slixmpp/features/feature_starttls/starttls.py

   1 """
   2     Slixmpp: The Slick XMPP Library
   3     Copyright (C) 2011  Nathanael C. Fritz
   4     This file is part of Slixmpp.
   5
   6     See the file LICENSE for copying permission.
   7 """
   8
   9 import logging
  10
  11 from slixmpp.stanza import StreamFeatures
  12 from slixmpp.xmlstream import RestartStream, register_stanza_plugin
  13 from slixmpp.plugins import BasePlugin
  14 from slixmpp.xmlstream.matcher import MatchXPath
  15 from slixmpp.xmlstream.handler import Callback
  16 from slixmpp.features.feature_starttls import stanza
  17
  18
  19 log = logging.getLogger(__name__)
  20
  21
  22 class FeatureSTARTTLS(BasePlugin):
  23
  24     name = 'feature_starttls'
  25     description = 'RFC 6120: Stream Feature: STARTTLS'
  26     dependencies = set()
  27     stanza = stanza
  28
  29     def plugin_init(self):
  30         self.xmpp.register_handler(
  31                 Callback('STARTTLS Proceed',
  32                         MatchXPath(stanza.Proceed.tag_name()),
  33                         self._handle_starttls_proceed,
  34                         instream=True))
  35         self.xmpp.register_feature('starttls',
  36                 self._handle_starttls,
  37                 restart=True,
  38                 order=self.config.get('order', 0))
  39
  40         self.xmpp.register_stanza(stanza.Proceed)
  41         self.xmpp.register_stanza(stanza.Failure)
  42         register_stanza_plugin(StreamFeatures, stanza.STARTTLS)
  43
  44     def _handle_starttls(self, features):
  45         """
  46         Handle notification that the server supports TLS.
  47
  48         Arguments:
  49             features -- The stream:features element.
  50         """
  51         if 'starttls' in self.xmpp.features:
  52             # We have already negotiated TLS, but the server is
  53             # offering it again, against spec.
  54             return False
  55         elif not self.xmpp.use_tls:
  56             return False
  57         else:
  58             self.xmpp.send(features['starttls'], now=True)
  59             return True
  60
  61     def _handle_starttls_proceed(self, proceed):
  62         """Restart the XML stream when TLS is accepted."""
  63         log.debug("Starting TLS")
  64         if self.xmpp.start_tls():
  65             self.xmpp.features.add('starttls')
  66             raise RestartStream()