index.js

const {
  TCPServer,
  UDPServer,
  createTCPServer,
  createUDPServer,
} = require('./server');
const EventEmitter = require('events');

/**
 * [DNS description]
 * @docs https://tools.ietf.org/html/rfc1034
 * @docs https://tools.ietf.org/html/rfc1035
 */
class DNS extends EventEmitter {
  constructor(options) {
    super();
    Object.assign(this, {
      port: 53,
      retries: 3,
      timeout: 3,
      nameServers: [
        '8.8.8.8',
        '114.114.114.114',
      ],
      rootServers: [
        'a', 'b', 'c', 'd', 'e', 'f',
        'g', 'h', 'i', 'j', 'k', 'l', 'm'
      ].map(x => `${x}.root-servers.net`)
    }, options);
  }
  /**
   * query
   * @param {*} questions 
   */
  query(name, type, cls) {
    const { port, nameServers } = this;
    const { Client: createResolver } = DNS;
    return Promise.race(nameServers.map(address => {
      const resolve = createResolver({ dns: address, port });
      return resolve(name, type, cls);
    }));
  }
  /**
   * resolve
   * @param {*} domain 
   * @param {*} type 
   * @param {*} cls 
   */
  resolve(domain, type = 'ANY', cls = DNS.Packet.CLASS.IN) {
    return this.query(domain, DNS.Packet.TYPE[type], cls);
  }
  resolveA(domain) {
    return this.resolve(domain, 'A');
  }
  resolveAAAA(domain) {
    return this.resolve(domain, 'AAAA');
  }
  resolveMX(domain) {
    return this.resolve(domain, 'MX');
  }
  resolveCNAME(domain) {
    return this.resolve(domain, 'CNAME');
  }
}

DNS.TCPServer = TCPServer;
DNS.UDPServer = UDPServer;
DNS.createServer = createUDPServer;
DNS.createUDPServer = createUDPServer;
DNS.createTCPServer = createTCPServer;

DNS.DoT = require('./client/tcp');
DNS.DoH = require('./client/doh');
DNS.Client = require('./client/udp');
DNS.Google = require('./client/google');
DNS.Packet = require('./packet');

module.exports = DNS;