active_record_extension.rb

module Extension::ActiveRecordExtension
  extend ActiveSupport::Concern

  included do
    # (参考)
    # OR operator in WHERE clause with Arel in Rails 4.2
    # http://stackoverflow.com/questions/27627390/or-operator-in-where-clause-with-arel-in-rails-4-2
    #
    # ActiveRecord::QueryMethods::WhereChain
    # https://github.com/rails/rails/blob/v4.2.1/activerecord/lib/active_record/relation/query_methods.rb
    ActiveRecord::QueryMethods::WhereChain.include(Module.new do
      def or(*scopes)
        bind_values  = []
        where_values = []

        scopes.each do |scope|
          temp_scope = scope.is_a?(Hash) ? @scope.model.where(scope) : scope
          where_values << temp_scope.arel_table.grouping(temp_scope.where_values.inject(:and))
          bind_values  += temp_scope.bind_values
        end

        @scope.where_values += [where_values.inject(:or)]
        @scope.bind_values  += bind_values
        @scope
      end
    end)
  end
end