diff -r 044dc196ec8a -r d3668ecd9137 src/ztfy/utils/timezone/__init__.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ztfy/utils/timezone/__init__.py	Wed Jun 20 16:29:53 2012 +0200
@@ -0,0 +1,61 @@
+### -*- coding: utf-8 -*- ####################################################
+##############################################################################
+#
+# Copyright (c) 2008-2010 Thierry Florac <tflorac AT ulthar.net>
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+
+__docformat__ = "restructuredtext"
+
+# import standard packages
+import pytz
+
+# import Zope3 interfaces
+from zope.interface.common.idatetime import ITZInfo
+from zope.publisher.interfaces.browser import IBrowserRequest
+
+# import local interfaces
+from ztfy.utils.timezone.interfaces import IServerTimezone
+
+# import Zope3 packages
+from zope.component import adapter, queryUtility
+from zope.interface import implementer
+
+# import local packages
+
+
+GMT = pytz.timezone('GMT')
+_tz = pytz.timezone('Europe/Paris')
+tz = _tz
+
+@implementer(ITZInfo)
+@adapter(IBrowserRequest)
+def tzinfo(request=None):
+    util = queryUtility(IServerTimezone)
+    if util is not None:
+        return pytz.timezone(util.timezone)
+    return GMT
+
+
+def tztime(value):
+    if not value:
+        return None
+    if not value.tzinfo:
+        value = GMT.localize(value)
+    return value.astimezone(tzinfo())
+
+
+def gmtime(value):
+    if not value:
+        return None
+    if not value.tzinfo:
+        value = GMT.localize(value)
+    return value.astimezone(GMT)