gajim-plural/gajim/common/caps_cache.py

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