mod_unified_push: Allow additional CORS headers for unified push (fixes #1985) - Request header "TTL" is mandated by the HTTP Push specification RFC 8030: https://datatracker.ietf.org/doc/html/rfc8030#section-5 - Firefox sends "Content-Encoding" with a HTTP form submission, so it is required when using the Unified Push testing tool at https://unifiedpush.org/test_wp.html (with the full URL being delivered by the UP-Example Android app) Adding both headers makes the Unified Push testing tool work from the browser. Resolves: https://issues.prosody.im/1985

local base64_encode = require"util.encodings".base64.encode;
local random_bytes = require"util.random".bytes;

local b64url = { ["+"] = "-", ["/"] = "_", ["="] = "" };
local function random_resource()
	return base64_encode(random_bytes(8)):gsub("[+/=]", b64url);
end

module:hook("pre-resource-bind", function (event)
	event.resource = random_resource();
end);