mod_http_oauth2: Make note about handling repeated RFC 6749 states > If an authorization code is used more than once, the authorization > server MUST deny the request and SHOULD revoke (when possible) all > tokens previously issued based on that authorization code. We should follow the SHOULD. The MUST is already covered by removing the code state from the cache.

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);