React Native

DNS Query MX Records

See more DNS Examples

Shows how to perform a DNS query to retrieve MX records.

Note: This example requires Chilkat v9.5.0.96 or later.

React Native

import { Dns, JsonObject } from '@chilkat/react-native'

async function chilkatExample() {
  const dns = new Dns();

  const json = new JsonObject();
  json.emitCompact = false;

  try {
    await dns.queryAsync('MX', 'somebody@gmail.com', json);
  } catch {
    console.log(dns.lastErrorText);
    return;
  }

  console.log(json.emit());

  // Sample response.
  // Parsing code below..

  // -------------------------------------------------------------------------------
  // Note: Chilkat will return the results sorted by "pref" from lowest to highest.
  // -------------------------------------------------------------------------------

  // {
  //   "answer": {
  //     "mx": [
  //       {
  //         "name": "gmail.com",
  //         "ttl": 491,
  //         "pref": 5,
  //         "domain": "gmail-smtp-in.l.google.com"
  //       },
  //       {
  //         "name": "gmail.com",
  //         "ttl": 491,
  //         "pref": 10,
  //         "domain": "alt1.gmail-smtp-in.l.google.com"
  //       },
  //       {
  //         "name": "gmail.com",
  //         "ttl": 491,
  //         "pref": 20,
  //         "domain": "alt2.gmail-smtp-in.l.google.com"
  //       },
  //       {
  //         "name": "gmail.com",
  //         "ttl": 491,
  //         "pref": 30,
  //         "domain": "alt3.gmail-smtp-in.l.google.com"
  //       },
  //       {
  //         "name": "gmail.com",
  //         "ttl": 491,
  //         "pref": 40,
  //         "domain": "alt4.gmail-smtp-in.l.google.com"
  //       }
  //     ]
  //   }
  // }

  // Use this online tool to generate parsing code from sample JSON: 
  // Generate Parsing Code from JSON

  let name = '';
  let ttl = 0;
  let pref = 0;
  let domain = '';

  let i = 0;
  const countI = json.sizeOfArray('answer.mx');
  while (i < countI) {
    json.i = i;
    name = json.stringOf('answer.mx[i].name');
    ttl = json.intOf('answer.mx[i].ttl');
    pref = json.intOf('answer.mx[i].pref');
    domain = json.stringOf('answer.mx[i].domain');
    i++;
  }
}