20100525110237_add_small_and_large_thumbnail_sizes.rb

class AddSmallAndLargeThumbnailSizes < ActiveRecord::Migration
  # added inline RefinerySetting class
  class RefinerySetting < ActiveRecord::Base
    serialize :value # stores into YAML format
    def self.find_or_set(name, the_value, options={})
      # if the database is not up to date yet then it won't know about scoping..
      if self.column_names.include?('scoping')
        options = {:scoping => nil}.merge(options)
        find_or_create_by_name_and_scoping(:name => name.to_s, :value => the_value, :scoping => options[:scoping]).value
      else
        find_or_create_by_name(:name => name.to_s, :value => the_value).value
      end
    end

    def value=(new_value)
      # must convert to string if true or false supplied otherwise it becomes 0 or 1, unfortunately.
      new_value = new_value.to_s if ["trueclass","falseclass"].include?(new_value.class.to_s.downcase)
      self[:value] = new_value
    end

  end
  def self.up
    image_thumbnails = RefinerySetting.find_or_set(:image_thumbnails, {})
    image_thumbnails = image_thumbnails.dup.update({
      :small => '110x110>',
      :medium => '225x255>',
      :large => '450x450>'
    })
    setting = RefinerySetting.find_by_name('image_thumbnails')
    setting.value = image_thumbnails
    setting.save!
  end

  def self.down
    # don't really need to reverse it, it's not destructive if you run it multiple times.
  end
end

gistfile2.txt