A Fix for Paperclip Rake Task (paperclip:refresh:thumbnails) - Compatible with ActiveRecord and Mongoid

paperclip.rake

module PaperclipMongoidPatch
  class << self 
    def obtain_class
      class_name = ENV['CLASS'] || ENV['class']
      raise "Must specify CLASS" unless class_name
      @klass = Object.const_get(class_name)
    end

    def obtain_attachments
      name = ENV['ATTACHMENT'] || ENV['attachment']
      raise "Class #{@klass.name} has no attachments specified" unless @klass.respond_to?(:attachment_definitions)
      if !name.blank? && @klass.attachment_definitions.keys.include?(name)
        [ name ]
      else
        @klass.attachment_definitions.keys
      end
    end

    def for_all_attachments
      klass = obtain_class
      names = obtain_attachments
      ids   = if defined?(Mongoid)
                klass.only(:id).map { |user| user.id }
              elsif defined?(ActiveRecord)
                klass.all(:select => 'id').map { |user| user.id }
              else
                klass.all.map { |user| user.id }
              end

      ids.each do |id|
        instance = klass.find(id)
        names.each do |name|
          result = if instance.send("#{ name }?")
                     yield(instance, name)
                   else
                     true
                   end
          print result ? "." : "x";
        end
      end
      puts " Done."
    end
  end
end

namespace :paperclip do
  desc "Refreshes both metadata and thumbnails."
  task :refresh => ["paperclip:refresh:metadata", "paperclip:refresh:thumbnails"]

  namespace :refresh do
    desc "Regenerates thumbnails for a given CLASS (and optional ATTACHMENT)."
    task :thumbnails => :environment do
      errors = []
      PaperclipMongoidPatch::for_all_attachments do |instance, name|
        result = instance.send(name).reprocess!
        errors << [instance.id, instance.errors] unless instance.errors.blank?
        result
      end
      errors.each{|e| puts "#{e.first}: #{e.last.full_messages.inspect}" }
    end

    desc "Regenerates content_type/size metadata for a given CLASS (and optional ATTACHMENT)."
    task :metadata => :environment do
      PaperclipMongoidPatch::for_all_attachments do |instance, name|
        if file = instance.send(name).to_file
          instance.send("#{name}_file_name=", instance.send("#{name}_file_name").strip)
          instance.send("#{name}_content_type=", file.content_type.strip)
          instance.send("#{name}_file_size=", file.size) if instance.respond_to?("#{name}_file_size")
          instance.save(:validate => false)
        else
          true
        end
      end
    end
  end

  desc "Cleans out invalid attachments. Useful after you've added new validations."
  task :clean => :environment do
    PaperclipMongoidPatch::for_all_attachments do |instance, name|
      instance.send(name).send(:validate)
      if instance.send(name).valid?
        true
      else
        instance.send("#{name}=", nil)
        instance.save
      end
    end
  end
end