beaker-plugin-dat/lib/dat-dns.js

Dat-protocol plugin for the Beaker browser

const log = require('loglevel')
const dns = require('dns')
const url = require('url')

const { HASH_REGEX } = require('./const')

exports.resolveName = function (name, cb) {
  // is it a hash?
  if (HASH_REGEX.test(name))
    return cb(null, name)

  // do a dns lookup
  log.debug('[DAT] DNS TXT lookup for name:', name)
  dns.resolveTxt(name, (err, records) => {
    log.debug('[DAT] DNS TXT results for', name, err || records)
    if (err)
      return cb(err)

    // scan the txt records for a dat URI
    for (var i=0; i < records.length; i++) {
      if (records[i][0].indexOf('dat://') === 0) {
        var urlp = url.parse(records[i][0])
        if (HASH_REGEX.test(urlp.host)) {
          log.debug('[DAT] DNS resolved', name, 'to', urlp.host)
          return cb(null, urlp.host)
        }
        log.debug('[DAT] DNS TXT record failed:', records[i], 'Must be a dat://{hash} url')
      }
    }

    cb({ code: 'ENOTFOUND' })
  })
}