Rack::GaTrack

Rack::GaTrack is a rack middleware that extracts Google Analytics Campaign params from the request. Specifically, it looks for a param utm_source in the request. If found, it creates a cookie with utm_source, utm_content, utm_term, utm_campaign,landing_page (path), referer, and time. Anytime utm_source is found in the request the cookie will be updated with the new Google Analytics Campaign params.

Let's say you want to track signups in your app from a specific campaign.

1. A user clicks a link on an external site that has your Google Analytics Campaign params in the request.
2. Rack::GaTrack finds utm_source param in the request and parses the other Google Analytics Campaign params from the request and saves them in a cookie.
3. If a user signs up now or in the future you can read the Google Analytics Campaign params from the env variables that Rack::GaTrack creates and save them to the created user record.

gem install rack-ga-track

Add the Rack::GaTrack to your application stack:

#Rails 4 in config/application.rb
class Application < Rails::Application
  config.middleware.use Rack::GaTrack
end

You can now access your Google Analytics Campaign params in env['ga_track.source'] env['ga_track.term'] env['ga_track.content'] env['ga_track.campaign'] env['ga_track.medium'] env['ga_track.referer'] env['ga_track.landing_page'] env['ga_track.time']

By default cookie is set for 30 days, you can extend time to live with :ttl option (default is 30 days).

#Rails 4 in config/application.rb
class Application < Rails::Application
  config.middleware.use Rack::GaTrack, :ttl => 3.months
end

The :domain option allows to customize cookie domain.

#Rails 4 in config/application.rb
class Application < Rails::Application
  config.middleware.use Rack::GaTrack, :domain => '.example.org'
end

Rack::GaTrack will set cookie on .example.org so it's accessible on www.example.org, app.example.org etc.