44 lines
1.7 KiB
JavaScript
44 lines
1.7 KiB
JavaScript
'use strict';
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exports = module.exports = {
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resolve: resolve
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};
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var assert = require('assert'),
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constants = require('./constants.js'),
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dns = require('dns'),
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_ = require('underscore');
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const DEFAULT_OPTIONS = { server: '127.0.0.1', timeout: 5000 }; // unbound runs on 127.0.0.1
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// a note on TXT records. It doesn't have quotes ("") at the DNS level. Those quotes
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// are added for DNS server software to enclose spaces. Such quotes may also be returned
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// by the DNS REST API of some providers
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function resolve(hostname, rrtype, options, callback) {
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assert.strictEqual(typeof hostname, 'string');
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assert.strictEqual(typeof rrtype, 'string');
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assert(options && typeof options === 'object');
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assert.strictEqual(typeof callback, 'function');
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const resolver = new dns.Resolver();
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options = _.extend({ }, DEFAULT_OPTIONS, options);
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// Only use unbound on a Cloudron
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if (constants.CLOUDRON) resolver.setServers([ options.server ]);
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// should callback with ECANCELLED but looks like we might hit https://github.com/nodejs/node/issues/14814
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const timerId = setTimeout(resolver.cancel.bind(resolver), options.timeout || 5000);
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resolver.resolve(hostname, rrtype, function (error, result) {
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clearTimeout(timerId);
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if (error && error.code === 'ECANCELLED') error.code = 'TIMEOUT';
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// result is an empty array if there was no error but there is no record. when you query a random
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// domain, it errors with ENOTFOUND. But if you query an existing domain (A record) but with different
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// type (CNAME) it is not an error and empty array
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// for TXT records, result is 2d array of strings
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callback(error, result);
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});
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}
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