--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/privilege.py	Fri Mar 02 12:59:38 2018 +0100
@@ -0,0 +1,309 @@
+#!/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-0356 (Privileged Entity) to manage rosters, messages and presences
+
+from wokkel import xmppim
+from wokkel.compat import IQ
+from wokkel import pubsub
+from wokkel import disco
+from wokkel.iwokkel import IPubSubService
+from twisted.python import log
+from twisted.python import failure
+from twisted.internet import defer
+from twisted.words.xish import domish
+from twisted.words.protocols.jabber import jid
+import time
+
+FORWARDED_NS = 'urn:xmpp:forward:0'
+PRIV_ENT_NS = 'urn:xmpp:privilege:1'
+PRIV_ENT_ADV_XPATH = '/message/privilege[@xmlns="{}"]'.format(PRIV_ENT_NS)
+ROSTER_NS = 'jabber:iq:roster'
+PERM_ROSTER = 'roster'
+PERM_MESSAGE = 'message'
+PERM_PRESENCE = 'presence'
+ALLOWED_ROSTER = ('none', 'get', 'set', 'both')
+ALLOWED_MESSAGE = ('none', 'outgoing')
+ALLOWED_PRESENCE = ('none', 'managed_entity', 'roster')
+TO_CHECK = {PERM_ROSTER:ALLOWED_ROSTER, PERM_MESSAGE:ALLOWED_MESSAGE, PERM_PRESENCE:ALLOWED_PRESENCE}
+
+
+class InvalidStanza(Exception):
+    pass
+
+class NotAllowedError(Exception):
+    pass
+
+class PrivilegesHandler(disco.DiscoClientProtocol):
+    #FIXME: need to manage updates, and database sync
+    #TODO: cache
+
+    def __init__(self, service_jid):
+        super(PrivilegesHandler, self).__init__()
+        self._permissions = {PERM_ROSTER: 'none',
+                             PERM_MESSAGE: 'none',
+                             PERM_PRESENCE: 'none'}
+        self._pubsub_service = None
+        self._backend = None
+        # FIXME: we use a hack supposing that our privilege come from hostname
+        #        and we are a component named [name].hostname
+        #        but we need to manage properly server
+        # TODO: do proper server handling
+        self.server_jid = jid.JID(service_jid.host.split('.', 1)[1])
+        self.caps_map = {}  # key: bare jid, value: dict of resources with caps hash
+        self.hash_map = {}  # key: (hash,version), value: dict with DiscoInfo instance (infos) and nodes to notify (notify)
+        self.roster_cache = {}  # key: jid, value: dict with "timestamp" and "roster"
+        self.presence_map = {}  # inverted roster: key: jid, value: set of entities who has this jid in roster (with presence of "from" or "both")
+        self.server = None
+
+    @property
+    def permissions(self):
+        return self._permissions
+
+    def connectionInitialized(self):
+        for handler in self.parent.handlers:
+            if IPubSubService.providedBy(handler):
+                self._pubsub_service = handler
+                break
+        self._backend = self.parent.parent.getServiceNamed('backend')
+        self.xmlstream.addObserver(PRIV_ENT_ADV_XPATH, self.onAdvertise)
+        self.xmlstream.addObserver('/presence', self.onPresence)
+
+    def onAdvertise(self, message):
+        """Managage the <message/> advertising privileges
+
+        self._permissions will be updated according to advertised privileged
+        """
+        privilege_elt = message.elements(PRIV_ENT_NS, 'privilege').next()
+        for perm_elt in privilege_elt.elements(PRIV_ENT_NS):
+            try:
+                if perm_elt.name != 'perm':
+                    raise InvalidStanza(u'unexpected element {}'.format(perm_elt.name))
+                perm_access = perm_elt['access']
+                perm_type = perm_elt['type']
+                try:
+                    if perm_type not in TO_CHECK[perm_access]:
+                        raise InvalidStanza(u'bad type [{}] for permission {}'.format(perm_type, perm_access))
+                except KeyError:
+                    raise InvalidStanza(u'bad permission [{}]'.format(perm_access))
+            except InvalidStanza as e:
+                log.msg("Invalid stanza received ({}), setting permission to none".format(e))
+                for perm in self._permissions:
+                    self._permissions[perm] = 'none'
+                break
+
+            self._permissions[perm_access] = perm_type or 'none'
+
+        log.msg('Privileges updated: roster={roster}, message={message}, presence={presence}'.format(**self._permissions))
+
+    ## roster ##
+
+    def getRoster(self, to_jid):
+        """
+        Retrieve contact list.
+
+        @return: Roster as a mapping from L{JID} to L{RosterItem}.
+        @rtype: L{twisted.internet.defer.Deferred}
+        """
+        # TODO: cache results
+        if self._permissions[PERM_ROSTER] not in ('get', 'both'):
+            log.msg("WARNING: permission not allowed to get roster")
+            raise failure.Failure(NotAllowedError('roster get is not allowed'))
+
+        def processRoster(result):
+            roster = {}
+            for element in result.query.elements(ROSTER_NS, 'item'):
+                item = xmppim.RosterItem.fromElement(element)
+                roster[item.entity] = item
+
+            return roster
+
+        iq = IQ(self.xmlstream, 'get')
+        iq.addElement((ROSTER_NS, 'query'))
+        iq["to"] = to_jid.userhost()
+        d = iq.send()
+        d.addCallback(processRoster)
+        return d
+
+    def _isSubscribedFrom(self, roster, entity, roster_owner_jid):
+        try:
+            return roster[entity.userhostJID()].subscriptionFrom
+        except KeyError:
+            return False
+
+    def isSubscribedFrom(self, entity, roster_owner_jid):
+        """Check if entity has presence subscription from roster_owner_jid
+
+        @param entity(jid.JID): entity to check subscription to
+        @param roster_owner_jid(jid.JID): owner of the roster to check
+        @return D(bool): True if entity has a subscription from roster_owner_jid
+        """
+        d = self.getRoster(roster_owner_jid)
+        d.addCallback(self._isSubscribedFrom, entity, roster_owner_jid)
+        return d
+
+    ## message ##
+
+    def sendMessage(self, priv_message, to_jid=None):
+        """Send privileged message (in the name of the server)
+
+        @param priv_message(domish.Element): privileged message
+        @param to_jid(jid.JID, None): main message destinee
+            None to use our own server
+        """
+        if self._permissions[PERM_MESSAGE] not in ('outgoing',):
+            log.msg("WARNING: permission not allowed to send privileged messages")
+            raise failure.Failure(NotAllowedError('privileged messages are not allowed'))
+
+        main_message = domish.Element((None, "message"))
+        if to_jid is None:
+            to_jid = self.server_jid
+        main_message['to'] = to_jid.full()
+        privilege_elt = main_message.addElement((PRIV_ENT_NS, 'privilege'))
+        forwarded_elt = privilege_elt.addElement((FORWARDED_NS, 'forwarded'))
+        priv_message['xmlns'] = 'jabber:client'
+        forwarded_elt.addChild(priv_message)
+        self.send(main_message)
+
+    def notifyPublish(self, pep_jid, nodeIdentifier, notifications):
+        """Do notifications using privileges"""
+        for subscriber, subscriptions, items in notifications:
+            message = self._pubsub_service._createNotification('items', pep_jid,
+                                               nodeIdentifier, subscriber,
+                                               subscriptions)
+            for item in items:
+                item.uri = pubsub.NS_PUBSUB_EVENT
+                message.event.items.addChild(item)
+            self.sendMessage(message)
+
+
+    def notifyRetract(self, pep_jid, nodeIdentifier, notifications):
+        for subscriber, subscriptions, items in notifications:
+            message = self._pubsub_service._createNotification('items', pep_jid,
+                                               nodeIdentifier, subscriber,
+                                               subscriptions)
+            for item in items:
+                retract = domish.Element((None, "retract"))
+                retract['id'] = item['id']
+                message.event.items.addChild(retract)
+            self.sendMessage(message)
+
+
+    # def notifyDelete(self, service, nodeIdentifier, subscribers,
+    #                        redirectURI=None):
+    #     # TODO
+    #     for subscriber in subscribers:
+    #         message = self._createNotification('delete', service,
+    #                                            nodeIdentifier,
+    #                                            subscriber)
+    #         if redirectURI:
+    #             redirect = message.event.delete.addElement('redirect')
+    #             redirect['uri'] = redirectURI
+    #         self.send(message)
+
+
+    ## presence ##
+
+    @defer.inlineCallbacks
+    def onPresence(self, presence_elt):
+        if self.server is None:
+            # FIXME: we use a hack supposing that our delegation come from hostname
+            #        and we are a component named [name].hostname
+            #        but we need to manage properly allowed servers
+            # TODO: do proper origin security check
+            _, self.server = presence_elt['to'].split('.', 1)
+        from_jid = jid.JID(presence_elt['from'])
+        from_jid_bare = from_jid.userhostJID()
+        if from_jid.host == self.server and from_jid_bare not in self.roster_cache:
+            roster = yield self.getRoster(from_jid_bare)
+            timestamp = time.time()
+            self.roster_cache[from_jid_bare] = {'timestamp': timestamp,
+                                                'roster': roster,
+                                                }
+            for roster_jid, roster_item in roster.iteritems():
+                if roster_item.subscriptionFrom:
+                    self.presence_map.setdefault(roster_jid, set()).add(from_jid_bare)
+
+        presence_type = presence_elt.getAttribute('type')
+        if presence_type != "unavailable":
+            # new resource available, we check entity capabilities
+            try:
+                c_elt = next(presence_elt.elements('http://jabber.org/protocol/caps', 'c'))
+                hash_ = c_elt['hash']
+                ver = c_elt['ver']
+            except (StopIteration, KeyError):
+                # no capabilities, we don't go further
+                return
+
+            # FIXME: hash is not checked (cf. XEP-0115)
+            disco_tuple = (hash_, ver)
+            jid_caps = self.caps_map.setdefault(from_jid_bare, {})
+            if from_jid.resource not in jid_caps:
+                jid_caps[from_jid.resource] = disco_tuple
+
+            if disco_tuple not in self.hash_map:
+                # first time we se this hash, what is behind it?
+                infos = yield self.requestInfo(from_jid)
+                self.hash_map[disco_tuple] = {
+                    'notify': {f[:-7] for f in infos.features if f.endswith('+notify')},
+                    'infos': infos
+                    }
+
+            # nodes are the nodes subscribed with +notify
+            nodes = tuple(self.hash_map[disco_tuple]['notify'])
+            if not nodes:
+                return
+            # publishers are entities which have granted presence access to our user + user itself
+            publishers = tuple(self.presence_map.get(from_jid_bare, ())) + (from_jid_bare,)
+
+            # FIXME: add "presence" access_model (for node) for getLastItems
+            last_items = yield self._backend.storage.getLastItems(publishers, nodes, ('open',), ('open',), True)
+            # we send message with last item, as required by https://xmpp.org/extensions/xep-0163.html#notify-last
+            for pep_jid, node, item, item_access_model in last_items:
+                self.notifyPublish(pep_jid, node, [(from_jid, None, [item])])
+
+    ## misc ##
+
+    @defer.inlineCallbacks
+    def getAutoSubscribers(self, recipient, nodeIdentifier, explicit_subscribers):
+        """get automatic subscribers, i.e. subscribers with presence subscription and +notify for this node
+
+        @param recipient(jid.JID): jid of the PEP owner of this node
+        @param nodeIdentifier(unicode): node
+        @param explicit_subscribers(set(jid.JID}: jids of people which have an explicit subscription
+        @return (list[jid.JID]): full jid of automatically subscribed entities
+        """
+        auto_subscribers = []
+        roster = yield self.getRoster(recipient)
+        for roster_jid, roster_item in roster.iteritems():
+            if roster_jid in explicit_subscribers:
+                continue
+            if roster_item.subscriptionFrom:
+                try:
+                    online_resources = self.caps_map[roster_jid]
+                except KeyError:
+                    continue
+                for res, hash_ in online_resources.iteritems():
+                     notify = self.hash_map[hash_]['notify']
+                     if nodeIdentifier in notify:
+                         full_jid = jid.JID(tuple=(roster_jid.user, roster_jid.host, res))
+                         auto_subscribers.append(full_jid)
+        defer.returnValue(auto_subscribers)