Migrate all Dragonfly images to Amazon S3 using rake task

dragonfly_tasks.rake

# This will move all images and other Dragonfly assets from your local server file system to Amazon S3.

namespace :dragonfly do
  task :migrate_to_s3 => :environment do
    # Adjust this line to meet your needs:
    { Product => [:image_uid, :other_uid], Page => :image_uid }.each do |klass, col|
      puts "Migrating #{klass.table_name}..."
      Array(col).each do |col|
        klass.where("#{col} != ''").find_each do |instance|
          begin
            old_uid = instance.send(col)
            puts "Migrating #{old_uid}..."
            old_path = Rails.root.join("public/system/dragonfly", Rails.env, old_uid)
            if File.exist?(old_path)
              new_uid = Dragonfly.app.store old_path
              instance.update_attributes col => new_uid
              FileUtils.rm_f old_path
              FileUtils.rm_f "#{old_path}.meta.yml"
              puts "Done"
            else
              puts "Already migrated"
            end
          rescue => e
            puts "Failed: #{e.message}"
          end
        end
      end
    end
  end
end