google_analytics.rb

class Rack::Tracker::GoogleAnalytics < Rack::Tracker::Handler

  self.allowed_tracker_options = [:cookie_domain, :user_id]

  class Send < OpenStruct
    def initialize(attrs = {})
      attrs.reverse_merge!(type: 'event')
      super
    end

    def write
      ['send', event].to_json.gsub(/\[|\]/, '')
    end

    def event
      { hitType: self.type }.merge(attributes.stringify_values).compact
    end

    def attributes
      Hash[to_h.slice(:category, :action, :label, :value).map { |k,v| [self.type.to_s + k.to_s.capitalize, v] }]
    end
  end

  class EnhancedEcommerce < OpenStruct
    def write
      hash = self.to_h
      label = hash[:label]
      attributes = hash.except(:label, :type).compact.stringify_values

      [
        "ec:#{self.type}",
        label,
        attributes.empty? ? nil : attributes
      ].compact.to_json.gsub(/\[|\]/, '')
    end
  end

  class Ecommerce < OpenStruct
    def write
      attributes = self.to_h.except(:type).compact.stringify_values

      [
        "ecommerce:#{self.type}",
        attributes
      ].to_json.gsub(/\[|\]/, '')
    end
  end

  class Parameter < OpenStruct
    include Rack::Tracker::JavaScriptHelper
    def write
      ['set', self.to_h.to_a].flatten.map { |v| %Q{'#{j(v)}'} }.join ', '
    end
  end

  def tracker
    options[:tracker].respond_to?(:call) ? options[:tracker].call(env) : options[:tracker]
  end

  def ecommerce_events
    events.select {|e| e.kind_of?(Ecommerce) }
  end

  def enhanced_ecommerce_events
    events.select {|e| e.kind_of?(EnhancedEcommerce) }
  end

  def pageview_url_script
    options[:pageview_url_script] || 'window.location.pathname + window.location.search'
  end

  private

  def tracker_option_key(key)
    key.to_s.camelize(:lower).to_sym
  end

  def tracker_option_value(value)
    value.to_s
  end
end