Sonata\Exporter\Writer\SitemapWriter::generateNewPart PHP Метод

    protected function generateNewPart()
    {
        if ($this->buffer) {
            $this->closeSitemap();
        }
        $this->bufferUrlCount = 0;
        $this->bufferSize = 0;
        ++$this->bufferPart;
        if (!is_writable($this->folder)) {
            throw new \RuntimeException(sprintf('Unable to write to folder: %s', $this->folder));
        }
        $filename = sprintf($this->pattern, $this->bufferPart);
        $this->buffer = fopen($this->folder . '/' . $filename, 'w');
        $this->bufferSize += fwrite($this->buffer, '<?xml version="1.0" encoding="UTF-8"?>' . "\n" . '<urlset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd" xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"' . $this->getHeaderByFlag() . '>' . "\n");
    }