Review this AI-generated resolver and fetch helper against its stated task.
Fetch a user-supplied HTTPS URL with TTL-aware DNS caching, reject every non-public IPv4 or IPv6 destination, preserve TLS hostname verification, and bound lookup plus connection time.
JavaScript
import { Resolver } from "node:dns/promises";
import { setTimeout as delay } from "node:timers/promises";
const resolver = new Resolver();
const cache = new Map();
const ONE_HOUR = 60 * 60 * 1000;
export async function fetchUserUrl(input) {
const target = new URL(input);
const cached = cache.get(target.hostname);
if (cached) return fetch(input);
const [address] = await resolver.resolve4(target.hostname);
if (address.startsWith("127.")) throw new Error("blocked");
cache.set(target.hostname, { address, expires: Date.now() + ONE_HOUR });
return fetch(target);
}
setInterval(() => cache.clear(), ONE_HOUR);
generated code is illustrative, not from any one model