view mod_presence_dedup/mod_presence_dedup.lua @ 5518:d87d0e4a8516

mod_http_oauth2: Validate the OpenID 'prompt' parameter Without support for affecting the login and consent procedure, it seems sensible to inform the client that they can't change anything with this parameter.
author Kim Alvefur <zash@zash.se>
date Mon, 05 Jun 2023 22:19:17 +0200
parents 19924a2c4a48
children
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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);