feat: ✨ add RSS and Atom feeds with caching and nice links

docker_dev/mysql_schema.sql

@@ -40,6 +40,17 @@ CREATE TABLE path_access_counts (
 	PRIMARY KEY(access_time, post_path, agent, referrer)
 );
 
+CREATE TABLE feed_cache (
+	search_path VARCHAR(255),
+	export_type VARCHAR(255),
+
+	feed_created_on DATETIME DEFAULT CURRENT_TIMESTAMP,
+
+	feed_content MEDIUMTEXT,
+
+	PRIMARY KEY(search_path, export_type)
+);
+
 INSERT INTO posts (post_path, post_path_depth, post_metadata, post_content)
 VALUES (
 	'/about',

www/mysql_adapter.php

@@ -44,7 +44,7 @@ class MySQLAdapter {
 		return $post_path;
 	}
 
-	function _exec($qery, $argtypes, ...$args) {
+	function _exec($qery, $argtypes = '', ...$args) {
 		$stmt = $this->raw->prepare($qery);
 		if($argtypes != ""){
 			$stmt->bind_param($argtypes, ...$args);

www/post_adapter.php

@@ -57,6 +57,11 @@ class PostHandler extends MySQLAdapter {
         parent::make_post_directory($directory);
     }
 
+	function update_or_create_post(...$args) {
+		$this->_exec("TRUNCATE feed_cache");
+		parent::update_or_create_post(...$args);
+	}
+
     function save_file($post_path, $file_path) {
 		$this->bump_post($post_path);
 		move_uploaded_file($file_path, $this->data_directory . $post_path);
@@ -101,6 +106,86 @@ class PostHandler extends MySQLAdapter {
 				$this->save_file($post_path, $file_path);
 		}
 	}
+
+	function try_get_cached_feed($path, $export_opt) {
+		$post_cache = $this->_exec("SELECT feed_content, feed_created_on
+		FROM feed_cache
+		WHERE search_path=? AND export_type=?", "ss", $path, $export_opt)->fetch_assoc();
+
+		if(!isset($post_cache)) {
+			return null;
+		}
+
+		return ['feed' => $post_cache['feed_content'], 'feed_ts' => $post_cache['feed_created_on']];
+	}
+
+	function construct_feed($path) {
+		$path = $this->_sanitize_path($path);
+
+		$feed = @new Feed;
+		
+		$feed->setTitle("DergFeed");
+		$feed->setLink("https://lucidragons.de" . $path);
+		$feed->setFeedLink("https://lucidragons.de/feeds/atom" . $path, "atom");
+
+		$feed->setDateModified(time());
+
+		$feed->setDescription("DergenFeed for all your " . $path . " needs <3");
+
+		$feed_posts = $this->_exec("SELECT 
+			post_path,
+			post_create_time, post_update_time,
+			post_content,
+			post_metadata
+		FROM posts
+		WHERE (post_path = ?) OR (post_path LIKE ?)
+		ORDER BY post_create_time DESC LIMIT 200",
+			"ss", $path, $path . '/%');
+
+		while($row = $feed_posts->fetch_array(MYSQLI_ASSOC)) {
+			$row = $this->_normalize_post_data($row);
+			$pmeta = $row['post_metadata'];
+			
+			if($pmeta['type'] == 'directory') {
+				continue;
+			}
+
+			$entry = $feed->createEntry();
+
+			$entry->setTitle($row['post_path'] . '> ' . $pmeta['title']);
+			$entry->setLink('https://lucidragons.de' . $row['post_path']);
+			$entry->setDateModified(strtotime($row['post_update_time']));
+			$entry->setDateCreated(strtotime($row['post_create_time']));
+
+			$entry->setDescription($pmeta['brief'] ?? $pmeta['title']);
+
+			$feed->addEntry($entry);
+		}
+
+		return $feed;
+	}
+
+	function get_laminas_feed($path, $export_opt) {
+		$path = $this->_sanitize_path($path);
+
+		$feed_cache = $this->try_get_cached_feed($path, $export_opt);
+
+		if(isset($feed_cache)) {			
+			return $feed_cache;
+		}
+
+		$feed = $this->construct_feed($path);
+
+		$this->_exec("INSERT INTO feed_cache 
+			(search_path, export_type, feed_content)
+		VALUES 
+			(?, 'atom', ?),
+			(?, 'rss', ?)",
+		"ssss", $path, $feed->export('atom'),
+			$path, $feed->export('rss'));
+
+		return $this->try_get_cached_feed($path, $export_opt);
+	}
 }
 
 ?>

www/router.php

@@ -111,6 +111,14 @@ function generate_website($SURI) {
 
             echo $twig->render('upload.html');
         }
+    } elseif(preg_match('/^\/feed(?:\/(rss|atom)(.*))?$/', $SURI, $match)) {
+        $feed = $adapter->get_laminas_feed($match[2] ?? '/', $match[1] ?? 'rss');
+
+        header('Content-Type: application/xml');
+        header('Cache-Control: max-age=1800');
+        header('Etag: W/"' . $SURI . '/' . strtotime($feed['feed_ts']) . '"');
+
+        echo $feed['feed'];
     } elseif(preg_match('/^\s*image/', $_SERVER['HTTP_ACCEPT'])) {
         header('Location: /raw' . $SURI);
         exit(0);

www/templates/fragments/filepath_bar.html

@@ -26,5 +26,11 @@
             <a href="/raw{{post.post_path}}">raw</a>
             <a href="/api/posts{{post.post_path}}">api</a>
         </li>
+        <li>
+            <a rel="alternate" type="application/rss+xml" target="_blank"
+               style="padding-left: 0.3rem;" href="/feed/rss{{post.post_path}}">
+                {{ fa['rss']|raw }}
+            </a>
+        </li>
     </menu>
 </div>

www/templates/pathed_content.html

@@ -2,6 +2,11 @@
 
 {% extends "root.html" %}
 
+{% block feed_links %}
+<link rel="alternate" type="application/rss+xml" title="DergSite Global Feed" href="https://lucidragons.de/feed">
+<link rel="alternate" type="application/atom+xml" title="DergSite Feed for {{post.post_path}}" href="https://lucidragons.de/feed/atom{{post.post_path}}">
+{% endblock %}
+
 {% block second_title %}
 <h2> {{ post.post_metadata.title }} </h2>
 {% endblock %}

www/templates/root.html

@@ -7,6 +7,10 @@
 
         <meta name="viewport" content="width=device-width,initial-scale=1">
     
+		{% block feed_links %}
+		<link rel="alternate" type="application/rss+xml" title="DergSite Global Feed" href="https://lucidragons.de/feed">
+		{% endblock %}
+
 		{% block extra_head %}{% endblock %}
 		
 		<script src="/static/banner.js" defer></script>