Thinking Sphinx extension to dynamically update Sphinx attributes

thinking_sphinx_updates.rb

# Simple interface to access sphinx dynamic attribute updates feature
# from ActiveRecord instances. Spinned off from http://panmind.org/
# (C) 2010 Panmind - Released under the terms of the Ruby license.
#
module PM
  module ThinkingSphinxUpdates
    def self.included(base)
      base.extend ClassMethods
    end

    def sphinx_update(key, value)
      return unless ThinkingSphinx.updates_enabled?

      key   = key.to_s
      value =
        case value
        when Date       then value.to_time.to_i
        when TrueClass  then 1
        when FalseClass then 0
        else value.to_i
        end

      self.class.core_index_names.each do |index_name|
        self.class.update_in_index index_name, sphinx_document_id, key, value
      end

      self.class.delta_index_names.each do |index_name|
        self.class.update_in_index index_name, sphinx_document_id, key, value
      end if self.class.delta_indexed_by_sphinx? && toggled_delta?

      return true

    rescue NoMethodError
      false
    end

    module ClassMethods
      def update_in_index(index, document_id, key, value)
        return unless ThinkingSphinx.sphinx_running? &&
          search_for_id(document_id, index)

        ThinkingSphinx::Configuration.instance.client.update(
          index, [key], {document_id => [value]}
        )
      end
    end
  end
end

ActiveRecord::Base.__send__ :include, PM::ThinkingSphinxUpdates