CODEWITHSUNDEEP
c#asp.net-mvcsignalrsignalr.client
Neo
Neo

Reputation: 16219

How to receive message for user specific using signalR c# MVC?

I have an MVC application.

I have implemented singalR to receive live notifications but how to get only user specific notifications.

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");

I'm able to get notification on UI perfectly fine but problem is

If user A using his own machine and his login he should get only his notification , I know webapp url is same.

for that i make below change but not any notification is visible after this change.

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);
            });
        });

Upvotes: 0

Views: 1970

Answers (2)

Aarif
Aarif

Reputation: 1675

Add a static class its instance will be created once and will persist information in memory like the instance of context

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() });
    }
}

and in your Hub

[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);
    }
}

Notification will be pushed to individual groups, for your problem you should create a separate group for each user as provided in code.

Upvotes: 2

Faiz Infy
Faiz Infy

Reputation: 91

Here is my example code in VB.Net (you may convert it to 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

You have to use Group. Basically what I do is 1 group is for 1 user. Define by the username.

Then just call the function:

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)

Lastly, javascript code to trigger that:

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

ID notification where you want to put the notification message.

Upvotes: 1

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