Now with multi connections

src/backend/server/src/Todo.Api/Hubs/TodoHub.cs

@@ -1,16 +1,62 @@
+using System.Collections.Concurrent;
+using System.Security.Claims;
 using System.Text.Json;
 using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.SignalR;
 using Todo.Api.Hubs.Models;
 using Todo.Core.Interfaces.Persistence;
 
-namespace Todo.Api.Hubs
+namespace Todo.Api.Hubs;
+
+[Authorize]
+public class TodoHub : Hub
 {
-    [Authorize]
-    public class TodoHub : Hub
-    {
     private readonly ITodoRepository _todoRepository;
 
+    private static readonly ConcurrentDictionary<string, List<string>> ConnectedUsers = new();
+
+    public override Task OnConnectedAsync()
+    {
+        var userId = Context.User.FindFirstValue("sub");
+
+        // Try to get a List of existing user connections from the cache
+        ConnectedUsers.TryGetValue(userId, out var existingUserConnectionIds);
+
+        // happens on the very first connection from the user
+        existingUserConnectionIds ??= new List<string>();
+
+        // First add to a List of existing user connections (i.e. multiple web browser tabs)
+        existingUserConnectionIds.Add(Context.ConnectionId);
+
+
+        // Add to the global dictionary of connected users
+        ConnectedUsers.TryAdd(userId, existingUserConnectionIds);
+
+        return base.OnConnectedAsync();
+    }
+
+    public override Task OnDisconnectedAsync(Exception? exception)
+    {
+        var userId = Context.User.FindFirstValue("sub");
+
+        ConnectedUsers.TryGetValue(userId, out var existingUserConnectionIds);
+
+        // remove the connection id from the List 
+        existingUserConnectionIds?.Remove(Context.ConnectionId);
+
+        // If there are no connection ids in the List, delete the user from the global cache (ConnectedUsers).
+        if (existingUserConnectionIds?.Count == 0)
+        {
+            // if there are no connections for the user,
+            // just delete the userName key from the ConnectedUsers concurent dictionary
+            ConnectedUsers.TryRemove(userId, out _);
+        }
+
+        return base.OnDisconnectedAsync(exception);
+    }
+
+
     public TodoHub(ITodoRepository todoRepository)
     {
         _todoRepository = todoRepository;
@@ -28,9 +74,11 @@ namespace Todo.Api.Hubs
                 .Select(t => new TodoResponse { Id = t.Id, Title = t.Title, Project = t.Project })
                 .ToList());
 
-            await Clients.Caller.SendAsync("getInboxTodos", serializedTodos);
+        await RunOnUserConnections(async (connections) =>
+            await Clients.Clients(connections).SendAsync("getInboxTodos", serializedTodos));
     }
 
+
     public async Task UpdateTodo(string todoId, bool todoStatus)
     {
         await _todoRepository.UpdateTodoStatus(todoId, todoStatus);
@@ -42,7 +90,8 @@ namespace Todo.Api.Hubs
                     { Id = t.Id, Title = t.Title, Status = t.Status, Project = t.Project })
                 .ToList());
 
-            await Clients.Caller.SendAsync("getInboxTodos", serializedTodos);
+        await RunOnUserConnections(async (connections) =>
+            await Clients.Clients(connections).SendAsync("getInboxTodos", serializedTodos));
     }
 
     public async Task GetTodos()
@@ -52,7 +101,8 @@ namespace Todo.Api.Hubs
             .Select(t => new TodoResponse { Id = t.Id, Title = t.Title, Status = t.Status, Project = t.Project })
             .ToList());
 
-            await Clients.Caller.SendAsync("todos", serializedTodos);
+        await RunOnUserConnections(async (connections) =>
+            await Clients.Clients(connections).SendAsync("todos", serializedTodos));
     }
 
     public async Task GetInboxTodos()
@@ -62,7 +112,8 @@ namespace Todo.Api.Hubs
             .Select(t => new TodoResponse { Id = t.Id, Title = t.Title, Status = t.Status, Project = t.Project })
             .ToList());
 
-            await Clients.Caller.SendAsync("getInboxTodos", serializedTodos);
+        await RunOnUserConnections(async (connections) =>
+            await Clients.Clients(connections).SendAsync("getInboxTodos", serializedTodos));
     }
 
     public async Task GetTodo(string todoId)
@@ -76,7 +127,8 @@ namespace Todo.Api.Hubs
             Title = todo.Title,
         });
 
-            await Clients.Caller.SendAsync("getTodo", serializedTodo);
+        await RunOnUserConnections(async (connections) =>
+            await Clients.Clients(connections).SendAsync("getTodo", serializedTodo));
     }
 
     public async Task ReplaceTodo(string updateTodoRequest)
@@ -101,7 +153,21 @@ namespace Todo.Api.Hubs
             Title = updatedTodo.Title,
         });
 
-            await Clients.Caller.SendAsync("getTodo", serializedTodo);
+        await RunOnUserConnections(async (connections) =>
+            await Clients.Clients(connections).SendAsync("getTodo", serializedTodo));
     }
+
+    private Task RunOnUserConnections(Func<IEnumerable<string>, Task> action)
+    {
+        var userId = Context.User.FindFirstValue("sub");
+        if (userId is null)
+            throw new InvalidOperationException("User id was invalid. Something has gone terribly wrong");
+
+        ConnectedUsers.TryGetValue(userId, out var connections);
+
+        if (connections is not null)
+            action(connections);
+
+        return Task.CompletedTask;
     }
 }

src/backend/server/src/Todo.Api/Startup.cs

@@ -27,6 +27,7 @@ namespace Todo.Api
         public void ConfigureServices(IServiceCollection services)
         {
             services.AddControllers();
+            services.AddHttpContextAccessor();
             services.AddCors(options =>
             {
                 options.AddDefaultPolicy(builder =>

src/backend/server/src/Todo.Api/Todo.Api.csproj

@@ -3,6 +3,7 @@
     <PropertyGroup>
         <TargetFramework>net6.0</TargetFramework>
         <DockerDefaultTargetOS>Linux</DockerDefaultTargetOS>
+        <Nullable>enable</Nullable>
     </PropertyGroup>
 
     <ItemGroup>

src/client/src/presentation/contexts/SocketContext.tsx

@@ -40,7 +40,9 @@ export const SocketProvider: FC = (props) => {
       process.env.NEXT_PUBLIC_SERVER_URL || "http://localhost:5000";
 
     const connection = new HubConnectionBuilder()
-      .withUrl(`${serverUrl}/hubs/todo`)
+      .withUrl(`${serverUrl}/hubs/todo`, {
+          withCredentials: true
+      })
       .withAutomaticReconnect()
       .configureLogging(LogLevel.Information)
       .build();