Mixpanel module as mixin for Activerecord classes

mixpanel.rb

require 'active_support/core_ext'

module Mixpanel
  module ClassMethods
    def mixpanel(*names)
      # Defines both class and instance accessors for class attributes.
      class_attribute :mp_attrs
      self.mp_attrs = names
    end
  end

  # instance methods
  def to_mixpanel
    self.mp_attrs.reduce({}) {|memo, attr|
      target = send(attr)
      memo[attr] = target.respond_to?(:item_value) ? target.item_value : target
      memo
    }
  end

  def self.included(base)
    base.extend ClassMethods
  end
end

class Foo < Object
  include Mixpanel

  attr_accessor :name

  mixpanel :name

  def to_s
    "Foo"
  end
end

class Bar < Object
  include Mixpanel

  attr_accessor :desc, :name

  mixpanel :name, :desc

  def to_s
    "Bar"
  end
end

class Foo2 < Foo
  attr_accessor :name2

  mixpanel :name2
end

t = Foo.new
t.name = "Foo"
p t.mp_attrs
p t
p t.to_mixpanel

t = Bar.new
t.name = "Bar"
t.desc = "Bar"

p t.mp_attrs
p t
p t.to_mixpanel

t3 = Foo2.new
t3.name2 = "Foo 2"
p t3.mp_attrs

Change to class_attribute as subclasses will be able to define their own mp_attrs without affecting base class