From 6d746453c75e2c482458f687585ef436a28a9888 Mon Sep 17 00:00:00 2001
From: Andrew Dolgov <noreply@fakecake.org>
Date: Thu, 20 Jun 2019 07:51:48 +0300
Subject: get_feeds_from_html: remove XML preamble hack move several related
 helper functions to Feeds class

---
 classes/feeds.php | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 87 insertions(+), 4 deletions(-)

(limited to 'classes/feeds.php')

diff --git a/classes/feeds.php b/classes/feeds.php
index 92bbd113b..2714f4596 100755
--- a/classes/feeds.php
+++ b/classes/feeds.php
@@ -1135,9 +1135,9 @@ class Feeds extends Handler_Protected {
 
 		$pdo = Db::pdo();
 
-		$url = fix_url($url);
+		$url = Feeds::fix_url($url);
 
-		if (!$url || !validate_feed_url($url)) return array("code" => 2);
+		if (!$url || !Feeds::validate_feed_url($url)) return array("code" => 2);
 
 		$contents = @fetch_file_contents($url, false, $auth_login, $auth_pass);
 
@@ -1153,8 +1153,8 @@ class Feeds extends Handler_Protected {
 			return array("code" => 5, "message" => $fetch_last_error);
 		}
 
-		if (mb_strpos($fetch_last_content_type, "html") !== FALSE && is_html($contents)) {
-			$feedUrls = get_feeds_from_html($url, $contents);
+		if (mb_strpos($fetch_last_content_type, "html") !== FALSE && Feeds::is_html($contents)) {
+			$feedUrls = Feeds::get_feeds_from_html($url, $contents);
 
 			if (count($feedUrls) == 0) {
 				return array("code" => 3);
@@ -1923,5 +1923,88 @@ class Feeds extends Handler_Protected {
         return $colormap[$sum];
 	}
 
+	static function get_feeds_from_html($url, $content) {
+		$url     = Feeds::fix_url($url);
+		$baseUrl = substr($url, 0, strrpos($url, '/') + 1);
+
+		libxml_use_internal_errors(true);
+		$feedUrls = [];
+
+		$doc = new DOMDocument();
+		if ($doc->loadHTML($content)) {
+			$xpath = new DOMXPath($doc);
+			$entries = $xpath->query('/html/head/link[@rel="alternate" and '.
+				'(contains(@type,"rss") or contains(@type,"atom"))]|/html/head/link[@rel="feed"]');
+
+			foreach ($entries as $entry) {
+				if ($entry->hasAttribute('href')) {
+					$title = $entry->getAttribute('title');
+					if ($title == '') {
+						$title = $entry->getAttribute('type');
+					}
+					$feedUrl = rewrite_relative_url(
+						$baseUrl, $entry->getAttribute('href')
+					);
+					$feedUrls[$feedUrl] = $title;
+				}
+			}
+		}
+		return $feedUrls;
+	}
+
+	static function is_html($content) {
+		return preg_match("/<html|DOCTYPE html/i", substr($content, 0, 8192)) !== 0;
+	}
+
+	static function validate_feed_url($url) {
+		$parts = parse_url($url);
+
+		return ($parts['scheme'] == 'http' || $parts['scheme'] == 'feed' || $parts['scheme'] == 'https');
+	}
+
+	/**
+	 * Fixes incomplete URLs by prepending "http://".
+	 * Also replaces feed:// with http://, and
+	 * prepends a trailing slash if the url is a domain name only.
+	 *
+	 * @param string $url Possibly incomplete URL
+	 *
+	 * @return string Fixed URL.
+	 */
+	static function fix_url($url) {
+
+		// support schema-less urls
+		if (strpos($url, '//') === 0) {
+			$url = 'https:' . $url;
+		}
+
+		if (strpos($url, '://') === false) {
+			$url = 'http://' . $url;
+		} else if (substr($url, 0, 5) == 'feed:') {
+			$url = 'http:' . substr($url, 5);
+		}
+
+		//prepend slash if the URL has no slash in it
+		// "http://www.example" -> "http://www.example/"
+		if (strpos($url, '/', strpos($url, ':') + 3) === false) {
+			$url .= '/';
+		}
+
+		//convert IDNA hostname to punycode if possible
+		if (function_exists("idn_to_ascii")) {
+			$parts = parse_url($url);
+			if (mb_detect_encoding($parts['host']) != 'ASCII')
+			{
+				$parts['host'] = idn_to_ascii($parts['host']);
+				$url = build_url($parts);
+			}
+		}
+
+		if ($url != "http:///")
+			return $url;
+		else
+			return '';
+	}
+
 }
 
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