SleekXMPP/sleekxmpp/plugins/xep_0115/caps.py

"""
    SleekXMPP: The Sleek XMPP Library
    Copyright (C) 2011 Nathanael C. Fritz, Lance J.T. Stout
    This file is part of SleekXMPP.

    See the file LICENSE for copying permission.
"""

import logging
import hashlib
import base64

import sleekxmpp
from sleekxmpp.stanza import StreamFeatures, Presence, Iq
from sleekxmpp.xmlstream import register_stanza_plugin
from sleekxmpp.xmlstream.handler import Callback
from sleekxmpp.xmlstream.matcher import StanzaPath
from sleekxmpp.exceptions import XMPPError, IqError, IqTimeout
from sleekxmpp.plugins.base import base_plugin
from sleekxmpp.plugins.xep_0115 import stanza, StaticCaps


log = logging.getLogger(__name__)


class xep_0115(base_plugin):

    """
    XEP-0115: Entity Capabalities
    """

    def plugin_init(self):
        self.xep = '0115'
        self.description = 'Entity Capabilities'
        self.stanza = stanza

        self.hashes = {'sha-1': hashlib.sha1, 
                       'md5': hashlib.md5}

        self.hash = self.config.get('hash', 'sha-1')
        self.caps_node = self.config.get('caps_node', None)
        self.broadcast = self.config.get('broadcast', True)

        if self.caps_node is None:
            ver = sleekxmpp.__version__
            self.caps_node = 'http://sleekxmpp.com/ver/%s' % ver

        register_stanza_plugin(Presence, stanza.Capabilities)
        register_stanza_plugin(StreamFeatures, stanza.Capabilities)

        self._disco_ops = ['cache_caps',
                           'get_caps',
                           'assign_verstring',
                           'get_verstring',
                           'supports',
                           'has_identity']

        self.xmpp.register_handler(
                Callback('Entity Capabilites',
                         StanzaPath('presence/caps'),
                         self._handle_caps))

        self.xmpp.add_filter('out', self._filter_add_caps)

        self.xmpp.add_event_handler('entity_caps', self._process_caps,
                                    threaded=True)

        self.xmpp.register_feature('caps',
                self._handle_caps_feature,
                restart=False,
                order=10010)

    def post_init(self):
        base_plugin.post_init(self)
        self.xmpp['xep_0030'].add_feature(stanza.Capabilities.namespace)

        self.disco = self.xmpp['xep_0030']
        self.static = StaticCaps(self.xmpp, self.disco.static)

        for op in self._disco_ops:
            self.disco._add_disco_op(op, getattr(self.static, op))

        self._run_node_handler = self.disco._run_node_handler

        self.disco.cache_caps = self.cache_caps
        self.disco.update_caps = self.update_caps
        self.disco.assign_verstring = self.assign_verstring
        self.disco.get_verstring = self.get_verstring

    def _filter_add_caps(self, stanza):
        if isinstance(stanza, Presence) and self.broadcast:
            ver = self.get_verstring(stanza['from'])
            if ver:
                stanza['caps']['node'] = self.caps_node
                stanza['caps']['hash'] = self.hash
                stanza['caps']['ver'] = ver
        return stanza

    def _handle_caps(self, presence):
        if not self.xmpp.is_component:
            if presence['from'] == self.xmpp.boundjid:
                return
        self.xmpp.event('entity_caps', presence)

    def _handle_caps_feature(self, features):
        # We already have a method to process presence with
        # caps, so wrap things up and use that.
        p = Presence()
        p['from'] = self.xmpp.boundjid.domain
        p.append(features['caps'])
        self.xmpp.features.add('caps')

        self.xmpp.event('entity_caps', p)

    def _process_caps(self, pres):
        if not pres['caps']['hash']:
            log.debug("Received unsupported legacy caps.")
            self.xmpp.event('entity_caps_legacy', pres)
            return

        existing_verstring = self.get_verstring(pres['from'].full)
        if str(existing_verstring) == str(pres['caps']['ver']):
            return
     
        if pres['caps']['hash'] not in self.hashes:
            try:
                log.debug("Unknown caps hash: %s", pres['caps']['hash'])
                self.disco.get_info(jid=pres['from'])
                return
            except XMPPError:
                return
   
        log.debug("New caps verification string: %s", pres['caps']['ver'])
        try:
            caps = self.disco.get_info(
                    jid=pres['from'],
                    node='%s#%s' % (pres['caps']['node'],
                                    pres['caps']['ver']))
                    
            if self._validate_caps(caps['disco_info'], 
                                   pres['caps']['hash'],
                                   pres['caps']['ver']):
                self.assign_verstring(pres['from'], pres['caps']['ver'])
        except XMPPError:
            log.debug("Could not retrieve disco#info results for caps")

    def _validate_caps(self, caps, hash, check_verstring):
        # Check Identities
        full_ids = caps.get_identities(dedupe=False)
        deduped_ids = caps.get_identities()
        if len(full_ids) != len(deduped_ids):
            log.debug("Duplicate disco identities found, invalid for caps")
            return False

        # Check Features

        full_features = caps.get_features(dedupe=False)
        deduped_features = caps.get_features()
        if len(full_features) != len(deduped_features):
            log.debug("Duplicate disco features found, invalid for caps")
            return False

        # Check Forms
        form_types = []
        deduped_form_types = set()
        for stanza in caps['substanzas']:
            if isinstance(stanza, self.xmpp['xep_0004'].stanza.Form):
                if 'FORM_TYPE' in stanza['fields']:
                    f_type = tuple(stanza['fields']['FORM_TYPE']['value'])
                    form_types.append(f_type)
                    deduped_form_types.add(f_type)
                    if len(form_types) != len(deduped_form_types):
                        log.debug("Duplicated FORM_TYPE values, invalid for caps")
                        return False

                    if len(f_type) > 1:
                        deduped_type = set(f_type)
                        if len(f_type) != len(deduped_type):
                            log.debug("Extra FORM_TYPE data, invalid for caps")
                            return False

                    if stanza['fields']['FORM_TYPE']['type'] != 'hidden':
                        log.debug("Field FORM_TYPE type not 'hidden', ignoring form for caps")
                        caps.xml.remove(stanza.xml)
                else:
                    log.debug("No FORM_TYPE found, ignoring form for caps")
                    caps.xml.remove(stanza.xml)

        verstring = self.generate_verstring(caps, hash)
        if verstring != check_verstring:
            log.debug("Verification strings do not match: %s, %s" % (
                verstring, check_verstring))
            return False

        self.cache_caps(verstring, caps)
        return True

    def generate_verstring(self, info, hash):
        hash = self.hashes.get(hash, None)
        if hash is None:
            return None

        S = ''

        # Convert None to '' in the identities
        def clean_identity(id):
            return map(lambda i: i or '', id)
        identities = map(clean_identity, info['identities'])

        identities = sorted(('/'.join(i) for i in identities))
        features = sorted(info['features'])
 
        S += '<'.join(identities) + '<'
        S += '<'.join(features) + '<'

        form_types = {}

        for stanza in info['substanzas']:
            if isinstance(stanza, self.xmpp['xep_0004'].stanza.Form):
                if 'FORM_TYPE' in stanza['fields']:
                    f_type = stanza['values']['FORM_TYPE']
                    if len(f_type):
                        f_type = f_type[0]
                    if f_type not in form_types:
                        form_types[f_type] = []
                    form_types[f_type].append(stanza)

        sorted_forms = sorted(form_types.keys())
        for f_type in sorted_forms:
            for form in form_types[f_type]:
                S += '%s<' % f_type
                fields = sorted(form['fields'].keys())
                fields.remove('FORM_TYPE')
                for field in fields:
                    S += '%s<' % field
                    vals = form['fields'][field].get_value(convert=False)
                    if vals is None:
                        S += '<'
                    else:
                        if not isinstance(vals, list):
                            vals = [vals]
                        S += '<'.join(sorted(vals)) + '<'

        binary = hash(S.encode('utf8')).digest()
        return base64.b64encode(binary)

    def update_caps(self, jid=None, node=None):
        try:
            info = self.disco.get_info(jid, node, local=True)
            if isinstance(info, Iq):
                info = info['disco_info']
            ver = self.generate_verstring(info, self.hash)
            self.disco.set_info(
                    jid=jid, 
                    node='%s#%s' % (self.caps_node, ver),
                    info=info)
            self.cache_caps(ver, info)
            self.assign_verstring(jid, ver)
        except XMPPError:
            return

    def get_verstring(self, jid=None):
        if jid in ('', None):
            jid = self.xmpp.boundjid.full
        return self._run_node_handler('get_verstring', jid)

    def assign_verstring(self, jid=None, verstring=None):
        if jid in (None, ''):
            jid = self.xmpp.boundjid.full
        return self._run_node_handler('assign_verstring', jid, 
                                      data={'verstring': verstring})

    def cache_caps(self, verstring=None, info=None):
        data = {'verstring': verstring, 'info': info}
        return self._run_node_handler('cache_caps', None, None, data=data)

    def get_caps(self, jid=None, verstring=None):
        if verstring is None:
            if jid is not None:
                verstring = self.get_verstring(jid)
            else:
                return None

        data = {'verstring': verstring}
        return self._run_node_handler('get_caps', jid, None, None, data)