Index.php

<?php
namespace Bitrix\Seo\Sitemap\File;
 
use Bitrix\Main\Text\Converter;
 
class Index extends Base
{
    const FILE_HEADER = '<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">';
    const FILE_FOOTER = '</sitemapindex>';
 
    const ENTRY_TPL = '<sitemap><loc>%s</loc><lastmod>%s</lastmod></sitemap>';
 
    public function createIndex(array $arIndex)
    {
        $str = self::XML_HEADER.self::FILE_HEADER;
 
        foreach ($arIndex as $file)
        {
            if(!$file->isSystem() && $file->isExists())
            {
                $e = [];
                $str .= sprintf(
                    self::ENTRY_TPL,
                    Converter::getXmlConverter()->encode($this->settings['PROTOCOL'].'://'.\CBXPunycode::toASCII($this->settings['DOMAIN'], $e).$this->getFileUrl($file)),
                    date('c', $file->getModificationTime())
                );
            }
        }
 
        $str .= self::FILE_FOOTER;
 
        $this->putContents($str);
    }
 
    public function appendIndexEntry($file)
    {
        if ($this->isExists() && $file->isExists())
        {
            $e = [];
            $fileUrlEnc = Converter::getXmlConverter()->encode($this->settings['PROTOCOL'].'://'.\CBXPunycode::toASCII($this->settings['DOMAIN'], $e).$this->getFileUrl($file));
 
            $contents = $this->getContents();
 
            $reg = "/".sprintf(preg_quote(self::ENTRY_TPL, "/"), preg_quote($fileUrlEnc, "/"), "[^<]*")."/";
 
            $newEntry = sprintf(
                self::ENTRY_TPL,
                $fileUrlEnc,
                date('c', $file->getModificationTime($file))
            );
 
            $count = 0;
            $contents = preg_replace($reg, $newEntry, $contents, 1, $count);
 
            if($count <= 0)
            {
                $contents = mb_substr($contents, 0, -mb_strlen(self::FILE_FOOTER))
                    .$newEntry.self::FILE_FOOTER;
            }
 
            $this->putContents($contents);
        }
        else
        {
            $this->createIndex(array($file));
        }
    }
}