/// <summary>
/// Registers a device in Azure Notification Hub.
/// </summary>
/// <remarks>
/// This first unregisters all existing user registrations
/// for the specified <paramref name="userId"/>.
/// </remarks>
/// <param name="userId">The user to subscribe.</param>
/// <param name="platform">The push notification platform.</param>
/// <param name="handle">Device handle.</param>
public virtual async Task RegisterAsync(Guid userId, PushNotificationPlatform platform, string handle)
{
// First clear the existing registration if it exists
if (await _notificationRegistrationRepository.ExistsAsync(userId))
{
var currentRegistration = await _notificationRegistrationRepository.GetAsync(userId);
await _notificationClient.UnregisterAsync(currentRegistration);
await _notificationRegistrationRepository.DeleteAsync(currentRegistration.Id);
}
// Create new registration and assign external id
var registration = await _notificationClient.RegisterAsync(new NotificationRegistration
{
Handle = handle,
PushNotificationPlatform = platform,
Id = userId
});
await _notificationRegistrationRepository.CreateAsync(registration);
}
/// <summary>
/// Notify a single user.
/// </summary>
/// <param name="context">The background context.</param>
public override async Task ExecuteAsync(BackgroundTaskContext context)
{
if (context is null)
{
throw new ArgumentNullException(nameof(context));
}
var notificationContext = (NotificationContext)context.Value;
// Check if we can reach the user that should be notified.
if (!await _notificationRegistrationRepository.ExistsAsync(notificationContext.NotifiedUserId))
{
_logger.LogTrace($"Couldn't get notification registration for user {notificationContext.NotifiedUserId}");
return;
}
var pushDetails = await _userRepository.GetPushDetailsAsync(notificationContext.NotifiedUserId);
await _notificationClient.SendNotificationAsync(pushDetails, notificationContext.Notification);
_logger.LogTrace($"Sent notification to user {notificationContext.NotifiedUserId}");
}