Mongoid inline relation definitions. Ruby makes it so easy ❤️

inline_relations.rb

# Mongoid inline relation definitions. Ruby makes it so easy.
# (`data` is effectively just a shortcut for `inline_embed_one(:data)` there.)
#
# Yes, it would make sense to create separate models, but my case is different.
# This application is used to track events of other apps, such as purchase, and
# it makes *more* sense to embed all order-related data. Instead of having model
# overload for each event being tracked, I just define them inline.

class OrderEvent
  include Analyzing::Event

  event_for :shop

  data do
    field :total_price, type: Float
    field :currency, type: String
    field :total_price_usd, type: Float
    field :name, type: String

    inline_embed_one :customer do
      field :first_name, type: String
      field :last_name, type: String
      field :email, type: String
    end

    inline_embed_many :line_items do
      field :name, type: String
      field :title, type: String
      field :price, type: Float
      field :quantity, type: Integer
      field :sku, type: String
    end
  end
end

mongoid_ext.rb

module MongoidExt
  extend ActiveSupport::Concern

  module ClassMethods
    # Public: Define embeds_one inline. Class and actual relation will be
    # created automatically for you.
    #
    # rel_name - The Symbol relation name. Class name will be created based
    #            on it. Additionally it will be used to define "embeds_one"
    #            relation.
    # options  - The Hash "embeds_one" options.
    # block    - The block used to define Mongoid Document.
    #
    # Examples
    #
    #   class Some
    #     inline_embed_one :association_name do
    #       # embedded class definition here
    #     end
    #   end
    def inline_embed_one(rel_name, options = {}, &block)
      em_class_name = rel_name.to_s.camelize
      em_class = Class.new

      const_set(em_class_name, em_class)

      em_class.tap do |klass|
        klass.send(:include, Mongoid::Document)
        klass.send(:include, MongoidExt)
        klass.class_eval(&block)
      end

      embeds_one rel_name, options.merge(class_name: "#{name}::#{em_class_name}", autobuild: true)
    end


    # Public: Define embeds_many inline. Class and actual relation will be
    # created automatically for you.
    #
    # rel_name - The Symbol relation name. Class name will be created based
    #            on it. Additionally it will be used to define "embeds_many"
    #            relation.
    # options  - The Hash "embeds_many" options.
    # block    - The block used to define Mongoid Document.
    #
    # Examples
    #
    #   class Some
    #     inline_embed_many :association_name do
    #       # embedded class definition here
    #     end
    #   end
    def inline_embed_many(rel_name, options = {}, &block)
      em_class_name = rel_name.to_s.singularize.camelize
      em_class = Class.new

      const_set(em_class_name, em_class)

      em_class.tap do |klass|
        klass.send(:include, Mongoid::Document)
        klass.send(:include, MongoidExt)
        klass.class_eval(&block)
      end

      embeds_many rel_name, options.merge(class_name: "#{name}::#{em_class_name}")
    end
  end
end