:gem: Devtoolium

Simple and secure remote browser with DevTools, based on DevTools

Remote debugging or the DevTools protocol for JavaScript is served insecured via --remote-debugging-port option on browsers and Node runtimes. This project adds a secure HTTPS and secure WebSockets server proxy to that endpoint, plus authentication, to let you share and expose these endpoints over the internet only to intended actors.

This is a self-hosted free open-source product, that you can get on npm, and use it to run a secure proxy server to make browser DevTools securely accessible remotely.

It adds HTTPS, WSS and authentication to --remote-debugging-port to automate, open the inspector, and debug from anywhere and collaborate securely on bugs by sharing the unique login URL.

This means you can serve the DevTools inspector frontend from a secure HTTPS server with authentication, as well as connect to all the normal devtools API endpoints and target websockets, but they're now encrypted and authenticated.

Get started:

$ browser --remote-debugging-port=9222
$ devtoolium 9222:mysite.com:8080

{
  devtooliumUp: {
    at: 2021-09-20T12:39:24.942Z,
    CHROME_PORT: 9222,
    SERVER_PORT: 8080,
    loginUrl: 'https://mysite.com:8080/login?token=a24a30ea17c71f6500b963b732cb2b69fb8d853f'
  }
}

Port 8080 is now running a HTTPS and WSS (secure websocket) server. It's safe to share with the internet. Pass out loginUrl to people you want to be able to connect, inspect and debug that browser.

DO NOT expose port 9222 (or whatever your browser debugging port is) to the public internet. This is the hole that devtoolium helps secure.

Now, all the DevTools endpoints will be available to anyone with loginUrl, enabling them to connect (via puppeteer, or whatever) to the browser you started, and even debug it via the Devtools inspector frontend.

How is this done?

Nothing fancy folks, just a simple HTTPS Proxy and WebSocket Proxy Server with authentication to help you securely expose DevTools (inlcuding all the endpoints like /json and all the ws:// endpoints for all the targets, and even the devtools-frontend: the inspector you see when you open hit Ctrl+Shift+I in your browser).

This lets you connect to browsers remotely to run automation workloads, or collaborate on bugs, securely, without needing to worry about how --remote-debugging-port creates an insecure HTTP server, and unencrypted websockets. Now, everything is encrypted.

Perfect for debugging remotely in collaboration with other humes. Connect to and debug remote tabs from any where, and even run DevTools inspector from any device*.

* It also modifies DevTools inspector files in-flight to try to make them work cross-browser. Right now Firefox and Chrome work completely, while iOS browsers (and Safari) have some issues, but they still load the DevTools inspector front-end just a couple things don't work properly.

Background

A version of this tool was originally part of the closed-source paid version of my secure remote browser, but the secure remote debugging capability proved so useful I decided to package it up, copy it out, and make it its own bona-fide open-source product for everyone to use, for free.

I searched around a bit before doing so, and while I couldn't find any current prior art that was up to date in 2021, here was some prior art that I found:

• auchenberg/devtools-remote - An experimental HTTP and WebSocket proxy for DevTools from 2016

Get it

$ npm i -g devtoolium.devtools
## or
$ npx devtoolium.devtools
## or
$ npm i --save devtoolium.devtools
## or
$ git clone https://github.com/i5ik/devtoolium.git
$ cd devtoolium/ 
$ npm i

Use it

From the command line:

devtoolium 9222:mysite.com:8888

Using npx:

npx devtoolium.devtools 9222:me.example.com:8080

From a NodeJS script:

import devtoolium from 'devtoolium.devtools';

devtoolium({
  browserPort: 9222,
  serverPort: 8888
}).then(serverStatus => console.log(`Login URL: ${serverStatus.loginUrl}`));

From the repository:

$ cd devtoolium/
$ npm start 9222:mydevtoolium.int:8555

BTW - Where does the name devtoolium come from?

It comes from secure remote 'n' authenticated devtools.

Security

For security, don't expose your browser port (by default 9222) to the public internet.

This server uses helmet, HTTPS, and WSS (secure WebSockets).

Once you start devtoolium (either via the command line or from the library) you will receive a login URL. That URL can be used to log you on to the secure DevTools server. Without it you will not be able to access any DevTools endpoints. Pass it out to those frens you wish to collaborate with on the solvage, ever venerable, of the buggs.

devtoolium uses cookie authentication to prevent unauthorized connections. The need for a secure remote connection utility for DevTools is well known

Certificates

By default, devtoolium looks for TLS certificates (cert.pem, chain.pem, fullchain.pem and privkey.pem) in path.resolve(os.homedir(), 'sslcerts') ($HOME/sslcerts on Windows). You can override that with the certBasePath option.

devtoolium will always throw an error and fail is certificates are not found.

API

All the options you see below can be accessed via script using their camel-cased variants. Globally installed command line usage (npm i -g devtoolium.devtools@latest) is shown for demonstrative purposes. The command line API is equivalent whether you use npx or npm start from the repository to run it.

Basic Use

The command line has a very simple format:

devtoolium <BROWSER_PORT>:<DOMAIN_NAME|IP_ADDRESS>:<SERVER_PORT> [certificatesPath]

Where DOMAIN_NAME|IP_ADDRESS is that of the server you run devtoolium on.

And certificatesPath is an optional file system path to override the default location to look for certificates.

Browser Port

The port that you have exposed the remote debugging protocol on, via the --remote-debugging-port Chrome command line argument. Simple the first positional argument after the command. I.e, say your browser is on port 51386, you'd start a server that is running remote DevTools with. For exmaple, to get up and running with chrome headless, make sure you have chrome installed, then try the following:

$ google-chrome-stable --headless --remote-debugging-port=51386 devtoolium 51386:mysite.example.com:8080

{
  devtooliumUp: {
    at: 2021-09-20T12:39:24.942Z,
    CHROME_PORT: 51386,
    SERVER_PORT: 8080,
    loginUrl: 'https://mysite.example.com:8080/login?token=a24a30ea17c71f6500b963b732cb2b69fb8d853f'
  }
}

There's no default, you must always specify a browser port. If the browser is not running on that port, devtoolium will thrown an error.

Background

Run it in the background, like so:

$ devtoolium 51386:doppelgange.pointbyne.org:8888 &

Or using pm2:

$ pm2 start devtoolium 9222:example.spacedemons.com:8433

Server Port

There's no default port, so you must always specify a server port.

Technical Details and Limitations

By default the Chrome DevTools Frontend does not work cross-browser. It only works in Chrome. This is not a policy of the DevTools team, simply because they don't have the bandwidth to support this right now. I opened a PR to bring cross-browser support to DevTools, but until and unless we make it happen, I am having devtoolium patch the DevTools frontend resources in-flight via the proxy, so it can work in any browser.

Because of this ad-hoc, "off-branch" solution, and given the fact that each version of Chrome may ship with a slightly different version of the DevTools front-end, you may find it breaks at any time.

Other disclaimers

This project has zero association, endorsement or any relationship with with Google, Chrome, the Chrome Dev team, Chrome DevTools front-end or any of the authors.