content_grouping.php

<?php

  /**
   * Script (PHP & Javascript) to send category information from Wordpress
   * to Universal Google Analytics (GA).
   *
   * The Wordpress category is passed using the Content Grouping feature of
   * GA, to the contentGroup1 group.
   *
   * If the function is_product() is defined, the script assumes the website
   * has an ecommerce, and the product category will be transmitted from the
   * 'product_cat' taxonomy to the contentGroup2 group.
   * 
   * This script should be placed just before the pageview is transmitted
   * to GA, ie. before the ga ('send', 'pageview') in the standard tracking
   * code, lest the grouping data is not transmitted to GA. You can either
   * copy & paste the script there, or include it as a file with the PHP 
   * function include() or the Wordpress function get_template_part().
   *
   * As an alternative, you could place this script wherever you want and
   * transmit the data to GA using a non-interaction event. If you do so,
   * you'll see the content grouping data in the Event -> Pages report
   * rather than in the Content -> All Pages one.
   * 
   * This script was improved thanks to the following resources; thanks
   * to the authors!
   * - https://www.highposition.com/blog/how-to-send-author-content-groups-
   *   wordpress-google-analytics/
   * - http://stackoverflow.com/a/34714363/2972183
   *
   * Created by Guido W. Pettinari on 08.01.2015.
   * Last version: https://gist.github.com/40fc029baf84a9ff8970
   */

  /* Extract the (first) category of the current post */
  $category = get_the_category();
  $category_name = $category[0]->cat_name;

  /* Product page */
  if (function_exists('is_product') && is_product()) {

    echo "<script> ga('set', 'contentGroup1', '" . "Prodotti" . "'); </script>\n";
  
    $terms = get_the_terms( get_the_ID(), 'product_cat' );
                         
    if ( $terms && !is_wp_error( $terms ) )
      echo "<script> ga('set', 'contentGroup2', '" . $terms[0]->name . "'); </script>\n";
    else
      echo "<script> ga('set', 'contentGroup2', '" . "Undefined Product" . "'); </script>\n";
  
  }

  /* Default behaviour: use Wordpress default 'category' taxonomy */
  else if ($category && !empty($category_name)) {

    echo "<script> ga('set', 'contentGroup1', '" . $category_name . "'); </script>\n";

  }

?>