Introducing qbrt

I recently blogged about discontinuing Positron. I’m trying a different tack with a new experiment, codenamed qbrt, that reuses an existing Gecko runtime (and its existing APIs) while simplifying the process of developing and packaging a desktop app using web technologies.

qbrt is a command-line interface written in Node.js and available via NPM:

npm install -g qbrt

Installing it also installs a Gecko runtime (currently a nightly build of Firefox, but in the future it could be a stable build of Firefox or a custom Gecko runtime). Its simplest use is then to invoke the ‘run’ command with a URL:

qbrt run https://eggtimer.org/

Which will start a process and load the URL into a native window:

URLs loaded in this way don’t have privileged access to the system. They’re treated as web content, not application chrome.

To load a desktop application with system privileges, point qbrt at a local directory containing a package.json file and main entry script:

qbrt run path/to/my/app/

For example, clone qbrt’s repo and try its example/ app:

git clone https://github.com/mozilla/qbrt.git
qbrt run qbrt/example/

This will start a process and load the app into a privileged context, giving it access to Gecko’s APIs for opening windows and loading web content along with system integration APIs for file manipulation, networking, process management, etc.

(Another good example is the “shell” app that qbrt uses to load URLs.)

To package an app for distribution, invoke the ‘package’ command, which creates a platform-specific package containing both the app’s resources and the Gecko runtime:

qbrt package path/to/my/app/

Note that while qbrt is written in Node.js, it doesn’t provide Node.js APIs to apps. It might be useful to do so, using SpiderNode, as we did with Positron, although Gecko’s existing APIs expose equivalent functionality.

Also, qbrt doesn’t yet support runtime version management (i.e. being able to specify which version of Gecko to use, and to switch between them). At the time you install it, it downloads the latest nightly build of Firefox. (You can update that nightly build by reinstalling qbrt.)

And the packaging support is primitive. qbrt creates a shell script (batch script on Windows) to launch your app, and it packages your app using a platform-specific format (ZIP on Windows, DMG on Mac, and tar/gzip on Linux). But it doesn’t set icons nor most other package meta-data, and it doesn’t create auto-installers nor support signing the package.

In general, qbrt is immature and unstable! It’s appropriate for testing, but it isn’t yet ready for you to ship apps with it.

Nevertheless, I’m keen to hear how it works for you, and whether it supports your use cases. What would you want to do with it, and what additional features would you need from it?


Originally published at Mykzilla.