push.rocks/smartdns

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@push.rocks/smartdns

A TypeScript library for smart DNS methods, supporting various DNS records and providers.

Install

To install @push.rocks/smartdns, use the following command with npm:

npm install @push.rocks/smartdns --save

Or with yarn:

yarn add @push.rocks/smartdns

Make sure you have a TypeScript environment set up to utilize the library effectively.

Usage

@push.rocks/smartdns is a comprehensive library aimed at facilitating smart DNS operations, leveraging TypeScript for enhanced development experience. This section aims to cover several real-world scenarios demonstrating the library's capabilities, from basic DNS lookups to more advanced DNS management tasks.

Getting Started

First, ensure you import the module into your TypeScript project:

import { Smartdns } from '@push.rocks/smartdns';

Basic DNS Record Lookup

Often, the need arises to fetch various DNS records for a domain. @push.rocks/smartdns simplifies this by providing intuitive methods.

Fetching A Records

To fetch an "A" record for a domain:

import { Smartdns } from '@push.rocks/smartdns';

const dnsManager = new Smartdns({});
const aRecords = await dnsManager.getRecordsA('example.com');
console.log(aRecords);

Fetching AAAA Records

Similarly, for "AAAA" records:

const aaaaRecords = await dnsManager.getRecordsAAAA('example.com');
console.log(aaaaRecords);

Fetching TXT Records

For "TXT" records:

const txtRecords = await dnsManager.getRecordsTxt('example.com');
console.log(txtRecords);

Advanced DNS Management

Beyond simple queries, @push.rocks/smartdns offers functionalities suitable for more complex DNS management scenarios.

Checking DNS Propagation

When changing DNS records, ensuring that the new records have propagated fully is crucial. @push.rocks/smartdns facilitates this with a method to check a DNS record until it is available globally.

const recordType = 'TXT'; // Record type: A, AAAA, CNAME, TXT etc.
const expectedValue = 'your_expected_value';
const isAvailable = await dnsManager.checkUntilAvailable('example.com', recordType, expectedValue);

if (isAvailable) {
  console.log('Record propagated successfully.');
} else {
  console.log('Record propagation failed or timed out.');
}

Leveraging DNS for Application Logic

DNS records can serve beyond mere domain-to-IP resolution; they can be instrumental in application logic, such as feature flagging or environment-specific configurations.

Example: Feature Flagging via TXT Records

Consider leveraging TXT records for enabling/disabling features dynamically without deploying new code.

const txtRecords = await dnsManager.getRecordsTxt('features.example.com');
const featureFlags = txtRecords.reduce((acc, record) => {
  const [flag, isEnabled] = record.value.split('=');
  acc[flag] = isEnabled === 'true';
  return acc;
}, {});

if (featureFlags['NewFeature']) {
  // Logic to enable the new feature
}

DNS Server Implementation

To implement a DNS server, @push.rocks/smartdns includes classes and methods to set up a UDP and HTTPS DNS server supporting DNSSEC.

Basic DNS Server Example

Here's a basic example of a UDP/HTTPS DNS server:

import { DnsServer } from '@push.rocks/smartdns';

const dnsServer = new DnsServer({
  httpsKey: 'path/to/key.pem',
  httpsCert: 'path/to/cert.pem',
  httpsPort: 443,
  udpPort: 53,
  dnssecZone: 'example.com',
});

dnsServer.registerHandler('*.example.com', ['A'], (question) => ({
  name: question.name,
  type: 'A',
  class: 'IN',
  ttl: 300,
  data: '127.0.0.1',
}));

dnsServer.start().then(() => console.log('DNS Server started'));

DNSSEC Support

@push.rocks/smartdns provides support for DNSSEC, including the generation, signing, and validation of DNS records.

DNSSEC Configuration

To configure DNSSEC for your DNS server:

import { DnsServer } from '@push.rocks/smartdns';

const dnsServer = new DnsServer({
  httpsKey: 'path/to/key.pem',
  httpsCert: 'path/to/cert.pem',
  httpsPort: 443,
  udpPort: 53,
  dnssecZone: 'example.com',
});

dnsServer.registerHandler('*.example.com', ['A'], (question) => ({
  name: question.name,
  type: 'A',
  class: 'IN',
  ttl: 300,
  data: '127.0.0.1',
}));

dnsServer.start().then(() => console.log('DNS Server with DNSSEC started'));

This setup ensures that DNS records are signed and can be verified for authenticity.

Handling DNS Queries Over Different Protocols

The library supports handling DNS queries over UDP and HTTPS.

Handling UDP Queries

UDP is the traditional means of DNS query transport.

import { DnsServer } from '@push.rocks/smartdns';
import dgram from 'dgram';

dnsServer.registerHandler('*.example.com', ['A'], (question) => ({
  name: question.name,
  type: 'A',
  class: 'IN',
  ttl: 300,
  data: '127.0.0.1',
}));

dnsServer.start().then(() => {
  console.log('UDP DNS Server started on port', dnsServer.getOptions().udpPort);
});

const client = dgram.createSocket('udp4');

client.on('message', (msg, rinfo) => {
  console.log(`Received ${msg} from ${rinfo.address}:${rinfo.port}`);
});

client.send(Buffer.from('example DNS query'), dnsServer.getOptions().udpPort, 'localhost');

Handling HTTPS Queries

DNS over HTTPS (DoH) is increasingly adopted for privacy and security.

import { DnsServer } from '@push.rocks/smartdns';
import https from 'https';
import fs from 'fs';

const dnsServer = new DnsServer({
  httpsKey: fs.readFileSync('path/to/key.pem'),
  httpsCert: fs.readFileSync('path/to/cert.pem'),
  httpsPort: 443,
  udpPort: 53,
  dnssecZone: 'example.com',
});

dnsServer.registerHandler('*.example.com', ['A'], (question) => ({
  name: question.name,
  type: 'A',
  class: 'IN',
  ttl: 300,
  data: '127.0.0.1',
}));

dnsServer.start().then(() => console.log('HTTPS DNS Server started'));

const client = https.request({
  hostname: 'localhost',
  port: 443,
  path: '/dns-query',
  method: 'POST',
  headers: {
    'Content-Type': 'application/dns-message'
  }
}, (res) => {
  res.on('data', (d) => {
    process.stdout.write(d);
  });
});

client.on('error', (e) => {
  console.error(e);
});

client.write(Buffer.from('example DNS query'));
client.end();

Testing

To ensure that the DNS server behaves as expected, it is important to write tests for various scenarios.

DNS Server Tests

Here is an example of how to test the DNS server with TAP:

import { expect, tap } from '@push.rocks/tapbundle';

import { DnsServer } from '@push.rocks/smartdns';

let dnsServer: DnsServer;

tap.test('should create an instance of DnsServer', async () => {
  dnsServer = new DnsServer({
    httpsKey: 'path/to/key.pem',
    httpsCert: 'path/to/cert.pem',
    httpsPort: 443,
    udpPort: 53,
    dnssecZone: 'example.com',
  });
  expect(dnsServer).toBeInstanceOf(DnsServer);
});

tap.test('should start the server', async () => {
  await dnsServer.start();
  expect(dnsServer.isRunning()).toBeTrue();
});

tap.test('should add a DNS handler', async () => {
  dnsServer.registerHandler('*.example.com', ['A'], (question) => ({
    name: question.name,
    type: 'A',
    class: 'IN',
    ttl: 300,
    data: '127.0.0.1',
  }));

  const response = dnsServer.processDnsRequest({
    type: 'query',
    id: 1,
    flags: 0,
    questions: [
      {
        name: 'test.example.com',
        type: 'A',
        class: 'IN',
      },
    ],
    answers: [],
  });

  expect(response.answers[0]).toEqual({
    name: 'test.example.com',
    type: 'A',
    class: 'IN',
    ttl: 300,
    data: '127.0.0.1',
  });
});

tap.test('should query the server over HTTP', async () => {
  // Assuming fetch or any HTTP client is available
  const query = dnsPacket.encode({
    type: 'query',
    id: 2,
    flags: dnsPacket.RECURSION_DESIRED,
    questions: [
      {
        name: 'test.example.com',
        type: 'A',
        class: 'IN',
      },
    ],
  });

  const response = await fetch('https://localhost:443/dns-query', {
    method: 'POST',
    body: query,
    headers: {
      'Content-Type': 'application/dns-message',
    }
  });

  expect(response.status).toEqual(200);

  const responseData = await response.arrayBuffer();
  const dnsResponse = dnsPacket.decode(Buffer.from(responseData));

  expect(dnsResponse.answers[0]).toEqual({
    name: 'test.example.com',
    type: 'A',
    class: 'IN',
    ttl: 300,
    data: '127.0.0.1',
  });
});

tap.test('should stop the server', async () => {
  await dnsServer.stop();
  expect(dnsServer.isRunning()).toBeFalse();
});

await tap.start();

Conclusion

@push.rocks/smartdns offers a versatile set of tools for DNS querying and management, tailored for applications at any scale. The examples provided illustrate the library's potential use cases, highlighting its applicability in various scenarios from basic lookups to facilitating complex application features through DNS.

For the full spectrum of functionalities, including detailed method documentation and additional use cases, consult the module's TypeDoc documentation. This will serve as a comprehensive guide to leveraging @push.rocks/smartdns effectively in your projects.

Remember, DNS changes might take time to propagate worldwide, and the utility methods provided by @push.rocks/smartdns for checking record availability will be invaluable in managing these changes seamlessly.

License and Legal Information

This repository contains open-source code that is licensed under the MIT License. A copy of the MIT License can be found in the license file within this repository.

Please note: The MIT License does not grant permission to use the trade names, trademarks, service marks, or product names of the project, except as required for reasonable and customary use in describing the origin of the work and reproducing the content of the NOTICE file.

Trademarks

This project is owned and maintained by Task Venture Capital GmbH. The names and logos associated with Task Venture Capital GmbH and any related products or services are trademarks of Task Venture Capital GmbH and are not included within the scope of the MIT license granted herein. Use of these trademarks must comply with Task Venture Capital GmbH's Trademark Guidelines, and any usage must be approved in writing by Task Venture Capital GmbH.

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