web-check/api/dns-server.js

import { promises as dnsPromises } from 'dns';
import axios from 'axios';
import middleware from './_common/middleware.js';
import { parseTarget } from './_common/parse-target.js';

const dnsHandler = async (url) => {
  try {
    const { hostname: domain } = parseTarget(url);
    const addresses = await dnsPromises.resolve4(domain);
    const results = await Promise.all(addresses.map(async (address) => {
      const hostname = await dnsPromises.reverse(address).catch(() => null);
      let dohDirectSupports = false;
      try {
        await axios.get(`https://${address}/dns-query`);
        dohDirectSupports = true;
      } catch (error) {
        dohDirectSupports = false;
      }
      return {
        address,
        hostname,
        dohDirectSupports,
      };
    }));

    return { domain, dns: results };
  } catch (error) {
    throw new Error(`An error occurred while resolving DNS. ${error.message}`); // This will be caught and handled by the commonMiddleware
  }
};


export const handler = middleware(dnsHandler);
export default handler;