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(s) 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

# app/models/merit/badge_rules.rb
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

# Check granted badges
current_user.badges # Returns an array of badges

# Grant or remove manually
current_user.add_badge(badge.id)
current_user.rm_badge(badge.id)

# List 10 badge grants in the last month
Badge.last_granted

# List 20 badge grants in the last week
Badge.last_granted(since_date: 1.week.ago, limit: 20)

# Get related entries of a given badge (unreleased)
Badge.find(1).users

---

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

# app/models/merit/point_rules.rb
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]

# Check awarded points
current_user.points # Returns an integer

# Score manually
current_user.add_points(20, 'Optional log message')
current_user.substract_points(10)

# List top 10 scored users in the last month
Merit::Score.top_scored

# List top 25 scored lists in the last week
Merit::Score.top_scored(
  table_name: :lists,
  since_date: 1.week.ago,
  limit: 25
)

---

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

• Move level from meritable model into Sash
• ActivityLog should replace add_points log parameter
• Extract logging from Judge to an Observer. See http://www.rubytapas.com/episodes/21-Domain-Model-Events
• FIXMES and TODOS.