--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sat_pubsub/delegation.py	Thu Apr 16 21:06:19 2015 +0200
@@ -0,0 +1,73 @@
+#!/usr/bin/python
+#-*- coding: utf-8 -*-
+#
+"""
+Copyright (c) 2015 Jérôme Poisson
+
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+---
+
+This module implements XEP-0355 (Namespace delegation) to use SàT Pubsub as PEP service
+"""
+
+from wokkel.subprotocols import XMPPHandler
+from wokkel import pubsub
+from twisted.python import log
+
+DELEGATION_NS = 'urn:xmpp:delegation:1'
+FORWARDED_NS = 'urn:xmpp:forward:0'
+DELEGATION_ADV_XPATH = '/message/delegation[@xmlns="{}"]'.format(DELEGATION_NS)
+
+class InvalidStanza(Exception):
+    pass
+
+class DelegationsHandler(XMPPHandler):
+
+    def __init__(self):
+        super(DelegationsHandler, self).__init__()
+
+    def connectionInitialized(self):
+        self.xmlstream.addObserver(DELEGATION_ADV_XPATH, self.onAdvertise)
+
+    def onAdvertise(self, message):
+        """Managage the <message/> advertising delegations"""
+        delegation_elt = message.elements(DELEGATION_NS, 'delegation').next()
+        delegated = {}
+        for delegated_elt in delegation_elt.elements(DELEGATION_NS):
+            try:
+                if delegated_elt.name != 'delegated':
+                    raise InvalidStanza(u'unexpected element {}'.format(delegated_elt.name))
+                try:
+                    namespace = delegated_elt['namespace']
+                except KeyError:
+                    raise InvalidStanza(u'was expecting a "namespace" attribute in delegated element')
+                delegated[namespace] = []
+                for attribute_elt in delegated_elt.elements(DELEGATION_NS, 'attribute'):
+                    try:
+                        delegated[namespace].append(attribute_elt["name"])
+                    except KeyError:
+                        raise InvalidStanza(u'was expecting a "name" attribute in attribute element')
+            except InvalidStanza as e:
+                log.msg("Invalid stanza received ({})".format(e))
+
+        log.msg(u'delegations updated:\n{}'.format(
+            u'\n'.join([u"    - namespace {}{}".format(ns,
+            u"" if not attributes else u" with filtering on {} attribute(s)".format(
+            u", ".join(attributes))) for ns, attributes in delegated.items()])))
+
+        if not pubsub.NS_PUBSUB in delegated:
+            log.msg(u"Didn't got pubsub delegation from server, can't act as a PEP service")
+