--- a/viewer.py	Thu Aug 04 10:54:57 2016 +0800
+++ b/viewer.py	Thu Aug 04 11:40:37 2016 +0800
@@ -47,7 +47,8 @@
 def urlencode(**kwargs):
     def joinparams(params):
         return ','.join(quote_plus(i, '(),') for i in params)
-    return '&'.join(quote_plus(k) + '=' + joinparams(v) for k, v in kwargs.items())
+    items = sorted(kwargs.items())
+    return '&'.join(quote_plus(k) + '=' + joinparams(v) for k, v in items)
 
 
 class BaseHandler(RequestHandler):