Writing Firefox Web Extensions at Milwaukee Hack and Tell

Just over two weeks ago, RokkinCat conducted their 14th Hack & Tell. Since I wasn't able to participate last October, I was eager to spend some time working on some project ideas I've been thinking about! This time, I didn't have a single strong idea - instead, I spent my time playing around writing extensions for Firefox using the new(ish) WebExtensions API.

I wrote two extensions, and did a lot of brainstorming on a third (well, the third is really more of a family of extensions - more on that in a bit).

The first extension, Scroll to nearest anchor, was based on a need I've perceived in my own browsing - oftentimes I want to link to a particular part of a page, but many pages these days don't make linking to internal anchors very easy or obvious. In the past, I've ended up just opening the developer console and writing some JavaScript and/or using the element inspector to find the HTML anchor. My friend Maxim mentioned a need for this functionality in one of our more recent chats, so that affirmed my desire to work on this!

The second extension, Russian Training Wheels (name pending), is an experiment based on experiences I've had when trying to read articles in Russian. Russian is a highly inflecting language (ex. отец "father" can be отец, отца, отцу, отцом, or отце depending on case - and that doesn't count plurals!), and so it takes some practice to recognize words you know (the fact that Russian is written in a different alphabet and is also highly irregular also doesn't help!). So, my experimental extension tries to offer a prospective student of Russian such as myself some help. You import your vocabulary list, and when you highlight a Russian word, it uses a stemming algorithm to compare that word to your vocabulary and tells you if you already know it.

The third "family" of extensions is based on integrating the browser more tightly with TiddlyWiki. I'm a big TiddlyWiki user, and I have a number of ideas for extensions to make referring to information in my wiki and adding to my wiki while browsing easier. The thing is, each of these extensions would have a lot of shared logic - they would need to know how to communicate with the wiki, the wiki would need plugins to know how to communicate with them, etc. So I figured I could create a framework, a higher-level extension/plugin coordinator I'm calling "TiddlyBroker". I haven't actually put down code for this yet, but I'm hoping too soon - if I do, maybe I'll write about it in a subsequent blog post.

The power (and limitations) of WebExtensions

I had a few other ideas for extensions - I probably spent the first hour or two of the hack and tell going through notes I'd written about ideas for extensions and cross-referencing them with the APIs to see what I could accomplish. For example, I would like to extend the built-in find function to add things like regular expression search, stemmed search, whole word search, fuzzy search, etc. (I'm on a bit of a search kick, if you couldn't tell!) Unfortunately, this doesn't seem to be possible (yet). I also ran into other limitations with the WebExtensions API - in my "Scroll to nearest anchor" extension, for example, I wanted to find the nearest anchor to the mouse cursor. As far as I could tell, there was no way to get the mouse position, short of tracking it once the page loaded, which seemed like overkill.

Which brings me to the perception that a sizable chunk of the Firefox community has had about WebExtensions - I've seen this with fellow power users on Twitter, and especially in the TiddlyWiki community with the loss of the extremely useful TiddlyFox extension: The WebExtension APIs, in their current form, just don't seem powerful enough, and a lot of useful legacy extensions have been left by the wayside. Many useful things are either impossible or only possible through some wacky HTML trickery.

Now, I understand: Mozilla is in the unenviable position of having an extension system attached to a collection of interpreters that fetch content from the far flung corners of the Internet - it's not like extending your editor, your window manager, or your shell. It's a security nightmare, and I think that Mozilla made the correct decision to restrict their initial APIs to make sure that their users are protected. (The fact that the browser is faster and lighter as a result certainly doesn't hurt!). I had a very friendly chat with some of the folks on the #webextensions channel on IRC - it sounds like new features will be coming in future releases, which would be great. It looks like WebExtensions and the Firefox userbase are going to have to learn to grow together.