Merit

Merit adds reputation behavior to Rails apps in the form of Badges, Points, and Rankings.

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Table of Contents

Installation

  1. Add gem 'merit' to your Gemfile
  2. Run rails g merit:install. This creates several migrations.
  3. Run rails g merit MODEL_NAME (e.g. user). This creates a migration and adds has_merit to MODEL_NAME.
  4. Run rake db:migrate
  5. Define badges in config/initializers/merit.rb. You can also define ORM: :active_record (default) or :mongoid.
  6. Configure reputation rules for your application in app/models/merit/*

Badges

Creating Badges

Create badges in config/initializers/merit.rb

Merit::Badge.create! takes a hash describing the badge: * :id integer (required) * :name this is how you reference the badge (required) * :level (optional) * :description (optional) * :custom_fields hash of anything else you want associated with the badge (optional)

Example

Merit::Badge.create!(
  id: 1,
  name: "year-member",
  description: "Active member for a year",
  custom_fields: { difficulty: :silver }
)

Defining Rules

Badges can be automatically given to any resource in your application based on rules and conditions you create. Badges can also have levels, and be permanent or temporary (A temporary badge is revoked when the conditions of the badge are no longer met).

Badge rules / conditions are defined in app/models/merit/badge_rules.rb initialize block by calling grant_on with the following parameters:

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? && user.email?
end

Other Actions

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

Displaying Badges

Meritable models have a badges method which returns an array of associated badges:

<ul>
<% current_user.badges.each do |badge| %>
  <li><%= badge.name %></li>
<% end %>
</ul>

Points

Defining 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:

Examples

# app/models/merit/point_rules.rb
score 10, to: :post_creator, on: 'comments#create', category: 'comment_activity' do |comment|
  comment.title.present?
end

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

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

proc = lambda { |photo| PhotoPointsCalculator.calculate_score_for(photo) }
score proc, on: 'photos#create'

Other Actions

# Score manually
current_user.add_points(20, category: 'Optional category')
current_user.subtract_points(10, category: 'Optional category')
# Query awarded points since a given date
score_points = current_user.score_points(category: 'Optional category')
score_points.where("created_at > '#{1.month.ago}'").sum(:num_points)

Displaying Points

Meritable models have a points method which returns an integer:

<%= current_user.points(category: 'Optional category') %>

If category left empty, it will return the sum of points for every category.

<%= current_user.points %>

Rankings

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

Defining Rules

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

set_rank accepts:

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: Committer.active do |committer|
  committer.branches > 1 && committer.followers >= 10
end

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

Displaying Rankings

<%= current_user.level %>

Getting Notifications

You can get observers notified any time merit changes reputation in your application.

It needs to implement the update method, which receives as parameter the following hash:

Example code (add your observer to app/models or app/observers):

# reputation_change_observer.rb
class ReputationChangeObserver
  def update(changed_data)
    description = changed_data[:description]

    # If user is your meritable model, you can query for it doing:
    user = User.where(sash_id: changed_data[:sash_id]).first

    # When did it happened:
    datetime = changed_data[:granted_at]
  end
end
# In `config/initializers/merit.rb`
config.add_observer 'ReputationChangeObserver'

Uninstalling Merit

  1. Run rails d merit:install
  2. Run rails d merit MODEL_NAME (e.g. user)
  3. Run rails g merit:remove MODEL_NAME (e.g. user)
  4. Run rake db:migrate
  5. Remove merit from your Gemfile