From 007a505ec1793e7441ce25313bd0e1b2bd086ce2 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Thu, 1 Feb 2024 18:13:25 +0100
Subject: [PATCH 01/10] Add API for RSS feed generation

---
 .../lib/system/rssFeed/RssFeed.class.php      |  53 +++++
 .../system/rssFeed/RssFeedCategory.class.php  |  12 ++
 .../system/rssFeed/RssFeedChannel.class.php   | 188 +++++++++++++++++
 .../system/rssFeed/RssFeedEnclosure.class.php |  13 ++
 .../lib/system/rssFeed/RssFeedItem.class.php  | 195 ++++++++++++++++++
 .../system/rssFeed/RssFeedSource.class.php    |  12 ++
 .../lib/system/rssFeed/XmlElement.class.php   |  30 +++
 7 files changed, 503 insertions(+)
 create mode 100644 wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php
 create mode 100644 wcfsetup/install/files/lib/system/rssFeed/RssFeedCategory.class.php
 create mode 100644 wcfsetup/install/files/lib/system/rssFeed/RssFeedChannel.class.php
 create mode 100644 wcfsetup/install/files/lib/system/rssFeed/RssFeedEnclosure.class.php
 create mode 100644 wcfsetup/install/files/lib/system/rssFeed/RssFeedItem.class.php
 create mode 100644 wcfsetup/install/files/lib/system/rssFeed/RssFeedSource.class.php
 create mode 100644 wcfsetup/install/files/lib/system/rssFeed/XmlElement.class.php

diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php
new file mode 100644
index 00000000000..a3d8354614c
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace wcf\system\rssFeed;
+
+final class RssFeed
+{
+    /**
+     * @var RssFeedChannel[]
+     */
+    private array $channels = [];
+
+    public function channel(RssFeedChannel $channel): static
+    {
+        $this->channels[] = $channel;
+
+        return $this;
+    }
+
+    public function render(): string
+    {
+        $header = <<<'EOT'
+            <?xml version="1.0" encoding="UTF-8"?>
+            <rss version="2.0"
+                xmlns:atom="http://www.w3.org/2005/Atom"
+                xmlns:content="http://purl.org/rss/1.0/modules/content/"
+                xmlns:dc="http://purl.org/dc/elements/1.1/"
+                xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
+            >
+        EOT;
+
+        $element = new XmlElement(
+            $header,
+            LIBXML_NOERROR | LIBXML_ERR_NONE | LIBXML_ERR_FATAL
+        );
+
+        foreach ($this->channels as $channel) {
+            $toDom = \dom_import_simplexml($element);
+            $fromDom = \dom_import_simplexml($channel->getXML());
+            $toDom->appendChild($toDom->ownerDocument->importNode($fromDom, true));
+        }
+
+        $dom = new \DOMDocument('1.0', 'UTF-8');
+        $dom->appendChild($dom->importNode(\dom_import_simplexml($element), true));
+        $dom->formatOutput = true;
+
+        return $dom->saveXML();
+    }
+
+    public function __toString(): string
+    {
+        return $this->render();
+    }
+}
diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeedCategory.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeedCategory.class.php
new file mode 100644
index 00000000000..1bac8b54cbb
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeedCategory.class.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace wcf\system\rssFeed;
+
+final class RssFeedCategory
+{
+    public function __construct(
+        public readonly string $name,
+        public readonly ?string $domain = null,
+    ) {
+    }
+}
diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeedChannel.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeedChannel.class.php
new file mode 100644
index 00000000000..ecbed1aedb4
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeedChannel.class.php
@@ -0,0 +1,188 @@
+<?php
+
+namespace wcf\system\rssFeed;
+
+use BadMethodCallException;
+
+final class RssFeedChannel
+{
+    private string $title;
+    private string $description;
+    private string $link;
+    private string $atomLinkSelf;
+    private string $language;
+    private string $copyright;
+    private string $lastBuildDate;
+    private string $pubDate;
+    private int $ttl = 60;
+
+    /**
+     * @var RssFeedCategory[]
+     */
+    private array $categories = [];
+
+    /**
+     * @var RssFeedItem[]
+     */
+    private array $items = [];
+
+    public function title(string $title): static
+    {
+        $this->title = $title;
+
+        return $this;
+    }
+
+    public function description(string $description): static
+    {
+        $this->description = $description;
+
+        return $this;
+    }
+
+    public function link(string $link): static
+    {
+        $this->link = $link;
+
+        return $this;
+    }
+
+    public function atomLinkSelf(string $link): static
+    {
+        $this->atomLinkSelf = $link;
+
+        return $this;
+    }
+
+    public function language(string $language): static
+    {
+        $this->language = $language;
+
+        return $this;
+    }
+
+    public function copyright(string $copyright): static
+    {
+        $this->copyright = $copyright;
+
+        return $this;
+    }
+
+    public function lastBuildDate(string $date): static
+    {
+        $this->lastBuildDate = $date;
+
+        return $this;
+    }
+
+    public function lastBuildDateFromTimestamp(int $timestamp): static
+    {
+        return $this->lastBuildDate(\gmdate('r', $timestamp));
+    }
+
+    public function pubDate(string $date): static
+    {
+        $this->pubDate = $date;
+
+        return $this;
+    }
+
+    public function pubDateFromTimestamp(int $timestamp): static
+    {
+        return $this->pubDate(\gmdate('r', $timestamp));
+    }
+
+    public function ttl(int $ttl): static
+    {
+        $this->ttl = $ttl;
+
+        return $this;
+    }
+
+    public function category(string $name, ?string $domain = null): static
+    {
+        $this->categories[] = new RssFeedCategory($name, $domain);
+
+        return $this;
+    }
+
+    public function item(RssFeedItem $item): static
+    {
+        $this->items[] = $item;
+
+        return $this;
+    }
+
+    public function getXML(): \SimpleXMLElement
+    {
+        $this->integrityCheck();
+
+        $element = new XmlElement(
+            '<?xml version="1.0" encoding="UTF-8"?><channel></channel>',
+            LIBXML_NOERROR | LIBXML_ERR_NONE | LIBXML_ERR_FATAL
+        );
+
+        if (isset($this->title)) {
+            $element->addChild('title', $this->title);
+        }
+        if (isset($this->description)) {
+            $element->addChild('description', $this->description);
+        }
+        if (isset($this->link)) {
+            $element->addChild('link', $this->link);
+        }
+        if (isset($this->language)) {
+            $element->addChild('language', $this->language);
+        }
+        if (isset($this->copyright)) {
+            $element->addChild('copyright', $this->copyright);
+        }
+        if (isset($this->lastBuildDate)) {
+            $element->addChild('lastBuildDate', $this->lastBuildDate);
+        }
+        if (isset($this->pubDate)) {
+            $element->addChild('pubDate', $this->pubDate);
+        }
+
+        if (isset($this->atomLinkSelf)) {
+            $atomLink = $element->addChild('xmlns:atom:link');
+            $atomLink->addAttribute('href', $this->atomLinkSelf);
+            $atomLink->addAttribute('rel', 'self');
+            $atomLink->addAttribute('type', 'application/rss+xml');
+        }
+
+        $element->addChild('ttl', $this->ttl);
+        $element->addChild('generator', 'WoltLab Suite' . (SHOW_VERSION_NUMBER ? ' ' . \WCF_VERSION : ''));
+
+        foreach ($this->categories as $category) {
+            $categoryElement = $element->addChild('category', $category->name);
+            if ($category->domain !== null) {
+                $categoryElement->addAttribute('domain', $category->domain);
+            }
+        }
+
+        foreach ($this->items as $item) {
+            $toDom = \dom_import_simplexml($element);
+            $fromDom = \dom_import_simplexml($item->getXML());
+            $toDom->appendChild($toDom->ownerDocument->importNode($fromDom, true));
+        }
+
+        return $element;
+    }
+
+    private function integrityCheck(): void
+    {
+        // Title, description and link are required.
+        if (!isset($this->title)) {
+            throw new BadMethodCallException("missing parameter 'title'");
+        }
+
+        if (!isset($this->description)) {
+            throw new BadMethodCallException("missing parameter 'description'");
+        }
+
+        if (!isset($this->link)) {
+            throw new BadMethodCallException("missing parameter 'link'");
+        }
+    }
+}
diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeedEnclosure.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeedEnclosure.class.php
new file mode 100644
index 00000000000..f87419767ca
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeedEnclosure.class.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace wcf\system\rssFeed;
+
+final class RssFeedEnclosure
+{
+    public function __construct(
+        public readonly string $url,
+        public readonly int $length,
+        public readonly string $type
+    ) {
+    }
+}
diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeedItem.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeedItem.class.php
new file mode 100644
index 00000000000..0599a427e4d
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeedItem.class.php
@@ -0,0 +1,195 @@
+<?php
+
+namespace wcf\system\rssFeed;
+
+use BadMethodCallException;
+
+final class RssFeedItem
+{
+    private string $title;
+    private string $link;
+    private string $description;
+    private string $author;
+    private string $comments;
+    private int $slashComments;
+    private RssFeedEnclosure $enclosure;
+    private string $guid;
+    private bool $guidIsPermalink = true;
+    private string $pubDate;
+    private string $creator;
+    private string $contentEncoded;
+    private RssFeedSource $source;
+
+    /**
+     * @var RssFeedCategory[]
+     */
+    private array $categories = [];
+
+    public function title(string $title): static
+    {
+        $this->title = $title;
+
+        return $this;
+    }
+
+    public function description(string $description): static
+    {
+        $this->description = $description;
+
+        return $this;
+    }
+
+    public function link(string $link): static
+    {
+        $this->link = $link;
+
+        return $this;
+    }
+
+    public function pubDate(string $pubDate): static
+    {
+        $this->pubDate = $pubDate;
+
+        return $this;
+    }
+
+    public function pubDateFromTimestamp(int $timestamp): static
+    {
+        return $this->pubDate(\gmdate('r', $timestamp));
+    }
+
+    public function creator(string $creator): static
+    {
+        $this->creator = $creator;
+
+        return $this;
+    }
+
+    public function guid(string $guid, bool $isPermalink = true): static
+    {
+        $this->guid = $guid;
+        $this->guidIsPermalink = $isPermalink;
+
+        return $this;
+    }
+
+    public function enclosure(string $url, int $length, string $type): static
+    {
+        $this->enclosure = new RssFeedEnclosure($url, $length, $type);
+
+        return $this;
+    }
+
+    public function contentEncoded(string $content): static
+    {
+        $this->contentEncoded = $content;
+
+        return $this;
+    }
+
+    public function comments(string $url): static
+    {
+        $this->comments = $url;
+
+        return $this;
+    }
+
+    public function slashComments(int $comments): static
+    {
+        $this->slashComments = $comments;
+
+        return $this;
+    }
+
+    public function category(string $name, ?string $domain = null): static
+    {
+        $this->categories[] = new RssFeedCategory($name, $domain);
+
+        return $this;
+    }
+
+    public function author(string $email): static
+    {
+        $this->author = $email;
+
+        return $this;
+    }
+
+    public function source(string $name, string $url): static
+    {
+        $this->source = new RssFeedSource($name, $url);
+
+        return $this;
+    }
+
+    public function getXML(): \SimpleXMLElement
+    {
+        $this->integrityCheck();
+
+        $element = new XmlElement(
+            '<?xml version="1.0" encoding="UTF-8"?><item></item>',
+            LIBXML_NOERROR | LIBXML_ERR_NONE | LIBXML_ERR_FATAL
+        );
+
+        if (isset($this->title)) {
+            $element->addChild('title', $this->title);
+        }
+        if (isset($this->link)) {
+            $element->addChild('link', $this->link);
+        }
+        if (isset($this->author)) {
+            $element->addChild('author', $this->author);
+        }
+        if (isset($this->description)) {
+            $element->addChildCData('description', $this->description);
+        }
+        if (isset($this->comments)) {
+            $element->addChild('comments', $this->comments);
+        }
+        if (isset($this->slashComments)) {
+            $element->addChild('xmlns:slash:comments', $this->slashComments);
+        }
+        if (isset($this->guid)) {
+            $guidElement = $element->addChild('guid', $this->guid);
+            if (!$this->guidIsPermalink) {
+                $guidElement->addAttribute('isPermaLink', 'false');
+            }
+        }
+        if (isset($this->pubDate)) {
+            $element->addChild('pubDate', $this->pubDate);
+        }
+        if (isset($this->creator)) {
+            $element->addChild('xmlns:dc:creator', $this->creator);
+        }
+        if (isset($this->contentEncoded)) {
+            $element->addChildCData('xmlns:content:encoded', $this->contentEncoded);
+        }
+        if (isset($this->source)) {
+            $sourceElement = $element->addChild('source', $this->source->name);
+            $sourceElement->addAttribute('url', $this->source->url);
+        }
+        if (isset($this->enclosure)) {
+            $enclosureElement = $element->addChild('enclosure');
+            $enclosureElement->addAttribute('url', $this->enclosure->url);
+            $enclosureElement->addAttribute('type', $this->enclosure->type);
+            $enclosureElement->addAttribute('length', $this->enclosure->length);
+        }
+
+        foreach ($this->categories as $category) {
+            $categoryElement = $element->addChild('category', $category->name);
+            if ($category->domain !== null) {
+                $categoryElement->addAttribute('domain', $category->domain);
+            }
+        }
+
+        return $element;
+    }
+
+    private function integrityCheck(): void
+    {
+        // All elements of an item are optional, however at least one of title or description must be present.
+        if (!isset($this->title) && !isset($this->description)) {
+            throw new BadMethodCallException("feed item needs either a 'title' or 'description'");
+        }
+    }
+}
diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeedSource.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeedSource.class.php
new file mode 100644
index 00000000000..b209ef314a7
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeedSource.class.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace wcf\system\rssFeed;
+
+final class RssFeedSource
+{
+    public function __construct(
+        public readonly string $name,
+        public readonly string $url,
+    ) {
+    }
+}
diff --git a/wcfsetup/install/files/lib/system/rssFeed/XmlElement.class.php b/wcfsetup/install/files/lib/system/rssFeed/XmlElement.class.php
new file mode 100644
index 00000000000..df94cd70f72
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/rssFeed/XmlElement.class.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace wcf\system\rssFeed;
+
+final class XmlElement extends \SimpleXMLElement
+{
+    public function addChild(string $name, ?string $value = null, ?string $namespace = null): ?static
+    {
+        if ($value !== null && \is_string($value)) {
+            $value = \str_replace('&', '&amp;', $value);
+        }
+
+        return parent::addChild($name, $value, $namespace);
+    }
+
+    public function addChildCData(string $name, string $value): static
+    {
+        $child = $this->addChild($name);
+        $child->addCData($value);
+
+        return $child;
+    }
+
+    private function addCData(string $value): void
+    {
+        $node = \dom_import_simplexml($this);
+        $no = $node->ownerDocument;
+        $node->appendChild($no->createCDATASection($value));
+    }
+}

From 893f873cb021a2e0dc036de5f4d053b6f9a28c21 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Thu, 1 Feb 2024 18:13:43 +0100
Subject: [PATCH 02/10] Make use of the new API for the article feed

---
 .../article/content/ArticleContent.class.php  |  33 ++++--
 .../lib/page/AbstractRssFeedPage.class.php    |  78 ++++++++++++
 .../lib/page/ArticleRssFeedPage.class.php     | 111 ++++++++++++++++++
 3 files changed, 210 insertions(+), 12 deletions(-)
 create mode 100644 wcfsetup/install/files/lib/page/AbstractRssFeedPage.class.php
 create mode 100644 wcfsetup/install/files/lib/page/ArticleRssFeedPage.class.php

diff --git a/wcfsetup/install/files/lib/data/article/content/ArticleContent.class.php b/wcfsetup/install/files/lib/data/article/content/ArticleContent.class.php
index 52f9965a6d9..d079ffbd2ea 100644
--- a/wcfsetup/install/files/lib/data/article/content/ArticleContent.class.php
+++ b/wcfsetup/install/files/lib/data/article/content/ArticleContent.class.php
@@ -87,18 +87,7 @@ public function getFormattedTeaser()
         if ($this->teaser) {
             return \nl2br(StringUtil::encodeHTML($this->teaser), false);
         } else {
-            $htmlOutputProcessor = new HtmlOutputProcessor();
-            $htmlOutputProcessor->setOutputType('text/simplified-html');
-            $htmlOutputProcessor->enableUgc = false;
-            $htmlOutputProcessor->process(
-                $this->content,
-                'com.woltlab.wcf.article.content',
-                $this->articleContentID,
-                false,
-                $this->languageID
-            );
-
-            return MessageUtil::truncateFormattedMessage($htmlOutputProcessor->getHtml(), 500);
+            return MessageUtil::truncateFormattedMessage($this->getSimplifiedFormattedContent(), 500);
         }
     }
 
@@ -122,6 +111,26 @@ public function getFormattedContent()
         return $processor->getHtml();
     }
 
+    /**
+     * Returns a simplified version of the formatted content.
+     * @since 6.1
+     */
+    public function getSimplifiedFormattedContent(): string
+    {
+        $htmlOutputProcessor = new HtmlOutputProcessor();
+        $htmlOutputProcessor->setOutputType('text/simplified-html');
+        $htmlOutputProcessor->enableUgc = false;
+        $htmlOutputProcessor->process(
+            $this->content,
+            'com.woltlab.wcf.article.content',
+            $this->articleContentID,
+            false,
+            $this->languageID
+        );
+
+        return $htmlOutputProcessor->getHtml();
+    }
+
     /**
      * Returns article object.
      *
diff --git a/wcfsetup/install/files/lib/page/AbstractRssFeedPage.class.php b/wcfsetup/install/files/lib/page/AbstractRssFeedPage.class.php
new file mode 100644
index 00000000000..95f70608e4f
--- /dev/null
+++ b/wcfsetup/install/files/lib/page/AbstractRssFeedPage.class.php
@@ -0,0 +1,78 @@
+<?php
+
+namespace wcf\page;
+
+use wcf\system\rssFeed\RssFeed;
+use wcf\system\rssFeed\RssFeedChannel;
+use wcf\system\WCF;
+use wcf\util\ArrayUtil;
+
+/**
+ * Generates RSS 2-Feeds.
+ *
+ * @author      Tim Duesterhus, Marcel Werk
+ * @copyright   2001-2024 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.1
+ */
+abstract class AbstractRssFeedPage extends AbstractAuthedPage
+{
+    /**
+     * @inheritDoc
+     */
+    public $useTemplate = false;
+
+    /**
+     * parsed contents of $_REQUEST['id']
+     * @var int[]
+     */
+    public array $objectIDs = [];
+
+    #[\Override]
+    public function readParameters()
+    {
+        parent::readParameters();
+
+        if (isset($_REQUEST['id'])) {
+            if (\is_array($_REQUEST['id'])) {
+                // ?id[]=1337&id[]=9001
+                $this->objectIDs = ArrayUtil::toIntegerArray($_REQUEST['id']);
+            } else {
+                // ?id=1337 or ?id=1337,9001
+                $this->objectIDs = ArrayUtil::toIntegerArray(\explode(',', $_REQUEST['id']));
+            }
+        }
+    }
+
+    #[\Override]
+    public function show()
+    {
+        parent::show();
+        if ($this->getPsr7Response()) {
+            return;
+        }
+
+        $output = $this->getRssFeed()->render();
+
+        @\header('Content-Type: application/rss+xml; charset=UTF-8');
+
+        echo $output;
+    }
+
+    protected function getDefaultChannel(): RssFeedChannel
+    {
+        $channel = new RssFeedChannel();
+        $channel
+            ->title(WCF::getLanguage()->get(\PAGE_TITLE))
+            ->description(WCF::getLanguage()->get(\PAGE_DESCRIPTION))
+            ->link(WCF::getPath())
+            ->language(WCF::getLanguage()->getFixedLanguageCode())
+            ->pubDateFromTimestamp(\TIME_NOW)
+            ->lastBuildDateFromTimestamp(\TIME_NOW)
+            ->atomLinkSelf(WCF::getRequestURI());
+
+        return $channel;
+    }
+
+    protected abstract function getRssFeed(): RssFeed;
+}
diff --git a/wcfsetup/install/files/lib/page/ArticleRssFeedPage.class.php b/wcfsetup/install/files/lib/page/ArticleRssFeedPage.class.php
new file mode 100644
index 00000000000..084d9fcd432
--- /dev/null
+++ b/wcfsetup/install/files/lib/page/ArticleRssFeedPage.class.php
@@ -0,0 +1,111 @@
+<?php
+
+namespace wcf\page;
+
+use wcf\data\article\AccessibleArticleList;
+use wcf\data\article\category\ArticleCategory;
+use wcf\data\article\CategoryArticleList;
+use wcf\system\exception\IllegalLinkException;
+use wcf\system\exception\PermissionDeniedException;
+use wcf\system\rssFeed\RssFeed;
+use wcf\system\rssFeed\RssFeedItem;
+use wcf\system\WCF;
+use wcf\util\StringUtil;
+
+/**
+ * Outputs a list of cms articles of a certain category as a rss feed.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2024 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.1
+ */
+class ArticleRssFeedPage extends AbstractRssFeedPage
+{
+    public ArticleCategory $category;
+    public int $categoryID = 0;
+    public AccessibleArticleList $articles;
+
+    #[\Override]
+    public function readParameters()
+    {
+        parent::readParameters();
+
+        if (isset($_REQUEST['id'])) {
+            $this->categoryID = \intval($_REQUEST['id']);
+            $this->category = ArticleCategory::getCategory($this->categoryID);
+            if ($this->category === null) {
+                throw new IllegalLinkException();
+            }
+            if (!$this->category->isAccessible()) {
+                throw new PermissionDeniedException();
+            }
+        }
+    }
+
+    #[\Override]
+    public function readData()
+    {
+        parent::readData();
+
+        if ($this->categoryID) {
+            $this->articles = new CategoryArticleList($this->categoryID);
+        } else {
+            $this->articles = new AccessibleArticleList();
+        }
+        $this->articles->sqlOrderBy = 'article.time ' . ARTICLE_SORT_ORDER;
+        $this->articles->sqlLimit = 20;
+        $this->articles->readObjects();
+    }
+
+    #[\Override]
+    protected function getRssFeed(): RssFeed
+    {
+        $feed = new RssFeed();
+        $channel = $this->getDefaultChannel();
+        if (isset($this->category)) {
+            $channel->title($this->category->getTitle());
+            $channel->description($this->category->getDecoratedObject()->getDescription());
+        } else {
+            $channel->title(WCF::getLanguage()->get('wcf.article.articles'));
+        }
+
+        if ($this->articles->valid()) {
+            $channel->lastBuildDateFromTimestamp($this->articles->current()->getTime());
+        }
+        $feed->channel($channel);
+
+        foreach ($this->articles as $article) {
+            $item = new RssFeedItem();
+            $item
+                ->title($article->getTitle())
+                ->link($article->getLink())
+                ->description(StringUtil::truncateHTML($article->getFormattedTeaser(), 255))
+                ->pubDateFromTimestamp($article->time)
+                ->creator($article->username)
+                ->guid($article->getLink())
+                ->contentEncoded($article->getArticleContent()->getSimplifiedFormattedContent())
+                ->slashComments($article->getArticleContent()->comments);
+
+            if ($article->getImage() !== null) {
+                $item->enclosure(
+                    $article->getImage()->getThumbnailLink('small'),
+                    $article->getImage()->smallThumbnailSize,
+                    $article->getImage()->smallThumbnailType
+                );
+            }
+
+            $category = $article->getDecoratedObject()->getCategory();
+            if ($category !== null) {
+                $item->category($category->getTitle());
+                foreach ($category->getParentCategories() as $category) {
+                    $item->category($category->getTitle());
+                }
+            }
+
+            $channel->item($item);
+        }
+
+        return $feed;
+    }
+}

From 36f9aaac75d96a336c2c76d271683ed8750f6296 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Fri, 2 Feb 2024 12:33:44 +0100
Subject: [PATCH 03/10] Apply suggestions from code review

Co-authored-by: Alexander Ebert <ebert@woltlab.com>
---
 wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php
index a3d8354614c..4af7d98077a 100644
--- a/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php
@@ -26,7 +26,7 @@ public function render(): string
                 xmlns:dc="http://purl.org/dc/elements/1.1/"
                 xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
             >
-        EOT;
+            EOT;
 
         $element = new XmlElement(
             $header,

From 85b2d28d30c0bee496b136b98248a07c9470a67b Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Sun, 4 Feb 2024 14:25:42 +0100
Subject: [PATCH 04/10] Make use of the `objectIDs` parameter

---
 wcfsetup/install/files/lib/page/ArticleRssFeedPage.class.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/wcfsetup/install/files/lib/page/ArticleRssFeedPage.class.php b/wcfsetup/install/files/lib/page/ArticleRssFeedPage.class.php
index 084d9fcd432..bf4d575869a 100644
--- a/wcfsetup/install/files/lib/page/ArticleRssFeedPage.class.php
+++ b/wcfsetup/install/files/lib/page/ArticleRssFeedPage.class.php
@@ -31,8 +31,8 @@ public function readParameters()
     {
         parent::readParameters();
 
-        if (isset($_REQUEST['id'])) {
-            $this->categoryID = \intval($_REQUEST['id']);
+        if ($this->objectIDs !== []) {
+            $this->categoryID = \reset($this->objectIDs);
             $this->category = ArticleCategory::getCategory($this->categoryID);
             if ($this->category === null) {
                 throw new IllegalLinkException();

From 36583b620d1e7d15bb670d99aba39880ea7f7afc Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Sun, 4 Feb 2024 14:26:28 +0100
Subject: [PATCH 05/10] Change references in templates to the new page

---
 com.woltlab.wcf/templates/articleList.tpl         | 6 +++---
 com.woltlab.wcf/templates/categoryArticleList.tpl | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/com.woltlab.wcf/templates/articleList.tpl b/com.woltlab.wcf/templates/articleList.tpl
index 8492fa0a294..518f45856fc 100644
--- a/com.woltlab.wcf/templates/articleList.tpl
+++ b/com.woltlab.wcf/templates/articleList.tpl
@@ -7,9 +7,9 @@
 	{/if}
 	
 	{if $__wcf->getUser()->userID}
-		<link rel="alternate" type="application/rss+xml" title="{lang}wcf.global.button.rss{/lang}" href="{link controller='ArticleFeed'}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}">
+		<link rel="alternate" type="application/rss+xml" title="{lang}wcf.global.button.rss{/lang}" href="{link controller='ArticleRssFeed'}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}">
 	{else}
-		<link rel="alternate" type="application/rss+xml" title="{lang}wcf.global.button.rss{/lang}" href="{link controller='ArticleFeed'}{/link}">
+		<link rel="alternate" type="application/rss+xml" title="{lang}wcf.global.button.rss{/lang}" href="{link controller='ArticleRssFeed'}{/link}">
 	{/if}
 {/capture}
 
@@ -104,7 +104,7 @@
 {/capture}
 
 {capture assign='contentInteractionDropdownItems'}
-	<li><a rel="alternate" href="{if $__wcf->getUser()->userID}{link controller='ArticleFeed'}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}{else}{link controller='ArticleFeed'}{/link}{/if}" class="rssFeed">{lang}wcf.global.button.rss{/lang}</a></li>
+	<li><a rel="alternate" href="{if $__wcf->getUser()->userID}{link controller='ArticleRssFeed'}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}{else}{link controller='ArticleRssFeed'}{/link}{/if}" class="rssFeed">{lang}wcf.global.button.rss{/lang}</a></li>
 {/capture}
 
 {include file='header'}
diff --git a/com.woltlab.wcf/templates/categoryArticleList.tpl b/com.woltlab.wcf/templates/categoryArticleList.tpl
index 392e7c8fadc..1db7eec872e 100644
--- a/com.woltlab.wcf/templates/categoryArticleList.tpl
+++ b/com.woltlab.wcf/templates/categoryArticleList.tpl
@@ -12,9 +12,9 @@
 	{/if}
 	
 	{if $__wcf->getUser()->userID}
-		<link rel="alternate" type="application/rss+xml" title="{lang}wcf.global.button.rss{/lang}" href="{link controller='ArticleFeed' id=$categoryID}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}">
+		<link rel="alternate" type="application/rss+xml" title="{lang}wcf.global.button.rss{/lang}" href="{link controller='ArticleRssFeed' id=$categoryID}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}">
 	{else}
-		<link rel="alternate" type="application/rss+xml" title="{lang}wcf.global.button.rss{/lang}" href="{link controller='ArticleFeed' id=$categoryID}{/link}">
+		<link rel="alternate" type="application/rss+xml" title="{lang}wcf.global.button.rss{/lang}" href="{link controller='ArticleRssFeed' id=$categoryID}{/link}">
 	{/if}
 {/capture}
 
@@ -69,7 +69,7 @@
 {/capture}
 
 {capture assign='contentInteractionDropdownItems'}
-	<li><a rel="alternate" href="{if $__wcf->getUser()->userID}{link controller='ArticleFeed' id=$categoryID}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}{else}{link controller='ArticleFeed' id=$categoryID}{/link}{/if}" class="rssFeed">{lang}wcf.global.button.rss{/lang}</a></li>
+	<li><a rel="alternate" href="{if $__wcf->getUser()->userID}{link controller='ArticleRssFeed' id=$categoryID}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}{else}{link controller='ArticleRssFeed' id=$categoryID}{/link}{/if}" class="rssFeed">{lang}wcf.global.button.rss{/lang}</a></li>
 {/capture}
 
 {include file='header'}

From a9da8426408c70fc88c0c153eb2bcc21c8cc69ba Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Sun, 4 Feb 2024 14:48:34 +0100
Subject: [PATCH 06/10] Add redirect to new rss feed page

---
 .../files/lib/page/AbstractFeedPage.class.php | 25 +++++++++++++++++++
 .../files/lib/page/ArticleFeedPage.class.php  |  3 +++
 2 files changed, 28 insertions(+)

diff --git a/wcfsetup/install/files/lib/page/AbstractFeedPage.class.php b/wcfsetup/install/files/lib/page/AbstractFeedPage.class.php
index cbf9a54144c..6b2a7f85617 100644
--- a/wcfsetup/install/files/lib/page/AbstractFeedPage.class.php
+++ b/wcfsetup/install/files/lib/page/AbstractFeedPage.class.php
@@ -2,8 +2,10 @@
 
 namespace wcf\page;
 
+use wcf\system\request\LinkHandler;
 use wcf\system\WCF;
 use wcf\util\ArrayUtil;
+use wcf\util\HeaderUtil;
 
 /**
  * Generates RSS 2-Feeds.
@@ -11,6 +13,7 @@
  * @author  Tim Duesterhus
  * @copyright   2001-2019 WoltLab GmbH
  * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @deprecated 6.1 use `AbstractRssFeedPage` instead
  */
 abstract class AbstractFeedPage extends AbstractAuthedPage
 {
@@ -96,4 +99,26 @@ public function show()
         // show template
         WCF::getTPL()->display($this->templateName, $this->application, false);
     }
+
+    protected function redirectToNewPage(string $className): void
+    {
+        $parameters = [];
+        $url = '';
+        if ($this->objectIDs !== []) {
+            if (\count($this->objectIDs) === 1) {
+                $parameters['id'] = \reset($this->objectIDs);
+            } else {
+                $url = 'id=' . \implode(',', $this->objectIDs);
+            }
+        }
+        if (isset($_REQUEST['at'])) {
+            $parameters['at'] = $_REQUEST['at'];
+        }
+        HeaderUtil::redirect(
+            LinkHandler::getInstance()->getControllerLink($className, $parameters, $url),
+            true,
+            false
+        );
+        exit;
+    }
 }
diff --git a/wcfsetup/install/files/lib/page/ArticleFeedPage.class.php b/wcfsetup/install/files/lib/page/ArticleFeedPage.class.php
index d1692c44342..e0a47030be9 100644
--- a/wcfsetup/install/files/lib/page/ArticleFeedPage.class.php
+++ b/wcfsetup/install/files/lib/page/ArticleFeedPage.class.php
@@ -15,6 +15,7 @@
  * @copyright   2001-2019 WoltLab GmbH
  * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
  * @since   3.0
+ * @deprecated 6.1 use `ArticleRssFeedPage` instead
  */
 class ArticleFeedPage extends AbstractFeedPage
 {
@@ -47,6 +48,8 @@ public function readParameters()
                 throw new PermissionDeniedException();
             }
         }
+
+        $this->redirectToNewPage(ArticleRssFeedPage::class);
     }
 
     /**

From b5eb998ac5d17e9bf14bbdc05cd32016f895ce4d Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Sun, 4 Feb 2024 14:48:44 +0100
Subject: [PATCH 07/10] Deprecate old code

---
 .../install/files/lib/data/IFeedEntryWithEnclosure.class.php     | 1 +
 wcfsetup/install/files/lib/data/article/FeedArticle.class.php    | 1 +
 .../install/files/lib/data/article/FeedArticleList.class.php     | 1 +
 3 files changed, 3 insertions(+)

diff --git a/wcfsetup/install/files/lib/data/IFeedEntryWithEnclosure.class.php b/wcfsetup/install/files/lib/data/IFeedEntryWithEnclosure.class.php
index 9ff7df58ec2..132cf8c5ec2 100644
--- a/wcfsetup/install/files/lib/data/IFeedEntryWithEnclosure.class.php
+++ b/wcfsetup/install/files/lib/data/IFeedEntryWithEnclosure.class.php
@@ -10,6 +10,7 @@
  * @author  Marcel Werk
  * @copyright   2001-2019 WoltLab GmbH
  * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @deprecated 6.1 use `wcf\system\rssFeed\RssFeedItem` instead
  */
 interface IFeedEntryWithEnclosure extends IFeedEntry
 {
diff --git a/wcfsetup/install/files/lib/data/article/FeedArticle.class.php b/wcfsetup/install/files/lib/data/article/FeedArticle.class.php
index 5b839da19f6..a1ba081d5aa 100644
--- a/wcfsetup/install/files/lib/data/article/FeedArticle.class.php
+++ b/wcfsetup/install/files/lib/data/article/FeedArticle.class.php
@@ -14,6 +14,7 @@
  * @copyright   2001-2019 WoltLab GmbH
  * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
  * @since   3.0
+ * @deprecated 6.1
  */
 class FeedArticle extends ViewableArticle implements IFeedEntryWithEnclosure
 {
diff --git a/wcfsetup/install/files/lib/data/article/FeedArticleList.class.php b/wcfsetup/install/files/lib/data/article/FeedArticleList.class.php
index af6642e36c5..aa7926cf3b9 100644
--- a/wcfsetup/install/files/lib/data/article/FeedArticleList.class.php
+++ b/wcfsetup/install/files/lib/data/article/FeedArticleList.class.php
@@ -9,6 +9,7 @@
  * @copyright   2001-2019 WoltLab GmbH
  * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
  * @since   3.0
+ * @deprecated 6.1
  *
  * @method  FeedArticle current()
  * @method  FeedArticle[]   getObjects()

From c049e54a2064d174a748e1a97280403c743e1482 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Sun, 4 Feb 2024 15:12:50 +0100
Subject: [PATCH 08/10] Add missing phpdoc

---
 .../install/files/lib/system/rssFeed/RssFeed.class.php    | 8 ++++++++
 .../files/lib/system/rssFeed/RssFeedCategory.class.php    | 8 ++++++++
 .../files/lib/system/rssFeed/RssFeedChannel.class.php     | 8 ++++++++
 .../files/lib/system/rssFeed/RssFeedEnclosure.class.php   | 8 ++++++++
 .../files/lib/system/rssFeed/RssFeedItem.class.php        | 8 ++++++++
 .../files/lib/system/rssFeed/RssFeedSource.class.php      | 8 ++++++++
 .../install/files/lib/system/rssFeed/XmlElement.class.php | 8 ++++++++
 7 files changed, 56 insertions(+)

diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php
index 4af7d98077a..871eee124b4 100644
--- a/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeed.class.php
@@ -2,6 +2,14 @@
 
 namespace wcf\system\rssFeed;
 
+/**
+ * Represents an rss feed.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2024 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.1
+ */
 final class RssFeed
 {
     /**
diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeedCategory.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeedCategory.class.php
index 1bac8b54cbb..e3f7497410f 100644
--- a/wcfsetup/install/files/lib/system/rssFeed/RssFeedCategory.class.php
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeedCategory.class.php
@@ -2,6 +2,14 @@
 
 namespace wcf\system\rssFeed;
 
+/**
+ * Represents an rss feed category.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2024 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.1
+ */
 final class RssFeedCategory
 {
     public function __construct(
diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeedChannel.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeedChannel.class.php
index ecbed1aedb4..d5aa375e404 100644
--- a/wcfsetup/install/files/lib/system/rssFeed/RssFeedChannel.class.php
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeedChannel.class.php
@@ -4,6 +4,14 @@
 
 use BadMethodCallException;
 
+/**
+ * Represents an rss feed channel.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2024 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.1
+ */
 final class RssFeedChannel
 {
     private string $title;
diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeedEnclosure.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeedEnclosure.class.php
index f87419767ca..664940772db 100644
--- a/wcfsetup/install/files/lib/system/rssFeed/RssFeedEnclosure.class.php
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeedEnclosure.class.php
@@ -2,6 +2,14 @@
 
 namespace wcf\system\rssFeed;
 
+/**
+ * Represents an rss feed enclosure.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2024 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.1
+ */
 final class RssFeedEnclosure
 {
     public function __construct(
diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeedItem.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeedItem.class.php
index 0599a427e4d..202ddfca4e6 100644
--- a/wcfsetup/install/files/lib/system/rssFeed/RssFeedItem.class.php
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeedItem.class.php
@@ -4,6 +4,14 @@
 
 use BadMethodCallException;
 
+/**
+ * Represents an rss feed item.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2024 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.1
+ */
 final class RssFeedItem
 {
     private string $title;
diff --git a/wcfsetup/install/files/lib/system/rssFeed/RssFeedSource.class.php b/wcfsetup/install/files/lib/system/rssFeed/RssFeedSource.class.php
index b209ef314a7..9d06ac440d5 100644
--- a/wcfsetup/install/files/lib/system/rssFeed/RssFeedSource.class.php
+++ b/wcfsetup/install/files/lib/system/rssFeed/RssFeedSource.class.php
@@ -2,6 +2,14 @@
 
 namespace wcf\system\rssFeed;
 
+/**
+ * Represents an rss source category.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2024 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.1
+ */
 final class RssFeedSource
 {
     public function __construct(
diff --git a/wcfsetup/install/files/lib/system/rssFeed/XmlElement.class.php b/wcfsetup/install/files/lib/system/rssFeed/XmlElement.class.php
index df94cd70f72..72fc0ff5b7e 100644
--- a/wcfsetup/install/files/lib/system/rssFeed/XmlElement.class.php
+++ b/wcfsetup/install/files/lib/system/rssFeed/XmlElement.class.php
@@ -2,6 +2,14 @@
 
 namespace wcf\system\rssFeed;
 
+/**
+ * Simplifies the use of SimpleXMLElement within the generation of RSS feeds.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2024 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.1
+ */
 final class XmlElement extends \SimpleXMLElement
 {
     public function addChild(string $name, ?string $value = null, ?string $namespace = null): ?static

From 885219cb79d74fca23a31916753ed37ea79c83ad Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Sun, 4 Feb 2024 15:19:36 +0100
Subject: [PATCH 09/10] Use new implementation for notification feed page

---
 .../templates/notificationList.tpl            |  4 +-
 .../lib/page/NotificationFeedPage.class.php   |  3 +
 .../page/NotificationRssFeedPage.class.php    | 63 +++++++++++++++++++
 3 files changed, 68 insertions(+), 2 deletions(-)
 create mode 100644 wcfsetup/install/files/lib/page/NotificationRssFeedPage.class.php

diff --git a/com.woltlab.wcf/templates/notificationList.tpl b/com.woltlab.wcf/templates/notificationList.tpl
index e5e849ec070..02660820d03 100644
--- a/com.woltlab.wcf/templates/notificationList.tpl
+++ b/com.woltlab.wcf/templates/notificationList.tpl
@@ -1,7 +1,7 @@
 {capture assign='contentTitleBadge'}<span class="badge jsNotificationsBadge">{#$__wcf->getUserNotificationHandler()->countAllNotifications()}</span>{/capture}
 
 {capture assign='headContent'}
-	<link rel="alternate" type="application/rss+xml" title="{lang}wcf.global.button.rss{/lang}" href="{link controller='NotificationFeed'}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}">
+	<link rel="alternate" type="application/rss+xml" title="{lang}wcf.global.button.rss{/lang}" href="{link controller='NotificationRssFeed'}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}">
 {/capture}
 
 {capture assign='contentInteractionPagination'}
@@ -15,7 +15,7 @@
 {/capture}
 
 {capture assign='contentInteractionDropdownItems'}
-	<li><a rel="alternate" href="{link controller='NotificationFeed'}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}">{lang}wcf.global.button.rss{/lang}</a></li>
+	<li><a rel="alternate" href="{link controller='NotificationRssFeed'}at={@$__wcf->getUser()->userID}-{@$__wcf->getUser()->accessToken}{/link}">{lang}wcf.global.button.rss{/lang}</a></li>
 {/capture}
 
 {include file='header'}
diff --git a/wcfsetup/install/files/lib/page/NotificationFeedPage.class.php b/wcfsetup/install/files/lib/page/NotificationFeedPage.class.php
index 1a52b1ad1b2..e4c25a79e08 100644
--- a/wcfsetup/install/files/lib/page/NotificationFeedPage.class.php
+++ b/wcfsetup/install/files/lib/page/NotificationFeedPage.class.php
@@ -13,6 +13,7 @@
  * @copyright   2001-2019 WoltLab GmbH
  * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
  * @since   3.0
+ * @deprecated 6.1 use `NotificationRssFeedPage` instead
  */
 class NotificationFeedPage extends AbstractFeedPage
 {
@@ -28,6 +29,8 @@ public function readParameters()
         }
 
         $this->title = WCF::getLanguage()->get('wcf.user.menu.community.notification');
+
+        $this->redirectToNewPage(NotificationRssFeedPage::class);
     }
 
     /**
diff --git a/wcfsetup/install/files/lib/page/NotificationRssFeedPage.class.php b/wcfsetup/install/files/lib/page/NotificationRssFeedPage.class.php
new file mode 100644
index 00000000000..f2ff35b4aa2
--- /dev/null
+++ b/wcfsetup/install/files/lib/page/NotificationRssFeedPage.class.php
@@ -0,0 +1,63 @@
+<?php
+
+namespace wcf\page;
+
+use wcf\system\exception\IllegalLinkException;
+use wcf\system\rssFeed\RssFeed;
+use wcf\system\rssFeed\RssFeedItem;
+use wcf\system\user\notification\event\AbstractUserNotificationEvent;
+use wcf\system\user\notification\UserNotificationHandler;
+use wcf\system\WCF;
+
+/**
+ * Shows a list of own user notifications in feed.
+ *
+ * @author      Joshua Ruesweg, Marcel Werk
+ * @copyright   2001-2024 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.1
+ */
+class NotificationRssFeedPage extends AbstractRssFeedPage
+{
+    #[\Override]
+    public function readParameters()
+    {
+        parent::readParameters();
+
+        if (!WCF::getUser()->userID) {
+            throw new IllegalLinkException();
+        }
+    }
+
+    #[\Override]
+    protected function getRssFeed(): RssFeed
+    {
+        $feed = new RssFeed();
+        $channel = $this->getDefaultChannel();
+        $channel->title(WCF::getLanguage()->get('wcf.user.menu.community.notification'));
+        $feed->channel($channel);
+
+        $notifications = UserNotificationHandler::getInstance()->getNotifications(20);
+        if ($notifications['notifications'] !== []) {
+            $channel->lastBuildDateFromTimestamp($notifications['notifications'][0]['time']);
+        }
+
+        foreach ($notifications['notifications'] as $notification) {
+            $event = $notification['event'];
+            \assert($event instanceof AbstractUserNotificationEvent);
+
+            $item = new RssFeedItem();
+            $item
+                ->title($event->getTitle())
+                ->link($event->getLink())
+                ->description($event->getExcerpt())
+                ->pubDateFromTimestamp($event->getTime())
+                ->creator($event->getAuthor()->username)
+                ->guid($event->getLink())
+                ->contentEncoded($event->getFormattedMessage());
+            $channel->item($item);
+        }
+
+        return $feed;
+    }
+}

From f922c091e21891f4a2198a2c443a2370b6c15a58 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Sun, 4 Feb 2024 15:19:45 +0100
Subject: [PATCH 10/10] Deprecate old code

---
 wcfsetup/install/files/lib/data/IFeedEntry.class.php | 1 +
 1 file changed, 1 insertion(+)

diff --git a/wcfsetup/install/files/lib/data/IFeedEntry.class.php b/wcfsetup/install/files/lib/data/IFeedEntry.class.php
index 6d3698ea685..c59e6a22c47 100644
--- a/wcfsetup/install/files/lib/data/IFeedEntry.class.php
+++ b/wcfsetup/install/files/lib/data/IFeedEntry.class.php
@@ -8,6 +8,7 @@
  * @author  Tim Duesterhus
  * @copyright   2001-2019 WoltLab GmbH
  * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @deprecated 6.1 use `wcf\system\rssFeed\RssFeedItem` instead
  */
 interface IFeedEntry extends IMessage
 {