Merit Gem: Reputation rules (badges, points and rankings) for Rails applications

Installation

1. Add gem 'merit' to your Gemfile
2. Run rails g merit:install
3. Run rails g merit MODEL_NAME (e.g. user)
4. Run rake db:migrate
5. Define badges you will use in config/initializers/merit.rb
6. Configure reputation rules for your application in app/models/merit/*

---

Defining badge rules

You may give badges to any resource on your application if some condition holds. Badges may have levels, and may be temporary. Define rules on app/models/merit/badge_rules.rb:

grant_on accepts:

• 'controller#action' string (similar to Rails routes)
• :badge for badge name
• :level for badge level
• :to method name over target_object which obtains object to badge
• :model_name (string) define controller's name if it differs from the model (like RegistrationsController for User model).
• :multiple (boolean) badge may be granted multiple times
• :temporary (boolean) if the receiver had the badge but the condition doesn't hold anymore, remove it. false by default (badges are kept forever).
• &block
  • empty (always grants)
  • a block which evaluates to boolean (recieves target object as parameter)
  • a block with a hash composed of methods to run on the target object with expected values

Examples

grant_on 'comments#vote', :badge => 'relevant-commenter', :to => :user do |comment|
  comment.votes.count == 5
end

grant_on ['users#create', 'users#update'], :badge => 'autobiographer', :temporary => true do |user|
  user.name.present? && user.address.present?
end

Grant manually

You may also grant badges "by hand" (optionally multiple times):

Badge.find(3).grant_to(current_user, :allow_multiple => true)

Similarly you can take back badges that have been granted:

Badge.find(3).delete_from(current_user)

---

Defining point rules

Points are given to "meritable" resources on actions-triggered, either to the action user or to the method(s) defined in the :to option. Define rules on app/models/merit/point_rules.rb:

score accepts:

• :on action as string or array of strings (similar to Rails routes)
• :to method(s) to send to the target_object (who should be scored?)
• &block
  • empty (always scores)
  • a block which evaluates to boolean (recieves target object as parameter)

Examples

score 10, :to => :post_creator, :on => 'comments#create' do |comment|
  comment.title.present?
end

score 20, :on => [
  'comments#create',
  'photos#create'
]

score 15, :on => 'reviews#create', :to => [:reviewer, :reviewed]

Score manually

You may also change user points "by hand":

current_user.add_points(20, 'Optional log message')

current_user.substract_points(10)

---

Defining rank rules

5 stars is a common ranking use case. They are not given at specified actions like badges, you should define a cron job to test if ranks are to be granted.

Define rules on app/models/merit/rank_rules.rb:

set_rank accepts:

• :level ranking level (greater is better)
• :to model or scope to check if new rankings apply
• :level_name attribute name (default is empty and results in 'level' attribute, if set it's appended like 'level_#{level_name}')

Check for rules on a rake task executed in background like:

task :cron => :environment do
  Merit::RankRules.new.check_rank_rules
end

Examples

set_rank :level => 2, :to => Commiter.active do |commiter|
  commiter.branches > 1 && commiter.followers >= 10
end

set_rank :level => 3, :to => Commiter.active do |commiter|
  commiter.branches > 2 && commiter.followers >= 20
end

---

To-do list

• target_object should be configurable (now it's singularized controller name)
• Should namespace app/models into Merit module.
• :value parameter (for star voting for example) should be configurable (depends on params[:value] on the controller).