Consent Google Analytics in Rails

_consent_banner.html.slim

/ app/views/cookies_eu/_consent_banner.html.slim

- unless session[:accept_google_analytics].present?
  = link_to t('cookies.deny'), url_for(controller: controller_name, action: action_name, accept_google_analytics: 'no' )
  = link_to t('cookies.ok'), url_for(controller: controller_name, action: action_name, accept_google_analytics: 'yes' )

_google_analytics.html.slim

/ app/views/shared/_google_analytics.html.slim

- if Rails.env.production? && session[:accept_google_analytics]
  / Global site tag (gtag.js) - Google Analytics
  script[
    async
    src=("https://www.googletagmanager.com/gtag/js?id=#{ENV['GOOGLE_ANALYTICS_TAG']}")]
  javascript:
    window.dataLayer = window.dataLayer || [];
    function gtag(){dataLayer.push(arguments);}
    gtag('js', new Date());
    gtag('config', #{ENV['GOOGLE_ANALYTICS_TAG']});

application.html.slim

/ app/views/layouts/application.html.slim

doctype html
html
  head
    = render 'shared/google_analytics'
    /...
   body
     = render 'cookies/consent_banner'

application_controller.rb

# app/controllers/application_controller.rb

class ApplicationController < ActionController::Base
  # [...]
  before_action :set_cookies_acceptation
    
  private
  
  def set_cookies_acceptation
    if !session[:accept_google_analytics].present?
      if params[:accept_google_analytics] == 'yes'
        session[:accept_google_analytics] = 'yes'
      end
      if params[:accept_google_analytics] == 'no'
        session[:accept_google_analytics] = 'no'
      end
    end
  end
end

fr.yml

# config/locales/fr.yml

fr:
  cookies:
    deny: Refuser
    ok: Accepter