InferenceRequest chatConversation)
             finally
             {
                 //ThreadLock.InferenceLock.Release();
-                ChatCancelation.CancelationTokens.TryRemove(conversationId, out _);
+                ChatCancellation.CancellationTokens.TryRemove(conversationId, out _);
 
             }
         }
@@ -83,6 +84,7 @@ public async Task InferenceRequest(InferenceRequest chatConversation)
         /// <param name="messageId">The unique identifier for the message.</param>
         /// <param name="chatConversation">The chat conversation to use for inference.</param>
         /// <returns>A Task that represents the asynchronous operation.</returns>
+        [SerialExecution("ModelOperation")]
         private async Task DoInferenceAndRespondToClient(ISingleClientProxy respondToClient, InferenceRequest chatConversation, CancellationToken cancellationToken)
         {
             // Create a context for the model and a chat session for the conversation

PalmHill.BlazorChat/Server/WebApi/ApiChatController.cs

@@ -59,7 +59,7 @@ public async Task<ActionResult<string>> Chat([FromBody] InferenceRequest convers
 
             var conversationId = conversation.Id;
             var cancellationTokenSource = new CancellationTokenSource();
-            ChatCancelation.CancelationTokens[conversationId] = cancellationTokenSource;
+            ChatCancellation.CancellationTokens[conversationId] = cancellationTokenSource;
 
             try
             {
@@ -80,7 +80,7 @@ public async Task<ActionResult<string>> Chat([FromBody] InferenceRequest convers
             finally
             {
                 //ThreadLock.InferenceLock.Release();
-                ChatCancelation.CancelationTokens.TryRemove(conversationId, out _);
+                ChatCancellation.CancellationTokens.TryRemove(conversationId, out _);
             }
 
             _logger.LogError(errorText);
@@ -98,7 +98,7 @@ public async Task<ActionResult<ChatMessage>> Ask(InferenceRequest chatConversati
 
             var conversationId = chatConversation.Id;
             var cancellationTokenSource = new CancellationTokenSource();
-            ChatCancelation.CancelationTokens[conversationId] = cancellationTokenSource;
+            ChatCancellation.CancellationTokens[conversationId] = cancellationTokenSource;
 
             var question = chatConversation.ChatMessages.LastOrDefault()?.Message;
             if (question == null)
@@ -137,7 +137,7 @@ public async Task<ActionResult<ChatMessage>> Ask(InferenceRequest chatConversati
         [HttpDelete("cancel/{conversationId}", Name = "CancelChat")]
         public async Task<bool> CancelChat(Guid conversationId)
         {
-            var cancelToken = ChatCancelation.CancelationTokens[conversationId];
+            var cancelToken = ChatCancellation.CancellationTokens[conversationId];
             if (cancelToken == null)
             {
                 return false;
@@ -154,6 +154,7 @@ public async Task<bool> CancelChat(Guid conversationId)
         /// </summary>
         /// <param name="conversation">The chat conversation for which to perform inference.</param>
         /// <returns>Returns the inference result as a string.</returns>
+        [SerialExecution("ModelOperation")]
         private async Task<string> DoInference(InferenceRequest conversation, CancellationToken cancellationToken)
         {
 

PalmHill.BlazorChat/Server/WebApi/AttachmentController.cs

@@ -98,6 +98,7 @@ public async Task<ActionResult<AttachmentInfo>> AddAttachment([FromForm] FileUpl
             return attachmentInfo;
         }
 
+        [SerialExecution("ModelOperation")]
         private async Task DoImportAsync(string? userId, AttachmentInfo attachmentInfo)
         {
             try