view mod_muc_occupant_id/mod_muc_occupant_id.lua @ 3670:6a437d6eb69f

mod_muc_occupant_id: add TODO regarding MAM handling
author Maxime “pep” Buquet <>
date Thu, 12 Sep 2019 01:16:26 +0200
parents 7b02b8de6d27
children d60efdb947fd
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-- Implementation of
-- XEP-0421: Anonymous unique occupant identifiers for MUCs


local uuid = require "util.uuid";
local hmac_sha256 = require "util.hashes".hmac_sha256;
local b64encode = require "util.encodings".base64.encode;

local xmlns_occupant_id = "urn:xmpp:occupant-id:0";

local function edit_occupant(event)
	local occupant, room = event.occupant,;
	local bare = occupant.bare_jid;

	-- TODO: Move the salt on the MUC component. Setting the salt on the room
	-- can be problematic when the room is destroyed. Next time it's recreated
	-- the salt will be different and so will be the unique_id. Or maybe we want
	-- this anyway?
	if room._data.occupant_id_salt == nil then
		local salt = uuid.generate();
		room._data.occupant_id_salt = salt;

	local unique_id = b64encode(hmac_sha256(bare, room._data.occupant_id_salt));

	-- TODO: Store this only once per bare jid and not once per occupant?
	local stanza = event.stanza;
	stanza:tag("occupant-id", { xmlns = xmlns_occupant_id })

local function handle_stanza(event)
	local stanza, occupant = event.stanza, event.occupant;

	if == "presence" and stanza.attr.type == "unavailable" then -- not required here

	-- TODO: Handle MAM.

	-- strip any existing <occupant-id/> tags to avoid forgery
	stanza:remove_children("occupant-id", xmlns_occupant_id);

	local unique_id = occupant.sessions[stanza.attr.from]
		:get_child("occupant-id", xmlns_occupant_id)
	stanza:tag("occupant-id", { xmlns = xmlns_occupant_id })

module:hook("muc-disco#info", function (event)
	event.reply:tag("feature", { var = xmlns_occupant_id }):up();

module:hook("muc-occupant-pre-join", edit_occupant);
module:hook("muc-occupant-groupchat", handle_stanza);