Add initial support for XEP-0198 for stream management.

1 files changed, 266 insertions, 0 deletions

diff --git a/sleekxmpp/plugins/xep_0198/stream_management.py b/sleekxmpp/plugins/xep_0198/stream_management.py
new file mode 100644
index 00000000..6ed1ea26
--- /dev/null
+++ b/sleekxmpp/plugins/xep_0198/stream_management.py
@@ -0,0 +1,266 @@
+"""
+    SleekXMPP: The Sleek XMPP Library
+    Copyright (C) 2012 Nathanael C. Fritz, Lance J.T. Stout
+    This file is part of SleekXMPP.
+
+    See the file LICENSE for copying permission.
+"""
+
+import logging
+import threading
+import collections
+
+from sleekxmpp.stanza import Message, Presence, Iq, StreamFeatures
+from sleekxmpp.xmlstream import register_stanza_plugin
+from sleekxmpp.xmlstream.handler import Callback, Waiter
+from sleekxmpp.xmlstream.matcher import MatchXPath, MatchMany
+from sleekxmpp.plugins.base import BasePlugin
+from sleekxmpp.plugins.xep_0198 import stanza
+
+
+log = logging.getLogger(__name__)
+
+
+MAX_SEQ = 2**32
+
+
+class XEP_0198(BasePlugin):
+
+    """
+    XEP-0198: Stream Management
+    """
+
+    name = 'xep_0198'
+    description = 'XEP-0198: Stream Management'
+    dependencies = set()
+    stanza = stanza
+
+    def plugin_init(self):
+        """Start the XEP-0198 plugin."""
+
+        # Only enable stream management for non-components,
+        # since components do not yet perform feature negotiation.
+        if self.xmpp.is_component:
+            return
+
+        #: The stream management ID for the stream. Knowing this value is
+        #: required in order to do stream resumption.
+        self.sm_id = self.config.get('sm_id', None)
+
+        #: A counter of handled incoming stanzas, mod 2^32.
+        self.handled = self.config.get('handled', 0)
+
+        #: A counter of unacked outgoing stanzas, mod 2^32.
+        self.seq = self.config.get('seq', 0)
+
+        #: The last ack number received from the server.
+        self.last_ack = self.config.get('last_ack', 0)
+
+        #: The number of stanzas to wait between sending ack requests to
+        #: the server. Setting this to ``1`` will send an ack request after
+        #: every sent stanza. Defaults to ``5``.
+        self.window = self.config.get('window', 5)
+
+        #: Control whether or not the ability to resume the stream will be
+        #: requested when enabling stream management. Defaults to ``True``.
+        self.allow_resume = self.config.get('allow_resume', True)
+
+        self.enabled = threading.Event()
+        self.unacked_queue = collections.deque()
+    
+        self.seq_lock = threading.Lock()
+        self.handled_lock = threading.Lock()
+        self.ack_lock = threading.Lock()
+
+        register_stanza_plugin(StreamFeatures, stanza.StreamManagement)
+        self.xmpp.register_stanza(stanza.Enable)
+        self.xmpp.register_stanza(stanza.Enabled)
+        self.xmpp.register_stanza(stanza.Resume)
+        self.xmpp.register_stanza(stanza.Resumed)
+        self.xmpp.register_stanza(stanza.Ack)
+        self.xmpp.register_stanza(stanza.RequestAck)
+
+        # Register the feature twice because it may be ordered two
+        # different ways: enabling after binding and resumption
+        # before binding.
+        self.xmpp.register_feature('sm',
+                self._handle_sm_feature,
+                restart=True,
+                order=self.config.get('order', 10100))
+        self.xmpp.register_feature('sm',
+                self._handle_sm_feature,
+                restart=True,
+                order=self.config.get('resume_order', 9000))
+
+        self.xmpp.register_handler(
+                Callback('Stream Management Enabled',
+                    MatchXPath(stanza.Enabled.tag_name()),
+                    self._handle_enabled,
+                    instream=True))
+
+        self.xmpp.register_handler(
+                Callback('Stream Management Resumed',
+                    MatchXPath(stanza.Resumed.tag_name()),
+                    self._handle_resumed,
+                    instream=True))
+
+        self.xmpp.register_handler(
+                Callback('Stream Management Failed',
+                    MatchXPath(stanza.Failed.tag_name()),
+                    self._handle_failed,
+                    instream=True))
+
+        self.xmpp.register_handler(
+                Callback('Stream Management Ack',
+                    MatchXPath(stanza.Ack.tag_name()),
+                    self._handle_ack,
+                    instream=True))
+
+        self.xmpp.register_handler(
+                Callback('Stream Management Request Ack',
+                    MatchXPath(stanza.RequestAck.tag_name()),
+                    self._handle_request_ack,
+                    instream=True))
+
+        self.xmpp.add_filter('in', self._handle_incoming)
+        self.xmpp.add_filter('out_sync', self._handle_outgoing)
+
+        self.xmpp.add_event_handler('need_ack', self.request_ack)
+
+    def send_ack(self):
+        """Send the current ack count to the server."""
+        ack = stanza.Ack(self.xmpp)
+        with self.handled_lock:
+            ack['h'] = self.handled
+        ack.send()
+
+    def request_ack(self, e=None):
+        """Request an ack from the server."""
+        req = stanza.RequestAck(self.xmpp)
+        req.send()
+
+    def _handle_sm_feature(self, features):
+        """
+        Enable or resume stream management.
+
+        If no SM-ID is stored, and resource binding has taken place,
+        stream management will be enabled.
+
+        If an SM-ID is known, and the server allows resumption, the
+        previous stream will be resumed.
+        """
+        if 'stream_management' in self.xmpp.features:
+            # We've already negotiated stream management,
+            # so no need to do it again.
+            return False
+        if not self.sm_id:
+            if 'bind' in self.xmpp.features:
+                self.enabled.set()
+                enable = stanza.Enable(self.xmpp)
+                enable['resume'] = self.allow_resume
+                enable.send()
+                self.handled = 0
+        elif self.sm_id and self.allow_resume:
+            self.enabled.set()
+            resume = stanza.Resume(self.xmpp)
+            resume['h'] = self.handled
+            resume['previd'] = self.sm_id
+            resume.send(now=True)
+
+            # Wait for a response before allowing stream feature processing
+            # to continue. The actual result processing will be done in the
+            # _handle_resumed() or _handle_failed() methods.
+            waiter = Waiter('resumed_or_failed',
+                    MatchMany([
+                        MatchXPath(stanza.Resumed.tag_name()),
+                        MatchXPath(stanza.Failed.tag_name())]))
+            self.xmpp.register_handler(waiter)
+            result = waiter.wait()
+            if result is not None and result.name == 'resumed':
+                return True
+        return False
+
+    def _handle_enabled(self, stanza):
+        """Save the SM-ID, if provided.
+        
+        Raises an :term:`sm_enabled` event.
+        """
+        self.xmpp.features.add('stream_management')
+        if stanza['id']:
+            self.sm_id = stanza['id']
+        self.xmpp.event('sm_enabled', stanza)
+
+    def _handle_resumed(self, stanza):
+        """Finish resuming a stream by resending unacked stanzas.
+
+        Raises a :term:`session_resumed` event.
+        """
+        self.xmpp.features.add('stream_management')
+        self._handle_ack(stanza)
+        for id, stanza in self.unacked_queue:
+            self.xmpp.send(stanza, now=True, use_filters=False)
+        self.xmpp.session_started_event.set()
+        self.xmpp.event('session_resumed', stanza)
+
+    def _handle_failed(self, stanza):
+        """
+        Disable and reset any features used since stream management was
+        requested (tracked stanzas may have been sent during the interval
+        between the enable request and the enabled response).
+
+        Raises an :term:`sm_failed` event.
+        """
+        self.enabled.clear()
+        self.unacked_queue.clear()
+        self.xmpp.event('sm_failed', stanza)
+
+    def _handle_ack(self, ack):
+        """Process a server ack by freeing acked stanzas from the queue.
+        
+        Raises a :term:`stanza_acked` event for each acked stanza.
+        """
+        if ack['h'] == self.last_ack:
+            return
+
+        with self.ack_lock:
+            num_acked = (ack['h'] - self.last_ack) % MAX_SEQ
+            log.debug("Ack: %s, Last Ack: %s, Num Acked: %s, Unacked: %s",
+                ack['h'], 
+                self.last_ack, 
+                num_acked, 
+                len(self.unacked_queue))
+            for x in range(num_acked):
+                seq, stanza = self.unacked_queue.popleft()
+                self.xmpp.event('stanza_acked', stanza)
+            self.last_ack = ack['h']
+
+    def _handle_request_ack(self, req):
+        """Handle an ack request by sending an ack."""
+        self.send_ack()
+
+    def _handle_incoming(self, stanza):
+        """Increment the handled counter for each inbound stanza."""
+        if not self.enabled.is_set():
+            return stanza
+
+        if isinstance(stanza, (Message, Presence, Iq)):
+            with self.handled_lock:
+                # Sequence numbers are mod 2^32
+                self.handled = (self.handled + 1) % MAX_SEQ
+        return stanza
+
+    def _handle_outgoing(self, stanza):
+        """Store outgoing stanzas in a queue to be acked."""
+        if not self.enabled.is_set():
+            return stanza
+
+        if isinstance(stanza, (Message, Presence, Iq)):
+            seq = None
+            with self.seq_lock:
+                # Sequence numbers are mod 2^32
+                self.seq = (self.seq + 1) % MAX_SEQ
+                seq = self.seq
+            self.unacked_queue.append((seq, stanza))
+            if len(self.unacked_queue) > self.window:
+                self.xmpp.event('need_ack')
+        return stanza