Extension Package Manager Research
This is a look at existing extension and package managers to get an idea of the state of the art and whether there is any reusable infrastructure.
jdiehl and DennisKehrig made a Brackets extension for extension management.
The third-party package manager for Sublime Text.
Package Control has a minimal user interface:
It leverages Sublime's "Goto Anything" UI to search packages. There are no ratings, reviews or information beyond just the couple of lines that appear there.
No restart is required for any package operations. Packages can include a text file that is displayed in a Sublime buffer when the package is installed or updated (specified in a messages.json file in the package repository).
Packages are hosted on GitHub or Bitbucket. In the documentation for package developers it is noted that the process for getting a new package in is basically to add your package location to the main repositories json file and issue a pull request.
Package Control automatically creates a version number for packages by looking at the repository update time and it also pulls from the description of the repository on GitHub or Bitbucket. Developers can create a custom package.json file with their own version number if they wish (or if their package does not work on all three platforms supported by Sublime).
Packages are automatically upgraded on startup.
Eclipse is built on a foundation of plugins, so extension management is a core feature.
npm is the package manager for Node. It's written in JavaScript for Node, so it may be possible to reuse npm bits, especially after node integration lands in Brackets.
A package system for browser-based components.
Another package system for browser-based components, created by Twitter. Somewhat similar to component, but seems simpler. Uses a component.json metadata file that's similar to npm's package.json.
Firefox's add-on manager and add-ons website have a long history and a lot of development behind them.
- Star ratings, reviews
- Collections
Different kinds of add-ons:
- Traditional add-ons: could access any public API in Firefox and use "XUL overlays" (see also "XBL") to augment the user interface in nearly unlimited ways
- Restartless add-ons: these can do much of what traditional add-ons did, and in the same style of code. However, there are limitations, as noted by the creator of Adblock Plus. Even so, in that same article, Wladimir says that it is worthwhile to go restartless
- Add-on SDK (Jetpack): Jetpacks are organized with an extensions-specific API to make extension writing easier. Jetpacks are built on CommonJS modules and are restartless. To date, they have been "statically linked": the SDK itself and any libraries your add-on depends on, are bundled in your package. Having the SDK statically linked has proven troublesome, so they are migrating the SDK into Firefox.
All of these add-ons are basically zipped directories.
The Ubuntu Software Centre is an open source "app store". It is notable as a graphical front end to apt which is a widely used Linux package manager that needs to be able to wrangle dependencies between lots of packages. The package management needed by Linux applications is likely an extreme case of what we would see in a Brackets extension ecosystem (though the Node community has proven with npm that a good package manager can result in the creation of many inter-related packages).
[nj] From a UX perspective, I think it would be good to aim for something between the bare-bones feel of Sublime (or npm) and the slick, app-store-like experience of Firefox or Ubuntu. We should expose more functionality that aids discovery than Sublime/npm, but avoid feeling too "marketingy". For example, perhaps we shouldn't have icons for extensions; we wouldn't want developers who create useful extensions to feel penalized in their appearance in the extension manager because they don't happen to have access to someone who can create nice artwork for them. On the other hand, we should have a good search mechanism, perhaps a categorization or keyword tagging scheme, and ultimately ratings and reviews, because those all aid discovery in practical ways.