From f96277192bd49fe02c319438eec7587984f126b0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Halil=20=C4=B0brahim=20Kalkan?= <hi_kalkan@yahoo.com>
Date: Tue, 4 Oct 2022 09:05:08 +0300
Subject: [PATCH] Double remove from cache if there is an active UOW.

---
 .../Entities/Caching/EntityCacheBase.cs       | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/framework/src/Volo.Abp.Ddd.Domain/Volo/Abp/Domain/Entities/Caching/EntityCacheBase.cs b/framework/src/Volo.Abp.Ddd.Domain/Volo/Abp/Domain/Entities/Caching/EntityCacheBase.cs
index 3f3b5fa42d..7e5b17b687 100644
--- a/framework/src/Volo.Abp.Ddd.Domain/Volo/Abp/Domain/Entities/Caching/EntityCacheBase.cs
+++ b/framework/src/Volo.Abp.Ddd.Domain/Volo/Abp/Domain/Entities/Caching/EntityCacheBase.cs
@@ -3,6 +3,7 @@ using Volo.Abp.Caching;
 using Volo.Abp.Domain.Entities.Events;
 using Volo.Abp.Domain.Repositories;
 using Volo.Abp.EventBus;
+using Volo.Abp.Uow;
 
 namespace Volo.Abp.Domain.Entities.Caching;
 
@@ -14,13 +15,16 @@ public abstract class EntityCacheBase<TEntity, TEntityCacheItem, TKey> :
 {
     protected IReadOnlyRepository<TEntity, TKey> Repository { get; }
     protected IDistributedCache<TEntityCacheItem, TKey> Cache { get; }
+    protected IUnitOfWorkManager UnitOfWorkManager { get; }
 
     protected EntityCacheBase(
         IReadOnlyRepository<TEntity, TKey> repository,
-        IDistributedCache<TEntityCacheItem, TKey> cache)
+        IDistributedCache<TEntityCacheItem, TKey> cache,
+        IUnitOfWorkManager unitOfWorkManager)
     {
         Repository = repository;
         Cache = cache;
+        UnitOfWorkManager = unitOfWorkManager;
     }
     
     public virtual async Task<TEntityCacheItem> FindAsync(TKey id)
@@ -48,6 +52,19 @@ public abstract class EntityCacheBase<TEntity, TEntityCacheItem, TKey> :
             return;
         }
         
+        /* Why we are using double remove:
+         * First Cache.RemoveAsync drops the cache item in a unit of work.
+         * Some other application / thread may read the value from database and put it to the cache again
+         * before the UOW completes.
+         * The second Cache.RemoveAsync drops the cache item after the database transaction is complete.
+         * Only the second Cache.RemoveAsync may not be enough if the application crashes just after the UOW completes.
+         */
+        
         await Cache.RemoveAsync(eventData.Entity.Id);
+        
+        if(UnitOfWorkManager.Current != null)
+        {
+            await Cache.RemoveAsync(eventData.Entity.Id, considerUow: true);
+        }
     }
 }
\ No newline at end of file