[TASK] Add stack to mark external links

Classes/UserFunc/ParseExternalLinks.php

@@ -0,0 +1,78 @@
+<?php
+namespace Cjel\TemplatesAide\UserFunc;
+
+/**
+ * This file is part of the "Site Templates" Extension for TYPO3 CMS.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE.txt file that was distributed with this source code.
+ *
+ * (c) 2021 Philipp Dieter <philipp@glanzstueck.agency>, Glanzstück GmbH
+ */
+
+use DiDom\Document;
+use DiDom\Element;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+
+class ParseExternalLinks
+{
+    /**
+     * @return string
+     */
+    public function render($content, $conf = [])
+    {
+        $domDocument = new \DOMDocument();
+        $testdocument = $domDocument->loadXML($content);
+        if ($testdocument === false) {
+            return $content;
+        }
+        $document = new Document($content);
+        $a = $document->find('a')[0];
+        $href = $a->getAttribute('href');
+        if (substr($href, 0, 7) != "http://"
+            && substr($href, 0, 8) != "https://"
+        ) {
+            return $content;
+        }
+        $parsedHref = parse_url($href);
+        if ($_SERVER['SERVER_NAME'] == $parsedHref['host']) {
+            return $content;
+        }
+        if ($a->getAttribute('target') == '_blank') {
+            $a->setAttribute('rel', 'noopener');
+        }
+        $class = $a->getAttribute('class');
+        if ($class) {
+            $class .= ' link link-external';
+        } else {
+            $class = 'link link-external';
+        }
+        $a->setAttribute('class', $class);
+        if ($conf['linkText']) {
+            $screenreaderHint = new Element('span', $conf['linkText'] . ' ');
+            $screenreaderHint->setAttribute('class', 'link-external-sr-only');
+            $a->prependChild($screenreaderHint);
+        }
+        if ($conf['iconFile']) {
+            $iconDataFile = GeneralUtility::getFileAbsFileName(
+                $conf['iconFile']
+            );
+            $iconData = file_get_contents($iconDataFile);
+            $icon = new Element('span');
+            $icon->setInnerHtml($iconData);
+            $icon->setAttribute('class', 'icon-link-external');
+            if ($iconPosition == 'start') {
+                $a->prepentChild($icon);
+            } else {
+                $a->appendChild($icon);
+            }
+        }
+        $innerHtml = $a->innerHtml();
+        $a->setInnerHtml(
+            '<span class="link-external-inner">'
+            . $innerHtml
+            . '</span>'
+        );
+        return $document->find('body')[0]->innerHtml();
+    }
+}