From 45f092a49d317182741886c806c296085a9a8a91 Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <tgx_world@hotmail.com>
Date: Mon, 3 Sep 2018 09:51:35 +0800
Subject: [PATCH] Extract `badge_posts` view management logic into a service
 object.

* Avoid defininig a global constant and method.

Fixes https://github.com/discourse/discourse/pull/6318
---
 db/fixtures/000_delayed_drops.rb | 36 +++--------------------------
 lib/badge_posts_view_manager.rb  | 39 ++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 33 deletions(-)
 create mode 100644 lib/badge_posts_view_manager.rb

diff --git a/db/fixtures/000_delayed_drops.rb b/db/fixtures/000_delayed_drops.rb
index 5b976a7bdb1..a46bfed42ea 100644
--- a/db/fixtures/000_delayed_drops.rb
+++ b/db/fixtures/000_delayed_drops.rb
@@ -2,6 +2,7 @@
 
 require 'migration/table_dropper'
 require 'migration/column_dropper'
+require 'badge_posts_view_manager'
 
 Migration::ColumnDropper.drop(
   table: 'user_profiles',
@@ -74,20 +75,6 @@ Migration::ColumnDropper.drop(
   }
 )
 
-VIEW_NAME = "badge_posts".freeze
-
-def badge_posts_view_exists?
-  sql = <<~SQL
-  SELECT 1
-  FROM pg_catalog.pg_views
-  WHERE schemaname
-  IN ('public')
-  AND viewname = '#{VIEW_NAME}';
-  SQL
-
-  DB.exec(sql) == 1
-end
-
 Migration::ColumnDropper.drop(
   table: 'posts',
   after_migration: 'DropVoteCountFromTopicsAndPosts',
@@ -96,27 +83,10 @@ Migration::ColumnDropper.drop(
   },
   on_drop: ->() {
     STDERR.puts "Removing superflous post columns!"
-
-    DB.exec("DROP VIEW #{VIEW_NAME}")
-    raise "Failed to drop '#{VIEW_NAME}' view" if badge_posts_view_exists?
+    BadgePostsViewManager.drop!
   },
   after_drop: -> () {
-    sql = <<~SQL
-    CREATE VIEW #{VIEW_NAME} AS
-    SELECT p.*
-    FROM posts p
-    JOIN topics t ON t.id = p.topic_id
-    JOIN categories c ON c.id = t.category_id
-    WHERE c.allow_badges AND
-          p.deleted_at IS NULL AND
-          t.deleted_at IS NULL AND
-          NOT c.read_restricted AND
-          t.visible AND
-          p.post_type IN (1,2,3)
-    SQL
-
-    DB.exec(sql)
-    raise "Failed to create '#{VIEW_NAME}' view" unless badge_posts_view_exists?
+    BadgePostsViewManager.create!
   }
 )
 
diff --git a/lib/badge_posts_view_manager.rb b/lib/badge_posts_view_manager.rb
new file mode 100644
index 00000000000..8ec2138f9fd
--- /dev/null
+++ b/lib/badge_posts_view_manager.rb
@@ -0,0 +1,39 @@
+class BadgePostsViewManager
+  VIEW_NAME = "badge_posts".freeze
+
+  def self.create!
+    sql = <<~SQL
+    CREATE VIEW #{VIEW_NAME} AS
+    SELECT p.*
+    FROM posts p
+    JOIN topics t ON t.id = p.topic_id
+    JOIN categories c ON c.id = t.category_id
+    WHERE c.allow_badges AND
+          p.deleted_at IS NULL AND
+          t.deleted_at IS NULL AND
+          NOT c.read_restricted AND
+          t.visible AND
+          p.post_type IN (1,2,3)
+    SQL
+
+    DB.exec(sql)
+    raise "Failed to create '#{VIEW_NAME}' view" unless badge_posts_view_exists?
+  end
+
+  def self.drop!
+    DB.exec("DROP VIEW #{VIEW_NAME}")
+    raise "Failed to drop '#{VIEW_NAME}' view" if badge_posts_view_exists?
+  end
+
+  def self.badge_posts_view_exists?
+    sql = <<~SQL
+    SELECT 1
+    FROM pg_catalog.pg_views
+    WHERE schemaname
+    IN ('public')
+    AND viewname = '#{VIEW_NAME}';
+    SQL
+
+    DB.exec(sql) == 1
+  end
+end