matomo.module

<?php

/**
 * @file
 * Drupal Module: Matomo
 *
 * Adds the required Javascript to all your Drupal pages to allow tracking by
 * the Matomo statistics package.
 *
 * @author: Alexander Hass <https://drupal.org/user/85918>
 */

/**
 * Define the default file extension list that should be tracked as download.
 */
define('MATOMO_TRACKFILES_EXTENSIONS', '7z|aac|arc|arj|asf|asx|avi|bin|csv|doc(x|m)?|dot(x|m)?|exe|flv|gif|gz|gzip|hqx|jar|jpe?g|js|mp(2|3|4|e?g)|mov(ie)?|msi|msp|pdf|phps|png|ppt(x|m)?|pot(x|m)?|pps(x|m)?|ppam|sld(x|m)?|thmx|qtm?|ra(m|r)?|sea|sit|tar|tgz|torrent|txt|wav|wma|wmv|wpd|xls(x|m|b)?|xlt(x|m)|xlam|xml|z|zip');

/**
 * Define default path exclusion list to remove tracking from admin pages,
 * see https://drupal.org/node/34970 for more information.
 */
define('MATOMO_PAGES', "admin\nadmin/*\nbatch\nnode/add*\nnode/*/*\nuser/*/*");

/**
 * Implements hook_theme().
 */
function matomo_theme() {
  return array(
    'matomo_admin_custom_var_table' => array(
      'render element' => 'form',
    ),
  );
}

/**
 * Implements hook_permission().
 */
function matomo_permission() {
  return array(
    'administer matomo' => array(
      'title' => t('Administer Matomo'),
      'description' => t('Perform maintenance tasks for Matomo.'),
    ),
    'opt-in or out of matomo tracking' => array(
      'title' => t('Opt-in or out of tracking'),
      'description' => t('Allow users to decide if tracking code will be added to pages or not.'),
    ),
    'use php for matomo tracking visibility' => array(
      'title' => t('Use PHP for tracking visibility'),
      'description' => t('Enter PHP code in the field for tracking visibility settings.'),
      'restrict access' => TRUE,
    ),
    'add js snippets for matomo' => array(
      'title' => t('Add JavaScript snippets'),
      'description' => 'Enter JavaScript code snippets for advanced Matomo functionality.',
      'restrict access' => TRUE,
    ),
  );
}

/**
 * Implements hook_menu().
 */
function matomo_menu() {
  $items['admin/config/system/matomo'] = array(
    'title' => 'Matomo Analytics',
    'description' => 'Configure the settings used to generate your Matomo tracking code.',
    'page callback' => 'backdrop_get_form',
    'page arguments' => array('matomo_admin_settings_form'),
    'access arguments' => array('administer matomo'),
    'type' => MENU_NORMAL_ITEM,
    'file' => 'matomo.admin.inc',
  );

  return $items;
}

/**
 * Implements hook_config_info().
 */
function matomo_config_info() {
  $info['matomo.settings'] = array(
    'label' => t('Matomo'),
    'group' => t('Configuration'),
  );
  return $info;
}

/**
 * Implements hook_preprocess_page().
 *
 * Insert JavaScript to the appropriate scope/region of the page, insert the
 * noscript fallback to page_bottom if enabled.
 */
function matomo_preprocess_page(&$variables) {
  global $user, $is_https;
  $config = config('matomo.settings');

  $id = $config->get('site_id');

  // Get page status code for visibility filtering.
  $status = backdrop_get_http_header('Status');
  $trackable_status_codes = array(
    '403 Forbidden',
    '404 Not Found',
  );

  // 1. Check if the matomo account number has a value.
  // 2. Track page views based on visibility value.
  // 3. Check if we should track the currently active user's role.
  if (preg_match('/^\d{1,}$/', $id) && (_matomo_visibility_pages() || in_array($status, $trackable_status_codes)) && _matomo_visibility_user($user)) {

    $url_http = $config->get('url_http');
    $url_https = $config->get('url_https');
    $scope = $config->get('js_scope');

    $set_custom_url = '';
    $set_document_title = '';

    // Add link tracking.
    $link_settings = array();
    $link_settings['trackMailto'] = $config->get('trackmailto');

    if (module_exists('colorbox') && ($track_colorbox = $config->get('trackcolorbox'))) {
      $link_settings['trackColorbox'] = $track_colorbox;
    }

    backdrop_add_js(array('matomo' => $link_settings), 'setting');
    backdrop_add_js(backdrop_get_path('module', 'matomo') . '/matomo.js');

    // Matomo can show a tree view of page titles that represents the site structure
    // if setDocumentTitle() provides the page titles as a "/" delimited list.
    // This may makes it easier to browse through the statistics of page titles
    // on larger sites.
    if ($config->get('page_title_hierarchy') == TRUE) {
      $titles = _matomo_get_hierarchy_titles();

      if ($config->get('page_title_hierarchy_exclude_home')) {
        // Remove the "Home" item from the titles to flatten the tree view.
        array_shift($titles);
      }

      // Remove all empty titles.
      $titles = array_filter($titles);

      if (!empty($titles)) {
        // Encode title, at least to keep "/" intact.
        $titles = array_map('rawurlencode', $titles);

        $set_document_title = backdrop_json_encode(implode('/', $titles));
      }
    }

    // Add messages tracking.
    $message_events = '';
    if ($message_types = $config->get('trackmessages')) {
      $message_types = array_values(array_filter($message_types));
      $status_heading = array(
        'status' => t('Status message'),
        'warning' => t('Warning message'),
        'error' => t('Error message'),
      );

      foreach (backdrop_get_messages(NULL, FALSE) as $type => $messages) {
        // Track only the selected message types.
        if (in_array($type, $message_types)) {
          foreach ($messages as $message) {
            $message_events .= '_paq.push(["trackEvent", ' . backdrop_json_encode(t('Messages')) . ', ' . backdrop_json_encode($status_heading[$type]) . ', ' . backdrop_json_encode(strip_tags($message)) . ']);';
          }
        }
      }
    }

    // If this node is a translation of another node, pass the original
    // node instead.
    if (module_exists('translation') && $config->get('translation_set')) {
      // Check we have a node object, it supports translation, and its
      // translated node ID (tnid) doesn't match its own node ID.
      $node = menu_get_object();
      if ($node && translation_supported_type($node->type) && !empty($node->tnid) && ($node->tnid != $node->nid)) {
        $source_node = node_load($node->tnid);
        $languages = language_list();
        $set_custom_url = backdrop_json_encode(url('node/' . $source_node->nid, array('language' => $languages[$source_node->language], 'absolute' => TRUE)));
      }
    }

    // Track access denied (403) and file not found (404) pages.
    if ($status == '403 Forbidden') {
      $set_document_title = '"403/URL = " + encodeURIComponent(document.location.pathname+document.location.search) + "/From = " + encodeURIComponent(document.referrer)';
    }
    elseif ($status == '404 Not Found') {
      $set_document_title = '"404/URL = " + encodeURIComponent(document.location.pathname+document.location.search) + "/From = " + encodeURIComponent(document.referrer)';
    }

    // #2693595: User has entered an invalid login and clicked on forgot
    // password link. This link contains the username or email address and may
    // get send to Matomo if we do not override it. Override only if 'name'
    // query param exists. Last custom url condition, this need to win.
    //
    // URLs to protect are:
    // - user/password?name=username
    // - user/password?name=foo@example.com
    if (arg(0) == 'user' && arg(1) == 'password' && array_key_exists('name', backdrop_get_query_parameters())) {
      $set_custom_url = backdrop_json_encode(url('user/password'));
    }

    // Add custom variables.
    $matomo_custom_vars = $config->get('custom_var');
    $custom_variable = '';
    for ($i = 1; $i < 6; $i++) {
      $custom_var_name = !empty($matomo_custom_vars['slots'][$i]['name']) ? $matomo_custom_vars['slots'][$i]['name'] : '';
      if (!empty($custom_var_name)) {
        $custom_var_value = !empty($matomo_custom_vars['slots'][$i]['value']) ? $matomo_custom_vars['slots'][$i]['value'] : '';
        $custom_var_scope = !empty($matomo_custom_vars['slots'][$i]['scope']) ? $matomo_custom_vars['slots'][$i]['scope'] : 'visit';

        $types = array();
        $node = menu_get_object();
        if (is_object($node)) {
          $types += array('node' => $node);
        }
        $custom_var_name = token_replace($custom_var_name, $types, array('clear' => TRUE));
        $custom_var_value = token_replace($custom_var_value, $types, array('clear' => TRUE));

        // Suppress empty custom names and/or variables.
        if (!backdrop_strlen(trim($custom_var_name)) || !backdrop_strlen(trim($custom_var_value))) {
          continue;
        }

        // Custom variables names and values are limited to 200 characters in
        // length. It is recommended to store values that are as small as
        // possible to ensure that the Matomo Tracking request URL doesn't go
        // over the URL limit for the webserver or browser.
        $custom_var_name = rtrim(substr($custom_var_name, 0, 200));
        $custom_var_value = rtrim(substr($custom_var_value, 0, 200));

        $custom_var_name = backdrop_json_encode($custom_var_name);
        $custom_var_value = backdrop_json_encode($custom_var_value);
        $custom_var_scope = backdrop_json_encode($custom_var_scope);
        $custom_variable .= "_paq.push(['setCustomVariable', $i, $custom_var_name, $custom_var_value, $custom_var_scope]);";
      }
    }

    // Add any custom code snippets if specified.
    $codesnippet_before = $config->get('codesnippet_before');
    $codesnippet_after = $config->get('codesnippet_after');

    // Build tracker code. See https://matomo.org/docs/javascript-tracking/#toc-asynchronous-tracking
    $script = 'var _paq = _paq || [];';
    $script .= '(function(){';
    $script .= 'var u=(("https:" == document.location.protocol) ? "' . check_url($url_https) . '" : "' . check_url($url_http) . '");';
    $script .= '_paq.push(["setSiteId", ' . backdrop_json_encode($config->get('site_id')) . ']);';
    $script .= '_paq.push(["setTrackerUrl", u+"matomo.php"]);';

    // Track logged in users across all devices.
    if ($config->get('trackuserid') && user_is_logged_in()) {
      // The USER_ID value should be a unique, persistent, and non-personally
      // identifiable string identifier that represents a user or signed-in
      // account across devices.
      $script .= '_paq.push(["setUserId", ' . backdrop_json_encode(matomo_user_id_hash($user->uid)) . ']);';
    }

    // Set custom url.
    if (!empty($set_custom_url)) {
      $script .= '_paq.push(["setCustomUrl", ' . $set_custom_url . ']);';
    }
    // Set custom document title.
    if (!empty($set_document_title)) {
      $script .= '_paq.push(["setDocumentTitle", ' . $set_document_title . ']);';
    }

    // Custom file download extensions.
    if (($config->get('track')) && !($config->get('trackfiles_extensions') == MATOMO_TRACKFILES_EXTENSIONS)) {
      $script .= '_paq.push(["setDownloadExtensions", ' . backdrop_json_encode($config->get('trackfiles_extensions')) . ']);';
    }

    // Disable tracking for visitors who have opted out from tracking via DNT (Do-Not-Track) header.
    if ($config->get('privacy_donottrack')) {
      $script .= '_paq.push(["setDoNotTrack", 1]);';
    }

    // Domain tracking type.
    global $cookie_domain;
    $domain_mode = $config->get('domain_mode');

    // Per RFC 2109, cookie domains must contain at least one dot other than the
    // first. For hosts such as 'localhost' or IP Addresses we don't set a cookie domain.
    if ($domain_mode == 1 && count(explode('.', $cookie_domain)) > 2 && !is_numeric(str_replace('.', '', $cookie_domain))) {
      $script .= '_paq.push(["setCookieDomain", ' . backdrop_json_encode($cookie_domain) . ']);';
    }

    // Ordering $custom_variable before $codesnippet_before allows users to add
    // custom code snippets that may use deleteCustomVariable() and/or getCustomVariable().
    if (!empty($custom_variable)) {
      $script .= $custom_variable;
    }
    if (!empty($codesnippet_before)) {
      $script .= $codesnippet_before;
    }

    // Site search tracking support.
    // NOTE: It's recommended not to call trackPageView() on the Site Search Result page.
    if (module_exists('search') && $config->get('site_search') && arg(0) == 'search' && $keys = matomo_search_get_keys()) {
      // Parameters:
      // 1. Search keyword searched for. Example: "Banana"
      // 2. Search category selected in your search engine. If you do not need
      //    this, set to false. Example: "Organic Food"
      // 3. Number of results on the Search results page. Zero indicates a
      //    'No Result Search Keyword'. Set to false if you don't know.
      //
      // hook_preprocess_search_results() is not executed if search result is
      // empty. Make sure the counter is set to 0 if there are no results.
      $script .= '_paq.push(["trackSiteSearch", ' . backdrop_json_encode($keys) . ', false, (window.matomo_search_results) ? window.matomo_search_results : 0]);';
    }
    else {
      $script .= '_paq.push(["trackPageView"]);';
    }

    // Add link tracking.
    if ($config->get('track')) {
      // Disable tracking of links with ".no-tracking" and ".colorbox" classes.
      $ignore_classes = array(
        'no-tracking',
        'colorbox',
      );
      // Disable the download & outlink tracking for specific CSS classes.
      // Custom code snippets with 'setIgnoreClasses' will override the value.
      // https://developer.matomo.org/api-reference/tracking-javascript#disable-the-download-amp-outlink-tracking-for-specific-css-classes
      $script .= '_paq.push(["setIgnoreClasses", ' . backdrop_json_encode($ignore_classes) . ']);';

      // Enable download & outlink link tracking.
      $script .= '_paq.push(["enableLinkTracking"]);';
    }

    if (!empty($message_events)) {
      $script .= $message_events;
    }
    if (!empty($codesnippet_after)) {
      $script .= $codesnippet_after;
    }

    $script .= 'var d=document,';
    $script .= 'g=d.createElement("script"),';
    $script .= 's=d.getElementsByTagName("script")[0];';
    $script .= 'g.type="text/javascript";';
    $script .= 'g.defer=true;';
    $script .= 'g.async=true;';

    // Should a local cached copy of the tracking code be used?
    if ($config->get('cache') && $url = _matomo_cache($url_http . 'matomo.js')) {
      // A dummy query-string is added to filenames, to gain control over
      // browser-caching. The string changes on every update or full cache
      // flush, forcing browsers to load a new copy of the files, as the
      // URL changed.
      $query_string = '?' . state_get('css_js_query_string', '0');

      $script .= 'g.src="' . $url . $query_string . '";';
    }
    else {
      $script .= 'g.src=u+"matomo.js";';
    }

    $script .= 's.parentNode.insertBefore(g,s);';
    $script .= '})();';

    // Add tracker code to scope.
    backdrop_add_js($script, array('scope' => $scope, 'type' => 'inline'));

    // Add the noscript fallback markup to the page_bottom string.
    if ($config->get('noscript')) {
      $src_url = ($is_https && !empty($url_https)) ? check_url($url_https) : check_url($url_http);
      $src_url = rtrim($src_url, '/') . "/matomo.php?idsite=$id&amp;rec=1";
      $img = '<img src="' . $src_url . '" style="border:0" alt="" />';
      $variables['page_bottom'] .= "<!-- Matomo --><noscript><p>$img</p></noscript><!-- End Matomo -->";
    }
  }
}

/**
 * Generate user id hash to implement USER_ID.
 *
 * The USER_ID value should be a unique, persistent, and non-personally
 * identifiable string identifier that represents a user or signed-in
 * account across devices.
 *
 * @param int $uid
 *   User id.
 *
 * @return string
 *   User id hash.
 */
function matomo_user_id_hash($uid) {
  return backdrop_hmac_base64($uid, backdrop_get_private_key() . backdrop_get_hash_salt());
}

/**
 * Implements hook_field_extra_fields().
 */
function matomo_field_extra_fields() {
  $extra['user']['user']['form']['matomo'] = array(
    'label' => t('Matomo configuration'),
    'description' => t('Matomo module form element.'),
    'weight' => 3,
  );

  return $extra;
}

/**
 * Implement hook_form_FORM_ID_alter().
 *
 * Allow users to decide if tracking code will be added to pages or not.
 */
function matomo_form_user_profile_form_alter(&$form, &$form_state) {
  $account = $form['#user'];

  if (user_access('opt-in or out of matomo tracking') && ($custom = config_get('matomo.settings', 'custom')) != 0 && _matomo_visibility_roles($account)) {
    $form['matomo'] = array(
      '#type' => 'fieldset',
      '#title' => t('Matomo configuration'),
      '#weight' => 3,
      '#collapsible' => TRUE,
      '#tree' => TRUE
    );

    switch ($custom) {
      case 1:
        $description = t('Users are tracked by default, but you are able to opt out.');
        break;

      case 2:
        $description = t('Users are <em>not</em> tracked by default, but you are able to opt in.');
        break;
    }

    // Migrate old piwik settings to matomo.
    if (isset($account->data['piwik']['custom'])) {
      $account->data['matomo']['custom'] = $account->data['piwik']['custom'];
    }

    $form['matomo']['custom'] = array(
      '#type' => 'checkbox',
      '#title' => t('Enable user tracking'),
      '#description' => $description,
      '#default_value' => isset($account->data['matomo']['custom']) ? $account->data['matomo']['custom'] : ($custom == 1),
    );

    return $form;
  }
}

/**
 * Implements hook_user_presave().
 */
function matomo_user_presave($account) {
  if (isset($account->matomo['custom'])) {
    $account->data['matomo']['custom'] = $account->matomo['custom'];
  }

  // Remove old piwik setting to complete migration to matomo.
  if (isset($account->data['piwik'])) {
    unset($account->data['piwik']);
  }
}

/**
 * Implements hook_cron().
 */
function matomo_cron() {
  $config = config('matomo.settings');
  // Regenerate the matomo.js every day.
  if (REQUEST_TIME - $config->get('last_cache') >= 86400 && $config->get('cache', 0)) {
    _matomo_cache($config->get('url_http', '') . 'matomo.js', TRUE);
    $config->set('last_cache', REQUEST_TIME);
    $config->save();
  }
}

/**
 * Implements hook_preprocess_search_results().
 *
 * Collects and adds the number of search results to the head.
 */
function matomo_preprocess_search_results(&$variables) {
  // There is no search result $variable available that hold the number of items
  // found. But the pager item mumber can tell the number of search results.
  global $pager_total_items;
  // But when there's no hit, that variable is NULL.
  if (is_array($pager_total_items)) {
    $num_results = (int) $pager_total_items[0];
  }
  else {
    $num_results = 0;
  }

  backdrop_add_js('window.matomo_search_results = ' . $num_results . ';', array('type' => 'inline', 'group' => JS_LIBRARY-1));
}

/**
 * Download/Synchronize/Cache tracking code file locally.
 *
 * @param $location
 *   The full URL to the external javascript file.
 * @param $sync_cached_file
 *   Synchronize tracking code and update if remote file have changed.
 * @return mixed
 *   The path to the local javascript file on success, boolean FALSE on failure.
 */
function _matomo_cache($location, $sync_cached_file = FALSE) {
  $path = 'public://matomo';
  $file_destination = $path . '/' . basename($location);

  if (!file_exists($file_destination) || $sync_cached_file) {
    // Download the latest tracking code.
    $result = backdrop_http_request($location);

    if ($result->code == 200) {
      if (file_exists($file_destination)) {
        // Synchronize tracking code and and replace local file if outdated.
        $data_hash_local = backdrop_hash_base64(file_get_contents($file_destination));
        $data_hash_remote = backdrop_hash_base64($result->data);
        // Check that the files directory is writable.
        if ($data_hash_local != $data_hash_remote && file_prepare_directory($path)) {
          // Save updated tracking code file to disk.
          file_unmanaged_save_data($result->data, $file_destination, FILE_EXISTS_REPLACE);
          // Based on Drupal Core backdrop_build_css_cache().
          if (config_get('system.core', 'preprocess_css') && config_get('system.core', 'clean_url') && extension_loaded('zlib')) {
            file_unmanaged_save_data(gzencode($result->data, 9, FORCE_GZIP), $file_destination . '.gz', FILE_EXISTS_REPLACE);
          }
          watchdog('matomo', 'Locally cached tracking code file has been updated.', array(), WATCHDOG_INFO);

          // Change query-strings on css/js files to enforce reload for all users.
          _backdrop_flush_css_js();
        }
      }
      else {
        // Check that the files directory is writable.
        if (file_prepare_directory($path, FILE_CREATE_DIRECTORY)) {
          // There is no need to flush JS here as core refreshes JS caches
          // automatically, if new files are added.
          file_unmanaged_save_data($result->data, $file_destination, FILE_EXISTS_REPLACE);
          if (config_get('system.core', 'preprocess_css') && config_get('system.core', 'clean_url')   && extension_loaded('zlib')) {
            file_unmanaged_save_data(gzencode($result->data, 9, FORCE_GZIP), $file_destination . '.gz', FILE_EXISTS_REPLACE);
          }
          watchdog('matomo', 'Locally cached tracking code file has been saved.', array(), WATCHDOG_INFO);

          // Return the local JS file path.
          return file_create_url($file_destination);
        }
      }
    }
  }
  else {
    // Return the local JS file path.
    return file_create_url($file_destination);
  }
}

/**
 * Delete cached files and directory.
 */
function matomo_clear_js_cache() {
  $path = 'public://matomo';
  if (file_prepare_directory($path)) {
    file_scan_directory($path, '/.*/', array('callback' => 'file_unmanaged_delete'));
    backdrop_rmdir($path);

    // Change query-strings on css/js files to enforce reload for all users.
    _backdrop_flush_css_js();

    watchdog('matomo', 'Local cache has been purged.', array(), WATCHDOG_INFO);
  }
}

/**
 * Helper function for grabbing search keys. Function is missing in D7.
 *
 * https://api.drupal.org/api/function/search_get_keys/6
 */
function matomo_search_get_keys() {
  static $return;
  if (!isset($return)) {
    // Extract keys as remainder of path
    // Note: support old GET format of searches for existing links.
    $path = explode('/', $_GET['q'], 3);
    $keys = empty($_REQUEST['keys']) ? '' : $_REQUEST['keys'];
    $return = count($path) == 3 ? $path[2] : $keys;
  }
  return $return;
}

/**
 * Tracking visibility check for an user object.
 *
 * @param $account
 *   A user object containing an array of roles to check.
 * @return boolean
 *   A decision on if the current user is being tracked by Matomo.
 */
function _matomo_visibility_user($account) {

  $enabled = FALSE;

  // Is current user a member of a role that should be tracked?
  if (_matomo_visibility_roles($account)) {

    // Use the user's block visibility setting, if necessary.
    if (($custom = config_get('matomo.settings', 'custom')) != 0) {
      if ($account->uid && isset($account->data['matomo']['custom'])) {
        $enabled = $account->data['matomo']['custom'];
      }
      else {
        $enabled = ($custom == 1);
      }
    }
    else {
      $enabled = TRUE;
    }

  }

  return $enabled;
}

/**
 * Based on visibility setting this function returns TRUE if GA code should
 * be added for the current role and otherwise FALSE.
 */
function _matomo_visibility_roles($account) {

  $visibility = config_get('matomo.settings', 'visibility_roles');
  $enabled = $visibility;
  $roles = array_filter(config_get('matomo.settings', 'roles'));

  if (!empty($roles)) {
    // One or more roles are selected.
    foreach ($account->roles as $role) {
      // Is the current user a member of one of these roles?
      if (isset($roles[$role]) && $role == $roles[$role]) {
        // Current user is a member of a role that should be tracked/excluded from tracking.
        $enabled = !$visibility;
        break;
      }
    }
  }
  else {
    // No role is selected for tracking, therefore all roles should be tracked.
    $enabled = TRUE;
  }

  return $enabled;
}

/**
 * Based on visibility setting this function returns TRUE if GA code should
 * be added to the current page and otherwise FALSE.
 */
function _matomo_visibility_pages() {
  static $page_match;

  // Cache visibility setting in hook_init for hook_footer.
  if (!isset($page_match)) {

    $visibility = config_get('matomo.settings', 'visibility_pages');
    $setting_pages = config_get('matomo.settings', 'pages');

    // Match path if necessary.
    if (!empty($setting_pages)) {
      // Convert path to lowercase. This allows comparison of the same path
      // with different case. Ex: /Page, /page, /PAGE.
      $pages = backdrop_strtolower($setting_pages);
      if ($visibility < 2) {
        // Convert the Drupal path to lowercase
        $path = backdrop_strtolower(backdrop_get_path_alias($_GET['q']));
        // Compare the lowercase internal and lowercase path alias (if any).
        $page_match = backdrop_match_path($path, $pages);
        if ($path != $_GET['q']) {
          $page_match = $page_match || backdrop_match_path($_GET['q'], $pages);
        }
        // When $visibility has a value of 0, the tracking code is displayed on
        // all pages except those listed in $pages. When set to 1, it
        // is displayed only on those pages listed in $pages.
        $page_match = !($visibility xor $page_match);
      }
      elseif (module_exists('php')) {
        $page_match = php_eval($setting_pages);
      }
      else {
        $page_match = FALSE;
      }
    }
    else {
      $page_match = TRUE;
    }

  }
  return $page_match;
}

/**
 * Get the page titles trail for the current page.
 *
 * Based on menu_get_active_breadcrumb().
 *
 * @return array
 *   All page titles, including current page.
 */
function _matomo_get_hierarchy_titles() {
  $titles = array();

  // No breadcrumb for the front page.
  if (backdrop_is_front_page()) {
    return $titles;
  }

  $item = menu_get_item();
  if (!empty($item['access'])) {
    $active_trail = menu_get_active_trail();

    // Allow modules to alter the breadcrumb, if possible, as that is much
    // faster than rebuilding an entirely new active trail.
    backdrop_alter('menu_breadcrumb', $active_trail, $item);

    // Remove the tab root (parent) if the current path links to its parent.
    // Normally, the tab root link is included in the breadcrumb, as soon as we
    // are on a local task or any other child link. However, if we are on a
    // default local task (e.g., node/%/view), then we do not want the tab root
    // link (e.g., node/%) to appear, as it would be identical to the current
    // page. Since this behavior also needs to work recursively (i.e., on
    // default local tasks of default local tasks), and since the last non-task
    // link in the trail is used as page title (see menu_get_active_title()),
    // this condition cannot be cleanly integrated into menu_get_active_trail().
    // menu_get_active_trail() already skips all links that link to their parent
    // (commonly MENU_DEFAULT_LOCAL_TASK). In order to also hide the parent link
    // itself, we always remove the last link in the trail, if the current
    // router item links to its parent.
    if (($item['type'] & MENU_LINKS_TO_PARENT) == MENU_LINKS_TO_PARENT) {
      array_pop($active_trail);
    }

    foreach ($active_trail as $parent) {
      $titles[] = $parent['title'];
    }
  }

  return $titles;
}

/**
 * Helper function to verify that Backdrop can make http requests.
 *
 * @return bool
 *   TRUE if http response was received, FALSE otherwise.
 */
function _matomo_check_http_request() {
  $works = &backdrop_static(__FUNCTION__);

  if (!isset($works)) {
    // Try to get the content of the front page.
    $result = backdrop_http_request(url('', array('absolute' => TRUE)), array(
      'max_redirects' => 0,
      'timeout' => 10,
    ));
    $works = isset($result->code) && ($result->code >= 100) && ($result->code < 600);
  }
  return $works;
}