typhoeus.rb

require 'typhoeus'

def download_typhoeus(urls, concurrency)
  hydra = Typhoeus::Hydra.new(max_concurrency: concurrency)

  urls.each do |url|
    request = Typhoeus::Request.new url
    request.on_complete do |response|
      write_file url, response.body
    end
    hydra.queue request
  end

  hydra.run
end