--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libervia/backend/plugins/plugin_xep_0280.py	Fri Jun 02 11:49:51 2023 +0200
@@ -0,0 +1,174 @@
+#!/usr/bin/env python3
+
+
+# SAT plugin for managing xep-0280
+# 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 libervia.backend.core.i18n import _, D_
+from libervia.backend.core.log import getLogger
+
+log = getLogger(__name__)
+from libervia.backend.core import exceptions
+from libervia.backend.core.constants import Const as C
+from twisted.words.protocols.jabber.error import StanzaError
+from twisted.internet import defer
+from wokkel import disco, iwokkel
+from zope.interface import implementer
+
+try:
+    from twisted.words.protocols.xmlstream import XMPPHandler
+except ImportError:
+    from wokkel.subprotocols import XMPPHandler
+
+
+PARAM_CATEGORY = "Misc"
+PARAM_NAME = "carbon"
+PARAM_LABEL = D_("Message carbons")
+NS_CARBONS = "urn:xmpp:carbons:2"
+
+PLUGIN_INFO = {
+    C.PI_NAME: "XEP-0280 Plugin",
+    C.PI_IMPORT_NAME: "XEP-0280",
+    C.PI_TYPE: "XEP",
+    C.PI_PROTOCOLS: ["XEP-0280"],
+    C.PI_DEPENDENCIES: [],
+    C.PI_MAIN: "XEP_0280",
+    C.PI_HANDLER: "yes",
+    C.PI_DESCRIPTION: D_("""Implementation of Message Carbons"""),
+}
+
+
+class XEP_0280(object):
+    #  TODO: param is only checked at profile connection
+    #       activate carbons on param change even after profile connection
+    # TODO: chat state notifications are not handled yet (and potentially other XEPs?)
+
+    params = """
+    <params>
+    <individual>
+    <category name="{category_name}" label="{category_label}">
+        <param name="{param_name}" label="{param_label}" value="true" type="bool" security="0" />
+     </category>
+    </individual>
+    </params>
+    """.format(
+        category_name=PARAM_CATEGORY,
+        category_label=D_(PARAM_CATEGORY),
+        param_name=PARAM_NAME,
+        param_label=PARAM_LABEL,
+    )
+
+    def __init__(self, host):
+        log.info(_("Plugin XEP_0280 initialization"))
+        self.host = host
+        host.memory.update_params(self.params)
+        host.trigger.add("message_received", self.message_received_trigger, priority=200000)
+
+    def get_handler(self, client):
+        return XEP_0280_handler()
+
+    def set_private(self, message_elt):
+        """Add a <private/> element to a message
+
+        this method is intented to be called on final domish.Element by other plugins
+        (in particular end 2 end encryption plugins)
+        @param message_elt(domish.Element): <message> stanza
+        """
+        if message_elt.name != "message":
+            log.error("addPrivateElt must be used with <message> stanzas")
+            return
+        message_elt.addElement((NS_CARBONS, "private"))
+
+    @defer.inlineCallbacks
+    def profile_connected(self, client):
+        """activate message carbons on connection if possible and activated in config"""
+        activate = self.host.memory.param_get_a(
+            PARAM_NAME, PARAM_CATEGORY, profile_key=client.profile
+        )
+        if not activate:
+            log.info(_("Not activating message carbons as requested in params"))
+            return
+        try:
+            yield self.host.check_features(client, (NS_CARBONS,))
+        except exceptions.FeatureNotFound:
+            log.warning(_("server doesn't handle message carbons"))
+        else:
+            log.info(_("message carbons available, enabling it"))
+            iq_elt = client.IQ()
+            iq_elt.addElement((NS_CARBONS, "enable"))
+            try:
+                yield iq_elt.send()
+            except StanzaError as e:
+                log.warning("Can't activate message carbons: {}".format(e))
+            else:
+                log.info(_("message carbons activated"))
+
+    def message_received_trigger(self, client, message_elt, post_treat):
+        """get message and handle it if carbons namespace is present"""
+        carbons_elt = None
+        for e in message_elt.elements():
+            if e.uri == NS_CARBONS:
+                carbons_elt = e
+                break
+
+        if carbons_elt is None:
+            # this is not a message carbons,
+            # we continue normal behaviour
+            return True
+
+        if message_elt["from"] != client.jid.userhost():
+            log.warning(
+                "The message carbon received is not from our server, hack attempt?\n{xml}".format(
+                    xml=message_elt.toXml()
+                )
+            )
+            return
+        forwarded_elt = next(carbons_elt.elements(C.NS_FORWARD, "forwarded"))
+        cc_message_elt = next(forwarded_elt.elements(C.NS_CLIENT, "message"))
+
+        # we replace the wrapping message with the CCed one
+        # and continue the normal behaviour
+        if carbons_elt.name == "received":
+            message_elt["from"] = cc_message_elt["from"]
+        elif carbons_elt.name == "sent":
+            try:
+                message_elt["to"] = cc_message_elt["to"]
+            except KeyError:
+                # we may not have "to" in case of message from ourself (from an other
+                # device)
+                pass
+        else:
+            log.warning(
+                "invalid message carbons received:\n{xml}".format(
+                    xml=message_elt.toXml()
+                )
+            )
+            return False
+
+        del message_elt.children[:]
+        for c in cc_message_elt.children:
+            message_elt.addChild(c)
+
+        return True
+
+@implementer(iwokkel.IDisco)
+class XEP_0280_handler(XMPPHandler):
+
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
+        return [disco.DiscoFeature(NS_CARBONS)]
+
+    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
+        return []