Carrierwave gem. How to rename uploaded image versions after recreating them?

Question

I have similar models as described in RailsCasts:

app/models/resident.rb:

class Resident < ActiveRecord::Base
  include PhotoConcern
end

app/models/employee.rb:

class Employee < ActiveRecord::Base
  include PhotoConcern
end

app/models/concerns/photo_concern.rb:

module PhotoConcern
  extend ActiveSupport::Concern

  included do
    mount_uploader :photo, PhotoUploader

    attr_accessor :photo_crop_x, :photo_crop_y, :photo_crop_w, :photo_crop_h

    after_save :crop_photo

    def crop_photo
      photo.recreate_versions! if photo_crop_x.present?
    end
  end
end

app/uploaders/photo_uploader.rb:

class PhotoUploader < CarrierWave::Uploader::Base
  include CarrierWave::MiniMagick

  storage :file

  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  version :cropped do
    process :crop
  end

  version :thumb, from_version: :cropped do
    process resize_to_fill: [100, 100]
  end

  version :avatar, from_version: :cropped do
    process resize_to_fill: [200, 200]
  end

  def crop
    return if model.photo_crop_x.blank?

    resize_to_limit(500, nil)
    resize_to_fit(500, nil)

    manipulate! do |img|
      size = model.photo_crop_w << 'x' << model.photo_crop_h
      offset = '+' << model.photo_crop_x << '+' << model.photo_crop_y

      img.crop("#{size}#{offset}")
      img
    end
  end
end

app/views/employees/show.slim

= image_tag (@employee.photo.present? ? @employee.photo.url(:avatar) : "client_#{@employee.sex}.png"), class: 'img-circle img-responsive'

I want to rename version files after cropping so my users don't struggle with a cache. It's described in CarrierWave wiki how to rename files but also it's written "In order to save the newly generated filename you have to call save! on the model after recreate_versions!".

How can I rename version files? I can't call save! in my Employee's after_save again because there are more hooks that shouldn't be called twice. Also, PhotoConcern is included into another class.

Related wiki articles:

• How to: Create random and unique filenames for all versioned files
• How to: Customize your version file names
• How to: Use a timestamp in file names

Answer 1

In order to save the newly generated filename you have to call save! on the model after recreate_versions!.

So I believe the answer to your doubts is included in the Carrierwave rubydocumentation

recreate_versions!(*versions) ⇒ Object

Recreate versions and reprocess them. This can be used to recreate versions if their parameters somehow have changed.

This method will store the *versions if they are not ommitted, otherwise the cached file will be stored.

# File 'lib/carrierwave/uploader/versions.rb', line 216

def recreate_versions!(*versions)
  # Some files could possibly not be stored on the local disk. This
  # doesn't play nicely with processing. Make sure that we're only
  # processing a cached file
  #
  # The call to store! will trigger the necessary callbacks to both
  # process this version and all sub-versions
  if versions.any?
    file = sanitized_file if !cached?
    # the file will be stored
    store_versions!(file, versions)
  else
    cache! if !cached?
    # If new_file is omitted, a previously cached file will be stored.
    store!
  end

What does store! do?

This is the rubydoc page about store!

store!(new_file = nil) ⇒ Object

Stores the file by passing it to this Uploader's storage engine. If new_file is omitted, a previously cached file will be stored

This method is included in your class PhotoUploader < CarrierWave::Uploader::Base and it uses with_callbacks to store your file using the callback :store. The callback triggers this method.

# File 'lib/carrierwave/uploader/store.rb', line 53

def store!(new_file=nil)
  cache!(new_file) if new_file && ((@cache_id != parent_cache_id) || @cache_id.nil?)
  if !cache_only and @file and @cache_id
    with_callbacks(:store, new_file) do
      new_file = storage.store!(@file)
      if delete_tmp_file_after_storage
        @file.delete unless move_to_store
        cache_storage.delete_dir!(cache_path(nil))
      end
      @file = new_file
      @cache_id = nil
    end
  end
end

What does store_versions! method do?

def store_versions!(new_file, versions=nil)
  if versions
    active = Hash[active_versions]
    versions.each { |v| active[v].try(:store!, new_file) } unless active.empty?
  else
    active_versions.each { |name, v| v.store!(new_file) }
  end
end

What are the Carrierwave callbacks and how to use them?

 after :store, :store_versions!

This question on SO explains and the wiki explain how callbacks work, by doing after :store, :my_method inside your version :low do block, you will execute my_method only on after :store callback (only for that version).

The :store callback corresponds to the execution of store!.

And what is the @filename attribute? How does recreate_versions! encode the filename?

@filename is defined with method filename in lib/carrierwave/uploader/store.rb

##
# Override this in your Uploader to change the filename.
#
# Be careful using record ids as filenames. If the filename is stored in the database
# the record id will be nil when the filename is set. Don't use record ids unless you
# understand this limitation.
#
# Do not use the version_name in the filename, as it will prevent versions from being
# loaded correctly.
#
# === Returns
#
# [String] a filename
#
def filename
  @filename
end

The guide from carrierwave suggest to use def filename to recreate unique filenames when recreating versions with recreate_version!.

This method does not save to the Database, to save to the database you need to calle save! on the appropriata Carrierwave callbacks, without breaking you Carrierwave GEM

I don't have the solution to this issue, but there is no documentation on this and we should start building it.