Rake Tasks to Clean Up Paperclip Attachment Directories

require 'fileutils'
include FileUtils
require 'pathname'

namespace :paperclip do
  desc "Remove Paperclip attachment directories with no entity"
  task :gc => :environment do
    current_trash = ((Pathname.new trash) + (Pathname.new Time.now.strftime("%Y-%m-%d.%H:%M:%S"))).cleanpath
    # This algorithm assumes that the attachments have a :path starting with "#{IMAGES_ROOT}/[class name]/:attachment/:id/"
    # This matches my setup, but may not match yours.
    # I wanted to get the attachment-dir-finding algorithm to be implementation-independent, but
    # it ended up being more time consuming than I wanted.
    # Change this to match your setup. If you get universal algorithm, please contact me. Thanks!
    klass = obtain_class.name.downcase
    klass_root = (Pathname.new "#{IMAGES_ROOT}/#{klass}").realpath
    Dir.glob("#{klass_root.to_s}/*/*/").each do |filename|
      path = Pathname.new filename
      name = path.basename.to_s
      if !name.starts_with? "."
        begin
          photo = Photo.find name
        rescue ActiveRecord::RecordNotFound 
          klass_trash = current_trash + (path.relative_path_from Pathname.new IMAGES_ROOT)
          mkdir_p klass_trash.to_s
          # p "#{path.to_s}, #{klass_trash.to_s}"
          mv path.to_s, klass_trash.to_s, :force => true, :verbose => true
        end
      end
    end
  end
  namespace :trash do
    desc "Empty the paperclip attachment trash"
    task :empty => :environment do
      rm_rf trash, :verbose => true
    end  
  end
end

def trash
  # Change this as appropriate
  File.expand_path "#{IMAGES_ROOT}/trash"
end