How can I set paperclip's storage mechanism based on the current Rails environment?

Question

I have a rails application that has multiple models with paperclip attachments that are all uploaded to S3. This app also has a large test suite that is run quite often. Th

Answer 1

After playing around with it for a while, I came up with a module that does what I want.

Inside app/models/shared/attachment_helper.rb:

module Shared
  module AttachmentHelper

    def self.included(base)
      base.extend ClassMethods
    end

    module ClassMethods
      def has_attachment(name, options = {})

        # generates a string containing the singular model name and the pluralized attachment name.
        # Examples: "user_avatars" or "asset_uploads" or "message_previews"
        attachment_owner    = self.table_name.singularize
        attachment_folder   = "#{attachment_owner}_#{name.to_s.pluralize}"

        # we want to create a path for the upload that looks like:
        # message_previews/00/11/22/001122deadbeef/thumbnail.png
        attachment_path     = "#{attachment_folder}/:uuid_partition/:uuid/:style.:extension"

        if Rails.env.production?
          options[:path]            ||= attachment_path
          options[:storage]         ||= :s3
          options[:url]             ||= ':s3_authenticated_url'
          options[:s3_credentials]  ||= File.join(Rails.root, 'config', 's3.yml')
          options[:s3_permissions]  ||= 'private'
          options[:s3_protocol]     ||= 'https'
        else
          # For local Dev/Test envs, use the default filesystem, but separate the environments
          # into different folders, so you can delete test files without breaking dev files.
          options[:path]  ||= ":rails_root/public/system/attachments/#{Rails.env}/#{attachment_path}"
          options[:url]   ||= "/system/attachments/#{Rails.env}/#{attachment_path}"
        end

        # pass things off to paperclip.
        has_attached_file name, options
      end
    end
  end
end

(Note: I'm using some custom paperclip interpolations above, like :uuid_partition, :uuid and :s3_authenticated_url. You'll need to modify things as needed for your particular application)

Now, for every model that has paperclip attachments, you just have to include this shared module, and call the has_attachment method (instead of paperclip's has_attached_file)

An example model file: app/models/user.rb:

class User < ActiveRecord::Base
  include Shared::AttachmentHelper  
  has_attachment :avatar, :styles => { :thumbnail => "100x100>" }
end

With this in place, you'll have files saved to the following locations, depending on your environment:

Development:

RAILS_ROOT + public/attachments/development/user_avatars/aa/bb/cc/aabbccddeeff/thumbnail.jpg

Test:

RAILS_ROOT + public/attachments/test/user_avatars/aa/bb/cc/aabbccddeeff/thumbnail.jpg

Production:

https://s3.amazonaws.com/your-bucket-name/user_avatars/aa/bb/cc/aabbccddeeff/thumbnail.jpg

This does exactly what I'm looking for, hopefully it'll prove useful to someone else too. :)

-John