Building a Jetpack Package for Userscripts

Most members of the userscript community already know about Anthony Lieuallen's User Script Compiler, and Gina Trapani's Greasemonkey Multi Script Compiler (GMSC) which she based on Anthony's compiler. These two compilers allow a user script author to convert their userscript in to a Firefox extension, at which point the author can add functionality/features that Firefox extensions have, and usersripts do not have. So for example they can add UI elements to the browser that work with the userscript, or read+write files from the file system, etc..

I've used both compilers in the past and I find they are very handy, especially when you want to package disparate user scripts together in a single Firefox extension, or add functionality to a existing userscript, essentially upgrading the user script.

Now, around the time that the Jetpack SDK was released last month I started thinking about how the possibility of creating compilers similar to the ones above but for making Jetpacks that use userscripts. The other goal that immediately struck me was to make a userscript manager out of Jetpack, which is an idea I know others have been thinking about, at least Tim Smart expressed the same idea in the #greasemonkey irc channel not long ago.

Well, last week I was toying around with the idea of running a userscript within a Jetpack, and I had a lot of success, because within a few hours I was able to create a Jetpack which contained a collection of userscripts and it worked perfectly!

After I accomplished this, I started thinking about a road map for these ideas, so here it is..

Roadmap

Here are my goals for this project:

Complete the Userscript Package

This package has got to be dead simple to use, so that adding a userscript to a jetpack is as simple as dropping the userscript(s) in to the data folder of your jetpack, requiring the userscript package, and adding a line or two of code to your jetpack's main module which would make the jetpack aware that it has a userscript and act accordingly.

Furthermore, I want this package to be extendable so that third party's can create APIs that will be available in the userscript sandboxes. For example, a common question asked by new userscript authors is how to store data to disk in a file, which they quickly learn that they cannot do. But, when this package is complete their new option would be to write their userscript as they normally would, then if they come to the point where they want more API features than the GM_* API provides, then they will have the option to compile their userscript in to a jetpack, at which point they can start providing their userscript with more APIs that allow things such as storing data to a file on the file system.

Create a Userscript to Jetpack Compiler

This could be a website, command line package, or both, I don't really care at this point, but this must exist, and shouldn't be difficult once the Userscript package is complete. All that should be needed is a sparse Jetpack skeleton, which takes 1 or more userscripts and dumps them into the data folder, then creates a basic main module to run the userscripts.

Create a Jetpack to Manage Userscripts

Simply put this would be an alternative to Greasemonkey, maybe not quite as advanced as Greasemonkey, or with as nice a UI, but works and has all of the advantages of a Jetpack, namely you can install/update/remove without the need to restart, and takes advantage of the jetpack-core APIs which should mean that I won't have to worry as much about platform changes.

The Userscript Jetpack Package

I've posted the code I was working with last week in a git repo which is available on Github here. If you'd like to help out then fork this project and start hacking.

Example

If you would like to see the example I was working on last week, then it is available on Github as well here. This example is a remake of the BetterGWO Firefox addon that I created last year with Gina's GMSC.

Conclusion

If any of those goals sparked your interest then consider helping out, I would enjoy the company. Otherwise, I hope to have at least the userscript package mainly complete by the end of this month, so stay tuned.