Javascript library for DNS over HTTPS lookups in web apps

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Try sending DoH lookups from your browser - https://dohjs.org

Contents

• Why DoHjs
  • Features
• Installation
• Quickstart
• Examples
• Docs
• Tests
• Web interface
• CORS Issues
• License

Why dohjs

The purpose of dohjs is described well in the Internet standard document for DNS over HTTPS (RFC 8484):

allowing web applications to access DNS information via existing browser APIs in a safe way consistent with Cross Origin Resource Sharing (CORS)

Features

• Fully compliant DNS over HTTPS client implementation
• Supports GET and POST wireformat queries
• Command line DNS over HTTPS lookup tool
• Web interface to try dohjs
• CORS proxy to get past CORS errors associated with DoH (source code here). This is mainly for use on https://dohjs.org.

Installation

If you're not using npm, you can skip to quickstart.

npm install dohjs

If you want to just use the command line tool dohjs to issue DoH lookups, install it globally (or use npx):

npm install -g dohjs

NOTE: The above command may need to be run as root (how to fix this)

Quickstart

A simple way to start is to include doh.js in your HTML file. You can include it from jsdelivr or your local installation.

<!-- from CDN -->
<script src="https://cdn.jsdelivr.net/npm/dohjs@latest/dist/doh.min.js"></script>
<!-- from local installation -->
<script src="/path/to/node_modules/dohjs/dist/doh.min.js"></script>

If your project is mostly nodejs-style (e.g. you're using browserify), you can require() dohjs like so:

const doh = require('dohjs');

Now here's a quick example of a DoH lookup using dohjs:

// create your stub resolver
const resolver = new doh.DohResolver('https://1.1.1.1/dns-query');

// lookup the A records for example.com and log the IP addresses to the console
resolver.query('example.com', 'A')
  .then(response => {
    response.answers.forEach(ans => console.log(ans.data));
  })
  .catch(err => console.error(err));

Examples

Checkout our examples to see dohjs in action. See examples/README for a description of the examples.

To serve thr examples, run npm start. Your browser will open up to an index of your current directory, then just navigate to the examples and open whatever html file you were wanting to look at.

Docs

API documentation for dohjs can be found in docs/README.md.

Documentation for the dohjs CLI is in docs/cli.md.

Contributing

We love contributors!

If you find a bug in dohjs, or you have a feature you'd like added, please open an issue and/or submit a pull request.

Tests

To run tests, clone the repo, and run:

npm test

Web interface

The web interface is available at https://dohjs.org.

See the gh-pages branch for code.

CORS issues

You'll probably get some CORS errors when sending DoH queries. A few ways to get around those are:

• Use a CORS proxy. At dohjs.org, there is an option to use a CORS proxy if you want to try it out.
• Disable CORS when you launch your browser sometimes works (e.g. google-chrome --user-data-dir=/tmp/asdf --disable-web-security)
• Run your own DoH server that sets the Access-Control-Allow-Origin header appropriately (e.g. Access-Control-Allow-Origin: * to allow everyone)

License

MIT (see LICENSE)