view sat/plugins/plugin_xep_0095.py @ 3913:944f51f9c2b4

core (xmpp): make `send` a blocking method, fix `sendMessageData` calls: original `send` method is blocking, and it is used as such by Wokkel and thus can't be changed to an async method easily. However, an Async method is necessary to have an async trigger at the very end of the send workflow for end-to-end encryption. To workaround that, `send` is an async method which call `a_send`, an async method which actually does the sending. This way legacy method can still call `send` while `a_send` can be await otherwise. Fix calls to `sendMessageData`: the method now being an `async` one, `ensureDeferred` had to be used in some calls.
author Goffi <goffi@goffi.org>
date Sat, 24 Sep 2022 16:31:39 +0200
parents be6d91572633
children 524856bd7b19
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#!/usr/bin/env python3


# SAT plugin for managing xep-0095
# Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program 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 Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from sat.core.i18n import _
from sat.core.constants import Const as C
from sat.core.log import getLogger

log = getLogger(__name__)
from sat.core import exceptions
from twisted.words.protocols.jabber import xmlstream
from twisted.words.protocols.jabber import error
from zope.interface import implementer
from wokkel import disco
from wokkel import iwokkel
import uuid


PLUGIN_INFO = {
    C.PI_NAME: "XEP 0095 Plugin",
    C.PI_IMPORT_NAME: "XEP-0095",
    C.PI_TYPE: "XEP",
    C.PI_PROTOCOLS: ["XEP-0095"],
    C.PI_MAIN: "XEP_0095",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Implementation of Stream Initiation"""),
}


IQ_SET = '/iq[@type="set"]'
NS_SI = "http://jabber.org/protocol/si"
SI_REQUEST = IQ_SET + '/si[@xmlns="' + NS_SI + '"]'
SI_PROFILE_HEADER = "http://jabber.org/protocol/si/profile/"
SI_ERROR_CONDITIONS = ("bad-profile", "no-valid-streams")


class XEP_0095(object):
    def __init__(self, host):
        log.info(_("Plugin XEP_0095 initialization"))
        self.host = host
        self.si_profiles = {}  # key: SI profile, value: callback

    def getHandler(self, client):
        return XEP_0095_handler(self)

    def registerSIProfile(self, si_profile, callback):
        """Add a callback for a SI Profile

        @param si_profile(unicode): SI profile name (e.g. file-transfer)
        @param callback(callable): method to call when the profile name is asked
        """
        self.si_profiles[si_profile] = callback

    def unregisterSIProfile(self, si_profile):
        try:
            del self.si_profiles[si_profile]
        except KeyError:
            log.error(
                "Trying to unregister SI profile [{}] which was not registered".format(
                    si_profile
                )
            )

    def streamInit(self, iq_elt, client):
        """This method is called on stream initiation (XEP-0095 #3.2)

        @param iq_elt: IQ element
        """
        log.info(_("XEP-0095 Stream initiation"))
        iq_elt.handled = True
        si_elt = next(iq_elt.elements(NS_SI, "si"))
        si_id = si_elt["id"]
        si_mime_type = iq_elt.getAttribute("mime-type", "application/octet-stream")
        si_profile = si_elt["profile"]
        si_profile_key = (
            si_profile[len(SI_PROFILE_HEADER) :]
            if si_profile.startswith(SI_PROFILE_HEADER)
            else si_profile
        )
        if si_profile_key in self.si_profiles:
            # We know this SI profile, we call the callback
            self.si_profiles[si_profile_key](client, iq_elt, si_id, si_mime_type, si_elt)
        else:
            # We don't know this profile, we send an error
            self.sendError(client, iq_elt, "bad-profile")

    def sendError(self, client, request, condition):
        """Send IQ error as a result

        @param request(domish.Element): original IQ request
        @param condition(str): error condition
        """
        if condition in SI_ERROR_CONDITIONS:
            si_condition = condition
            condition = "bad-request"
        else:
            si_condition = None

        iq_error_elt = error.StanzaError(condition).toResponse(request)
        if si_condition is not None:
            iq_error_elt.error.addElement((NS_SI, si_condition))

        client.send(iq_error_elt)

    def acceptStream(self, client, iq_elt, feature_elt, misc_elts=None):
        """Send the accept stream initiation answer

        @param iq_elt(domish.Element): initial SI request
        @param feature_elt(domish.Element): 'feature' element containing stream method to use
        @param misc_elts(list[domish.Element]): list of elements to add
        """
        log.info(_("sending stream initiation accept answer"))
        if misc_elts is None:
            misc_elts = []
        result_elt = xmlstream.toResponse(iq_elt, "result")
        si_elt = result_elt.addElement((NS_SI, "si"))
        si_elt.addChild(feature_elt)
        for elt in misc_elts:
            si_elt.addChild(elt)
        client.send(result_elt)

    def _parseOfferResult(self, iq_elt):
        try:
            si_elt = next(iq_elt.elements(NS_SI, "si"))
        except StopIteration:
            log.warning("No <si/> element found in result while expected")
            raise exceptions.DataError
        return (iq_elt, si_elt)

    def proposeStream(
        self,
        client,
        to_jid,
        si_profile,
        feature_elt,
        misc_elts,
        mime_type="application/octet-stream",
    ):
        """Propose a stream initiation

        @param to_jid(jid.JID): recipient
        @param si_profile(unicode): Stream initiation profile (XEP-0095)
        @param feature_elt(domish.Element): feature element, according to XEP-0020
        @param misc_elts(list[domish.Element]): list of elements to add
        @param mime_type(unicode): stream mime type
        @return (tuple): tuple with:
            - session id (unicode)
            - (D(domish_elt, domish_elt): offer deferred which returl a tuple
                with iq_elt and si_elt
        """
        offer = client.IQ()
        sid = str(uuid.uuid4())
        log.debug(_("Stream Session ID: %s") % offer["id"])

        offer["from"] = client.jid.full()
        offer["to"] = to_jid.full()
        si = offer.addElement("si", NS_SI)
        si["id"] = sid
        si["mime-type"] = mime_type
        si["profile"] = si_profile
        for elt in misc_elts:
            si.addChild(elt)
        si.addChild(feature_elt)

        offer_d = offer.send()
        offer_d.addCallback(self._parseOfferResult)
        return sid, offer_d


@implementer(iwokkel.IDisco)
class XEP_0095_handler(xmlstream.XMPPHandler):

    def __init__(self, plugin_parent):
        self.plugin_parent = plugin_parent
        self.host = plugin_parent.host

    def connectionInitialized(self):
        self.xmlstream.addObserver(
            SI_REQUEST, self.plugin_parent.streamInit, client=self.parent
        )

    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
        return [disco.DiscoFeature(NS_SI)] + [
            disco.DiscoFeature(
                "http://jabber.org/protocol/si/profile/{}".format(profile_name)
            )
            for profile_name in self.plugin_parent.si_profiles
        ]

    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
        return []