From aac4d3eefb328b9186faa9a80234f9d76e95122e Mon Sep 17 00:00:00 2001
From: sbwalker <shaun.walker@siliqon.com>
Date: Mon, 26 Feb 2024 14:28:38 -0500
Subject: [PATCH] improve caching for static rendering

---
 Oqtane.Server/Extensions/CacheExtensions.cs   | 79 +++++++++++++++++++
 .../CacheInvalidationEventSubscriber.cs       |  3 +-
 Oqtane.Server/Services/SiteService.cs         | 12 ++-
 3 files changed, 89 insertions(+), 5 deletions(-)
 create mode 100644 Oqtane.Server/Extensions/CacheExtensions.cs

diff --git a/Oqtane.Server/Extensions/CacheExtensions.cs b/Oqtane.Server/Extensions/CacheExtensions.cs
new file mode 100644
index 000000000..1aff73f55
--- /dev/null
+++ b/Oqtane.Server/Extensions/CacheExtensions.cs
@@ -0,0 +1,79 @@
+using Microsoft.Extensions.Caching.Memory;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Oqtane.Extensions
+{
+    public static class CacheExtensions
+    {
+        private static string _cachekeys = "cachekeys";
+
+        public static TItem GetOrCreate<TItem>(this IMemoryCache cache, string key, Func<ICacheEntry, TItem> factory, bool track)
+        {
+            if (!cache.TryGetValue(key, out object result))
+            {
+                using ICacheEntry entry = cache.CreateEntry(key);
+                result = factory(entry);
+                entry.Value = result;
+
+                if (track)
+                {
+                    // track the cache key
+                    List<string> cachekeys;
+                    if (!cache.TryGetValue(_cachekeys, out cachekeys))
+                    {
+                        cachekeys = new List<string>();
+                    }
+                    if (!cachekeys.Contains(key))
+                    {
+                        cachekeys.Add(key);
+                        cache.Set(_cachekeys, cachekeys, new MemoryCacheEntryOptions { Priority = CacheItemPriority.NeverRemove });
+                    }
+                }
+            }
+
+            return (TItem)result;
+        }
+
+        public static void Remove(this IMemoryCache cache, string key, bool track)
+        {
+            List<string> cachekeys;
+
+            if (track && key.EndsWith("*"))
+            {
+                // wildcard cache key removal
+                var prefix = key.Substring(0, key.Length - 1);
+                if (cache.TryGetValue(_cachekeys, out cachekeys) && cachekeys.Any())
+                {
+                    for (var i = cachekeys.Count - 1; i >= 0; i--)
+                    {
+                        if (cachekeys[i].StartsWith(prefix))
+                        {
+                            cache.Remove(cachekeys[i]);
+                            cachekeys.RemoveAt(i);
+                        }
+                    }
+                    cache.Set(_cachekeys, cachekeys, new MemoryCacheEntryOptions { Priority = CacheItemPriority.NeverRemove });
+                }
+            }
+            else
+            {
+                cache.Remove(key);
+            }
+
+            // reconcile all tracked cache keys
+            if (track && cache.TryGetValue(_cachekeys, out cachekeys) && cachekeys.Any())
+            {
+                for (var i = cachekeys.Count - 1; i >= 0; i--)
+                {
+                    if (!cache.TryGetValue(cachekeys[i], out _))
+                    {
+                        cachekeys.RemoveAt(i);
+                    }
+                }
+                cache.Set(_cachekeys, cachekeys, new MemoryCacheEntryOptions { Priority = CacheItemPriority.NeverRemove });
+            }
+        }
+    }
+}
diff --git a/Oqtane.Server/Infrastructure/EventSubscribers/CacheInvalidationEventSubscriber.cs b/Oqtane.Server/Infrastructure/EventSubscribers/CacheInvalidationEventSubscriber.cs
index 5bf1fd146..4c9ee85dc 100644
--- a/Oqtane.Server/Infrastructure/EventSubscribers/CacheInvalidationEventSubscriber.cs
+++ b/Oqtane.Server/Infrastructure/EventSubscribers/CacheInvalidationEventSubscriber.cs
@@ -1,4 +1,5 @@
 using Microsoft.Extensions.Caching.Memory;
+using Oqtane.Extensions;
 using Oqtane.Models;
 using Oqtane.Shared;
 
@@ -18,7 +19,7 @@ public void EntityChanged(SyncEvent syncEvent)
             // when site entities change (ie. site, pages, modules, etc...) a site refresh event is raised and the site cache item needs to be refreshed
             if (syncEvent.EntityName == EntityNames.Site && syncEvent.Action == SyncEventActions.Refresh)
             {
-                _cache.Remove($"site:{syncEvent.TenantId}:{syncEvent.EntityId}");
+                _cache.Remove($"site:{syncEvent.TenantId}:{syncEvent.EntityId}*", true);
             }
 
             // when a site entity is updated the hosting model may have changed, so the client assemblies cache items need to be refreshed
diff --git a/Oqtane.Server/Services/SiteService.cs b/Oqtane.Server/Services/SiteService.cs
index c1b1a1abe..60804ce2c 100644
--- a/Oqtane.Server/Services/SiteService.cs
+++ b/Oqtane.Server/Services/SiteService.cs
@@ -65,15 +65,19 @@ public async Task<Site> GetSiteAsync(int siteId)
             Site site = null;
             if (!_accessor.HttpContext.User.Identity.IsAuthenticated)
             {
-                site = _cache.GetOrCreate($"site:{_accessor.HttpContext.GetAlias().SiteKey}", entry => 
+                site = _cache.GetOrCreate($"site:{_accessor.HttpContext.GetAlias().SiteKey}", entry =>
                 {
                     entry.SlidingExpiration = TimeSpan.FromMinutes(30);
                     return GetSite(siteId);
-                });
+                }, true);
             }
-            else
+            else // authenticated - cached per user
             {
-                site = GetSite(siteId);
+                site = _cache.GetOrCreate($"site:{_accessor.HttpContext.GetAlias().SiteKey}:{_accessor.HttpContext.User.UserId}", entry =>
+                {
+                    entry.SlidingExpiration = TimeSpan.FromMinutes(30);
+                    return GetSite(siteId);
+                }, true);
             }
             return await Task.Run(() => site);
         }