PaperClip and Rails 2.1

These are a couple of quick tips for using PaperClip 2.1.2 and Rails 2.1. I don't know if there is a difference with other version combinations.

For security reasons, you may want to store your attachment out of the public directory:

class DocumentVersion < ActiveRecord::Base
  belongs_to :document
  has_attached_file :version,
                    :path => ":rails_root/documents/:class/:id/:style/:basename.:extension"
  ...
end

To access this:

send_file(@document_version.version.path)

I found the directory defaults a little odd, so if you want to specify it:

class Picture < ActiveRecord::Base
  has_attached_file :image,
                    :path => ":rails_root/public/images/pictures/:class/:id/:style/:basename.:extension",
                    :url => "/images/pictures/:class/:id/:style/:basename.:extension"
end

Note the :url parameter. If you set the path, you must set the :url accordingly. Of course, this only matters if you are going to call the url method.