libervia-backend/libervia/backend/plugins/plugin_xep_0422.py

#!/usr/bin/env python3

# Copyright (C) 2009-2026 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 typing import Optional, List, Tuple, Union, NamedTuple
from collections import namedtuple

from twisted.words.protocols.jabber import xmlstream
from twisted.words.xish import domish
from tx_xmpp import disco
from zope.interface import implementer

from libervia.backend.core.constants import Const as C
from libervia.backend.core.i18n import _
from libervia.backend.core.log import getLogger
from libervia.backend.core.core_types import SatXMPPEntity
from libervia.backend.memory.sqla_mapping import History
from libervia.backend.tools.common.async_utils import async_lru

log = getLogger(__name__)


PLUGIN_INFO = {
    C.PI_NAME: "Message Fastening",
    C.PI_IMPORT_NAME: "XEP-0422",
    C.PI_TYPE: "XEP",
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: ["XEP-0359", "XEP-0422"],
    C.PI_MAIN: "XEP_0422",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Implementation Message Fastening"""),
}

NS_FASTEN = "urn:xmpp:fasten:0"


class FastenMetadata(NamedTuple):
    elements: List[domish.Element]
    id: str
    history: Optional[History]
    clear: bool
    shell: bool


class XEP_0422(object):

    def __init__(self, host):
        log.info(_("XEP-0422 (Message Fastening) plugin initialization"))
        self.host = host
        host.register_namespace("fasten", NS_FASTEN)

    def get_handler(self, __):
        return XEP_0422_handler()

    def apply_to_elt(
        self,
        message_elt: domish.Element,
        origin_id: str,
        clear: Optional[bool] = None,
        shell: Optional[bool] = None,
        children: Optional[List[domish.Element]] = None,
        external: Optional[List[Union[str, Tuple[str, str]]]] = None,
    ) -> domish.Element:
        """Generate, add and return <apply-to> element

        @param message_elt: wrapping <message> element
        @param origin_id: origin ID of the target message
        @param clear: set to True to remove a fastening
        @param shell: set to True when using e2ee shell
            cf. https://xmpp.org/extensions/xep-0422.html#encryption
        @param children: element to fasten to the target message
            <apply-to> element is returned, thus children can also easily be added
            afterwards
        @param external: <external> element to add
            cf. https://xmpp.org/extensions/xep-0422.html#external-payloads
            the list items can either be a str with only the element name,
            or a tuple which must then be (namespace, name)
        @return: <apply-to> element, which is already added to the wrapping message_elt
        """
        apply_to_elt = message_elt.addElement((NS_FASTEN, "apply-to"))
        apply_to_elt["id"] = origin_id
        if clear is not None:
            apply_to_elt["clear"] = C.bool_const(clear)
        if shell is not None:
            apply_to_elt["shell"] = C.bool_const(shell)
        if children is not None:
            for child in children:
                apply_to_elt.addChild(child)
        if external is not None:
            for ext in external:
                external_elt = apply_to_elt.addElement("external")
                if isinstance(ext, str):
                    external_elt["name"] = ext
                else:
                    ns, name = ext
                    external_elt["name"] = name
                    external_elt["element-namespace"] = ns
        return apply_to_elt

    @async_lru(maxsize=5)
    async def get_fastened_elts(
        self, client: SatXMPPEntity, message_elt: domish.Element
    ) -> Optional[FastenMetadata]:
        """Get fastened elements

        if the message contains no <apply-to> element, None is returned
        """
        try:
            apply_to_elt = next(message_elt.elements(NS_FASTEN, "apply-to"))
        except StopIteration:
            return None
        else:
            origin_id = apply_to_elt.getAttribute("id")
            if not origin_id:
                log.warning(f"Received invalid fastening message: {message_elt.toXml()}")
                return None
            elements = apply_to_elt.children
            if not elements:
                log.warning(f"No element to fasten: {message_elt.toXml()}")
                return None
            history = await self.host.memory.storage.get(
                client,
                History,
                History.origin_id,
                origin_id,
                (History.messages, History.subjects, History.thread),
            )
            return FastenMetadata(
                elements,
                origin_id,
                history,
                C.bool(apply_to_elt.getAttribute("clear", C.BOOL_FALSE)),
                C.bool(apply_to_elt.getAttribute("shell", C.BOOL_FALSE)),
            )


@implementer(disco.IDisco)
class XEP_0422_handler(xmlstream.XMPPHandler):

    def getDiscoInfo(self, __, target, nodeIdentifier=""):
        return [disco.DiscoFeature(NS_FASTEN)]

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