photomix/app/uploaders/file_uploader.rb

# encoding: utf-8

class FileUploader < CarrierWave::Uploader::Base

  # Include RMagick or ImageScience support
       include CarrierWave::RMagick
  #     include CarrierWave::ImageScience

  # Choose what kind of storage to use for this uploader
  #storage :file
  if ENV['S3_KEY']
    storage :s3
    
    def cache_dir
      "#{RAILS_ROOT}/tmp/uploads" if ENV['HEROKU'] == 'true'
    end
  else
    storage :file
  end

  # 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
    #{}"uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
    "uploads/files/#{model.album.path}"
  end

  # Provide a default URL as a default if there hasn't been a file uploaded
  #     def default_url
  #       "/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

  # Create different versions of your uploaded files
       version :collection do
         process :resize_to_fill => [200, 200]
         def store_dir
           "uploads/thumbs/#{model.album.path}"
         end
       end
       version :album do
         process :resize_to_fill => [100, 100]
         def store_dir
           "uploads/thumbs/#{model.album.path}"
         end
       end
       version :preview do
         process :resize_to_fit => [210, 210]
         def store_dir
           "uploads/thumbs/#{model.album.path}"
         end
       end
       version :single do
         process :resize_to_limit => [950, 950]
         def store_dir
           "uploads/thumbs/#{model.album.path}"
         end
       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
  #       %w(jpg jpeg gif png)
  #     end

  # Override the filename of the uploaded files
  #     def filename
  #       "something.jpg" if original_filename
  #     end

end