public async Task <SubscriptionUsers> Subscribe(SubscriptionUsers subscription)
{
// We're storing at most one subscription per user, so delete old ones.
// Alternatively, you could let the user register multiple subscriptions from different browsers/devices.
var userId = GetUserId();
var oldSubscriptions = _context.SubscriptionUsers.Where(e => e.UserId == userId);
_context.SubscriptionUsers.RemoveRange(oldSubscriptions);
// Store new subscription
subscription.UserId = userId;
_context.SubscriptionUsers.Attach(subscription);
await _context.SaveChangesAsync();
return(subscription);
}
public async Task SubscribeToNotifications(SubscriptionUsers subscription)
{
var response = await httpClient.PutAsJsonAsync("subscriptions/subscribe", subscription);
response.EnsureSuccessStatusCode();
}
private static async Task TrackAndSendNotificationsAsync(NotificationUsers notification, SubscriptionUsers subscription)
{
// In a realistic case, some other backend process would track
// order delivery progress and send us notifications when it
// changes. Since we don't have any such process here, fake it.
await Task.Delay(NotificationWithStatus.PreparationDuration);
await SendNotificationAsync(notification, subscription, "Your notification has been dispatched!");
await Task.Delay(NotificationWithStatus.DeliveryDuration);
await SendNotificationAsync(notification, subscription, "Your notification is now delivered. Enjoy!");
}
private static async Task SendNotificationAsync(NotificationUsers notification, SubscriptionUsers subscription, string message)
{
// For a real application, generate your own
var publicKey = "BNJd4yM_aOPtUZqI7IG8XWJNIHcg3iHHdmrWgv-6jLxMXySWeX7fRsl-xZcwj59GjYDWAwf4oc8UevQuViWgyPg";
var privateKey = "W4Y49mec2mx6KoJ2I1yHgl0GoButX25SX1Sr2-GDl1I";
var pushSubscription = new PushSubscription(subscription.Url, subscription.P256dh, subscription.Auth);
var vapidDetails = new VapidDetails("mailto:<*****@*****.**>", publicKey, privateKey);
var webPushClient = new WebPushClient();
try
{
var payload = JsonSerializer.Serialize(new
{
message,
url = $"mynotifications/{notification.NotificationId}",
});
await webPushClient.SendNotificationAsync(pushSubscription, payload, vapidDetails);
}
catch (Exception ex)
{
Console.Error.WriteLine("Error sending push notification: " + ex.Message);
}
}
