Ojs\CoreBundle\Service\Twig\OjsExtension::sanitize PHP Метод

    public function sanitize($string)
    {
        $string = strip_tags($string, '<a><blockquote><b><u><i>');
        $dom = new \DOMDocument();
        $dom->loadHTML($string, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
        foreach ($dom->getElementsByTagName('*') as $node) {
            /** @var \DOMElement $node */
            for ($i = $node->attributes->length - 1; $i >= 0; $i--) {
                /** @var \DOMAttr $attribute */
                $attribute = $node->attributes->item($i);
                if ($node->nodeName == 'a') {
                    if ($attribute->name === 'href') {
                        $url = filter_var($attribute->value, FILTER_SANITIZE_URL);
                        if (!filter_var($url, FILTER_VALIDATE_URL)) {
                            $node->parentNode->removeChild($node);
                        }
                    } elseif ($attribute->name === 'rel') {
                        $relValues = array('alternate', 'author', 'bookmark', 'help', 'license', 'next', 'nofollow', 'noreferer', 'prefetch', 'prev', 'search', 'tag');
                        if (!in_array($attribute->value, $relValues, true)) {
                            $node->setAttributeNode(new \DOMAttr('rel', 'nofollow'));
                        }
                    } elseif ($attribute->name === 'target') {
                        $targetValues = array('_blank', '_self', '_parent', '_top');
                        if (!in_array($attribute->value, $targetValues, true)) {
                            $node->setAttributeNode(new \DOMAttr('target', '_blank'));
                        }
                    } else {
                        $node->removeAttributeNode($attribute);
                    }
                } else {
                    $node->removeAttributeNode($attribute);
                }
            }
        }
        return $dom->saveHTML();
    }