Single server presence

samples/ChatSample/DefaultPresenceManager.cs

@@ -0,0 +1,78 @@
+
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.Extensions.DependencyInjection;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using System;
+using Microsoft.AspNetCore.Sockets;
+
+namespace ChatSample
+{
+    // TODO: not possible to use TClient instead of (implicit) IClientProxy
+    // public class DefaultPresenceManager<THub> : IPresenceManager where THub : HubWithPresence<TClient>
+    public class DefaultPresenceManager<THub> : IPresenceManager where THub : HubWithPresence
+    {
+        private IHubContext<THub> _hubContext;
+        private HubLifetimeManager<THub> _lifetimeManager;
+        private readonly IServiceScopeFactory _serviceScopeFactory;
+
+        public DefaultPresenceManager(IHubContext<THub> hubContext, HubLifetimeManager<THub> lifetimeManager, IServiceScopeFactory serviceScopeFactory)
+        {
+            _hubContext = hubContext;
+            _lifetimeManager = lifetimeManager;
+            _serviceScopeFactory = serviceScopeFactory;
+        }
+
+        private readonly ConcurrentDictionary<Connection, UserDetails> usersOnline 
+            = new ConcurrentDictionary<Connection, UserDetails>();
+
+        public IEnumerable<UserDetails> UsersOnline => usersOnline.Values;
+
+        public async Task UserJoined(Connection connection)
+        {
+            // `context.User?.Identity?.Name ?? string.Empty` ?
+            var user = new UserDetails(connection.ConnectionId, connection.User.Identity.Name);
+
+            await Notify(hub => hub.OnUserJoined(user));
+
+            usersOnline.TryAdd(connection, user);
+        }
+
+        public async Task UserLeft(Connection connection)
+        {
+            usersOnline.TryRemove(connection, out UserDetails user);
+
+            await Notify(hub => hub.OnUserLeft(user));
+        }
+
+        private async Task Notify(Func<THub, Task> invocation)
+        {
+            foreach (var connection in usersOnline.Keys)
+            {
+                using (var scope = _serviceScopeFactory.CreateScope())
+                {
+                    var hubActivator = scope.ServiceProvider.GetRequiredService<IHubActivator<THub, IClientProxy>>();
+                    var hub = hubActivator.Create();
+
+                    hub.Clients = _hubContext.Clients;
+                    hub.Context = new HubCallerContext(connection);
+                    hub.Groups = new GroupManager<THub>(connection, _lifetimeManager);
+
+                    try
+                    {
+                        await invocation(hub);
+                    }
+                    catch
+                    {
+                        // TODO: log
+                    }
+                    finally
+                    {
+                        hubActivator.Release(hub);
+                    }
+                }
+            }
+        }
+    }
+}

samples/ChatSample/HubWithPresence.cs

@@ -0,0 +1,55 @@
+using Microsoft.AspNetCore.SignalR;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using System;
+
+namespace ChatSample
+{
+    public class HubWithPresence : HubWithPresence<IClientProxy>
+    {
+        public HubWithPresence(IPresenceManager presenceManager)
+            : base(presenceManager)
+        {
+        }
+    }
+
+    public class HubWithPresence<TClient> : Hub<TClient>
+    {
+        private IPresenceManager _presenceManager;
+
+        public HubWithPresence(IPresenceManager presenceManager)
+        {
+            _presenceManager = presenceManager;
+        }
+
+        public IEnumerable<UserDetails> UsersOnline
+        {
+            get
+            {
+                return _presenceManager.UsersOnline;
+            }
+        }
+
+        public override Task OnConnectedAsync()
+        {
+            _presenceManager.UserJoined(Context.Connection);
+            return base.OnConnectedAsync();
+        }
+
+        public override Task OnDisconnectedAsync(Exception exception)
+        {
+            _presenceManager.UserLeft(Context.Connection);
+            return base.OnDisconnectedAsync(exception);
+        }
+
+        public virtual Task OnUserJoined(UserDetails user)
+        {
+            return Task.CompletedTask;
+        }
+
+        public virtual Task OnUserLeft(UserDetails user)
+        {
+            return Task.CompletedTask;
+        }
+    }
+}

samples/ChatSample/Hubs/Chat.cs

@@ -1,20 +1,19 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
 using System.Threading.Tasks;
-using System.Collections.Generic;
-using System.Collections.Concurrent;
 using Microsoft.AspNetCore.Authorization;
-using Microsoft.AspNetCore.SignalR;
 
 namespace ChatSample.Hubs
 {
     // TODO: Make this work
     [Authorize]
-    public class Chat : Hub
+    public class Chat : HubWithPresence
     {
-        private static readonly ConcurrentDictionary<string, string> usersOnline = new ConcurrentDictionary<string, string>();
+        public Chat(IPresenceManager presenceManager)
+            : base(presenceManager)
+        {
+        }
 
         public override async Task OnConnectedAsync()
         {
@@ -23,16 +22,18 @@ namespace ChatSample.Hubs
                 Context.Connection.Dispose();
             }
 
-            await Clients.Client(Context.ConnectionId).InvokeAsync("SetUsersOnline", usersOnline);
-            usersOnline.TryAdd(Context.ConnectionId, Context.User.Identity.Name);
-
-            await Clients.All.InvokeAsync("OnConnected", Context.ConnectionId, Context.User.Identity.Name);
+            await Clients.Client(Context.ConnectionId).InvokeAsync("SetUsersOnline", UsersOnline);
+            await base.OnConnectedAsync();
         }
 
-        public override Task OnDisconnectedAsync(Exception ex)
+        public override Task OnUserJoined(UserDetails user)
         {
-            usersOnline.TryRemove(Context.ConnectionId, out var value);
-            return Clients.All.InvokeAsync("OnDisconnected", Context.ConnectionId, Context.User.Identity.Name);
+            return Clients.Client(Context.ConnectionId).InvokeAsync("UserJoined", user);
+        }
+
+        public override Task OnUserLeft(UserDetails user)
+        {
+            return Clients.Client(Context.ConnectionId).InvokeAsync("UserLeft", user);
         }
 
         public async Task Send(string message)

samples/ChatSample/IPresenceManager.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.AspNetCore.Sockets;
+
+namespace ChatSample
+{
+    public class UserDetails
+    {
+        public UserDetails(string connectionId, string name)
+        {
+            ConnectionId = connectionId;
+            Name = name;
+        }
+
+        public string ConnectionId { get; }
+        public string Name { get; }
+    }
+
+    public interface IPresenceManager
+    {
+        IEnumerable<UserDetails> UsersOnline { get; }
+        Task UserJoined(Connection connection);
+        Task UserLeft(Connection connection);
+    }
+}

samples/ChatSample/Startup.cs

@@ -8,6 +8,7 @@ using ChatSample.Services;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
+using Microsoft.AspNetCore.SignalR;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
@@ -56,6 +57,8 @@ namespace ChatSample
             services.AddSignalR();
 
             services.AddAuthentication();
+
+            services.AddSingleton<IPresenceManager, DefaultPresenceManager<Chat>>();
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.

samples/ChatSample/Views/Home/Index.cshtml

@@ -30,9 +30,7 @@ connection.onClosed = e => {
 };
 
 connection.on('SetUsersOnline', function (usersOnline) {
-    for (var user in usersOnline) {
-        addUserOnline(user, usersOnline[user]);
-    }
+    usersOnline.forEach(user => addUserOnline(user));
 });
 
 connection.on('OnConnected', function (id, userName) {
@@ -43,6 +41,16 @@ connection.on('OnConnected', function (id, userName) {
 connection.on('OnDisconnected', function (id, userName) {
     appendLine('User ' + userName + ' left the chat');
     document.getElementById(id).outerHTML = '';
+}
+
+connection.on('UserJoined', function (user) {
+    appendLine('User ' + userName + ' joined the chat');
+    addUserOnline(user);
+});
+
+connection.on('UserLeft', function (user) {
+    appendLine('User ' + userName + ' left the chat');
+    document.getElementById(user.ConnectionId).outerHTML = '';
 });
 
 connection.on('Send', function (userName, message) {

src/Microsoft.AspNetCore.SignalR/Hub.cs

@@ -9,7 +9,6 @@ namespace Microsoft.AspNetCore.SignalR
 {
     public class Hub : Hub<IClientProxy>
     {
-
     }
 
     public class Hub<TClient> : IDisposable

src/Microsoft.AspNetCore.SignalR/SignalRAppBuilderExtensions.cs

@@ -32,9 +32,14 @@ namespace Microsoft.AspNetCore.Builder
             _routes = routes;
         }
 
-        public void MapHub<THub>(string path) where THub : Hub
+        public void MapHub<THub>(string path) where THub : Hub<IClientProxy>
         {
             _routes.MapEndpoint<HubEndPoint<THub>>(path);
         }
+
+        public void MapHub<THub, TClient>(string path) where THub : Hub<TClient>
+        {
+            _routes.MapEndpoint<HubEndPoint<THub, TClient>>(path);
+        }
     }
 }

src/Microsoft.AspNetCore.SignalR/SignalRDependencyInjectionExtensions.cs

@@ -14,6 +14,8 @@ namespace Microsoft.Extensions.DependencyInjection
             services.AddSockets();
             services.AddSingleton(typeof(HubLifetimeManager<>), typeof(DefaultHubLifetimeManager<>));
             services.AddSingleton(typeof(IHubContext<>), typeof(HubContext<>));
+            // TODO: this breaks because of hardcoded IClientProxy
+            // services.AddSingleton(typeof(IHubContext<,>), typeof(HubContext<,>));
             services.AddSingleton(typeof(HubEndPoint<>), typeof(HubEndPoint<>));
             services.AddSingleton<IConfigureOptions<SignalROptions>, SignalROptionsSetup>();
             services.AddSingleton<JsonNetInvocationAdapter>();