Read EXIF data with a Dragonfly Analyzer

dragonfly.rb

require 'dragonfly'
require 'exif_analyser'

Dragonfly.app.configure do
  plugin ExifAnalyser.new
end

exif_analyser.rb

class ExifAnalyser
  def call(app, opts = {})
    # OS X: `brew install exiftool`
    # Ubuntu: `apt-get libimage-exiftool-perl`
    app.env[:exiftool_command] = opts[:exiftool_command] || 'exiftool'

    app.define :exif do |*_args|
      begin
        shell_eval { |path| "#{app.env[:exiftool_command]} -j #{path}" }
      rescue Dragonfly::Shell::CommandFailed => e
        Dragonfly.debug(e)
        nil
      end
    end
  end
end