From 7a21f9655249a20d6ff97807946ef4fdc02c5024 Mon Sep 17 00:00:00 2001
From: sbwalker <shaun.walker@siliqon.com>
Date: Wed, 31 May 2023 09:36:32 -0400
Subject: [PATCH] added IEventSubscriber amd EventDistributorHostedService to
 optimize event processing

---
 .../CacheInvalidationEventSubscriber.cs       | 24 ++++++
 .../CacheInvalidationHostedService.cs         | 45 -----------
 .../EventDistributorHostedService .cs         | 80 +++++++++++++++++++
 .../Interfaces/IEventSubscriber.cs            |  9 +++
 Oqtane.Server/Oqtane.Server.csproj            |  2 +-
 5 files changed, 114 insertions(+), 46 deletions(-)
 create mode 100644 Oqtane.Server/Infrastructure/EventSubscribers/CacheInvalidationEventSubscriber.cs
 delete mode 100644 Oqtane.Server/Infrastructure/HostedServices/CacheInvalidationHostedService.cs
 create mode 100644 Oqtane.Server/Infrastructure/HostedServices/EventDistributorHostedService .cs
 create mode 100644 Oqtane.Server/Infrastructure/Interfaces/IEventSubscriber.cs

diff --git a/Oqtane.Server/Infrastructure/EventSubscribers/CacheInvalidationEventSubscriber.cs b/Oqtane.Server/Infrastructure/EventSubscribers/CacheInvalidationEventSubscriber.cs
new file mode 100644
index 00000000..e608546d
--- /dev/null
+++ b/Oqtane.Server/Infrastructure/EventSubscribers/CacheInvalidationEventSubscriber.cs
@@ -0,0 +1,24 @@
+using Microsoft.Extensions.Caching.Memory;
+using Oqtane.Models;
+using Oqtane.Shared;
+
+namespace Oqtane.Infrastructure.EventSubscribers
+{
+    public class CacheInvalidationEventSubscriber : IEventSubscriber
+    {
+        private readonly IMemoryCache _cache;
+
+        public CacheInvalidationEventSubscriber(IMemoryCache cache)
+        {
+            _cache = cache;
+        }
+
+        public void EntityChanged(SyncEvent syncEvent)
+        {
+            if (syncEvent.EntityName == "Site" && syncEvent.Action == SyncEventActions.Refresh)
+            {
+                _cache.Remove($"site:{syncEvent.TenantId}:{syncEvent.EntityId}");
+            }
+        }
+    }
+}
diff --git a/Oqtane.Server/Infrastructure/HostedServices/CacheInvalidationHostedService.cs b/Oqtane.Server/Infrastructure/HostedServices/CacheInvalidationHostedService.cs
deleted file mode 100644
index 68eade75..00000000
--- a/Oqtane.Server/Infrastructure/HostedServices/CacheInvalidationHostedService.cs
+++ /dev/null
@@ -1,45 +0,0 @@
-using System.Threading.Tasks;
-using System.Threading;
-using Microsoft.Extensions.Hosting;
-using Oqtane.Models;
-using Microsoft.Extensions.Caching.Memory;
-using Oqtane.Shared;
-
-namespace Oqtane.Infrastructure
-{
-    public class CacheInvalidationHostedService : IHostedService
-    {
-        private readonly ISyncManager _syncManager;
-        private readonly IMemoryCache _cache;
-
-        public CacheInvalidationHostedService(ISyncManager syncManager, IMemoryCache cache)
-        {
-            _syncManager = syncManager;
-            _cache = cache;
-        }
-
-        void EntityChanged(object sender, SyncEvent e)
-        {
-            if (e.EntityName == "Site" && e.Action == SyncEventActions.Refresh)
-            {
-                _cache.Remove($"site:{e.TenantId}:{e.EntityId}");
-            }
-        }
-
-        public Task StartAsync(CancellationToken cancellationToken)
-        {
-            _syncManager.EntityChanged += EntityChanged;
-
-            return Task.CompletedTask;
-        }
-
-        public Task StopAsync(CancellationToken cancellationToken)
-        {
-            return Task.CompletedTask;
-        }
-        public void Dispose()
-        {
-            _syncManager.EntityChanged -= EntityChanged;
-        }
-    }
-}
diff --git a/Oqtane.Server/Infrastructure/HostedServices/EventDistributorHostedService .cs b/Oqtane.Server/Infrastructure/HostedServices/EventDistributorHostedService .cs
new file mode 100644
index 00000000..5c0ffa1c
--- /dev/null
+++ b/Oqtane.Server/Infrastructure/HostedServices/EventDistributorHostedService .cs	
@@ -0,0 +1,80 @@
+using System.Threading.Tasks;
+using System.Threading;
+using Microsoft.Extensions.Hosting;
+using Oqtane.Models;
+using System;
+using System.Reflection;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Caching.Memory;
+using System.Collections.Generic;
+using Microsoft.Extensions.Logging;
+using Oqtane.Shared;
+
+namespace Oqtane.Infrastructure
+{
+    public class EventDistributorHostedService : IHostedService
+    {
+        private readonly IServiceProvider _serviceProvider;
+        private readonly ISyncManager _syncManager;
+        private readonly IMemoryCache _cache;
+        private readonly ILogger<EventDistributorHostedService> _filelogger;
+
+        public EventDistributorHostedService(IServiceProvider serviceProvider, ISyncManager syncManager, IMemoryCache cache, ILogger<EventDistributorHostedService> filelogger)
+        {
+            _serviceProvider = serviceProvider;
+            _syncManager = syncManager;
+            _cache = cache;
+            _filelogger = filelogger;
+        }
+
+        void EntityChanged(object sender, SyncEvent syncEvent)
+        {
+            List<Type> eventSubscribers = _cache.GetOrCreate($"eventsubscribers", entry =>
+            {
+                eventSubscribers = new List<Type>();
+                var assemblies = AppDomain.CurrentDomain.GetOqtaneAssemblies();
+                foreach (Assembly assembly in assemblies)
+                {
+                    foreach (var type in assembly.GetTypes(typeof(IEventSubscriber)))
+                    {
+                        eventSubscribers.Add(type);
+                    }
+                }
+                entry.Priority = CacheItemPriority.NeverRemove;
+                return eventSubscribers;
+            });
+
+            foreach (var type in eventSubscribers)
+            {
+                try
+                {
+                    var obj = ActivatorUtilities.CreateInstance(_serviceProvider, type) as IEventSubscriber;
+                    if (obj != null)
+                    {
+                        obj.EntityChanged(syncEvent);
+                    }
+                }
+                catch (Exception ex)
+                {
+                    _filelogger.LogError(Utilities.LogMessage(this, $"Error In EventSubscriber {type.AssemblyQualifiedName} - {ex.Message}"));
+                }
+            }
+        }
+
+        public Task StartAsync(CancellationToken cancellationToken)
+        {
+            _syncManager.EntityChanged += EntityChanged;
+
+            return Task.CompletedTask;
+        }
+
+        public Task StopAsync(CancellationToken cancellationToken)
+        {
+            return Task.CompletedTask;
+        }
+        public void Dispose()
+        {
+            _syncManager.EntityChanged -= EntityChanged;
+        }
+    }
+}
diff --git a/Oqtane.Server/Infrastructure/Interfaces/IEventSubscriber.cs b/Oqtane.Server/Infrastructure/Interfaces/IEventSubscriber.cs
new file mode 100644
index 00000000..11d154bf
--- /dev/null
+++ b/Oqtane.Server/Infrastructure/Interfaces/IEventSubscriber.cs
@@ -0,0 +1,9 @@
+using Oqtane.Models;
+
+namespace Oqtane.Infrastructure
+{
+    public interface IEventSubscriber
+    {
+        void EntityChanged(SyncEvent syncEvent);
+    }
+}
diff --git a/Oqtane.Server/Oqtane.Server.csproj b/Oqtane.Server/Oqtane.Server.csproj
index 21142b27..612d59a2 100644
--- a/Oqtane.Server/Oqtane.Server.csproj
+++ b/Oqtane.Server/Oqtane.Server.csproj
@@ -61,6 +61,6 @@
   </Target>
   <ItemGroup>
     <!-- extends watching group to include *.dll files and exclude the ones cause an infinite loop -->
-    <Watch Include="**\*.dll" Exclude="**\Microsoft.EntityFrameworkCore.*.dll;**\Oqtane.Database.*.dll;"/>
+    <Watch Include="**\*.dll" Exclude="**\Microsoft.EntityFrameworkCore.*.dll;**\Oqtane.Database.*.dll;" />
   </ItemGroup>
 </Project>