Context.User在Signalr上奇怪地变为null

Question

在SignalR中,我体验到Context.User突然变成空值,并且它有时完全为空但是这永远不会发生,因为只有授权用户才能访问集线器.

这些奇怪行为的原因是什么？我在Visual Studio 2013上使用SignalR 2.0和ASP.NET MVC 4.

[Authorize]
public class FeedHub : Hub
{        
    public override Task OnConnected()
    {
        var name = Context.User.Identity.Name;// here is User is not null
        var user = GetUser();// but it is changing to null inside this private method

        return base.OnConnected();
    }

    private User GetUser()
    {
        var name = Context.User.Identity.Name;// here is User property is null and throws exception
        return null;//
    }


    public override Task OnDisconnected()
    {
        //In here Context.User property is sometimes null but in my opinion this should never be null
        // because Hub is protected by Authorize attribute.

        return base.OnDisconnected();
    }
  }

Answer 1

我用于Context.ConnectionId我的 SignalR 2.0 项目，我对它非常满意。

在本例中存储connid static string，或者astatic List来存储传入的连接id，因为http是无状态的，每次回发都会删除该信息。

public class FeedHub : Hub

{   
    static string username = ""; 

    public override Task OnConnected() //event to fire whenever someone joins
    {
    var name = Context.ConnectionId;//capture the unique incoming connection id
    var username = name;//write it into the static string
    return base.OnConnected();
    }

    public override Task OnDisconnected() //event to fire whenever someone quits
    {
    //In here Context.User property is sometimes null because you only recognize authorized users.
    return base.OnDisconnected();
    }
}