@nictool/dns-resource-record/rr/mx.js

DNS Resource Records

import RR from '../rr.js'

export default class MX extends RR {
  constructor(opts) {
    super(opts)
  }

  /****** Resource record specific setters   *******/
  setPreference(val) {
    if (val === undefined) val = this?.default?.preference
    if (val === undefined) this.throwHelp('MX: preference is required')
    this.is16bitInt('MX', 'preference', val)
    this.set('preference', val)
  }

  setExchange(val) {
    if (!val) this.throwHelp('MX: exchange is required')

    if (this.isIPv4(val) || this.isIPv6(val))
      this.throwHelp(`MX: exchange must be a FQDN`)

    this.isFullyQualified('MX', 'exchange', val)
    this.isValidHostname('MX', 'exchange', val)

    // RFC 4034: letters in the DNS names ... are lower cased
    this.set('exchange', val.toLowerCase())
  }

  getDescription() {
    return 'Mail Exchanger'
  }

  getRdataFields(arg) {
    return ['preference', 'exchange']
  }

  getRFCs() {
    return [1035, 2181, 7505]
  }

  getTypeId() {
    return 15
  }

  getCanonical() {
    return {
      owner: 'example.com.',
      ttl: 43200,
      class: 'IN',
      type: 'MX',
      preference: 0,
      exchange: 'mail.example.com.',
    }
  }

  /******  IMPORTERS   *******/
  fromTinydns(opts) {
    // @fqdn:ip:x:dist:ttl:timestamp:lo
    // eslint-disable-next-line no-unused-vars
    const [owner, ip, x, preference, ttl, ts, loc] = opts.tinyline
      .substring(1)
      .split(':')

    return new MX({
      type: 'MX',
      owner: this.fullyQualify(owner),
      exchange: this.fullyQualify(/\./.test(x) ? x : `${x}.mx.${owner}`),
      preference: parseInt(preference, 10) || 0,
      ttl: parseInt(ttl, 10),
      timestamp: ts,
      location: loc !== '' && loc !== '\n' ? loc : '',
    })
  }

  fromBind(opts) {
    // test.example.com  3600  IN  MX  preference exchange
    const [owner, ttl, c, type, preference, exchange] =
      opts.bindline.split(/\s+/)

    return new MX({
      owner,
      ttl: parseInt(ttl, 10),
      class: c,
      type,
      preference: parseInt(preference),
      exchange,
    })
  }

  /******  EXPORTERS   *******/
  toBind(zone_opts) {
    return `${this.getPrefix(zone_opts)}\t${this.get('preference')}\t${this.getFQDN('exchange', zone_opts)}\n`
  }

  toTinydns() {
    return `@${this.getTinyFQDN('owner')}::${this.getTinyFQDN('exchange')}:${this.get('preference')}:${this.getTinydnsPostamble()}\n`
  }
}