added counter cache for photos on StatusMessage

Gemfile.lock

@@ -128,6 +128,7 @@ GEM
       uuidtools
     childprocess (0.2.3)
       ffi (~> 1.0.6)
+    chronic (0.6.6)
     client_side_validations (3.1.3)
     cloudfiles (1.4.10)
       mime-types (>= 1.16)
@@ -424,6 +425,9 @@ GEM
     webmock (1.6.2)
       addressable (>= 2.2.2)
       crack (>= 0.1.7)
+    whenever (0.7.0)
+      activesupport (>= 2.3.4)
+      chronic (~> 0.6.3)
     will_paginate (3.0.2)
     xpath (0.1.4)
       nokogiri (~> 1.3)
@@ -515,5 +519,6 @@ DEPENDENCIES
   typhoeus
   vanna!
   webmock
+  whenever
   will_paginate (= 3.0.2)
   yard

app/models/photo.rb

@@ -17,15 +17,20 @@ class Photo < ActiveRecord::Base
   xml_attr :text
   xml_attr :status_message_guid
 
-  belongs_to :status_message, :foreign_key => :status_message_guid, :primary_key => :guid
+  belongs_to :status_message, :foreign_key => :status_message_guid, :primary_key => :guid, :counter_cache => :photos_count
 
   attr_accessible :text, :pending
   validate :ownership_of_status_message
 
   before_destroy :ensure_user_picture
   after_destroy :clear_empty_status_message
+
   after_create :queue_processing_job
 
+  after_save do
+    self.status_message.update_photos_counter if status_message
+  end
+
   def clear_empty_status_message
     if self.status_message_guid && self.status_message.text_and_photos_blank?
       self.status_message.destroy

app/models/status_message.rb

@@ -178,13 +178,18 @@ class StatusMessage < Post
   def queue_gather_oembed_data
     Resque.enqueue(Jobs::GatherOEmbedData, self.id, self.oembed_url)
   end 
-  
+
   def contains_oembed_url_in_text?
     require 'uri'
     urls = URI.extract(self.raw_message, ['http', 'https'])
     self.oembed_url = urls.find{|url| ENDPOINT_HOSTS_STRING.match(URI.parse(url).host)}
   end
 
+  def update_photos_counter
+    StatusMessage.where(:id => self.id).
+      update_all(:photos_count => self.photos.count)
+  end
+
   protected
   def presence_of_content
     if text_and_photos_blank?

db/migrate/20110911213207_counter_cache_on_post_comments.rb

@@ -1,5 +1,6 @@
 class CounterCacheOnPostComments < ActiveRecord::Migration
   class Post < ActiveRecord::Base; end
+
   def self.up
     add_column :posts, :comments_count, :integer, :default => 0
     execute <<SQL if Post.count > 0

db/migrate/20111217042006_add_photo_counter_cache_to_post.rb

@@ -0,0 +1,15 @@
+class AddPhotoCounterCacheToPost < ActiveRecord::Migration
+  class Post < ActiveRecord::Base; end
+
+  def self.up
+    add_column :posts, :photos_count, :integer, :default => 0
+    execute <<SQL if Post.count > 0
+      UPDATE posts
+      SET photos_count = (SELECT COUNT(*) FROM photos WHERE photos.status_message_guid = posts.guid)
+SQL
+  end
+
+  def self.down
+    remove_column :posts, :photos_count
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20111207233503) do
+ActiveRecord::Schema.define(:version => 20111217042006) do
 
   create_table "account_deletions", :force => true do |t|
     t.string  "diaspora_handle"
@@ -314,6 +314,7 @@ ActiveRecord::Schema.define(:version => 20111207233503) do
     t.integer  "likes_count",                         :default => 0
     t.integer  "comments_count",                      :default => 0
     t.integer  "o_embed_cache_id"
+    t.integer  "photos_count",                        :default => 0
   end
 
   add_index "posts", ["author_id", "root_guid"], :name => "index_posts_on_author_id_and_root_guid", :unique => true