mod_http_oauth2: Implement stateless dynamic client registration Replaces previous explicit registration that required either the additional module mod_adhoc_oauth2_client or manually editing the database. That method was enough to have something to test with, but would not probably not scale easily. Dynamic client registration allows creating clients on the fly, which may be even easier in theory. In order to not allow basically unauthenticated writes to the database, we implement a stateless model here. per_host_key := HMAC(config -> oauth2_registration_key, hostname) client_id := JWT { client metadata } signed with per_host_key client_secret := HMAC(per_host_key, client_id) This should ensure everything we need to know is part of the client_id, allowing redirects etc to be validated, and the client_secret can be validated with only the client_id and the per_host_key. A nonce injected into the client_id JWT should ensure nobody can submit the same client metadata and retrieve the same client_secret

-- Ignore disabled offline storage
--
-- Copyright (C) 2019-2020 Thilo Molitor
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

-- depend on mod_mam to make sure mam is at least loaded and active
module:depends "mam";

-- ignore offline messages and don't return any error (the message will be already in MAM at this point)
-- this is *only* triggered if mod_offline is *not* loaded and completely ignored otherwise
module:hook("message/offline/handle", function(event)
	local log = event.origin and event.origin.log or module._log;
	if log then
		log("info", "Ignoring offline message (mod_offline seems *not* to be loaded)...");
	end
	return true;
end, -100);