Add counter cache for article followers

Victor Costa
1 parent d0472735
Showing 2 changed files with 24 additions and 1 deletions Show diff stats
app/models/article_follower.rb
db/migrate/20150909091347_add_followers_count_to_article.rb
 class ArticleFollower < ActiveRecord::Base
   attr_accessible :article_id, :person_id, :since
-  belongs_to :article
+  belongs_to :article, :counter_cache => :followers_count
   belongs_to :person
+
+  after_create do |article_follower|
+    ArticleFollower.update_cache_counter(:followers_count, article_follower.article, 1)
+  end
+
+  after_destroy do |article_follower|
+    ArticleFollower.update_cache_counter(:followers_count, article_follower.article, -1)
+  end
 end
@@ -0,0 +1,15 @@
+class AddFollowersCountToArticle < ActiveRecord::Migration
+
+  def self.up
+    add_column :articles, :followers_count, :integer, :default => 0
+    add_column :article_versions, :followers_count, :integer
+
+    execute "update articles set followers_count = (select count(*) from article_followers where article_followers.article_id = articles.id)"
+  end
+
+  def self.down
+    remove_column :article_versions, :followers_count
+    remove_column :articles, :followers_count
+  end
+
+end
1	1	class ArticleFollower < ActiveRecord::Base
2	2	attr_accessible :article_id, :person_id, :since
3		- belongs_to :article
	3	+ belongs_to :article, :counter_cache => :followers_count
4	4	belongs_to :person
	5	+
	6	+ after_create do \|article_follower\|
	7	+ ArticleFollower.update_cache_counter(:followers_count, article_follower.article, 1)
	8	+ end
	9	+
	10	+ after_destroy do \|article_follower\|
	11	+ ArticleFollower.update_cache_counter(:followers_count, article_follower.article, -1)
	12	+ end
5	13	end
...	...
...	...	@@ -0,0 +1,15 @@
	1	+class AddFollowersCountToArticle < ActiveRecord::Migration
	2	+
	3	+ def self.up
	4	+ add_column :articles, :followers_count, :integer, :default => 0
	5	+ add_column :article_versions, :followers_count, :integer
	6	+
	7	+ execute "update articles set followers_count = (select count(*) from article_followers where article_followers.article_id = articles.id)"
	8	+ end
	9	+
	10	+ def self.down
	11	+ remove_column :article_versions, :followers_count
	12	+ remove_column :articles, :followers_count
	13	+ end
	14	+
	15	+end
...	...