File versioning in Ruby on Rails with Paperclip & acts_as_versioned

This short tutorial shows you how to manage file versioning in Ruby on Rails by making Paperclip falling in love with acts_as_versioned. Paperclip & acts_as_versioned are plug-ins for Ruby on Rails: Paperclip manages file upload, acts_as_versioned enables models versioning.

Patch Paperclip

I patched Paperclip to keep old files when a new revision is saved. A fork of Paperclip adding the option keep_old_files to make Paperclip working with acts_as_versioned is available here: http://github.com/pcreux/paperclip/tree/master. You can install it running:

script/plugin install pcreux_paperclip

Update your Paperclip + acts_as_versioned model

Just three things to do:

1. update the url & path to store your files by ‘version’
2. set the option keep_old_files to true when a new version get saved
3. add the interpolation of :version

class Document < ActiveRecord::Base
  has_attached_file :attachment,
                    :url => "/system/attachments/:id/:version/:style/:basename.:extension",
                    :path => ":rails_root/public/system/attachments/:id/:version/:style/:basename.:extension",
                    :keep_old_files => :version_condition_met?
                    
  acts_as_versioned
  
  Paperclip.interpolates :version do |attachement, style|
    attachement.instance.version.to_s
  end
end

I hope it helps. :)