如何使用signalR c＃MVC接收特定于用户的消息？

Question

我有一个MVC应用程序。

我已经实现了signalR来接收实时通知，但是如何只获取用户特定的通知。

NotificationSend.cs

public class NotificationSend : Hub
{
    private static IHubContext hubContext = GlobalHost.ConnectionManager.GetHubContext<NotificationSend>();
    public static ConcurrentDictionary<string, MyUserType> MyUsers = new ConcurrentDictionary<string, MyUserType>();

    public override Task OnConnected()
    {
        MyUsers.TryAdd(Context.ConnectionId, new MyUserType() { ConnectionId = Context.ConnectionId });
        return base.OnConnected();
    }

    public override Task OnDisconnected(bool stopCalled)
    {
        MyUserType garbage;

        MyUsers.TryRemove(Context.ConnectionId, out garbage);

        return base.OnDisconnected(stopCalled);
    }

    public static void SendToUser(string messageText)
    {
        hubContext.Clients.Client(MyUsers.Keys.ToList().FirstOrDefault()).Notification(messageText);
    }

    public static void StopLoader(string messageText)
    {
        hubContext.Clients.Client(MyUsers.Keys.ToList().FirstOrDefault()).Stoploader(messageText);
    }
}
public class MyUserType
{
    public string ConnectionId { get; set; }
}

HomeController.cs

public class HomeController : Controller
    {

    public async Task<ActionResult> SaveData()
        {
         foreach (var mydata in DataList)
                {
                   // save data code and show below message on UI
                   NotificationSend.SendToUser(mydata.Name + ": Data saved");

我能够在UI上获得完全正常的通知，但问题是

如果用户A使用他自己的机器和他的登录他应该只获得他的通知，我知道webapp url是相同的。

为此我做了以下更改，但在此更改后没有任何通知可见。

string UserID = User.Identity.Name;
hubContext.Clients.User(UserID).Notification(mydata.Name + ": Data saved");

Layout.js

$(function () {
            var notification = $.connection.notificationSend;
            console.log(notification);
            notification.client.Notification = function (Count) {
                $('#liveupdate').empty();
                $('#liveupdate').show();
                $('#liveupdate').append(Count);
            };
            $.connection.hub.start().done(function () {
                var connectionId = $.connection.hub.id;
                console.log("Connected Successfully");
            }).fail(function (response) {
                console.log("not connected" + response);
            });
        });

Answer 1

添加一个静态类，它的实例将被创建一次，并将信息保存在内存中，就像上下文的实例一样

public static class NotificationsResourceHandler
{
    private static readonly IHubContext myContext;       
    public static Dictionary<string, string> Groups;



    static NotificationsResourceHandler()
    {
        myContext = GlobalHost.ConnectionManager.GetHubContext<MyHub>();   
        Groups = new Dictionary<string, string>();
    }

    public static void BroadcastNotification(dynamic model, NotificationType notificationType, string userName)
    {
        myContext.Clients.Group(userName).PushNotification(new { Data = model, Type = notificationType.ToString() });
    }
}

在你的中心

[HubName("yourHub")]
public class MyHub : Hub
{
    public override Task OnConnected()
    {
        var userEmail = Context.QueryString["useremail"]?.ToLower();
        if (userEmail == null) throw new Exception("Unable to Connect to Signalr hub");

        if (NotificationsResourceHandler.Groups.All(x => x.Value != userEmail))
        {
            NotificationsResourceHandler.Groups.Add(Context.ConnectionId, userEmail);
            Groups.Add(Context.ConnectionId, userEmail);
        }
        return base.OnConnected();
    }

    public override Task OnDisconnected(bool stopCalled)
    {
        NotificationsResourceHandler.Groups.Remove(Context.ConnectionId);
        Clients.All.removeConnection(Context.ConnectionId);

        return base.OnDisconnected(stopCalled);
    }
}

通知将被推送到各个组，对于您的问题，您应该为代码中提供的每个用户创建一个单独的组。

Answer 2

这是我在VB.Net中的示例代码（您可以将其转换为C＃）：

Public Class SignalRHub
    Inherits Hub

    Private Shared hubContext As IHubContext = GlobalHost.ConnectionManager.GetHubContext(Of SignalRHub)()

    Public Sub SendToAll(ByVal msg As String)
        hubContext.Clients.All.addNewMessageToPage(msg)
    End Sub

    Public Shared Sub SendToUser(ByVal user As String, ByVal msg As String)
        hubContext.Clients.Group(user).addNewMessageToPage(msg)
    End Sub

    Public Overrides Function OnConnected() As Task
        Dim name As String = Context.User.Identity.Name
        Groups.Add(Context.ConnectionId, name)
        Return MyBase.OnConnected()
    End Function

End Class

你必须使用Group。基本上我所做的是1组是为1个用户。按用户名定义。

然后只需调用函数：

Dim user As User = idb.Users.Where(Function(a) a.id = userid).FirstOrDefault
Dim msg as string = "Any notification message"
SignalRHub.SendToUser(user.UserName, msg)

最后，javascript代码触发：

var notification = $.connection.signalRHub;
notification.client.addNewMessageToPage = function (msg) {
    $("#notification").prepend(msg);
}

要通知消息的ID通知。