ProcessWIre SiteMap Generator.

pw-sitemap-xml.php

<?php
/**
 * 
 * Based on Ryan Cramer´s Code
 * ProcessWire Template to power a sitemap.xml 
 * 
 * Purpose: Render sitemap.xml for this special conditions
 * 
 * / [home](/) Without children!
 * /page-that-holds-the-tree/ [Page that holds the tree of the web.] With all his children.
 * 
 * Add more pages in the Array().
 *
 * 1. Copy this file to /site/templates/sitemap-xml.php
 * 2. Add the new template from the admin.
 *    Under the "URLs" section, set it to NOT use trailing slashes.
 * 3. Create a new page at the root level, use your sitemap-xml template
 *    and name the page "sitemap.xml".
 *
 * Note: hidden pages (and their children) are excluded from the sitemap.
 * If you have hidden pages that you want to be included, you can do so 
 * by specifying the ID or path to them in an array sent to the
 * renderSiteMapXML() method at the bottom of this file. For instance:
 *
 * echo renderSiteMapXML(array('/hidden/page/', '/another/hidden/page/')); 
 *
 */

$useMain = false;
 
function renderSitemapPage(Page $page) {
  return 
    "\n<url>" .
    "\n\t<loc>" . $page->httpUrl . "</loc>" .
    "\n\t<lastmod>" . date("Y-m-d", $page->modified) . "</lastmod>" .
    "\n</url>";
}
 
function renderSitemapChildren(Page $page) {
 
  $out = '';
  $newParents = new PageArray();
  $children = $page->children;
  
  foreach($children as $child) {
    $out .= renderSitemapPage($child);
    if($child->numChildren) $newParents->add($child);
      else wire('pages')->uncache($child);
  }
  
  foreach($newParents as $newParent) {
    $out .= renderSitemapChildren($newParent);
    wire('pages')->uncache($newParent);
  }
  
  return $out;
}
 
function renderSitemapXML(array $paths = array()) {
  
  $out =  
    '<?xml version="1.0" encoding="UTF-8"?>' . "\n" .
    '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">';
  
  //array_unshift($paths, '/'); // prepend homepage

  $out .= renderSitemapPage(wire('pages')->get('/'));
  
  foreach($paths as $path) {
    $page = wire('pages')->get($path); 
    if(!$page->id) continue; 
    $out .= renderSitemapPage($page);
    if($page->numChildren) $out .= renderSitemapChildren($page);
  }
  
  $out .= "\n</urlset>";
  return $out; 
}
 
header("Content-Type: text/xml");
 
echo renderSitemapXML(array('/page-that-holds-the-tree/'));  
// If you want to include other hidden pages: 
// echo renderSitemapXML(array('/path/to/hidden/page/'));