Add canonical urls anywhere possible

Sources/Display.php

@@ -350,6 +350,11 @@ function Display()
 		'current_page' => $_REQUEST['start'] / $modSettings['defaultMaxMessages'] + 1,
 		'num_pages' => floor($topicinfo['numReplies'] / $modSettings['defaultMaxMessages']) + 1
 	);
+	if (isset ($_REQUEST['topicname'])) {
+		$context['canonical_url'] = "/forum/{$_REQUEST['topicname']}?start={$_REQUEST['start']}";
+	} else {
+		$context['canonical_url'] = $scripturl . '?topic=' . $topic . '.' . $_REQUEST['start'];
+	}
 
 	// Figure out all the link to the next/prev/first/last/etc. for wireless mainly.
 	$context['links'] = array(

Themes/default/index.template.php

@@ -94,6 +94,9 @@ function template_main_above()
         <link rel="stylesheet" type="text/css" href="http://rock.ru/forum/markitup/sets/bbcode/style.css" />
         <link rel="alternate" type="application/rss+xml" title="Новые сообщения в теме" href="http://rock.ru/forum/yarss.php?topic=' . $context['current_topic'] . '" />';
 
+	if (!empty($context['canonical_url']))
+		echo '
+	<link rel="canonical" href="' . $context['canonical_url'] . '"/>';
 
 	// If we're in a board, or a topic for that matter, the index will be the board's index.
 	if (!empty($context['current_board'])) {