mod_http_oauth2: Advertise the currently supported id_token signing algorithm This field is REQUIRED. The algorithm RS256 MUST be included, but isn't because we don't implement it, as that would require implementing a pile of additional cryptography and JWT stuff. Instead the id_token is signed using the client secret, which allows verification by the client, since it's a shared secret per OpenID Connect Core 1.0 § 10.1 under Symmetric Signatures. OpenID Connect Discovery 1.0 has a lot of REQUIRED and MUST clauses that are not supported here, but that's okay because this is served from the RFC 8414 OAuth 2.0 Authorization Server Metadata .well-known endpoint!

local jid = require "util.jid";
local st = require "util.stanza";

local nick_pattern = module:get_option_string("muc_restrict_nick_pattern", "^%w+$");

module:hook("muc-occupant-pre-join", function (event)
	local nick = jid.resource(event.occupant.nick);
	if not nick:match(nick_pattern) then
		local reply = st.error_reply(event.stanza, "modify", "policy-violation", "Unacceptable nickname, please try another");
		module:send(reply);
		return true;
	end
end);