With paperclip, how can I change the image location to a “:parent_model_id/:id” folder format?

Question

Given that I have a Listing model that has many images and each image has one attachment, how can I have the

Answer 1

Ah, I finally figured it out. I needed to use Paperclip.interpolates.

This post from thoughtbot sort of explains it, but it's slightly outdated.

First, create a config/initializers/paperclip.rb file and add the following:

Paperclip.interpolates :listing_id do |attachment, style|
  attachment.instance.listing_id # or whatever you've named your User's login/username/etc. attribute
end

Which means that now in my images model I can refer to :listing_id like so:

class Image < ActiveRecord::Base
    belongs_to :listing #Rails ActiveRecord Relation. An image belongs to a post. 

    # paperclip data
    has_attached_file :photo, :styles => { :medium => "300x300>", :thumb => "100x100>" }, 
    :url => "/system/:attachment/:listing_id/:id/:style_:filename" #location where to output the server. :LISTING_ID is defined in config/initializers/paperclib.rb

end

PS: You need to restart the server before the changes in initializers.rb take effect.