497 lines
16 KiB
Python
497 lines
16 KiB
Python
# Copyright (C) 2007 Tomasz Melcer <liori AT exroot.org>
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# Travis Shirk <travis AT pobox.com>
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# Copyright (C) 2007-2014 Yann Leboulanger <asterix AT lagaule.org>
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# Copyright (C) 2008 Brendan Taylor <whateley AT gmail.com>
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# Jonathan Schleifer <js-gajim AT webkeks.org>
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# Copyright (C) 2008-2009 Stephan Erb <steve-e AT h3c.de>
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#
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# This file is part of Gajim.
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#
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# Gajim is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published
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# by the Free Software Foundation; version 3 only.
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#
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# Gajim is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with Gajim. If not, see <http://www.gnu.org/licenses/>.
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"""
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Module containing all XEP-115 (Entity Capabilities) related classes
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Basic Idea:
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CapsCache caches features to hash relationships. The cache is queried
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through ClientCaps objects which are hold by contact instances.
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"""
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import base64
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import hashlib
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from collections import namedtuple
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import logging
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log = logging.getLogger('gajim.c.caps_cache')
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import nbxmpp
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from nbxmpp import (NS_XHTML_IM, NS_ESESSION, NS_CHATSTATES,
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NS_JINGLE_ICE_UDP, NS_JINGLE_RTP_AUDIO, NS_JINGLE_RTP_VIDEO,
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NS_JINGLE_FILE_TRANSFER_5)
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# Features where we cannot safely assume that the other side supports them
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FEATURE_BLACKLIST = [NS_CHATSTATES, NS_XHTML_IM, NS_ESESSION,
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NS_JINGLE_ICE_UDP, NS_JINGLE_RTP_AUDIO, NS_JINGLE_RTP_VIDEO,
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NS_JINGLE_FILE_TRANSFER_5]
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# Query entry status codes
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NEW = 0
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QUERIED = 1
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CACHED = 2 # got the answer
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FAKED = 3 # allow NullClientCaps to behave as it has a cached item
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################################################################################
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### Public API of this module
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################################################################################
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capscache = None
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muc_caps_cache = None
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def initialize(logger):
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"""
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Initialize this module
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"""
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global capscache
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global muc_caps_cache
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capscache = CapsCache(logger)
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muc_caps_cache = MucCapsCache()
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def client_supports(client_caps, requested_feature):
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lookup_item = client_caps.get_cache_lookup_strategy()
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cache_item = lookup_item(capscache)
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supported_features = cache_item.features
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if requested_feature in supported_features:
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return True
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if not supported_features and cache_item.status in (NEW, QUERIED, FAKED):
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# assume feature is supported, if we don't know yet, what the client
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# is capable of
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return requested_feature not in FEATURE_BLACKLIST
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return False
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def create_suitable_client_caps(node, caps_hash, hash_method, fjid=None):
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"""
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Create and return a suitable ClientCaps object for the given node,
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caps_hash, hash_method combination.
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"""
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if not node or not caps_hash:
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if fjid:
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client_caps = NoClientCaps(fjid)
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else:
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# improper caps, ignore client capabilities.
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client_caps = NullClientCaps()
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elif not hash_method:
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client_caps = OldClientCaps(caps_hash, node)
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else:
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client_caps = ClientCaps(caps_hash, node, hash_method)
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return client_caps
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def compute_caps_hash(identities, features, dataforms=None, hash_method='sha-1'):
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"""
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Compute caps hash according to XEP-0115, V1.5
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dataforms are nbxmpp.DataForms objects as common.dataforms don't allow several
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values without a field type list-multi
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"""
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if dataforms is None:
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dataforms = []
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def sort_identities_key(i):
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return (i['category'], i.get('type', ''), i.get('xml:lang', ''))
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def sort_dataforms_key(dataform):
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f = dataform.getField('FORM_TYPE')
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return (bool(f), f.getValue())
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S = ''
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identities.sort(key=sort_identities_key)
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for i in identities:
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c = i['category']
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type_ = i.get('type', '')
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lang = i.get('xml:lang', '')
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name = i.get('name', '')
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S += '%s/%s/%s/%s<' % (c, type_, lang, name)
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features.sort()
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for f in features:
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S += '%s<' % f
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dataforms.sort(key=sort_dataforms_key)
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for dataform in dataforms:
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# fields indexed by var
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fields = {}
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for f in dataform.getChildren():
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fields[f.getVar()] = f
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form_type = fields.get('FORM_TYPE')
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if form_type:
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S += form_type.getValue() + '<'
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del fields['FORM_TYPE']
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for var in sorted(fields.keys()):
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S += '%s<' % var
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values = sorted(fields[var].getValues())
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for value in values:
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S += '%s<' % value
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if hash_method == 'sha-1':
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hash_ = hashlib.sha1(S.encode('utf-8'))
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elif hash_method == 'md5':
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hash_ = hashlib.md5(S.encode('utf-8'))
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else:
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return ''
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return base64.b64encode(hash_.digest()).decode('utf-8')
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################################################################################
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### Internal classes of this module
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################################################################################
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class AbstractClientCaps:
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"""
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Base class representing a client and its capabilities as advertised by a
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caps tag in a presence
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"""
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def __init__(self, caps_hash, node):
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self._hash = caps_hash
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self._node = node
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self._hash_method = None
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def get_discover_strategy(self):
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return self._discover
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def _discover(self, connection, jid):
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"""
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To be implemented by subclasses
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"""
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raise NotImplementedError
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def get_cache_lookup_strategy(self):
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return self._lookup_in_cache
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def _lookup_in_cache(self, caps_cache):
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"""
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To be implemented by subclasses
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"""
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raise NotImplementedError
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def get_hash_validation_strategy(self):
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return self._is_hash_valid
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def _is_hash_valid(self, identities, features, dataforms):
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"""
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To be implemented by subclasses
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"""
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raise NotImplementedError
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class ClientCaps(AbstractClientCaps):
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"""
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The current XEP-115 implementation
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"""
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def __init__(self, caps_hash, node, hash_method):
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AbstractClientCaps.__init__(self, caps_hash, node)
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assert hash_method != 'old'
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self._hash_method = hash_method
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def _lookup_in_cache(self, caps_cache):
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return caps_cache[(self._hash_method, self._hash)]
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def _discover(self, connection, jid):
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connection.get_module('Discovery').disco_contact(
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jid, '%s#%s' % (self._node, self._hash))
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def _is_hash_valid(self, identities, features, dataforms):
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computed_hash = compute_caps_hash(
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identities, features, dataforms=dataforms,
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hash_method=self._hash_method)
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return computed_hash == self._hash
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class OldClientCaps(AbstractClientCaps):
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"""
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Old XEP-115 implementation. Kept around for background compatibility
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"""
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def __init__(self, caps_hash, node):
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AbstractClientCaps.__init__(self, caps_hash, node)
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self._hash_method = 'old'
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def _lookup_in_cache(self, caps_cache):
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return caps_cache[('old', self._node + '#' + self._hash)]
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def _discover(self, connection, jid):
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connection.get_module('Discovery').disco_contact(jid)
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def _is_hash_valid(self, identities, features, dataforms):
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return True
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class NoClientCaps(AbstractClientCaps):
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"""
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For clients that don't support XEP-0115
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"""
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def __init__(self, fjid):
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AbstractClientCaps.__init__(self, fjid, fjid)
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self._hash_method = 'no'
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def _lookup_in_cache(self, caps_cache):
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return caps_cache[('no', self._node)]
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def _discover(self, connection, jid):
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connection.get_module('Discovery').disco_contact(jid)
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def _is_hash_valid(self, identities, features, dataforms):
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return True
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class NullClientCaps(AbstractClientCaps):
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"""
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This is a NULL-Object to streamline caps handling if a client has not
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advertised any caps or has advertised them in an improper way
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Assumes (almost) everything is supported.
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"""
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_instance = None
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def __new__(cls, *args, **kwargs):
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"""
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Make it a singleton.
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"""
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if not cls._instance:
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cls._instance = super(NullClientCaps, cls).__new__(
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cls, *args, **kwargs)
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return cls._instance
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def __init__(self):
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AbstractClientCaps.__init__(self, None, None)
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self._hash_method = 'dummy'
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def _lookup_in_cache(self, caps_cache):
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# lookup something which does not exist to get a new CacheItem created
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cache_item = caps_cache[('dummy', '')]
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# Mark the item as cached so that protocol/caps.py does not update it
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cache_item.status = FAKED
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return cache_item
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def _discover(self, connection, jid):
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pass
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def _is_hash_valid(self, identities, features, dataforms):
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return False
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class CapsCache:
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"""
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This object keeps the mapping between caps data and real disco features they
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represent, and provides simple way to query that info
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"""
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def __init__(self, logger=None):
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# our containers:
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# __cache is a dictionary mapping: pair of hash method and hash maps
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# to CapsCacheItem object
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# __CacheItem is a class that stores data about particular
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# client (hash method/hash pair)
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self.__cache = {}
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class CacheItem:
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# __names is a string cache; every string long enough is given
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# another object, and we will have plenty of identical long
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# strings. therefore we can cache them
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__names = {}
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def __init__(self, hash_method, hash_, logger):
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# cached into db
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self.hash_method = hash_method
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self.hash = hash_
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self._features = []
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self._identities = []
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self._logger = logger
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self.status = NEW
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self._recently_seen = False
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def _get_features(self):
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return self._features
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def _set_features(self, value):
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self._features = []
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for feature in value:
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self._features.append(self.__names.setdefault(feature, feature))
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features = property(_get_features, _set_features)
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def _get_identities(self):
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list_ = []
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for i in self._identities:
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# transforms it back in a dict
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d = dict()
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d['category'] = i[0]
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if i[1]:
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d['type'] = i[1]
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if i[2]:
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d['xml:lang'] = i[2]
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if i[3]:
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d['name'] = i[3]
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list_.append(d)
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return list_
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def _set_identities(self, value):
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self._identities = []
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for identity in value:
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# dict are not hashable, so transform it into a tuple
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t = (identity['category'], identity.get('type'),
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identity.get('xml:lang'), identity.get('name'))
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self._identities.append(self.__names.setdefault(t, t))
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identities = property(_get_identities, _set_identities)
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def set_and_store(self, identities, features):
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self.identities = identities
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self.features = features
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if self.hash_method != 'no':
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self._logger.add_caps_entry(self.hash_method, self.hash,
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identities, features)
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self.status = CACHED
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def update_last_seen(self):
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if not self._recently_seen:
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self._recently_seen = True
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if self.hash_method != 'no':
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self._logger.update_caps_time(self.hash_method,
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self.hash)
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def is_valid(self):
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"""
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Returns True if identities and features for this cache item
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are known.
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"""
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return self.status in (CACHED, FAKED)
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self.__CacheItem = CacheItem
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self.logger = logger
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def initialize_from_db(self):
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self._remove_outdated_caps()
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for hash_method, hash_, identities, features in \
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self.logger.iter_caps_data():
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x = self[(hash_method, hash_)]
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x.identities = identities
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x.features = features
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x.status = CACHED
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def _remove_outdated_caps(self):
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"""
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Remove outdated values from the db
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"""
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self.logger.clean_caps_table()
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def __getitem__(self, caps):
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if caps in self.__cache:
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return self.__cache[caps]
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hash_method, hash_ = caps
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x = self.__CacheItem(hash_method, hash_, self.logger)
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self.__cache[(hash_method, hash_)] = x
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return x
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def query_client_of_jid_if_unknown(self, connection, jid, client_caps):
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"""
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Start a disco query to determine caps (node, ver, exts). Won't query if
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the data is already in cache
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"""
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lookup_cache_item = client_caps.get_cache_lookup_strategy()
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q = lookup_cache_item(self)
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if q.status == NEW:
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# do query for bare node+hash pair
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# this will create proper object
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q.status = QUERIED
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discover = client_caps.get_discover_strategy()
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discover(connection, jid)
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else:
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q.update_last_seen()
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def forget_caps(self, client_caps):
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hash_method = client_caps._hash_method
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hash_ = client_caps._hash
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key = (hash_method, hash_)
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if key in self.__cache:
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del self.__cache[key]
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class MucCapsCache:
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DiscoInfo = namedtuple('DiscoInfo', ['identities', 'features', 'data'])
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def __init__(self):
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self.cache = {}
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def append(self, stanza):
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jid = stanza.getFrom()
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identities, features, data = [], [], []
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query_childs = stanza.getQueryChildren()
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if not query_childs:
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log.warning('%s returned empty disco info', jid)
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return
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for child in query_childs:
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if child.getName() == 'identity':
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attr = {}
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for key in child.getAttrs().keys():
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attr[key] = child.getAttr(key)
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identities.append(attr)
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elif child.getName() == 'feature':
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features.append(child.getAttr('var'))
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elif child.getName() == 'x':
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if child.getNamespace() == nbxmpp.NS_DATA:
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from gajim.common.modules import dataforms
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data.append(dataforms.extend_form(node=child))
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if nbxmpp.NS_MUC not in features:
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# Not a MUC, don't cache info
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return
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self.cache[jid] = self.DiscoInfo(identities, features, data)
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def is_cached(self, jid):
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return jid in self.cache
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def supports(self, jid, feature):
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if jid in self.cache:
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if feature in self.cache[jid].features:
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return True
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return False
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def has_mam(self, jid):
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try:
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if nbxmpp.NS_MAM_2 in self.cache[jid].features:
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return True
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if nbxmpp.NS_MAM_1 in self.cache[jid].features:
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return True
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except (KeyError, AttributeError):
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return False
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def get_mam_namespace(self, jid):
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try:
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if nbxmpp.NS_MAM_2 in self.cache[jid].features:
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return nbxmpp.NS_MAM_2
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if nbxmpp.NS_MAM_1 in self.cache[jid].features:
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return nbxmpp.NS_MAM_1
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except (KeyError, AttributeError):
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return
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def is_subject_change_allowed(self, jid, affiliation):
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allowed = True
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if affiliation in ('owner', 'admin'):
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return allowed
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if jid in self.cache:
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for form in self.cache[jid].data:
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try:
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allowed = form['muc#roominfo_changesubject'].value
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except KeyError:
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pass
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return allowed
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