prevent duplicate users in online users list signalr - asp.net-mvc

Question

I am working on online users list. My code is:
public class User
{
public string id;
public string name;
public string dpExtension;
}
public class OnlineUsers : Hub
{
private Entities db = new Entities();
public static ConcurrentDictionary<string, User> users = new ConcurrentDictionary<string, User>();
public override System.Threading.Tasks.Task OnConnected()
{
User u = new User();
u.id = "visitor";
u.name = "Visitor";
u.dpExtension = "";
if (Context.User.Identity.IsAuthenticated)
{
u.id = Context.User.Identity.GetUserId();
var da = db.AspNetUsers.Find(u.id);
u.name = da.Email;
u.dpExtension = da.dpExtension;
}
User abc;
var data = users.TryGetValue(Context.ConnectionId, out abc);
if (!data)
{
users.TryAdd(Context.ConnectionId, u);
}
Clients.All.showConnected(users);
return base.OnConnected();
}
public override System.Threading.Tasks.Task OnDisconnected(bool stopCalled)
{
User abc;
users.TryRemove(Context.ConnectionId, out abc);
Clients.All.showConnected(users);
return base.OnDisconnected(stopCalled);
}
}
Now if the user has opened one browser tab, it is shown once in list and that's fine. But if user opens two tabs it is shown in list twice. How can I show one user only once in list?

Answer 1

You need to map ConnectionIds to one User. You can read a lot in this article - http://www.asp.net/signalr/overview/guide-to-the-api/mapping-users-to-connections .
I've added a few things in your code, you could see what was going on in this article:
public class User
{
public string dpExtension;
public string id;
public string name;
}
public class Map
{
public string UserId { get; set; }
public User User { get; set; }
public List<string> Connections { get; set; }
}
public class OnlineUsers : Hub
{
public static readonly List<Map> maps = new List<Map>();
private readonly Entities db = new Entities();
public override Task OnConnected()
{
var user = new User { id = "visitor", name = "Visitor", dpExtension = "" };
if (Context.User.Identity.IsAuthenticated)
{
user.id = Context.User.Identity.GetUserId();
var da = db.AspNetUsers.Find(user.id);
user.name = da.Email;
user.dpExtension = da.dpExtension;
}
Map data = maps.FirstOrDefault(t => t.UserId == user.id);
if (data == null)
{
maps.Add(new Map() {
UserId = user.id,
User = user,
Connections = new List<string>() { Context.ConnectionId }
});
}
else
{
data.Connections.Add(Context.ConnectionId);
}
Clients.All.showConnected(maps.Select(m => m.User));
return base.OnConnected();
}
public override System.Threading.Tasks.Task OnDisconnected(bool stopCalled)
{
var map = maps.FirstOrDefault(t => t.Connections.Contains(Context.ConnectionId));
if (map != null)
{
map.Connections.Remove(Context.ConnectionId);
if (map.Connections.Count <= 0)
{
maps.Remove(map);
}
}
Clients.All.showConnected(maps.Select(m => m.User));
return base.OnDisconnected(stopCalled);
}
}