1 files changed, 123 insertions, 0 deletions
diff --git a/sleekxmpp/features/feature_mechanisms/mechanisms.py b/sleekxmpp/features/feature_mechanisms/mechanisms.py
new file mode 100644
index 00000000..7a877793
--- /dev/null
+++ b/sleekxmpp/features/feature_mechanisms/mechanisms.py
@@ -0,0 +1,123 @@
+"""
+    SleekXMPP: The Sleek XMPP Library
+    Copyright (C) 2011  Nathanael C. Fritz
+    This file is part of SleekXMPP.
+
+    See the file LICENSE for copying permission.
+"""
+
+import logging
+
+from sleekxmpp.stanza import StreamFeatures
+from sleekxmpp.xmlstream import RestartStream, register_stanza_plugin
+from sleekxmpp.xmlstream.matcher import *
+from sleekxmpp.xmlstream.handler import *
+from sleekxmpp.plugins.base import base_plugin
+from sleekxmpp.features.feature_mechanisms import stanza
+
+
+log = logging.getLogger(__name__)
+
+
+class feature_mechanisms(base_plugin):
+
+    def plugin_init(self):
+        self.name = 'SASL Mechanisms'
+        self.rfc = '6120'
+        self.description = "SASL Stream Feature"
+        self.stanza = stanza
+
+        register_stanza_plugin(StreamFeatures, stanza.Mechanisms)
+        self.xmpp.register_stanza(stanza.Success)
+        self.xmpp.register_stanza(stanza.Failure)
+        self.xmpp.register_stanza(stanza.Auth)
+
+        self._mechanism_handlers = {}
+        self._mechanism_priorities = []
+
+        self.xmpp.register_handler(
+                Callback('SASL Success',
+                         MatchXPath(stanza.Success.tag_name()),
+                         self._handle_success,
+                         instream=True,
+                         once=True))
+        self.xmpp.register_handler(
+                Callback('SASL Failure',
+                         MatchXPath(stanza.Failure.tag_name()),
+                         self._handle_fail,
+                         instream=True,
+                         once=True))
+
+        self.xmpp.register_feature('mechanisms',
+                self._handle_sasl_auth,
+                restart=True,
+                order=self.config.get('order', 100))
+
+    def register(self, name, handler, priority=0):
+        """
+        Register a handler for a SASL authentication mechanism.
+
+        Arguments:
+            name     -- The name of the mechanism (all caps)
+            handler  -- The function that will perform the
+                        authentication. The function must
+                        return True if it is able to carry
+                        out the authentication, False if
+                        a required condition is not met.
+            priority -- An integer value indicating the
+                        preferred ordering for the mechanism.
+                        High values will be attempted first.
+        """
+        self._mechanism_handlers[name] = handler
+        self._mechanism_priorities.append((priority, name))
+        self._mechanism_priorities.sort(reverse=True)
+
+    def remove(self, name):
+        """
+        Remove support for a given SASL authentication mechanism.
+
+        Arguments:
+            name -- The name of the mechanism to remove (all caps)
+        """
+        if name in self._mechanism_handlers:
+            del self._mechanism_handlers[name]
+
+        p = self._mechanism_priorities
+        self._mechanism_priorities = [i for i in p if i[1] != name]
+
+    def _handle_sasl_auth(self, features):
+        """
+        Handle authenticating using SASL.
+
+        Arguments:
+            features -- The stream features stanza.
+        """
+        if 'mechanisms' in self.xmpp.features:
+            # SASL authentication has already succeeded, but the
+            # server has incorrectly offered it again.
+            return False
+
+        for priority, mech in self._mechanism_priorities:
+            if mech in features['mechanisms']:
+                log.debug('Attempt to use SASL %s' % mech)
+                if self._mechanism_handlers[mech]():
+                    break
+        else:
+            log.error("No appropriate login method.")
+            self.xmpp.event("no_auth", direct=True)
+            self.xmpp.disconnect()
+
+        return True
+
+    def _handle_success(self, stanza):
+        """SASL authentication succeeded. Restart the stream."""
+        self.xmpp.authenticated = True
+        self.xmpp.features.add('mechanisms')
+        raise RestartStream()
+
+    def _handle_fail(self, stanza):
+        """SASL authentication failed. Disconnect and shutdown."""
+        log.info("Authentication failed: %s" % stanza['condition'])
+        self.xmpp.event("failed_auth", stanza, direct=True)
+        self.xmpp.disconnect()
+        return True