Removing obsolete NotificationDbSaver hosted service

BTCPayServer/Services/Notifications/NotificationManager.cs

@@ -0,0 +1,87 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Security.Claims;
+using System.Text;
+using System.Threading.Tasks;
+using BTCPayServer.Data;
+using BTCPayServer.Models.NotificationViewModels;
+using Microsoft.AspNetCore.Identity;
+using Microsoft.Extensions.Caching.Memory;
+
+namespace BTCPayServer.Services.Notifications
+{
+    public class NotificationManager
+    {
+        private readonly ApplicationDbContextFactory _factory;
+        private readonly UserManager<ApplicationUser> _userManager;
+        private readonly IMemoryCache _memoryCache;
+
+        public NotificationManager(ApplicationDbContextFactory factory, UserManager<ApplicationUser> userManager, IMemoryCache memoryCache)
+        {
+            _factory = factory;
+            _userManager = userManager;
+            _memoryCache = memoryCache;
+        }
+
+        private const int _cacheExpiryMs = 5000;
+        public NotificationSummaryViewModel GetSummaryNotifications(ClaimsPrincipal user)
+        {
+            var userId = _userManager.GetUserId(user);
+
+            if (_memoryCache.TryGetValue<NotificationSummaryViewModel>(userId, out var obj))
+                return obj;
+
+            var resp = FetchNotificationsFromDb(userId);
+            _memoryCache.Set(userId, resp, new MemoryCacheEntryOptions().SetAbsoluteExpiration(TimeSpan.FromMilliseconds(_cacheExpiryMs)));
+
+            return resp;
+        }
+
+        private NotificationSummaryViewModel FetchNotificationsFromDb(string userId)
+        {
+            var resp = new NotificationSummaryViewModel();
+            using (var _db = _factory.CreateContext())
+            {
+                resp.UnseenCount = _db.Notifications
+                    .Where(a => a.ApplicationUserId == userId && !a.Seen)
+                    .Count();
+
+                if (resp.UnseenCount > 0)
+                {
+                    try
+                    {
+                        resp.Last5 = _db.Notifications
+                            .Where(a => a.ApplicationUserId == userId && !a.Seen)
+                            .OrderByDescending(a => a.Created)
+                            .Take(5)
+                            .Select(a => a.ViewModel())
+                            .ToList();
+                    }
+                    catch (System.IO.InvalidDataException)
+                    {
+                        // invalid notifications that are not pkuzipable, burn them all
+                        var notif = _db.Notifications.Where(a => a.ApplicationUserId == userId);
+                        _db.Notifications.RemoveRange(notif);
+                        _db.SaveChanges();
+
+                        resp.UnseenCount = 0;
+                        resp.Last5 = new List<NotificationViewModel>();
+                    }
+                }
+                else
+                {
+                    resp.Last5 = new List<NotificationViewModel>();
+                }
+            }
+
+            return resp;
+        }
+    }
+
+    public class NotificationSummaryViewModel
+    {
+        public int UnseenCount { get; set; }
+        public List<NotificationViewModel> Last5 { get; set; }
+    }
+}