Preventing Paperclip from deleting/overwriting attachments on update

Question

I\'m having a hard time figuring out how to prevent Paperclip from deleting the old version of an attachment (image).

I have a model, Site, which has an attachment,

Answer 1

Because attachments are defined at the class level, Paperclip interpolates the symbols in your strings using it's own interpolation library. You can create your own interpolations using this library.

I would add a field to the model called attachment_version or something similar, and then increment this version number each time the file is changed. Then, create an interpolation for it in an initializer file:

Paperclip.interpolates :version do |attachment, style|
  attachment.instance.attachment_version
end

Now you can use :version in your strings:

class Model < ActiveRecord::Base
  has_attached_file :something, :path => " :rails_root/public/somethings/etc/:version.:extension"
end

See the wiki documentation for more information.

[Update]

After some digging around (see the comments to this answer), I've come to the conclusion that Paperclip will still delete the old attachment due to code that's called in Paperclip::Atachment#attach. Probably the best way to deal with this is to create a new storage engine based on Paperclip::Storage::Filesystem and overwrite #flush_deletes. Note that there is no way in that method to tell if a file is being queued for deletion because of the model it belongs to being deleted or a new file is being uploaded in its place.