acts as most popular

• 1. acts_as_most_popular Wolfram Arnold RubyFocus

2. User Activity Tracking 3.

• Join between:

• • Viewable entity

• • • (user profile, image, post, video ...)

• • Activity tracking

• • • (viewings, comments, ratings ...)

4.

• Item.find(:all,

• :select => 'items.*,

• COUNT(*) AS viewing_count',

• :joins => :viewings,

• :limit => limit,

• :group => 'viewings.item_id',

• :order => 'viewing_count DESC')

5.

• acts_as_most_popular

6. acts_as_most_popular

• I want:

• • Most popular list from cache

• • Cache populared from database once

• • List automatically kept sorted & indexed in cache

• I need:

• • A caching framework

• • Ideally something common, transparent & flexible

7. Cache Money 8. Cache Money

• Transparent

• • find vs. get_cache

• Sequence

• • AR Cache SQL

• • find->get-> select

• • update-> set -> update

• • create-> add -> insert

• • destroy -> delete/expire -> delete

• Maintains indices automatically!

9. Cache Money

• Instance methods on models:

• • get

• • set

• • repository

• Automatic key handling

• • User.set(new_key)

• • ->Key: User:1/new_key

10. Solution 11. acts_as_most_popular

• Additional index, sorted by activity count

• • primed on first access

• • maintained via after_add, after_remove callbacks

12. Definition

• class Item < ActiveRecord::Base

• has_many :viewings

• acts_as_most_popular

• :activity_association => :viewings,

• :limit => 5,

• :db_finder_args =>

• { :select => 'item_id,

• COUNT(*) AS activity_count',

• :group => 'item_id' }

• end

13. Usage

• class StatsController < Application

• def most_popular

• @items = Item.most_popular

• end

• end

14. References

• Cache Money

• http://magicscalingsprinkles.wordpress.com/2008/12/11/introducing-cache-money/

• http://github.com/nkallen/cache-money/tree/master

• Images

• http://www.flickr.com/photos/flirtykitty/142229288/

• http://www.flickr.com/photos/jojakeman/2434236126/

15.

• Thank You!

• Wolfram Arnold

• RubyFocus

• [email_address]