Real-time notification upon registration using SignalR

Question

I want to send real-time notification in ASP.NET Boilerplate. Notification is saving successfully in Abp.NotificationSubscription table on subscription. When I publish the notification, the notification got saved in the Abp.Notification table but it is not displayed to the user in real-time.

My server-side code:

public async Task<RegisterOutput> Register(RegisterInput input)
{
    public async Task<RegisterOutput> Register(RegisterInput input)
    {
      var user = await _userRegistrationManager.RegisterAsync(
          input.Name,
          input.Surname,
          input.EmailAddress,
          input.UserName,
          input.Password,
          true
      );

      _notificationSubscriptionManager.SubscribeToAllAvailableNotifications(user.ToUserIdentifier());
      await _appNotifier.WelcomeToTheApplicationAsync(user);

      var notification = _userNotificationManager.GetUserNotifications(user.ToUserIdentifier());
      await _realTimeNotifier.SendNotificationsAsync(notification.ToArray());

      // ...
    }
}

_appNotifier implements WelcomeToTheApplicationAsync(user):

public async Task WelcomeToTheApplicationAsync(User user)
{
    await _notificationPublisher.PublishAsync(
        AppNotificationName.WelcomeToTheApplication,
        new SendNotificationData("Naeem", "Hello I have sended this notification to you"),
        severity: NotificationSeverity.Success,
        userIds: new[] { user.ToUserIdentifier() }
    );
}

SendNotificationData inherits from NotificationData:

public class SendNotificationData : NotificationData
{
    public string name { get; set; }
    public string message { get; set; }

    public SendNotificationData(string _name, string _message)
    {
        name = _name;
        message = _message;
    }
}

Answer 1

I want to sent welcome notification to the user when he registers itself by using the register link on the login page. In the CloudbaseLine.Application project ... we have AccountAppService which contain the code for registering the user and sending notification to it after successful registration but the problem is notification go saved in Abp.NotificationSubscriptionTable and UserNotificationTable but user cannot received them.

public async Task<RegisterOutput> Register(RegisterInput input)
{
    var user = await _userRegistrationManager.RegisterAsync(
        input.Name,
        input.Surname,
        input.EmailAddress,
        input.UserName,
        input.Password,
        true
    );

    _notificationSubscriptionManager.SubscribeToAllAvailableNotifications(user.ToUserIdentifier());
    await _appNotifier.WelcomeToTheApplicationAsync(user);

    var notification = _userNotificationManager.GetUserNotifications(user.ToUserIdentifier());
    await _realTimeNotifier.SendNotificationsAsync(notification.ToArray());

    // ...
}

public async Task WelcomeToTheApplicationAsync(User user)
{
    await _notificationPublisher.PublishAsync(
        AppNotificationName.WelcomeToTheApplication,
        new SendNotificationData("Naeem", "Hello I have sended this notification to you"),
        severity: NotificationSeverity.Success,
        userIds: new[] { user.ToUserIdentifier() }
    );
}

The user is not connected to the SignalR hub in the Register method.

One way to handle that is to enqueue a background job:

await _backgroundJobManager.EnqueueAsync<WelcomeNotificationJob, UserIdentifier>(
    user.ToUserIdentifier(),
    delay: TimeSpan.FromSeconds(5)
);

public class WelcomeNotificationJob : BackgroundJob<UserIdentifier>, ITransientDependency
{
    private readonly IRealTimeNotifier _realTimeNotifier;
    private readonly IUserNotificationManager _userNotificationManager;

    public WelcomeNotificationJob(
        IRealTimeNotifier realTimeNotifier,
        IUserNotificationManager userNotificationManager)
    {
        _realTimeNotifier = realTimeNotifier;
        _userNotificationManager = userNotificationManager;
    }

    [UnitOfWork]
    public override void Execute(UserIdentifier args)
    {
        var notifications = _userNotificationManager.GetUserNotifications(args);
        AsyncHelper.RunSync(() => _realTimeNotifier.SendNotificationsAsync(notifications.ToArray()));
    }
}

Don't forget to register data formatters for custom notification data types, on the client side:

abp.notifications.messageFormatters['CloudBaseLine.Notification.SendNotificationData'] = function (userNotification) {
    return userNotification.notification.data.message;
}