1 files changed, 102 insertions, 0 deletions
diff --git a/engine/handlers/cache_handler.php b/engine/handlers/cache_handler.php
new file mode 100644
index 000000000..7706c2c92
--- /dev/null
+++ b/engine/handlers/cache_handler.php
@@ -0,0 +1,102 @@
+<?php
+/**
+ * Cache handler.
+ *
+ * External access to cached CSS and JavaScript views. The cached file URLS
+ * should be of the form: cache/<type>/<viewtype>/<name/of/view>.<unique_id>.<type> where
+ * type is either css or js, view is the name of the cached view, and
+ * unique_id is an identifier that is updated every time the cache is flushed.
+ * The simplest way to maintain a unique identifier is to use the lastcache
+ * variable in Elgg's config object.
+ *
+ * @see elgg_register_simplecache_view()
+ *
+ * @package Elgg.Core
+ * @subpackage Cache
+ */
+
+// Get dataroot
+require_once(dirname(dirname(__FILE__)) . '/settings.php');
+$mysql_dblink = mysql_connect($CONFIG->dbhost, $CONFIG->dbuser, $CONFIG->dbpass, true);
+if (!$mysql_dblink) {
+	echo 'Cache error: unable to connect to database server';
+	exit;
+}
+
+if (!mysql_select_db($CONFIG->dbname, $mysql_dblink)) {
+	echo 'Cache error: unable to connect to Elgg database';
+	exit;
+}
+
+$query = "select name, value from {$CONFIG->dbprefix}datalists
+		where name in ('dataroot', 'simplecache_enabled')";
+
+$result = mysql_query($query, $mysql_dblink);
+if (!$result) {
+	echo 'Cache error: unable to get the data root';
+	exit;
+}
+while ($row = mysql_fetch_object($result)) {
+	${$row->name} = $row->value;
+}
+mysql_free_result($result);
+
+
+$dirty_request = $_GET['request'];
+// only alphanumeric characters plus /, ., and _ and no '..'
+$filter = array("options" => array("regexp" => "/^(\.?[_a-zA-Z0-9\/]+)+$/"));
+$request = filter_var($dirty_request, FILTER_VALIDATE_REGEXP, $filter);
+if (!$request || !$simplecache_enabled) {
+	echo 'Cache error: bad request';
+	exit;
+}
+
+// testing showed regex to be marginally faster than array / string functions over 100000 reps
+// it won't make a difference in real life and regex is easier to read.
+// <type>/<viewtype>/<name/of/view.and.dots>.<ts>.<type>
+$regex = '|([^/]+)/([^/]+)/(.+)\.([^\.]+)\.([^.]+)$|';
+preg_match($regex, $request, $matches);
+
+$type = $matches[1];
+$viewtype = $matches[2];
+$view = $matches[3];
+$ts = $matches[4];
+
+// If is the same ETag, content didn't changed.
+$etag = $ts;
+if (isset($_SERVER['HTTP_IF_NONE_MATCH']) && trim($_SERVER['HTTP_IF_NONE_MATCH']) == "\"$etag\"") {
+	header("HTTP/1.1 304 Not Modified");
+	exit;
+}
+
+switch ($type) {
+	case 'css':
+		header("Content-type: text/css", true);
+		$view = "css/$view";
+		break;
+	case 'js':
+		header('Content-type: text/javascript', true);
+		$view = "js/$view";
+		break;
+}
+
+header('Expires: ' . gmdate('D, d M Y H:i:s \G\M\T', strtotime("+6 months")), true);
+header("Pragma: public", true);
+header("Cache-Control: public", true);
+header("ETag: \"$etag\"");
+
+$filename = $dataroot . 'views_simplecache/' . md5($viewtype . $view);
+
+if (file_exists($filename)) {
+	$contents = file_get_contents($filename);
+} else {
+	// someone trying to access a non-cached file or a race condition with cache flushing
+	mysql_close($mysql_dblink);
+	require_once(dirname(dirname(__FILE__)) . "/start.php");
+	elgg_regenerate_simplecache();
+
+	elgg_set_viewtype($viewtype);
+	$contents = elgg_view($view);
+}
+
+echo $contents;