Add support for roster versioning.

This was XEP-0237, but is now part of RFC 6121.

Roster backends should now expose two additional methods:

version(jid):
    Return the version of the given JID's roster.
set_version(jid, version):
    Update the version of the given JID's roster.

A new state field will be passed to the backend if an item
has been marked for removal. This is 'removed' which will
be set to True.

sleekxmpp/clientxmpp.py

@@ -18,6 +18,7 @@ import logging
 
 from sleekxmpp.stanza import StreamFeatures
 from sleekxmpp.basexmpp import BaseXMPP
+from sleekxmpp.exceptions import XMPPError
 from sleekxmpp.xmlstream import XMLStream
 from sleekxmpp.xmlstream.matcher import MatchXPath
 from sleekxmpp.xmlstream.handler import Callback
@@ -111,6 +112,7 @@ class ClientXMPP(BaseXMPP):
         self.register_plugin('feature_session')
         self.register_plugin('feature_mechanisms',
                 pconfig={'use_mech': sasl_mech} if sasl_mech else None)
+        self.register_plugin('feature_rosterver')
 
     @property
     def password(self):
@@ -240,6 +242,8 @@ class ClientXMPP(BaseXMPP):
         iq = self.Iq()
         iq['type'] = 'get'
         iq.enable('roster')
+        if 'rosterver' in self.features:
+            iq['roster']['ver'] = self.client_roster.version
 
         if not block and callback is None:
             callback = lambda resp: self._handle_roster(resp, request=True)
@@ -279,15 +283,22 @@ class ClientXMPP(BaseXMPP):
                         to a request for the roster, and not an
                         empty acknowledgement from the server.
         """
+        if iq['from'].bare and iq['from'].bare != self.boundjid.bare:
+            raise XMPPError(condition='service-unavailable')
         if iq['type'] == 'set' or (iq['type'] == 'result' and request):
+            roster = self.client_roster
+            if iq['roster']['ver']:
+                roster.version = iq['roster']['ver']
             for jid in iq['roster']['items']:
                 item = iq['roster']['items'][jid]
-                roster = self.roster[iq['to'].bare]
                 roster[jid]['name'] = item['name']
                 roster[jid]['groups'] = item['groups']
                 roster[jid]['from'] = item['subscription'] in ['from', 'both']
                 roster[jid]['to'] = item['subscription'] in ['to', 'both']
                 roster[jid]['pending_out'] = (item['ask'] == 'subscribe')
+
+                roster[jid].save(remove=(item['subscription'] == 'remove'))
+                     
             self.event('roster_received', iq)
 
         self.event("roster_update", iq)

sleekxmpp/features/__init__.py

@@ -6,4 +6,4 @@
     See the file LICENSE for copying permission.
 """
 
-__all__ = ['feature_starttls', 'feature_mechanisms', 'feature_bind']
+__all__ = ['feature_starttls', 'feature_mechanisms', 'feature_bind', 'feature_rosterver']

sleekxmpp/features/feature_rosterver/__init__.py

@@ -0,0 +1,10 @@
+"""
+    SleekXMPP: The Sleek XMPP Library
+    Copyright (C) 2012  Nathanael C. Fritz
+    This file is part of SleekXMPP.
+
+    See the file LICENSE for copying permission.
+"""
+
+from sleekxmpp.features.feature_rosterver.rosterver import feature_rosterver
+from sleekxmpp.features.feature_rosterver.stanza import RosterVer

sleekxmpp/features/feature_rosterver/rosterver.py

@@ -0,0 +1,42 @@
+"""
+    SleekXMPP: The Sleek XMPP Library
+    Copyright (C) 2012  Nathanael C. Fritz
+    This file is part of SleekXMPP.
+
+    See the file LICENSE for copying permission.
+"""
+
+import logging
+
+from sleekxmpp.stanza import Iq, StreamFeatures
+from sleekxmpp.features.feature_rosterver import stanza
+from sleekxmpp.xmlstream import register_stanza_plugin
+from sleekxmpp.plugins.base import base_plugin
+
+
+log = logging.getLogger(__name__)
+
+
+class feature_rosterver(base_plugin):
+
+    def plugin_init(self):
+        self.name = 'Roster Versioning'
+        self.rfc = '6121'
+        self.description = 'Roster Versioning'
+        self.stanza = stanza
+
+        self.xmpp.register_feature('rosterver',
+                self._handle_rosterver,
+                restart=False,
+                order=9000)
+
+        register_stanza_plugin(StreamFeatures, stanza.RosterVer)
+
+    def _handle_rosterver(self, features):
+        """Enable using roster versioning.
+
+        Arguments:
+            features -- The stream features stanza.
+        """
+        log.debug("Enabling roster versioning.")
+        self.xmpp.features.add('rosterver')

sleekxmpp/features/feature_rosterver/stanza.py

@@ -0,0 +1,17 @@
+"""
+    SleekXMPP: The Sleek XMPP Library
+    Copyright (C) 2012  Nathanael C. Fritz
+    This file is part of SleekXMPP.
+
+    See the file LICENSE for copying permission.
+"""
+
+from sleekxmpp.xmlstream import ElementBase
+
+
+class RosterVer(ElementBase):
+
+    name = 'ver'
+    namespace = 'urn:xmpp:features:rosterver'
+    interfaces = set()
+    plugin_attrib = 'rosterver'

sleekxmpp/roster/item.py

@@ -134,6 +134,7 @@ class RosterItem(object):
                 'subscription': 'none',
                 'name': '',
                 'groups': []}
+
         self._db_state = {}
         self.load()
 
@@ -171,16 +172,25 @@ class RosterItem(object):
             return self._state
         return None
 
-    def save(self):
+    def save(self, remove=False):
         """
         Save the item's state information to an external datastore,
         if one has been provided.
+
+        Arguments:
+            remove -- If True, expunge the item from the datastore.
         """
         self['subscription'] = self._subscription()
+        if remove:
+            self._state['removed'] = True
         if self.db:
             self.db.save(self.owner, self.jid,
                          self._state, self._db_state)
 
+        # Finally, remove the in-memory copy if needed.
+        if remove:
+            del self.xmpp.roster[self.owner][self.jid]
+
     def __getitem__(self, key):
         """Return a state field's value."""
         if key in self._state:

sleekxmpp/roster/single.py

@@ -57,12 +57,29 @@ class RosterNode(object):
         self.auto_authorize = True
         self.auto_subscribe = True
         self.last_status = None
+        self._version = ''
         self._jids = {}
 
         if self.db:
+            if hasattr(self.db, 'version'):
+                self._version = self.db.version(self.jid)
             for jid in self.db.entries(self.jid):
                 self.add(jid)
     
+    @property
+    def version(self):
+        """Retrieve the roster's version ID."""
+        if self.db and hasattr(self.db, 'version'):
+            self._version = self.db.version(self.jid)
+        return self._version
+
+    @version.setter
+    def version(self, version):
+        """Set the roster's version ID."""
+        self._version = version
+        if self.db and hasattr(self.db, 'set_version'):
+            self.db.set_version(self.jid, version)
+
     def __getitem__(self, key):
         """
         Return the roster item for a subscribed JID.
@@ -75,6 +92,17 @@ class RosterNode(object):
             self.add(key, save=True)
         return self._jids[key]
 
+    def __delitem__(self, key):
+        """
+        Remove a roster item from the local storage.
+
+        To remove an item from the server, use the remove() method.
+        """
+        if isinstance(key, JID):
+            key = key.bare
+        if key in self._jids:
+            del self._jids[key]
+
     def __len__(self):
         """Return the number of JIDs referenced by the roster."""
         return len(self._jids)

sleekxmpp/stanza/roster.py

@@ -36,7 +36,30 @@ class Roster(ElementBase):
     namespace = 'jabber:iq:roster'
     name = 'query'
     plugin_attrib = 'roster'
-    interfaces = set(('items',))
+    interfaces = set(('items', 'ver'))
+
+    def get_ver(self):
+        """
+        Ensure handling an empty ver attribute propery.
+
+        The ver attribute is special in that the presence of the
+        attribute with an empty value is important for boostrapping
+        roster versioning.
+        """
+        return self.xml.attrib.get('ver', None)
+ 
+    def set_ver(self, ver):
+        """
+        Ensure handling an empty ver attribute propery.
+
+        The ver attribute is special in that the presence of the
+        attribute with an empty value is important for boostrapping
+        roster versioning.
+        """
+        if ver is not None:
+            self.xml.attrib['ver'] = ver
+        else:
+            del self.xml.attrib['ver']
 
     def set_items(self, items):
         """