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August 10, 2016

Filed under: tech»web

RIP Chrome apps

Update: Well, that was prescient.

At least once a day, I log into the Chrome Web Store dashboard to check on support requests and see how many users I've still got. Caret has held steady for the last year or so at about 150,000 active users, give or take ten thousand, and the support and feature requests have settled into a predictable rut:

  • People who can't run Caret because their version of Chrome is too old, and I've started using new ES6 features that aren't supported six browser versions back.
  • People who want split-screen support, and are out of luck barring a major rewrite.
  • People who don't like the built-in search/replace functionality, which makes sense, because it's honestly pretty terrible.
  • People who don't like the icons, and are just going to have to get over it.

In a few cases, however, users have more interesting questions about the fundamental capabilies of developer tooling, like file system monitoring or plugging into the OS in a deeper way. And there I have bad news, because as far as I can tell, Chrome apps are no longer actively developed by the Chromium team at all, and probably never will be again.

I don't think Chrome apps are going away immediately — they're still useful and used by a lot of third-party companies — but it's pretty clear from the dev side of things that Google's heart isn't in it anymore. New APIs have ceased to roll out, and apps don't get much play at conferences. The new party line is all about progressive web apps, with browser extensions for the few cases where you need more capabilities.

Now, progressive web apps are great, and anything that moves offline applications away from a single browser and out to the wider web is a good thing. But the fact remains that while a large number of Chrome apps can become PWAs with little fuss, Caret can't. Because it interacts with the filesystem so heavily, in a way that assumes a broader ecosystem of file-based tools (like Git or Node), there's actually no path forward for it using browser-only APIs. As such, it's an interesting litmus test for just how far web apps can actually reach — not, as some people have wrongly assumed, because there's an inherent performance penalty on the web, but because of fundamental limits in the security model of the browser.

Bounding boxes

What's considered "possible" for a web app in, say, 2020? It may be easier to talk about what isn't possible, which avoids the judgment call on what is "suitable." For example, it's a safe bet that the following capabilities won't ever be added to the web, even though they've been hotly debated in and out of standards committees for years:

  • Read/write file access (died when the W3C pulled the plug on the Directories part of the Filesystem API)
  • Non-HTTP sockets and networking (an endless number of reasons, but mostly "routers are awful")

There are also a bunch of APIs that are in experimental stages, but which I seriously doubt will see stable deployment in multiple browsers, such as:

  • Web Bluetooth (enormous security and usability issues)
  • Web USB (same as Bluetooth, but with added attacks from the physical connection)
  • Battery status (privacy concerns)
  • Web MIDI

It's tough to get worked up about a lot of the initiatives in the second list, which mostly read as a bad case of mobile envy. There are good reasons not to let a web page have drive-by access to hardware, and who's hooking up a MIDI keyboard to a browser anyway? The physical web is a better answer to most of these problems.

When you look at both lists together, one thing is clear: Chrome apps have clearly been a testing ground for web features. Almost all the not-to-be-implemented web APIs have counterparts in Chrome apps. And in the end, the web did learn from it — mainly that even in a sandboxed, locked-down, centrally distributed environment, giving developers that much power with so little install friction could be really dangerous. Rogue extensions and apps are a serious problem for Chrome, as I can attest: about once a week, shady people e-mail me to ask if they can purchase Caret. They don't explicitly say that they're going to use it to distribute malware and takeover ads, but the subtext is pretty clear.

The great thing about the web is that it can run code without any installation step, but that's also the worst thing about it. Even as a huge fan of the platform, the idea that any of the uncountable pages I visit in any given week could access USB directly is pretty chilling, especially when combined with exploits for devices that are plugged in, like hacking a phone (a nice twist on the drive-by jailbreak of iOS 4). Access to the file system opens up an even bigger can of worms.

Basically, all the things that we want as developers are probably too dangerous to hand out to the web. I wish that weren't true, but it is.

Untrusted computing

Let's assume that all of the above is true, and the web can't safely expand for developer tools. You can still build powerful apps in a browser, they just have to be supported by a server. For example, you can use a service like Cloud 9 (now an AWS subsidiary) to work on a hosted VM. This is the revival of the thick-client model: offline capabilities in a pinch, but ultimately you're still going to need an internet connection to get work done.

In this vision, we are leaning more on the browser sandbox: creating a two-tier system with the web as a client runtime, and a native tier for more trust on the local machine. But is that true? Can the web be made safe? Is it safe now? The answer is, at best, "it depends." Every third-party embed or script exposes your users to risk — if you use an ad network, you don't have any real idea who could be reading their auth cookies or tracking their movements. The miracle of the web isn't that it is safe, it's that it manages to be useful despite how rampantly unsafe its defaults are.

So along with the shift back to thick clients has come a change in the browser vendors' attitude toward powerful API features. For example, you can no longer use geolocation or the camera/microphone in Chrome on pages that aren't served over HTTPS, with other browsers to follow. Safari already disallows third-party cookie access as a general rule. New APIs, like Service Worker, require HTTPS. And I don't think it's hard to imagine a world where an API also requires a strict Content Security Policy that bans third-party embeds altogether (another place where Chrome apps led the way).

The packaged app security model was that if you put these safeguards into place and verified the package contents, you could trust the code to access additional capabilities. But trusting the client was a mistake when people were writing Quakebots, and it stayed a mistake in the browser. In the new model, those controls are the minimum just to keep what you had. Anything extra that lives solely on the client is going to face a serious uphill battle.

Mind the gap

The longer that I work on Caret, the less I'm upset by the idea that its days are numbered. Working on a moderately-successful open source project is exhausting: people have no problems making demands, sending in random changes, or asking the same questions over and over again. It's like having a second boss, but one that doesn't pay me or offer me any opportunities for advancement. It's good for exposure, but people die from exposure.

The one regret that I will have is the loss of Caret's educational value. Since its early days, there's been a small but steady stream of e-mail from teachers who are using it in classrooms, both because Chromebooks are huge in education and because Caret provides a pretty good editor with almost no fuss (you don't even have to be signed in). If you're a student, or poor, or a poor student, it's a pretty good starter option, with no real competition for its market niche.

There are alternatives, but they tend to be online-only (like Mozilla's Thimble) or they're not Chromebook friendly (Atom) or they're completely unacceptable in a just world (Vim). And for that reason alone, I hope Chrome keeps packaged apps around, even if they refuse to spend any time improving the infrastructure. Google's not great at end-of-life maintenance, but there are a lot of people counting on this weird little ecosystem they've enabled. It would be a shame to let that die.

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