424 lines
12 KiB
Python
424 lines
12 KiB
Python
# -*- coding:utf-8 -*-
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## src/common/caps.py
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##
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## 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) 2007-2008 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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'''
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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 gajim
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import helpers
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import base64
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import hashlib
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from common.xmpp import NS_XHTML_IM, NS_RECEIPTS, NS_ESESSION, NS_CHATSTATES
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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_RECEIPTS, NS_ESESSION]
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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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def initialize(logger):
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''' Initializes this module '''
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global capscache
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capscache = CapsCache(logger)
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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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elif supported_features == [] and cache_item.queried in (0, 1):
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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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else:
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return False
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def compute_caps_hash(identities, features, dataforms=[], hash_method='sha-1'):
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'''Compute caps hash according to XEP-0115, V1.5
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dataforms are xmpp.DataForms objects as common.dataforms don't allow several
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values without a field type list-multi'''
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def sort_identities_func(i1, i2):
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cat1 = i1['category']
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cat2 = i2['category']
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if cat1 < cat2:
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return -1
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if cat1 > cat2:
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return 1
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type1 = i1.get('type', '')
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type2 = i2.get('type', '')
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if type1 < type2:
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return -1
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if type1 > type2:
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return 1
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lang1 = i1.get('xml:lang', '')
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lang2 = i2.get('xml:lang', '')
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if lang1 < lang2:
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return -1
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if lang1 > lang2:
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return 1
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return 0
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def sort_dataforms_func(d1, d2):
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f1 = d1.getField('FORM_TYPE')
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f2 = d2.getField('FORM_TYPE')
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if f1 and f2 and (f1.getValue() < f2.getValue()):
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return -1
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return 1
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S = ''
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identities.sort(cmp=sort_identities_func)
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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(cmp=sort_dataforms_func)
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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)
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elif hash_method == 'md5':
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hash_ = hashlib.md5(S)
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else:
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return ''
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return base64.b64encode(hash_.digest())
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################################################################################
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### Internal classes of this module
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################################################################################
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class AbstractClientCaps(object):
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'''
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Base class representing a client and its capabilities as advertised by
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a 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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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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''' To be implemented by subclassess '''
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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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''' To be implemented by subclassess '''
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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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''' To be implemented by subclassess '''
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raise NotImplementedError()
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class ClientCaps(AbstractClientCaps):
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''' The current XEP-115 implementation '''
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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.discoverInfo(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(identities, features,
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dataforms=dataforms, 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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''' Old XEP-115 implemtation. Kept around for background competability. '''
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def __init__(self, caps_hash, node):
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AbstractClientCaps.__init__(self, caps_hash, node)
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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.discoverInfo(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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def __init__(self):
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AbstractClientCaps.__init__(self, None, None)
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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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assert cache_item.queried == 0
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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(object):
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'''
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This object keeps the mapping between caps data and real disco
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features they 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(object):
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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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# not cached into db:
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# have we sent the query?
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# 0 == not queried
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# 1 == queried
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# 2 == got the answer
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self.queried = 0
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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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self._logger.add_caps_entry(self.hash_method, self.hash,
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identities, features)
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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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# get data from logger...
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if self.logger is not None:
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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.queried = 2
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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).
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Won't query if 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.queried == 0:
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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.queried = 1
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discover = client_caps.get_discover_strategy()
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discover(connection, jid)
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################################################################################
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### Caps network coding
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################################################################################
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class ConnectionCaps(object):
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'''
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This class highly depends on that it is a part of Connection class.
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'''
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def _capsPresenceCB(self, con, presence):
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'''
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Handle incoming presence stanzas... This is a callback for xmpp
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registered in connection_handlers.py
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'''
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# we will put these into proper Contact object and ask
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# for disco... so that disco will learn how to interpret
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# these caps
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pm_ctrl = None
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try:
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jid = helpers.get_full_jid_from_iq(presence)
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except:
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# Bad jid
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return
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contact = gajim.contacts.get_contact_from_full_jid(self.name, jid)
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if contact is None:
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room_jid, nick = gajim.get_room_and_nick_from_fjid(jid)
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contact = gajim.contacts.get_gc_contact(
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self.name, room_jid, nick)
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pm_ctrl = gajim.interface.msg_win_mgr.get_control(jid, self.name)
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if contact is None:
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# TODO: a way to put contact not-in-roster
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# into Contacts
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return
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caps_tag = presence.getTag('c')
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if not caps_tag:
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# presence did not contain caps_tag
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client_caps = NullClientCaps()
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else:
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hash_method, node, caps_hash = caps_tag['hash'], caps_tag['node'], caps_tag['ver']
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if not node or not caps_hash:
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# improper caps in stanza, 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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capscache.query_client_of_jid_if_unknown(self, jid, client_caps)
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contact.client_caps = client_caps
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if pm_ctrl:
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pm_ctrl.update_contact()
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def _capsDiscoCB(self, jid, node, identities, features, dataforms):
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contact = gajim.contacts.get_contact_from_full_jid(self.name, jid)
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if not contact:
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room_jid, nick = gajim.get_room_and_nick_from_fjid(jid)
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contact = gajim.contacts.get_gc_contact(self.name, room_jid, nick)
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if contact is None:
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return
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lookup = contact.client_caps.get_cache_lookup_strategy()
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cache_item = lookup(capscache)
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if cache_item.queried == 2:
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return
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else:
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validate = contact.client_caps.get_hash_validation_strategy()
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hash_is_valid = validate(identities, features, dataforms)
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if hash_is_valid:
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cache_item.set_and_store(identities, features)
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else:
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contact.client_caps = NullClientCaps()
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# vim: se ts=3:
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