add file download event

Oqtane.Server/Infrastructure/HostedServices/CacheInvalidationHostedService.cs

@@ -0,0 +1,45 @@
+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;
+        }
+    }
+}