PLEASE READ:

There is a new gem for various tracking and analytics services, which includes all the functionality of rack-google-analytics. So if you need more than just google, checkout the rack-tracker gem.

Rack google Analytics

Simple Rack middleware to help injecting the Google Analytics tracking code in your website.

This middleware injects the Google Analytics tracking code into the correct place of any request only when the response's Content-Type header contains html (therefore text/html and similar).

Usage

Gemfile

gem 'rack-google-analytics'

Sinatra

## app.rb
use Rack::GoogleAnalytics, :tracker => 'UA-xxxxxx-x'

Padrino

## app/app.rb
use Rack::GoogleAnalytics, :tracker => 'UA-xxxxxx-x'

Rails 3.X and Rails 4.X

## application.rb:
config.middleware.use Rack::GoogleAnalytics, :tracker => 'UA-xxxxxx-x'

Options

:anonymize_ip - sets the tracker to remove the last octet from all IP addresses, see https://developers.google.com/analytics/devguides/collection/gajs/methods/gaJSApi_gat?hl=de#_gat._anonymizeIp for details.
:domain - sets the domain name for the GATC cookies. Defaults to auto.
:site_speed_sample_rate - Defines a new sample set size for Site Speed data collection, see https://developers.google.com/analytics/devguides/collection/gajs/methods/gaJSApiBasicConfiguration?hl=de#_gat.GA_Tracker_._setSiteSpeedSampleRate
:adjusted_bounce_rate_timeouts - An array of times in seconds that the tracker will use to set timeouts for adjusted bounce rate tracking. See http://analytics.blogspot.ca/2012/07/tracking-adjusted-bounce-rate-in-google.html for details.
:enhanced_link_attribution - Enables Enhanced Link Attribution.
:advertising - Enables Display Features.
:ecommerce - Enables Ecommerce Tracking.

If you are not sure what's best, go with the defaults, and read here if you should opt-out.

Event Tracking

In your application controller, you may track an event. For example:

ga_track_event("Users", "Login", "Standard")

See https://developers.google.com/analytics/devguides/collection/analyticsjs/events

Custom Push

In your application controller, you may push arbritrary data. For example:

ga_push("_addItem", "ID", "SKU")

Dynamic Tracking Code

You may instead define your tracking code as a lambda taking the Rack environment, so that you may set the tracking code dynamically based upon information in the Rack environment. For example:

config.middleware.use Rack::GoogleAnalytics, :tracker => lambda { |env|
        return env[:site_ga].tracker if env[:site_ga]
}

Special use case: Event tracking only

If you already set up your Google Analytics analytics.js tracker object with pageview tracking in your templates/frontend (inside the <head>), the only thing you might want to use the rack-google-analytics middleware for is to track server-side events which you can't properly track in the forntend. In that case simply use the middleware without specifying the :tracker option, then it will only render the event tracking code (ga('send', hitType: 'event', ..)) and nothing else.

config.middleware.use Rack::GoogleAnalytics

Thread Safety

This middleware should be thread safe. Although my experience in such areas is limited, having taken the advice of those with more experience; I defer the call to a shallow copy of the environment, if this is of consequence to you please review the implementation.

Note on Patches/Pull Requests

Fork the project.
Make your feature addition or bug fix.
Add tests for it. This is important so I don't break it in a future version unintentionally.
Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
Send me a pull request. Bonus points for topic branches.

Copyright

Copyright (c) 2009-2012 Lee Hambley. See LICENSE for details. With thanks to Ralph von der Heyden and Simon Schoeters - And the biggest hand to Arthur Chiu for the huge work that went into the massive 0.9 re-factor.