+---
+
+Private Attachments
+-------------------
+If you want to place files behind a controller in order to perform validation you can.
+
+In your routes.rb file mount the paperclip engine with any path you'd like.
+Ex:
+ruby
+mount PaperclipPrivate::Engine => 'paperclip/'
+
+
+You have to register class names and their attachments with the whitelist registry. This can happen in the controller or in config/paperclip_private.rb
+The following example would whitelist the class PrivateAttachment's file:
+ruby
+require 'paperclip_private'
+PaperclipPrivate::Whitelist.register({PrivateAttachment: :file})
+
+You can also pass an array of names like {PrivateAttachment: [:file, :avatar]}.
+
+Then in your model add privacy: :private to the has_attached_file options. This can also accept a lambda that gets passed the attachment instance and expects back either :private or :public.
+Then add the method can_download_attachment?.
+The method can_download_attachment? gets passed the controller instance and the params and is expected to return true, false, or raise Paperclip::Errors::AccessDeniedError.
+The controller is passed so that methods like current_user can be run on it to get the user instance for validation puprposes. Duplicated params gets passed to do things like allow anyone if the style is :thumb or to only allow :original to paid users.
+Ex:
+```ruby
- has_attached_file :file, privacy: :private +
- def can_download_attachment?(controller, params)
- params[:style] == :thumb || (!controller.current_user.nil? && created_by == controller.current_user.id)
- end +```