Re: [w3ctag/design-reviews] TAG review for making app updates more predictable, `update_token` (Issue #1076)

martinthomson left a comment (w3ctag/design-reviews#1076)

@Dp-Goog Thank you for your proposal and contribution, the TAG has discussed this (with thanks to @christianliebel who drafted most of this comment).

We understand your proposal introduces an additional update mechanism for app shortcuts for Chromium-based browsers. Specifically, your proposal suggests adding an `update_token` member to trigger manifest updates only when its value changes. Without this member, updates would always occur at the next possible opportunity. This approach seems to address specific challenges, such as unnecessarily triggering icon updates due to CDN re-encodings or minor design alterations.

We have reservations about introducing an update_token member for this purpose. This mechanism appears unconventional within the web platform (which values would you expect there?), and there is a risk that developers may overlook the `update_token` field. Additionally, updating shortcuts seems to be handled differently by various engines: While Chromium-based browsers prompt users with a confirmation dialog for security-critical updates, WebKit appears not to update shortcuts once added to the home screen or dock.

We believe updating app shortcuts and icons after installation must be possible, but there should be a single approach to it. We recommend that you start a broader discussion within the WebApps working group to explore an approach that ideally works across various engines and platforms. The results of this discussion could enhance the Updating the manifest section of the Web App Manifest specification, which currently lacks a detailed description (see https://www.w3.org/TR/appmanifest/#updating).

As one possible solution to the issue with CDN re-encodings, we suggest treating icons as Cache-Control: immutable, which means that there is no guarantee that the icon would update unless the URL changes (that would be down to UA choices). This would achieve a similar outcome to your proposal without needing an update_token. The consequence being that authors relying on automatic icon updates would have to be informed about this change, though (as above) that's already uncertain.

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Received on Tuesday, 29 April 2025 03:41:59 UTC