Pre-loading polymorphic associations for Atom feeds

app/controllers/accounts_controller.rb

@@ -7,7 +7,14 @@ class AccountsController < ApplicationController
   def show
     respond_to do |format|
       format.html { @statuses = @account.statuses.order('id desc').with_includes.with_counters.paginate(page: params[:page], per_page: 10)}
-      format.atom { @entries  = @account.stream_entries.order('id desc').with_includes.paginate_by_max_id(20, params[:max_id] || nil) }
+
+      format.atom do
+        @entries = @account.stream_entries.order('id desc').with_includes.paginate_by_max_id(20, params[:max_id] || nil)
+
+        ActiveRecord::Associations::Preloader.new.preload(@entries.select { |a| a.activity_type == 'Status' }, :mentioned_accounts, reblog: :account, thread: :account)
+        ActiveRecord::Associations::Preloader.new.preload(@entries.select { |a| a.activity_type == 'Favourite' }, status: [:account, :thread, :mentioned_accounts])
+        ActiveRecord::Associations::Preloader.new.preload(@entries.select { |a| a.activity_type == 'Follow' }, :target_account)
+      end
     end
   end
 

app/models/concerns/paginable.rb

@@ -0,0 +1,7 @@
+module Paginable
+  extend ActiveSupport::Concern
+
+  included do
+    scope :paginate_by_max_id, -> (limit, max_id) { order('id desc').limit(limit).where(max_id.nil? ? '1=1' : ['id < ?', max_id]) }
+  end
+end

app/models/status.rb

@@ -1,4 +1,6 @@
 class Status < ActiveRecord::Base
+  include Paginable
+
   belongs_to :account, inverse_of: :statuses
 
   belongs_to :thread, foreign_key: 'in_reply_to_id', class_name: 'Status', inverse_of: :replies
@@ -15,9 +17,8 @@ class Status < ActiveRecord::Base
   validates :uri, uniqueness: true, unless: 'local?'
   validates :text, presence: true, if: Proc.new { |s| s.local? && !s.reblog? }
 
-  scope :with_counters,      -> { select('statuses.*, (select count(r.id) from statuses as r where r.reblog_of_id = statuses.id) as reblogs_count, (select count(f.id) from favourites as f where f.status_id = statuses.id) as favourites_count') }
-  scope :with_includes,      -> { includes(:account, reblog: :account, thread: :account) }
-  scope :paginate_by_max_id, -> (limit, max_id) { order('id desc').limit(limit).where(max_id.nil? ? '1=1' : ['id < ?', max_id]) }
+  scope :with_counters, -> { select('statuses.*, (select count(r.id) from statuses as r where r.reblog_of_id = statuses.id) as reblogs_count, (select count(f.id) from favourites as f where f.status_id = statuses.id) as favourites_count') }
+  scope :with_includes, -> { includes(:account, :mentioned_accounts, reblog: [:account, :mentioned_accounts], thread: [:account, :mentioned_accounts]) }
 
   def local?
     self.uri.nil?

app/models/stream_entry.rb

@@ -1,11 +1,12 @@
 class StreamEntry < ActiveRecord::Base
+  include Paginable
+
   belongs_to :account, inverse_of: :stream_entries
   belongs_to :activity, polymorphic: true
 
   validates :account, :activity, presence: true
 
-  scope :with_includes,      -> { includes(:activity) }
-  scope :paginate_by_max_id, -> (limit, max_id) { order('id desc').limit(limit).where(max_id.nil? ? '1=1' : ['id < ?', max_id]) }
+  scope :with_includes, -> { includes(:activity) }
 
   def object_type
     orphaned? ? :activity : (targeted? ? :activity : self.activity.object_type)