Bring back some legacy functions and session vars for better backwards compatibility

program/include/rcube.php

@@ -348,6 +348,7 @@ class rcube
       $options['port']     = $_SESSION['storage_port'];
       $options['ssl']      = $_SESSION['storage_ssl'];
       $options['password'] = $this->decrypt($_SESSION['password']);
+      $_SESSION[$driver.'_host'] = $_SESSION['storage_host'];
     }
 
     $options = $this->plugins->exec_hook("storage_init", $options);

program/include/rcube_bc.inc

@@ -385,3 +385,8 @@ function rcube_idn_to_utf8($str)
 {
     return rcube_utils::idn_to_utf8($str);
 }
+
+function send_future_expire_header($offset = 2600000)
+{
+    return rcmail::get_instance()->output->future_expire_header($offset);
+}

program/include/rcube_output.php

@@ -237,6 +237,21 @@ abstract class rcube_output
         }
     }
 
+    /**
+     * Send header with expire date 30 days in future
+     *
+     * @param int Expiration time in seconds
+     */
+    public function future_expire_header($offset = 2600000)
+    {
+        if (headers_sent())
+            return;
+
+        header("Expires: " . gmdate("D, d M Y H:i:s", time()+$offset) . " GMT");
+        header("Cache-Control: max-age=$offset");
+        header("Pragma: ");
+    }
+
 
     /**
      * Show error page and terminate script execution