gistfile1.rb

module MultiClip
  def self.included( base )
    base.extend( ClassMethods )
  end

  module ClassMethods

    def has_attached_files( configs )

      after_initialize    :gen_subdirs
      before_save         :populate_legacy_columns

      # Setup paperclip logic for each provided config
      configs.each do |asset, config|
        # Initial paperclip init
        has_attached_file asset,
                    :storage        => :s3,
                    :s3_credentials => "#{Rails.root}/config/s3.yml",
                    :path           => "/media/:sub_path/:class/:attachment/:style.:filename",
                    :bucket         => 'FOOBUCKET'

        # Set validations
        validates_attachment_content_type asset, :content_type => config[:content_types]
        # Generate random filename
        before_post_process :randomize_file_names
      end

      # Store the configs for usage in callbacks
      self.instance_variable_set( "@_multiclip", configs )
    end
  end

  private

    # Requires sub_path column in included model
    def gen_subdirs
      self.sub_path ||= ran_subdirs
    end

    # Creates string for sub dir path eg: "01/16"
    def ran_subdirs
      rand_dirs = []
      2.times { |i| rand_dirs << rand(16).to_s.rjust(2, "0") }
      rand_dirs.join("/")
    end
    
    # Creates a alphanumeric random hash
    def randomize_file_names
      # Get configs
      self.class.instance_variable_get( "@_multiclip" ).each do |file_attr, config|
        # Check for an upload
        uploaded_filename = send( :"#{file_attr}_file_name" )
        if uploaded_filename
          # Extract files extension
          extension = File.extname( uploaded_filename ).downcase 
          # Rewrite filename
          self.send( file_attr ).instance_write( :file_name, "#{SecureRandom.hex(16)}#{extension}" )
        end
      end
    end

    # Loads up the legacy columns
    def populate_legacy_columns
      # Get configs
      self.class.instance_variable_get( "@_multiclip" ).each do |file_attr, config|
        # Make sure there is a legacy column and an upload set
        if self.respond_to?( :"#{config[:legacy_column]}=" ) && send( :"#{file_attr}_file_name" )
          path = send( file_attr ).path
          self.send( :"#{config[:legacy_column]}=", path[1..path.length] ) 
        end
      end
    end
end