Utility function to reindex an Ohm model or populate a new added index

OhmUtils.rb

#
# Utility function to reindex an Ohm model or populate a new added index
# The functions is idempotent
# only use over 'index', not 'reference' indexes
#
# use:
#    class Table < Ohm::Model
#      include OhmUtils
#
#      ...
#      attribute :new_field
#      ...
#      ...
#      index :new_field
#      ...
#    end
#
#
#    Table.reindex(:new_field)
#
module OhmUtils

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

  module ClassMethods

    def reindex(indice)
      raise 'only indexes, no references' if indice.to_s[-3..-1] == '_id'
      raise 'index name not found' unless self.indices.include?(indice)

      self.all.each do |item|
        self.db.sadd "#{item.send(:model)}:indices:#{indice.to_s}:#{item.send(indice)}", item.id
      end

    end

  end

end

Nice try but I think it's simpler to just Class.all.map(&:save). This way Ohm will recreate the index for you.