Merge branch 'main' into security-models

src/lib/Feed.php

@@ -1,15 +1,55 @@
 <?php
+
+/**
+ * Information for a feed item
+ */
+class FeedItem {
+
+    /** @var string The title of the feed item */
+    public string $title = '';
+
+    /** @var string The unique ID for the feed item */
+    public string $guid = '';
+
+    /** @var string The link to the original content */
+    public string $link = '';
+
+    /** @var string When this item was published */
+    public string $publishedOn = '';
+
+    /** @var ?string When this item was last updated */
+    public ?string $updatedOn = null;
+
+    /** @var string The content for the item */
+    public string $content = '';
+}
+
 /**
  * Feed retrieval, parsing, and manipulation
  */
 class Feed {
 
+    /** @var string The URL for the feed */
+    public string $url = '';
+
+    /** @var string The title of the feed */
+    public string $title = '';
+
+    /** @var ?string When the feed was last updated */
+    public ?string $updatedOn = null;
+
+    /** @var FeedItem[] The items contained in the feed */
+    public array $items = [];
+
     /** @var string The XML namespace for Atom feeds */
     public const string ATOM_NS = 'http://www.w3.org/2005/Atom';
 
     /** @var string The XML namespace for the `<content:encoded>` tag that allows HTML content in a feed */
     public const string CONTENT_NS = 'http://purl.org/rss/1.0/modules/content/';
 
+    /** @var string The XML namespace for XHTML */
+    public const string XHTML_NS = 'http://www.w3.org/1999/xhtml';
+
     /**
      * When parsing XML into a DOMDocument, errors are presented as warnings; this creates an exception for them
      *
@@ -45,24 +85,135 @@ class Feed {
     }
 
     /**
-     * Get the value of a child element by its tag name
+     * Get the value of a child element by its tag name for an RSS feed
      *
      * @param DOMElement $element The parent element
      * @param string $tagName The name of the tag whose value should be obtained
      * @return string The value of the element (or "[element] not found" if that element does not exist)
      */
-    private static function eltValue(DOMElement $element, string $tagName): string {
+    private static function rssValue(DOMElement $element, string $tagName): string {
         $tags = $element->getElementsByTagName($tagName);
         return $tags->length == 0 ? "$tagName not found" : $tags->item(0)->textContent;
     }
 
+    /**
+     * Extract items from an RSS feed
+     *
+     * @param DOMDocument $xml The XML received from the feed
+     * @param string $url The actual URL for the feed
+     * @return array|Feed[]|string[] ['ok' => feed] if successful, ['error' => message] if not
+     */
+    private static function fromRSS(DOMDocument $xml, string $url): array {
+        $channel = $xml->getElementsByTagName('channel')->item(0);
+        if (!($channel instanceof DOMElement)) {
+            return ['error' => "Channel element not found ($channel->nodeType)"];
+        }
+
+        $feed = new Feed();
+        $feed->title = self::rssValue($channel, 'title');
+        $feed->url   = $url;
+
+        // The Atom namespace provides a lastBuildDate, which contains the last time an item in the feed was updated; if
+        // that is not present, use the pubDate element instead
+        $feed->updatedOn = self::rssValue($channel, 'lastBuildDate');
+        if ($feed->updatedOn == 'lastBuildDate not found') {
+            $feed->updatedOn = self::rssValue($channel, 'pubDate');
+            if ($feed->updatedOn == 'pubDate not found') $feed->updatedOn = null;
+        }
+        $feed->updatedOn = Data::formatDate($feed->updatedOn);
+
+        foreach ($channel->getElementsByTagName('item') as $xmlItem) {
+            $itemGuid = self::rssValue($xmlItem, 'guid');
+            $updNodes = $xmlItem->getElementsByTagNameNS(Feed::ATOM_NS,    'updated');
+            $encNodes = $xmlItem->getElementsByTagNameNS(Feed::CONTENT_NS, 'encoded');
+            $item     = new FeedItem();
+            $item->guid        = $itemGuid == 'guid not found' ? self::rssValue($xmlItem, 'link') : $itemGuid;
+            $item->title       = self::rssValue($xmlItem, 'title');
+            $item->link        = self::rssValue($xmlItem, 'link');
+            $item->publishedOn = Data::formatDate(self::rssValue($xmlItem, 'pubDate'));
+            $item->updatedOn   = Data::formatDate($updNodes->length > 0 ? $updNodes->item(0)->textContent : null);
+            $item->content     = $encNodes->length > 0
+                ? $encNodes->item(0)->textContent
+                : self::rssValue($xmlItem, 'description');
+            $feed->items[] = $item;
+        }
+
+        return ['ok' => $feed];
+    }
+
+    /**
+     * Get the value of a child element by its tag name for an Atom feed
+     *
+     * (Atom feeds can have type attributes on nearly any value. For our purposes, types "text" and "html" will work as
+     * regular string values; for "xhtml", though, we will need to get the `<div>` and extract its contents instead.)
+     *
+     * @param DOMElement $element The parent element
+     * @param string $tagName The name of the tag whose value should be obtained
+     * @return string The value of the element (or "[element] not found" if that element does not exist)
+     */
+    private static function atomValue(DOMElement $element, string $tagName): string {
+        $tags = $element->getElementsByTagName($tagName);
+        if ($tags->length == 0) return "$tagName not found";
+        $tag = $tags->item(0);
+        if (!($tag instanceof DOMElement)) return $tag->textContent;
+        if ($tag->hasAttributes() && $tag->attributes->getNamedItem('type') == 'xhtml') {
+            $div = $tag->getElementsByTagNameNS(Feed::XHTML_NS, 'div');
+            if ($div->length == 0) return "-- invalid XHTML content --";
+            return $div->item(0)->textContent;
+        }
+        return $tag->textContent;
+    }
+
+    /**
+     * Extract items from an Atom feed
+     *
+     * @param DOMDocument $xml The XML received from the feed
+     * @param string $url The actual URL for the feed
+     * @return array|Feed[] ['ok' => feed]
+     */
+    private static function fromAtom(DOMDocument $xml, string $url): array {
+        /** @var DOMElement $root */
+        $root = $xml->getElementsByTagNameNS(self::ATOM_NS, 'feed')->item(0);
+        $feed = new Feed();
+        $feed->title = self::atomValue($root, 'title');
+        $feed->url   = $url;
+
+        $feed->updatedOn = self::atomValue($root, 'updated');
+        if ($feed->updatedOn == 'pubDate not found') $feed->updatedOn = null;
+        $feed->updatedOn = Data::formatDate($feed->updatedOn);
+
+        foreach ($root->getElementsByTagName('entry') as $xmlItem) {
+            $guid = self::atomValue($xmlItem, 'id');
+            $link = '';
+            foreach ($xmlItem->getElementsByTagName('link') as $linkElt) {
+                if ($linkElt->hasAttributes()) {
+                    $relAttr = $linkElt->attributes->getNamedItem('rel');
+                    if ($relAttr && $relAttr->value == 'alternate') {
+                        $link = $linkElt->attributes->getNamedItem('href')->value;
+                        break;
+                    }
+                }
+            }
+            if ($link == '' && str_starts_with($guid, 'http')) $link = $guid;
+
+            $item = new FeedItem();
+            $item->guid        = $guid;
+            $item->title       = self::atomValue($xmlItem, 'title');
+            $item->link        = $link;
+            $item->publishedOn = Data::formatDate(self::atomValue($xmlItem, 'published'));
+            $item->updatedOn   = Data::formatDate(self::atomValue($xmlItem, 'updated'));
+            $item->content     = self::atomValue($xmlItem, 'content');
+            $feed->items[] = $item;
+        }
+
+        return ['ok' => $feed];
+    }
+
     /**
      * Retrieve the feed
      *
-     * @param string $url
-     * @return array|DOMDocument[]|string[]|DOMElement[]
-     *      ['ok' => feedXml, 'url' => actualUrl, 'channel' => channel, 'updated' => updatedDate] if successful,
-     *      ['error' => message] if not
+     * @param string $url The URL of the feed to retrieve
+     * @return array|Feed[]|string[] ['ok' => feed] if successful, ['error' => message] if not
      */
     public static function retrieveFeed(string $url): array {
         $feedReq = curl_init($url);
@@ -83,26 +234,9 @@ class Feed {
             if (array_key_exists('error', $parsed)) {
                 $result['error'] = $parsed['error'];
             } else {
-                $result['ok']  = $parsed['ok'];
-                $result['url'] = curl_getinfo($feedReq, CURLINFO_EFFECTIVE_URL);
-
-                $channel = $result['ok']->getElementsByTagName('channel')->item(0);
-                if ($channel instanceof DOMElement) {
-                    $result['channel'] = $channel;
-                } else {
-                    return ['error' => "Channel element not found ($channel->nodeType)"];
-                }
-
-                // In Atom feeds, lastBuildDate contains the last time an item in the feed was updated; if that is not
-                // present, use the pubDate element instead
-                $updated = self::eltValue($channel, 'lastBuildDate');
-                if ($updated == 'lastBuildDate not found') {
-                    $updated = self::eltValue($channel, 'pubDate');
-                    if ($updated == 'pubDate not found') $updated = null;
-                }
-                $result['updated'] = Data::formatDate($updated);
-                return $result;
-
+                $extract = $parsed['ok']->getElementsByTagNameNS(self::ATOM_NS, 'feed')->length > 0
+                    ? self::fromAtom(...) : self::fromRSS(...);
+                $result  = $extract($parsed['ok'], curl_getinfo($feedReq, CURLINFO_EFFECTIVE_URL));
             }
         } else {
             $result['error'] = "Prospective feed URL $url returned HTTP Code $code: $feedContent";
@@ -112,35 +246,14 @@ class Feed {
         return $result;
     }
 
-    /**
-     * Extract the fields we need to keep from the feed
-     *
-     * @param DOMElement $item The item from the feed
-     * @return array The fields for the item as an associative array
-     */
-    private static function itemFields(DOMElement $item): array {
-        $itemGuid = self::eltValue($item, 'guid');
-        $updNodes = $item->getElementsByTagNameNS(self::ATOM_NS,    'updated');
-        $encNodes = $item->getElementsByTagNameNS(self::CONTENT_NS, 'encoded');
-        return [
-            'guid'      => $itemGuid == 'guid not found' ? self::eltValue($item, 'link') : $itemGuid,
-            'title'     => self::eltValue($item, 'title'),
-            'link'      => self::eltValue($item, 'link'),
-            'published' => Data::formatDate(self::eltValue($item, 'pubDate')),
-            'updated'   => Data::formatDate($updNodes->length > 0 ? $updNodes->item(0)->textContent : null),
-            'content'   => $encNodes->length > 0 ? $encNodes->item(0)->textContent
-                                                 : self::eltValue($item, 'description')
-        ];
-    }
-
     /**
      * Update a feed item
      *
      * @param int $itemId The ID of the item to be updated
-     * @param array $item The fields from the updated item
+     * @param FeedItem $item The item to be updated
      * @param SQLite3 $db A database connection to use for the update
      */
-    private static function updateItem(int $itemId, array $item, SQLite3 $db): void {
+    private static function updateItem(int $itemId, FeedItem $item, SQLite3 $db): void {
         $query = $db->prepare(<<<'SQL'
             UPDATE item
                SET title        = :title,
@@ -150,10 +263,10 @@ class Feed {
                    is_read      = 0
              WHERE id = :id
             SQL);
-        $query->bindValue(':title',     $item['title']);
-        $query->bindValue(':published', $item['published']);
-        $query->bindValue(':updated',   $item['updated']);
-        $query->bindValue(':content',   $item['content']);
+        $query->bindValue(':title',     $item->title);
+        $query->bindValue(':published', $item->publishedOn);
+        $query->bindValue(':updated',   $item->updatedOn);
+        $query->bindValue(':content',   $item->content);
         $query->bindValue(':id',        $itemId);
         $query->execute();
     }
@@ -162,10 +275,10 @@ class Feed {
      * Add a feed item
      *
      * @param int $feedId The ID of the feed to which the item should be added
-     * @param array $item The fields for the item
+     * @param FeedItem $item The item to be added
      * @param SQLite3 $db A database connection to use for the addition
      */
-    private static function addItem(int $feedId, array $item, SQLite3 $db): void {
+    private static function addItem(int $feedId, FeedItem $item, SQLite3 $db): void {
         $query = $db->prepare(<<<'SQL'
             INSERT INTO item (
                 feed_id, item_guid, item_link, title, published_on, updated_on, content
@@ -174,12 +287,12 @@ class Feed {
             )
             SQL);
         $query->bindValue(':feed',      $feedId);
-        $query->bindValue(':guid',      $item['guid']);
-        $query->bindValue(':link',      $item['link']);
-        $query->bindValue(':title',     $item['title']);
-        $query->bindValue(':published', $item['published']);
-        $query->bindValue(':updated',   $item['updated']);
-        $query->bindValue(':content',   $item['content']);
+        $query->bindValue(':guid',      $item->guid);
+        $query->bindValue(':link',      $item->link);
+        $query->bindValue(':title',     $item->title);
+        $query->bindValue(':published', $item->publishedOn);
+        $query->bindValue(':updated',   $item->updatedOn);
+        $query->bindValue(':content',   $item->content);
         $query->execute();
     }
 
@@ -187,23 +300,22 @@ class Feed {
      * Update a feed's items
      *
      * @param int $feedId The ID of the feed to which these items belong
-     * @param DOMElement $channel The RSS feed items
+     * @param Feed $feed The extracted Atom or RSS feed items
      * @return array ['ok' => true] if successful, ['error' => message] if not
      */
-    public static function updateItems(int $feedId, DOMElement $channel, SQLite3 $db): array {
+    public static function updateItems(int $feedId, Feed $feed, SQLite3 $db): array {
         try {
-            foreach ($channel->getElementsByTagName('item') as $rawItem) {
-                $item = self::itemFields($rawItem);
+            foreach ($feed->items as $item) {
                 $existsQuery = $db->prepare(
                     'SELECT id, published_on, updated_on FROM item WHERE feed_id = :feed AND item_guid = :guid');
                 $existsQuery->bindValue(':feed', $feedId);
-                $existsQuery->bindValue(':guid', $item['guid']);
+                $existsQuery->bindValue(':guid', $item->guid);
                 $exists = $existsQuery->execute();
                 if ($exists) {
                     $existing = $exists->fetchArray(SQLITE3_ASSOC);
                     if ($existing) {
-                        if (   $existing['published_on']     != $item['published']
-                            || $existing['updated_on'] ?? '' != $item['updated'] ?? '') {
+                        if (   $existing['published_on']       != $item->publishedOn
+                            || ($existing['updated_on'] ?? '') != ($item->updatedOn ?? '')) {
                             self::updateItem($existing['id'], $item, $db);
                         }
                     } else {
@@ -234,13 +346,14 @@ class Feed {
         $feedId = $feedResult ? $feedResult->fetchArray(SQLITE3_NUM)[0] : -1;
         if ($feedId < 0) return ['error' => "No feed for URL $url found"];
 
-        $feed = self::retrieveFeed($url);
-        if (array_key_exists('error', $feed)) return $feed;
+        $feedExtract = self::retrieveFeed($url);
+        if (array_key_exists('error', $feedExtract)) return $feedExtract;
 
-        $itemUpdate = self::updateItems($feedId, $feed['channel'], $db);
+        $feed = $feedExtract['ok'];
+        $itemUpdate = self::updateItems($feedId, $feed, $db);
         if (array_key_exists('error', $itemUpdate)) return $itemUpdate;
 
-        $urlUpdate = $url == $feed['url'] ? '' : ', url = :url';
+        $urlUpdate = $url == $feed->url ? '' : ', url = :url';
         $feedUpdate = $db->prepare(<<<SQL
             UPDATE feed
                SET title      = :title,
@@ -249,11 +362,11 @@ class Feed {
                    $urlUpdate
              WHERE id = :id
             SQL);
-        $feedUpdate->bindValue(':title',   self::eltValue($feed['channel'], 'title'));
-        $feedUpdate->bindValue(':updated', $feed['updated']);
+        $feedUpdate->bindValue(':title',   $feed->title);
+        $feedUpdate->bindValue(':updated', $feed->updatedOn);
         $feedUpdate->bindValue(':checked', Data::formatDate('now'));
         $feedUpdate->bindValue(':id',      $feedId);
-        if ($urlUpdate != '') $feedUpdate->bindValue(':url', $feed['url']);
+        if ($urlUpdate != '') $feedUpdate->bindValue(':url', $feed->url);
         $feedUpdate->execute();
 
         return ['ok' => true];
@@ -266,24 +379,25 @@ class Feed {
      * @return array ['ok' => feedId] if successful, ['error' => message] if not
      */
     public static function add(string $url, SQLite3 $db): array {
-        $feed = self::retrieveFeed($url);
-        if (array_key_exists('error', $feed)) return $feed;
+        $feedExtract = self::retrieveFeed($url);
+        if (array_key_exists('error', $feedExtract)) return $feedExtract;
 
+        $feed = $feedExtract['ok'];
         $query = $db->prepare(<<<'SQL'
             INSERT INTO feed (user_id, url, title, updated_on, checked_on)
             VALUES (:user, :url, :title, :updated, :checked)
             SQL);
         $query->bindValue(':user',    $_SESSION[Key::USER_ID]);
-        $query->bindValue(':url',     $feed['url']);
-        $query->bindValue(':title',   self::eltValue($feed['channel'], 'title'));
-        $query->bindValue(':updated', $feed['updated']);
+        $query->bindValue(':url',     $feed->url);
+        $query->bindValue(':title',   $feed->title);
+        $query->bindValue(':updated', $feed->updatedOn);
         $query->bindValue(':checked', Data::formatDate('now'));
         $result = $query->execute();
 
         $feedId = $result ? $db->lastInsertRowID() : -1;
         if ($feedId < 0) return ['error' => $db->lastErrorMsg()];
 
-        $result = self::updateItems($feedId, $feed['channel'], $db);
+        $result = self::updateItems($feedId, $feed, $db);
         if (array_key_exists('error', $result)) return $result;
 
         return ['ok' => $feedId];
@@ -294,6 +408,7 @@ class Feed {
      *
      * @param array $existing The existing RSS feed
      * @param string $url The URL with which the existing feed should be modified
+     * @param SQLite3 $db The database connection on which to execute the update
      * @return bool[]|string[] [ 'ok' => true ] if successful, [ 'error' => message ] if not
      */
     public static function update(array $existing, string $url, SQLite3 $db): array {
@@ -307,7 +422,9 @@ class Feed {
     }
 
     /**
-     * @param SQLite3 $db
+     * Refresh all feeds
+     *
+     * @param SQLite3 $db The database connection to use for refreshing feeds
      * @return array|true[] ['ok => true] if successful, ['error' => message] if not (may have multiple error lines)
      */
     public static function refreshAll(SQLite3 $db): array {

src/public/index.php

@@ -35,7 +35,7 @@ page_head('Welcome'); ?>
 if ($item) {
     while ($item) { ?>
         <p><a href=/item?id=<?=$item['id']?>><?=$item['item_title']?></a><br>
-            <?=$item['feed_title']?><br><small><em><?=date_time($item['as_of'])?></em></small><?php
+            <?=htmlentities($item['feed_title'])?><br><small><em><?=date_time($item['as_of'])?></em></small><?php
         $item = $result->fetchArray(SQLITE3_ASSOC);
     }
 } else { ?>

src/public/item.php

@@ -31,7 +31,7 @@ if ($_SERVER['REQUEST_METHOD'] == 'POST') {
 }
 
 $query = $db->prepare(<<<'SQL'
-    SELECT item.title AS item_title, item.item_link, item.published_on, item.updated_on, item.content, item.is_encoded,
+    SELECT item.title AS item_title, item.item_link, item.published_on, item.updated_on, item.content,
            feed.title AS feed_title
       FROM item INNER JOIN feed ON feed.id = item.feed_id
      WHERE item.id      = :id