requires_approval

Installation

To install, just add requires_approval to your Gemfile

# Gemfile
gem "requires_approval"

Activation

To activate, use the requires_approval_for method in your class definition

# app/models/user.rb
# 
# - first_name :string
# - last_name :string
# - birthday :date
# - created_at :datetime
# - updated_at :datetime

class User < ActiveRecord::Base
  requires_approval_for(:first_name, :last_name)
end

And create a migration that adds the necessary table and fields for your requires_approval model

# db/migrate/TIMESTAMP_add_user_versions.rb
def self.up
  User.prepare_tables_for_requires_approval
end

This does the equivalent of the the following

# Generated migration
def self.up
  create_table(:user_versions, :force => true) do |t|
    t.string(:first_name)
    t.string(:last_name)
    t.integer(:user_id)
    t.boolean(:is_approved)
    t.timestamps
  end
  add_index(:user_versions, [:user_id, :is_approved])

  # starts all new records out as frozen so they don't show up
  add_column(:users, :is_frozen, :boolean, :default => true)

end

Usage

The first_name and last_name methods are now delegated to the user’s latest_unapproved_version

u = User.new
u.first_name = "Dan"
u.first_name => nil
u.latest_unapproved_version.first_name => "Dan"
u.pending_changes => {
  "first_name" => {
    "was" => nil,
    "became" => "Dan"
  }
}
u.save

u.approve_attributes(:first_name)

u.first_name => "Dan"

# it created one version and approved it
u.versions.count => 1

# so it won't show up as an unapproved version
u.latest_unapproved_version => nil
u.pending_changes => {}

Denying attributes

You can also deny changes. If you do so, they just disappear from the latest_unapproved_version

u = User.create(:first_name => "X", :last_name => "Y")
u.approve_all_attributes

u.update_attribute(:first_name => "Dan")
u.pending_changes => {
  "first_name" => {
    "was" => "X",
    "became" => "Dan"
  }
}

u.deny_attributes(:first_name)
# no more changes
u.pending_changes => {}

FYI, this doesn’t actually remove the latest_unapproved_version, it just sets its values to be the same as the values in the parent record.

Contributing to requires_approval