gajim-plural/gajim/common/caps_cache.py

497 lines
16 KiB
Python

# 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/>.
"""
Module containing all XEP-115 (Entity Capabilities) related classes
Basic Idea:
CapsCache caches features to hash relationships. The cache is queried
through ClientCaps objects which are hold by contact instances.
"""
import base64
import hashlib
from collections import namedtuple
import logging
log = logging.getLogger('gajim.c.caps_cache')
import nbxmpp
from nbxmpp import (NS_XHTML_IM, NS_ESESSION, NS_CHATSTATES,
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]
# 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
################################################################################
### Public API of this module
################################################################################
capscache = None
muc_caps_cache = None
def initialize(logger):
"""
Initialize this module
"""
global capscache
global muc_caps_cache
capscache = CapsCache(logger)
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
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
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 = []
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 = ''
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
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':
hash_ = hashlib.sha1(S.encode('utf-8'))
elif hash_method == 'md5':
hash_ = hashlib.md5(S.encode('utf-8'))
else:
return ''
return base64.b64encode(hash_.digest()).decode('utf-8')
################################################################################
### 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):
"""
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):
"""
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):
"""
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
def _lookup_in_cache(self, caps_cache):
return caps_cache[(self._hash_method, self._hash)]
def _discover(self, connection, jid):
connection.get_module('Discovery').disco_contact(
jid, '%s#%s' % (self._node, self._hash))
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
class OldClientCaps(AbstractClientCaps):
"""
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)]
def _discover(self, connection, jid):
connection.get_module('Discovery').disco_contact(jid)
def _is_hash_valid(self, identities, features, dataforms):
return True
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
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
hash_ = client_caps._hash
key = (hash_method, hash_)
if key in self.__cache:
del self.__cache[key]
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:
log.warning('%s returned empty disco info', jid)
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:
from gajim.common.modules import dataforms
data.append(dataforms.extend_form(node=child))
if nbxmpp.NS_MUC not in features:
# Not a MUC, don't cache info
return
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
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
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 ('owner', '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