Papertrail and Carrierwave

Question

I have a model that use both: Carrierwave for store photos, and PaperTrail for versioning.

I also configured Carrierwave for store diferent files when upda

Answer 1

Here is a bit updated version of monkeypatch from @rabusmar, I use it for rails 4.2.0 and paper_trail 4.0.0.beta2, in /config/initializers/paper_trail.rb.

The second method override is required if you use optional object_changes column for versions. It works in a bit strange way for carrierwave + fog if you override filename in uploader, old value will be from cloud and new one from local filename, but in my case it's ok.

Also I have not checked if it works correctly when you restore old version.

module PaperTrail
  module Model
    module InstanceMethods
      private

      # override to keep only basename for carrierwave attributes in object hash
      def item_before_change
        previous = self.dup
        # `dup` clears timestamps so we add them back.
        all_timestamp_attributes.each do |column|
          if self.class.column_names.include?(column.to_s) and not send("#{column}_was").nil?
            previous[column] = send("#{column}_was")
          end
        end
        enums = previous.respond_to?(:defined_enums) ? previous.defined_enums : {}
        previous.tap do |prev|
          prev.id = id # `dup` clears the `id` so we add that back
          changed_attributes.select { |k,v| self.class.column_names.include?(k) }.each do |attr, before|
            if defined?(CarrierWave::Uploader::Base) && before.is_a?(CarrierWave::Uploader::Base)
              prev.send(:write_attribute, attr, before.url && File.basename(before.url))
            else
              before = enums[attr][before] if enums[attr]
              prev[attr] = before
            end
          end
        end
      end

      # override to keep only basename for carrierwave attributes in object_changes hash
      def changes_for_paper_trail
        _changes = changes.delete_if { |k,v| !notably_changed.include?(k) }
        if PaperTrail.serialized_attributes?
          self.class.serialize_attribute_changes(_changes)
        end
        if defined?(CarrierWave::Uploader::Base)
          Hash[
              _changes.to_hash.map do |k, values|
                [k, values.map { |value| value.is_a?(CarrierWave::Uploader::Base) ? value.url && File.basename(value.url) : value }]
              end
          ]
        else
          _changes.to_hash
        end
      end

    end
  end
end

Answer 2

You can override item_before_change on your versioned model so you don't call the uploader accesor directly and use write_attribute instead. Alternatively, since you might want to do that for several models, you can monkey-patch the method directly, like this:

module PaperTrail
  module Model
    module InstanceMethods
      private
        def item_before_change
          previous = self.dup
          # `dup` clears timestamps so we add them back.
          all_timestamp_attributes.each do |column|
            previous[column] = send(column) if respond_to?(column) && !send(column).nil?
          end
          previous.tap do |prev|
            prev.id = id
            changed_attributes.each do |attr, before|
              if defined?(CarrierWave::Uploader::Base) && before.is_a?(CarrierWave::Uploader::Base)
                prev.send(:write_attribute, attr, before.url && File.basename(before.url))
              else
                prev[attr] = before
              end
            end
          end
        end
    end
  end
end

Not sure if it's the best solution, but it seems to work.

Answer 3

Adding @beardedd's comment as an answer because I think this is a better way to handle the problem.

Name your database columns something like picture_filename and then in your model mount the uploader using:

class User < ActiveRecord::Base has_paper_trail mount_uploader :picture, PictureUploader, mount_on: :picture_filename end

You still use the user.picture.url attribute to access your model but PaperTrail will store revisions under picture_filename.