diff --git a/var/Typecho/Request.php b/var/Typecho/Request.php
index 626678d2..68f0e3b3 100644
--- a/var/Typecho/Request.php
+++ b/var/Typecho/Request.php
@@ -218,10 +218,7 @@ class Typecho_Request
     public static function getUrlPrefix()
     {
         if (empty(self::$_urlPrefix)) {
-            $isSecure = (!empty($_SERVER['HTTPS']) && 'off' != strtolower($_SERVER['HTTPS'])) 
-                || (!empty($_SERVER['SERVER_PORT']) && 443 == $_SERVER['SERVER_PORT']);
-
-            self::$_urlPrefix = ($isSecure ? 'https' : 'http') 
+            self::$_urlPrefix = (self::isSecure() ? 'https' : 'http') 
                 . '://' . (isset($_SERVER['HTTP_HOST']) ? $_SERVER['HTTP_HOST'] : $_SERVER['SERVER_NAME'])
                 . (in_array($_SERVER['SERVER_PORT'], array(80, 443)) ? '' : ':' . $_SERVER['SERVER_PORT']);
         }