Export ActiveRecord Tables to CSV

exporter.rb

require 'csv'

module Exporter
  DEFAULT_EXPORT_TABLES = [ Invoice, InvoiceItem, Item, Merchant, Transaction, User ]
  DESTINATION_FOLDER = "tmp/"

  def self.included(klass)
    klass.extend ClassLevelMethods
  end

  def self.export_tables_to_csv(tables = DEFAULT_EXPORT_TABLES)
    tables.each &:export_table_to_csv
  end

  def data
    self.class.column_names.map { |column| send(column) }
  end

  module ClassLevelMethods
    def export_table_to_csv
      CSV.open(filename_for_class, "w") do |output_file|
        output_file << column_names
        data.each{ |row| output_file << row }
      end
    end

    def filename_for_class
      [DESTINATION_FOLDER, to_s.pluralize.underscore, '.csv'].join
    end

    def data
      all.map(&:data)
    end
  end
end

class ActiveRecord::Base
  include Exporter
end

Tested, just needed two minor fixes.

The Module having three jobs here (hosting class methods, defining instance methods for the including class, defining class methods for the including class) is kind of awesome and, at the same time, makes me feel a bit uncomfortable. Is that unreasonable?