Example controller action to ping Google Analytics on a direct file download

example.rb

require "uri"
require "net/http"

def download
  tracking_params = 
    {
      v:   1, 
      t:  'event', 
      ec: 'testing', 
      el: 'direct', 
      ea: 'download', 
      tid: GA_TRACKING_ID,
      uip: request.fullpath,
      dr:  request.headers["HTTP_REFERER"],
      cid: request.uuid,
      dl:  request.original_url,
      ua:  request.headers["User-Agent"]
    }

  x = Net::HTTP.post_form(URI.parse('http://www.google-analytics.com/collect'), tracking_params)
  send_file PATH_TO_FILE
end