From 0040569fb2f501281af46ef33de7eeb3d8f220f2 Mon Sep 17 00:00:00 2001
From: EngincanV <enginveske@gmail.com>
Date: Wed, 7 Apr 2021 17:54:58 +0300
Subject: [PATCH] Blogging: Publish PostChangedEvent for cache invalidation

---
 .../Volo/Blogging/Posts/PostAppService.cs     | 20 +++++++++++++++++--
 .../Blogging/Posts/PostCacheInvalidator.cs    |  8 +++-----
 .../Volo/Blogging/Posts/PostChangedEvent.cs   |  9 +++++++++
 3 files changed, 30 insertions(+), 7 deletions(-)
 create mode 100644 modules/blogging/src/Volo.Blogging.Domain/Volo/Blogging/Posts/PostChangedEvent.cs

diff --git a/modules/blogging/src/Volo.Blogging.Application/Volo/Blogging/Posts/PostAppService.cs b/modules/blogging/src/Volo.Blogging.Application/Volo/Blogging/Posts/PostAppService.cs
index d804e7a004..7b42d25f84 100644
--- a/modules/blogging/src/Volo.Blogging.Application/Volo/Blogging/Posts/PostAppService.cs
+++ b/modules/blogging/src/Volo.Blogging.Application/Volo/Blogging/Posts/PostAppService.cs
@@ -6,6 +6,7 @@ using System.Collections.Generic;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.Extensions.Caching.Distributed;
 using Volo.Abp.Caching;
+using Volo.Abp.EventBus.Local;
 using Volo.Blogging.Comments;
 using Volo.Blogging.Tagging;
 using Volo.Blogging.Tagging.Dtos;
@@ -21,13 +22,15 @@ namespace Volo.Blogging.Posts
         private readonly ITagRepository _tagRepository;
         private readonly ICommentRepository _commentRepository;
         private readonly IDistributedCache<List<PostCacheItem>> _postsCache;
+        private readonly ILocalEventBus _localEventBus;
 
         public PostAppService(
             IPostRepository postRepository,
             ITagRepository tagRepository,
             ICommentRepository commentRepository,
             IBlogUserLookupService userLookupService,
-            IDistributedCache<List<PostCacheItem>> postsCache
+            IDistributedCache<List<PostCacheItem>> postsCache,
+            ILocalEventBus localEventBus
         )
         {
             UserLookupService = userLookupService;
@@ -35,6 +38,7 @@ namespace Volo.Blogging.Posts
             _tagRepository = tagRepository;
             _commentRepository = commentRepository;
             _postsCache = postsCache;
+            _localEventBus = localEventBus;
         }
         
         public async Task<ListResultDto<PostWithDetailsDto>> GetListByBlogIdAndTagName(Guid id, string tagName)
@@ -84,7 +88,7 @@ namespace Volo.Blogging.Posts
                 async () => await GetTimeOrderedPostsAsync(blogId),
                 () => new DistributedCacheEntryOptions
                 {
-                    AbsoluteExpiration = DateTimeOffset.Now.AddHours(6)
+                    AbsoluteExpiration = DateTimeOffset.Now.AddHours(1)
                 }
             );
 
@@ -155,6 +159,7 @@ namespace Volo.Blogging.Posts
             await _commentRepository.DeleteOfPost(id);
 
             await _postRepository.DeleteAsync(id);
+            await PublishPostChangedEventAsync(post.BlogId);
         }
 
         [Authorize(BloggingPermissions.Posts.Update)]
@@ -176,6 +181,7 @@ namespace Volo.Blogging.Posts
 
             var tagList = SplitTags(input.Tags);
             await SaveTags(tagList, post);
+            await PublishPostChangedEventAsync(post.BlogId);
 
             return ObjectMapper.Map<Post, PostWithDetailsDto>(post);
         }
@@ -201,6 +207,7 @@ namespace Volo.Blogging.Posts
 
             var tagList = SplitTags(input.Tags);
             await SaveTags(tagList, post);
+            await PublishPostChangedEventAsync(post.BlogId);
 
             return ObjectMapper.Map<Post, PostWithDetailsDto>(post);
         }
@@ -297,5 +304,14 @@ namespace Volo.Blogging.Posts
 
             return Task.FromResult(filteredPostDtos);
         }
+
+        private async Task PublishPostChangedEventAsync(Guid blogId)
+        {
+            await _localEventBus.PublishAsync(
+                new PostChangedEvent
+                {
+                    BlogId = blogId
+                });
+        }
     }
 }
diff --git a/modules/blogging/src/Volo.Blogging.Domain/Volo/Blogging/Posts/PostCacheInvalidator.cs b/modules/blogging/src/Volo.Blogging.Domain/Volo/Blogging/Posts/PostCacheInvalidator.cs
index abbfcd8d88..e18e6de23b 100644
--- a/modules/blogging/src/Volo.Blogging.Domain/Volo/Blogging/Posts/PostCacheInvalidator.cs
+++ b/modules/blogging/src/Volo.Blogging.Domain/Volo/Blogging/Posts/PostCacheInvalidator.cs
@@ -2,12 +2,11 @@
 using System.Threading.Tasks;
 using Volo.Abp.Caching;
 using Volo.Abp.DependencyInjection;
-using Volo.Abp.Domain.Entities.Events;
 using Volo.Abp.EventBus;
 
 namespace Volo.Blogging.Posts
 {
-    public class PostCacheInvalidator : ILocalEventHandler<EntityChangedEventData<Post>>, ITransientDependency
+    public class PostCacheInvalidator : ILocalEventHandler<PostChangedEvent>, ITransientDependency
     {
         protected IDistributedCache<List<PostCacheItem>> Cache { get; }
 
@@ -16,10 +15,9 @@ namespace Volo.Blogging.Posts
             Cache = cache;
         }
         
-        public virtual async Task HandleEventAsync(EntityChangedEventData<Post> eventData)
+        public virtual async Task HandleEventAsync(PostChangedEvent post)
         {
-            var cacheKey = eventData.Entity.BlogId.ToString();
-            await Cache.RemoveAsync(cacheKey);
+            await Cache.RemoveAsync(post.BlogId.ToString());
         }
     }
 }
\ No newline at end of file
diff --git a/modules/blogging/src/Volo.Blogging.Domain/Volo/Blogging/Posts/PostChangedEvent.cs b/modules/blogging/src/Volo.Blogging.Domain/Volo/Blogging/Posts/PostChangedEvent.cs
new file mode 100644
index 0000000000..c32ed92224
--- /dev/null
+++ b/modules/blogging/src/Volo.Blogging.Domain/Volo/Blogging/Posts/PostChangedEvent.cs
@@ -0,0 +1,9 @@
+using System;
+
+namespace Volo.Blogging.Posts
+{
+    public class PostChangedEvent
+    {
+        public Guid BlogId { get; set; }
+    }
+}
\ No newline at end of file