File

mod_presence_dedup/mod_presence_dedup.lua @ 5296:0f5657db1cfc

mod_isolate_host: handle server-generated stanzas The hook for setting the no_host_isolation is only called for c2s sessions. This does not work for stanzas generated by the server, such as PEP notifications or presence probe answers. To handle that, we do per-stanza checks for the case that the origin is local.
author Jonas Schäfer <jonas@wielicki.name>
date Sat, 01 Apr 2023 12:03:08 +0200
parent 3445:19924a2c4a48
line wrap: on
line source

local st = require "util.stanza";
local cache = require "util.cache";
local add_filter = require "util.filters".add_filter;

local cache_size = module:get_option_number("presence_dedup_cache_size", 100);

-- stanza equality tests
local function attr_eq(a, b)
	if a == b then return true; end -- unlikely but not impossible
	for k,v in pairs(a) do if b[k] ~= v then return false; end end
	for k,v in pairs(b) do if a[k] ~= v then return false; end end
	return true;
end

local function st_eq(a, b)
	if a == b then return true; end
	if type(b) ~= "table" then return false; end
	if getmetatable(b) ~= st.stanza_mt then return false; end
	if a.name ~= b.name then return false; end
	if #a ~= #b then return false; end
	if not attr_eq(a.attr, b.attr) then return false; end
	for i = 1, #a do if not st_eq(a[i], b[i]) then return false; end end
	return true;
end

local function dedup_presence(stanza, session)
	if session.presence_cache and session.presence
	and getmetatable(stanza) == st.stanza_mt and stanza.name == "presence"
	and stanza.attr.xmlns == nil and stanza.attr.from then
		local cached = session.presence_cache:get(stanza.attr.from);
		if st_eq(stanza, cached) then
			return nil;
		else
			session.presence_cache:set(stanza.attr.from, st.clone(stanza));
		end
	end
	return stanza;
end

module:hook("presence/initial",	function (event)
	local session = event.origin;
	session.presence_cache = cache.new(cache_size);
	add_filter(session, "stanzas/out", dedup_presence, 90);
end);