diff options
Diffstat (limited to 'slixmpp/plugins/xep_0198/stream_management.py')
| -rw-r--r-- | slixmpp/plugins/xep_0198/stream_management.py | 313 |
1 files changed, 313 insertions, 0 deletions
diff --git a/slixmpp/plugins/xep_0198/stream_management.py b/slixmpp/plugins/xep_0198/stream_management.py new file mode 100644 index 00000000..acf37cd7 --- /dev/null +++ b/slixmpp/plugins/xep_0198/stream_management.py @@ -0,0 +1,313 @@ +""" + Slixmpp: The Slick XMPP Library + Copyright (C) 2012 Nathanael C. Fritz, Lance J.T. Stout + This file is part of Slixmpp. + + See the file LICENSE for copying permission. +""" + +import logging +import threading +import collections + +from slixmpp.stanza import Message, Presence, Iq, StreamFeatures +from slixmpp.xmlstream import register_stanza_plugin +from slixmpp.xmlstream.handler import Callback, Waiter +from slixmpp.xmlstream.matcher import MatchXPath, MatchMany +from slixmpp.plugins.base import BasePlugin +from slixmpp.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 + default_config = { + #: The last ack number received from the server. + '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``. + 'window': 5, + + #: The stream management ID for the stream. Knowing this value is + #: required in order to do stream resumption. + 'sm_id': None, + + #: A counter of handled incoming stanzas, mod 2^32. + 'handled': 0, + + #: A counter of unacked outgoing stanzas, mod 2^32. + 'seq': 0, + + #: Control whether or not the ability to resume the stream will be + #: requested when enabling stream management. Defaults to ``True``. + 'allow_resume': True, + + 'order': 10100, + 'resume_order': 9000 + } + + 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 + + self.window_counter = self.window + self.window_counter_lock = threading.Lock() + + 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) + + # Only end the session when a </stream> element is sent, + # not just because the connection has died. + self.xmpp.end_session_on_disconnect = False + + # 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.order) + self.xmpp.register_feature('sm', + self._handle_sm_feature, + restart=True, + order=self.resume_order) + + 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('session_end', self.session_end) + + def plugin_end(self): + if self.xmpp.is_component: + return + + self.xmpp.unregister_feature('sm', self.order) + self.xmpp.unregister_feature('sm', self.resume_order) + self.xmpp.del_event_handler('session_end', self.session_end) + self.xmpp.del_filter('in', self._handle_incoming) + self.xmpp.del_filter('out_sync', self._handle_outgoing) + self.xmpp.remove_handler('Stream Management Enabled') + self.xmpp.remove_handler('Stream Management Resumed') + self.xmpp.remove_handler('Stream Management Failed') + self.xmpp.remove_handler('Stream Management Ack') + self.xmpp.remove_handler('Stream Management Request Ack') + self.xmpp.remove_stanza(stanza.Enable) + self.xmpp.remove_stanza(stanza.Enabled) + self.xmpp.remove_stanza(stanza.Resume) + self.xmpp.remove_stanza(stanza.Resumed) + self.xmpp.remove_stanza(stanza.Ack) + self.xmpp.remove_stanza(stanza.RequestAck) + + def session_end(self, event): + """Reset stream management state.""" + self.enabled.clear() + self.unacked_queue.clear() + self.sm_id = None + self.handled = 0 + self.seq = 0 + self.last_ack = 0 + + 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 + self.xmpp.send_raw(str(ack)) + + def request_ack(self, e=None): + """Request an ack from the server.""" + req = stanza.RequestAck(self.xmpp) + self.xmpp.send_queue.put(str(req)) + + 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() + + # 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, use_filters=False) + 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 + num_unacked = len(self.unacked_queue) + log.debug("Ack: %s, Last Ack: %s, " + \ + "Unacked: %s, Num Acked: %s, " + \ + "Remaining: %s", + ack['h'], + self.last_ack, + num_unacked, + num_acked, + num_unacked - num_acked) + 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)) + with self.window_counter_lock: + self.window_counter -= 1 + if self.window_counter == 0: + self.window_counter = self.window + self.request_ack() + return stanza |