diff --git a/sat/plugins/plugin_xep_0444.py b/sat/plugins/plugin_xep_0444.py
new file mode 100644
index 00000000..2bfa7146
--- /dev/null
+++ b/sat/plugins/plugin_xep_0444.py
@@ -0,0 +1,171 @@
+#!/usr/bin/env python3
+
+# Libervia plugin for XEP-0444
+# 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 .
+
+from typing import List, Iterable
+from copy import deepcopy
+
+from twisted.words.protocols.jabber import jid, xmlstream
+from twisted.words.xish import domish
+from twisted.internet import defer
+from wokkel import disco, iwokkel
+from zope.interface import implementer
+
+from sat.core.constants import Const as C
+from sat.core.i18n import _
+from sat.core.log import getLogger
+from sat.core import exceptions
+from sat.core.core_types import SatXMPPEntity
+from sat.memory.sqla_mapping import History
+
+log = getLogger(__name__)
+
+PLUGIN_INFO = {
+ C.PI_NAME: "Message Reactions",
+ C.PI_IMPORT_NAME: "XEP-0444",
+ C.PI_TYPE: C.PLUG_TYPE_XEP,
+ C.PI_MODES: C.PLUG_MODE_BOTH,
+ C.PI_PROTOCOLS: ["XEP-0444"],
+ C.PI_DEPENDENCIES: ["XEP-0334"],
+ C.PI_MAIN: "XEP_0444",
+ C.PI_HANDLER: "yes",
+ C.PI_DESCRIPTION: _("""Message Reactions implementation"""),
+}
+
+NS_REACTIONS = "urn:xmpp:reactions:0"
+
+
+class XEP_0444:
+
+ def __init__(self, host):
+ log.info(_("Message Reactions initialization"))
+ host.registerNamespace("reactions", NS_REACTIONS)
+ self.host = host
+ self._h = host.plugins["XEP-0334"]
+ host.bridge.addMethod(
+ "messageReactionsSet",
+ ".plugin",
+ in_sign="ssas",
+ out_sign="",
+ method=self._reactionsSet,
+ async_=True,
+ )
+ host.trigger.add("messageReceived", self._messageReceivedTrigger)
+
+ def getHandler(self, client):
+ return XEP_0444_Handler()
+
+ async def _messageReceivedTrigger(
+ self,
+ client: SatXMPPEntity,
+ message_elt: domish.Element,
+ post_treat: defer.Deferred
+ ) -> bool:
+ return True
+
+ def _reactionsSet(self, message_id: str, profile: str, reactions: List[str]) -> None:
+ client = self.host.getClient(profile)
+ return defer.ensureDeferred(
+ self.setReactions(client, message_id)
+ )
+
+ def sendReactions(
+ self,
+ client: SatXMPPEntity,
+ dest_jid: jid.JID,
+ message_id: str,
+ reactions: Iterable[str]
+ ) -> None:
+ """Send the stanza containing the reactions
+
+ @param dest_jid: recipient of the reaction
+ @param message_id: either or message's ID
+ see https://xmpp.org/extensions/xep-0444.html#business-id
+ """
+ message_elt = domish.Element((None, "message"))
+ message_elt["from"] = client.jid.full()
+ message_elt["to"] = dest_jid.full()
+ reactions_elt = message_elt.addElement((NS_REACTIONS, "reactions"))
+ reactions_elt["id"] = message_id
+ for r in set(reactions):
+ reactions_elt.addElement("reaction", content=r)
+ self._h.addHintElements(message_elt, [self._h.HINT_STORE])
+ client.send(message_elt)
+
+ async def addReactionsToHistory(
+ self,
+ history: History,
+ from_jid: jid.JID,
+ reactions: Iterable[str]
+ ) -> None:
+ """Update History instance with given reactions
+
+ @param history: storage History instance
+ will be updated in DB
+ "summary" field of history.extra["reactions"] will also be updated
+ @param from_jid: author of the reactions
+ @param reactions: list of reactions
+ """
+ history.extra = deepcopy(history.extra) if history.extra else {}
+ h_reactions = history.extra.setdefault("reactions", {})
+ # reactions mapped by originating JID
+ by_jid = h_reactions.setdefault("by_jid", {})
+ # reactions are sorted to in summary to keep a consistent order
+ h_reactions["by_jid"][from_jid.userhost()] = sorted(list(set(reactions)))
+ h_reactions["summary"] = sorted(list(set().union(*by_jid.values())))
+ await self.host.memory.storage.session_add(history)
+
+ async def setReactions(
+ self,
+ client: SatXMPPEntity,
+ message_id: str,
+ reactions: Iterable[str]
+ ) -> None:
+ """Set and replace reactions to a message
+
+ @param message_id: internal ID of the message
+ @param rections: lsit of emojis to used to react to the message
+ use empty list to remove all reactions
+ """
+ if not message_id:
+ raise ValueError("message_id can't be empty")
+ history = await self.host.memory.storage.get(
+ client, History, History.uid, message_id,
+ joined_loads=[History.messages, History.subjects]
+ )
+ if history is None:
+ raise exceptions.NotFound(
+ f"message to retract not found in database ({message_id})"
+ )
+ mess_id = history.origin_id or history.stanza_id
+ if not mess_id:
+ raise exceptions.DataError(
+ "target message has neither origin-id nor message-id, we can't send a "
+ "reaction"
+ )
+ await self.addReactionsToHistory(history, client.jid, reactions)
+ self.sendReactions(client, history.dest_jid, mess_id, reactions)
+
+
+@implementer(iwokkel.IDisco)
+class XEP_0444_Handler(xmlstream.XMPPHandler):
+
+ def getDiscoInfo(self, requestor, service, nodeIdentifier=""):
+ return [disco.DiscoFeature(NS_REACTIONS)]
+
+ def getDiscoItems(self, requestor, service, nodeIdentifier=""):
+ return []