view mod_muc_moderation/mod_muc_moderation.lua @ 5668:ecfd7aece33b

mod_measure_modules: Report module statuses via OpenMetrics Someone in the chat asked about a health check endpoint, which reminded me of mod_http_status, which provides access to module statuses with full details. After that, this idea came about, which seems natural. As noted in the README, it could be used to monitor that critical modules are in fact loaded correctly. As more modules use the status API, the more useful this module and mod_http_status becomes.
author Kim Alvefur <zash@zash.se>
date Fri, 06 Oct 2023 18:34:39 +0200
parents 2e30af180da5
children 5ccc03c33158
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-- mod_muc_moderation
--
-- Copyright (C) 2015-2021 Kim Alvefur
--
-- This file is MIT licensed.
--
-- Implements: XEP-0425: Message Moderation
--
-- Imports
local dt = require "util.datetime";
local id = require "util.id";
local jid = require "util.jid";
local st = require "util.stanza";

-- Plugin dependencies
local mod_muc = module:depends "muc";

local muc_util = module:require "muc/util";
local valid_roles = muc_util.valid_roles;

local muc_log_archive = module:open_store("muc_log", "archive");

if not muc_log_archive.set then
	module:log("warn", "Selected archive storage module does not support message replacement, no tombstones will be saved");
end

-- Namespaces
local xmlns_fasten = "urn:xmpp:fasten:0";
local xmlns_moderate = "urn:xmpp:message-moderate:0";
local xmlns_occupant_id = "urn:xmpp:occupant-id:0";
local xmlns_retract = "urn:xmpp:message-retract:0";

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

-- TODO error registry, requires Prosody 0.12+

-- moderate : function (string, string, string, boolean, string) : boolean, enum, enum, string
local function moderate(actor, room_jid, stanza_id, retract, reason)
	local room_node = jid.split(room_jid);
	local room = mod_muc.get_room_from_jid(room_jid);

	-- Permissions is based on role, which is a property of a current occupant,
	-- so check if the actor is an occupant, otherwise if they have a reserved
	-- nickname that can be used to retrieve the role.
	local actor_nick = room:get_occupant_jid(actor);
	if not actor_nick then
		local reserved_nickname = room:get_affiliation_data(jid.bare(actor), "reserved_nickname");
		if reserved_nickname then
			actor_nick = room.jid .. "/" .. reserved_nickname;
		end
	end

	-- Retrieve their current role, iff they are in the room, otherwise what they
	-- would have based on affiliation.
	local affiliation = room:get_affiliation(actor);
	local role = room:get_role(actor_nick) or room:get_default_role(affiliation);
	if valid_roles[role or "none"] < valid_roles.moderator then
		return false, "auth", "forbidden", "You need a role of at least 'moderator'";
	end

	-- Original stanza to base tombstone on
	local original, err;
	if muc_log_archive.get then
		original, err = muc_log_archive:get(room_node, stanza_id);
	else
		-- COMPAT missing :get API
		err = "item-not-found";
		for i, item in muc_log_archive:find(room_node, { key = stanza_id, limit = 1 }) do
			if i == stanza_id then
				original, err = item, nil;
			end
		end
	end

	if not original then
		if err == "item-not-found" then
			return false, "modify", "item-not-found";
		else
			return false, "wait", "internal-server-error";
		end
	end


	local announcement = st.message({ from = room_jid, type = "groupchat", id = id.medium(), })
		:tag("apply-to", { xmlns = xmlns_fasten, id = stanza_id })
			:tag("moderated", { xmlns = xmlns_moderate, by = actor_nick })

	if retract then
		announcement:tag("retract", { xmlns = xmlns_retract }):up();
	end

	if reason then
		announcement:text_tag("reason", reason);
	end

	local moderated_occupant_id = original:get_child("occupant-id", xmlns_occupant_id);
	if room.get_occupant_id and moderated_occupant_id then
		announcement:add_direct_child(moderated_occupant_id);
	end

	local actor_occupant = room:get_occupant_by_real_jid(actor) or room:new_occupant(jid.bare(actor), actor_nick);
	if room.get_occupant_id then
		-- This isn't a regular broadcast message going through the events occupant_id.lib hooks so we do this here
		announcement:add_direct_child(st.stanza("occupant-id", { xmlns = xmlns_occupant_id; id = room:get_occupant_id(actor_occupant) }))
	end

	if muc_log_archive.set and retract then
		local tombstone = st.message({ from = original.attr.from, type = "groupchat", id = original.attr.id })
			:tag("moderated", { xmlns = xmlns_moderate, by = actor_nick })
				:tag("retracted", { xmlns = xmlns_retract, stamp = dt.datetime() }):up();

		if room.get_occupant_id then
			tombstone:add_direct_child(st.stanza("occupant-id", { xmlns = xmlns_occupant_id; id = room:get_occupant_id(actor_occupant) }))

			if moderated_occupant_id then
				-- Copy occupant id from moderated message
				tombstone:add_child(moderated_occupant_id);
			end
		end

		if reason then
			tombstone:text_tag("reason", reason);
		end
		tombstone:reset();

		local was_replaced = muc_log_archive:set(room_node, stanza_id, tombstone);
		if not was_replaced then
			return false, "wait", "internal-server-error";
		end
	end

	-- Done, tell people about it
	module:log("info", "Message with id '%s' in room %s moderated by %s, reason: %s", stanza_id, room_jid, actor, reason);
	room:broadcast_message(announcement);

	return true;
end

-- Main handling
module:hook("iq-set/bare/" .. xmlns_fasten .. ":apply-to", function (event)
	local stanza, origin = event.stanza, event.origin;

	local actor = stanza.attr.from;
	local room_jid = stanza.attr.to;

	-- Collect info we need
	local apply_to = stanza.tags[1];
	local moderate_tag = apply_to:get_child("moderate", xmlns_moderate);
	if not moderate_tag then return end -- some other kind of fastening?

	local reason = moderate_tag:get_child_text("reason");
	local retract = moderate_tag:get_child("retract", xmlns_retract);

	local stanza_id = apply_to.attr.id;

	local ok, error_type, error_condition, error_text = moderate(actor, room_jid, stanza_id, retract, reason);
	if not ok then
		origin.send(st.error_reply(stanza, error_type, error_condition, error_text));
		return true;
	end

	origin.send(st.reply(stanza));
	return true;
end);

module:hook("muc-message-is-historic", function (event)
	-- Ensure moderation messages are stored
	if event.stanza.attr.from == event.room.jid then
		return event.stanza:get_child("apply-to", xmlns_fasten);
	end
end, 1);