Intent to Experiment: Progressive Web Apps as URL Handlers

[Mandy Chen (SHE/HER)]

Contact emails

lu.h...@microsoft.com, mandy...@microsoft.com, luig...@microsoft.com, m...@chromium.org

Explainer

https://github.com/WICG/pwa-url-handler

Specification

Pending

API spec

Yes

Design docs

https://github.com/WICG/pwa-url-handler
https://docs.google.com/document/d/19dGklalQTRtRrG3PKrVbDRmYPLHGLnsGEwUaed7sAFQ/edit?usp=sharing
https://docs.google.com/document/d/14-_u_DSUKCC0XT9rWgQz9SytDQpCet--KVROV_YTkGw/edit?usp=sharing

Summary

Enables web applications to register as https URL handlers using their web app manifest.

Blink component

UI>Browser>WebAppInstalls

TAG review

https://github.com/w3ctag/design-reviews/issues/552

TAG review status

Pending

Risks

Interoperability and Compatibility

This feature is new to the web and web apps that do not opt in will not be affected because any additions to the web app manifest will be optional. Browser behavior will also not be affected if there are no installed apps that opt in. Browser that do not support this feature will not be adversely affected by new members in the web app manifest.

Gecko: No signal (https://github.com/mozilla/standards-positions/issues/550)

WebKit: No signal (https://lists.webkit.org/pipermail/webkit-dev/2021-July/031920.html)

Web developers: Positive (https://techcommunity.microsoft.com/t5/discussions/click-url-to-open-pwa-automatically/m-p/2192994)

Security

https://github.com/WICG/pwa-url-handler/blob/main/explainer.md#security-considerations

Goals for experimentation

Allow third party developers to use the API and provide feedback.

Reason this experiment is being extended

N/A, not extending.

Ongoing technical constraints

None

Debuggability

Debug functionality will be added to the the DevTools(F12) Application pane.

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?

No

Supported in the browser on Windows, Mac, and Linux. Integration with OS features will vary.

Is this feature fully tested by web-platform-tests?

No

DevTrial instructions

https://web.dev/pwa-url-handler/

Flag name

#enable-desktop-pwas-url-handling

Tracking bug

https://bugs.chromium.org/p/chromium/issues/detail?id=1072058

Launch bug

https://bugs.chromium.org/p/chromium/issues/detail?id=1072757

Link to entry on the Chrome Platform Status

https://www.chromestatus.com/feature/5739732661174272

Links to previous Intent discussions

Intent to prototype: https://groups.google.com/a/chromium.org/g/blink-dev/c/2Sv3fCWEi_Q/m/yrSoJP8mAAAJ
Ready for Trial: https://groups.google.com/a/chromium.org/g/blink-dev/c/7NTGauH8Mxs

This intent message was generated by Chrome Platform Status.

 

[Mike West]

In Chrome's internal security review, folks had some questions about the revalidation schedule (which seems pretty critical). It's not clear to me from the docs linked here what that looks like in Chromium's implementation. Can you clarify the mechanism and the guarantees it provides?

I'd also note that I appreciate the work y'all have done with Chrome's permissions/UX folks to deal with concerns in https://docs.google.com/document/d/1pL9VexY86o3YW-iP1iN_O2fzj9QBqvBQm7CWMl5Djf0/edit#heading=h.aqp7s0iku4eb. I'll confirm with them that you're on the same page. :)

-mike

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[Mandy Chen (SHE/HER)]

Web app origin association revalidation schedule is the same as that of manifest update. It’s triggered by app launch or app page load, and it’s throttled to once a day. When the browser restarts, we also clear any last updated timestamp information, so on the next app launch/page load, we also update the manifest and revalidate web app origin associations. See the “On Manifest Update” section of the Web App Origin Association design doc: Web App Origin Association Design - Google Docs.

 

Let me know if there’re more questions. Thank you!

[Lu Huang]

Adding to Mandy's reply re. Chromium's implementation: 

- Web app manifest content does not have to change for WAOA file changes to get validated during the manifest update check.
- WAOA files needed by a particular web app can be revalidated at most once a day (because of the web app manifest update throttle period).
- There is no upper limit to the time before WAOA files are revalidated if the browser never navigates to the app's scope. 

    - It's possible for the user to always dismiss the app picker dialog when URL handling happens. The app never updates and WAOA files are never revalidated.

Broadly speaking, the guarantee we have in the Chromium implementation is that any app that is actively visited (*) by the user will have its required WAOA files revalidated. 

(*) There is an unlikely edge case: if an app is visited actively but never navigates any URL within its scope, manifest update and WAOA revalidation will not take place.

[Mike West]

I've confirmed with folks internally that y'all are on the same page with regard to the UX, thanks!

I should have asked previously: in what timeframe do you plan to run the origin trial?

-mike

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/da039342-8d33-45a8-a4c3-17b292b60d60n%40chromium.org.

[Lu Huang]

Thanks for confirming with others. We would like to get permission to start OT in Chromium M93, running through M95. Planning to add user preferences WebUI in M94.

[Mike West]

LGTM, thank you.

-mike

[Lu Huang]

Update: there was an A11Y bug which blocked the start in M93. This bug has been fixed in M95 and we are working on merging it back to M94. We would now like to start OT in M94, to run through M97. 

[Chris Harrelson]

LGTM!

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/82c84b6a-2ffc-4bf1-816c-2fc6e5ecfbc2n%40chromium.org.

[Lu Huang]

Origin Trial now active at:  https://developer.chrome.com/origintrials/#/view_trial/-5376172055173529599

[Thomas Steiner]

Article updated accordingly: https://web.dev/pwa-url-handler/#register-for-ot

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/be75ea22-e110-43f7-96a1-8848a12ae57en%40chromium.org.

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