fab-manager/app/uploaders/project_cao_uploader.rb

class ProjectCaoUploader < CarrierWave::Uploader::Base
  # Include RMagick or MiniMagick support:
  # include CarrierWave::RMagick
  #include CarrierWave::MiniMagick
  include UploadHelper

  # Choose what kind of storage to use for this uploader:
  storage :file
  after :remove, :delete_empty_dirs
  # storage :fog

  # Override the directory where uploaded files will be stored.
  # This is a sensible default for uploaders that are meant to be mounted:

  def store_dir
    "#{base_store_dir}/#{model.id}"
  end

  def base_store_dir
    "uploads/#{model.class.to_s.underscore}"
  end

  # Provide a default URL as a default if there hasn't been a file uploaded:
  # def default_url
  #   # For Rails 3.1+ asset pipeline compatibility:
  #   # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))
  #
  #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
  # end

  # Process files as they are uploaded:
  # process :scale => [200, 300]
  #
  # def scale(width, height)
  #   # do something
  # end


  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
  def extension_white_list
    ENV['ALLOWED_EXTENSIONS'].split(' ')
  end

  # Override the filename of the uploaded files:
  # Avoid using model.id or version_name here, see uploader/store.rb for details.
  #def filename
    #"avatar.#{file.extension}" if original_filename
  #end
end