nginx-proxy-manager/backend/lib/express/cors.js

export default (req, res, next) => {
	if (req.headers.origin) {
		res.set({
			"Access-Control-Allow-Origin": req.headers.origin,
			"Access-Control-Allow-Credentials": true,
			"Access-Control-Allow-Methods": "OPTIONS, GET, POST",
			"Access-Control-Allow-Headers":
				"Content-Type, Cache-Control, Pragma, Expires, Authorization, X-Dataset-Total, X-Dataset-Offset, X-Dataset-Limit",
			"Access-Control-Max-Age": 5 * 60,
			"Access-Control-Expose-Headers": "X-Dataset-Total, X-Dataset-Offset, X-Dataset-Limit",
		});
		next();
	} else {
		// No origin
		next();
	}
};