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:
enable = stanza.Enable(self.xmpp)
enable['resume'] = self.allow_resume
enable.send()
self.enabled = True
self.handled = 0
self.unacked_queue.clear()
waiter = Waiter(
'enabled_or_failed',
MatchMany([
MatchXPath(stanza.Enabled.tag_name()),
MatchXPath(stanza.Failed.tag_name())
]))
self.xmpp.register_handler(waiter)
result = yield from waiter.wait()
elif self.sm_id and self.allow_resume and 'bind' not in self.xmpp.features:
self.enabled = True
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 = yield from waiter.wait()
if result is not None and result.name == 'resumed':
return True
return False
