File

net.http: Send entire HTTP request header as one write When opportunistic writes are enabled this reduces the number of syscalls and TCP packets sent on the wire. Experiments with TCP Fast Open made this even more obvious. That table trick probably wasn't as efficient. Lua generates bytecode for a table with zero array slots and space for two entries in the hash part, plus code to set [2] and [4]. I didn't verify but I suspect it would have had to resize the table when setting [1] and [3], although probably only once. Concatenating the strings directly in Lua is easier to read and involves no extra table or function call.

local saslprep = require "util.encodings".stringprep.saslprep;

local _ENV = nil;
-- luacheck: std none

local function external(self, message)
	message = saslprep(message);
	local state
	self.username, state = self.profile.external(message);

	if state == false then
		return "failure", "account-disabled";
	elseif state == nil  then
		return "failure", "not-authorized";
	elseif state == "expired" then
		return "false", "credentials-expired";
	end

	return "success";
end

local function init(registerMechanism)
	registerMechanism("EXTERNAL", {"external"}, external);
end

return {
	init = init;
}