PSA: WebUSB in Extension Service Workers
Ajay Rahatekar
Contact emails
chen...@chromium.org
Explainer
https://github.com/WICG/webusb/blob/main/extension-service-worker-explainer.md
Specification
Summary
Allows web developers to use WebUSB API when responding to extension events by exposing WebUSB API to Service Workers registered by browser extensions. This API will not yet be exposed to Service Workers registered by sites but the implementation experience gained by supporting the API for extensions will be valuable for such a future project.
Blink component
Risks
Interoperability and Compatibility
Gecko: Negative (https://github.com/mozilla/standards-positions/issues/100) Mozilla has not provided a position on this feature but their position on WebUSB is negative
WebKit: Negative (https://github.com/WebKit/standards-positions/issues/68) Apple has not implemented WebUSB due to concerns about fingerprinting
Web developers: No signals
Other signals: Extension team approves of exposing these APIs to extension service workers. (https://docs.google.com/document/d/1s01BVkz-mb18p-gwXmzhM6DdioOh0JMzx_kCJzsLd7U/preview, internal-only)
WebView application risks
None, WebUSB is not available in WebViews.
Debuggability
Devtools
Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?
No
Is this feature fully tested by web-platform-tests?
No, testing for Extensions is covered by Chrome browser tests but the WebUSB API in general is fully tested by web-platform-tests.
Flag name
chrome://flags/#enable-web-usb-on-extension-service-worker
Requires code in //chrome?
True
Tracking bug
https://bugs.chromium.org/p/chromium/issues/detail?id=1303193
Launch bug
https://launch.corp.google.com/launch/4200812 (sorry, Googlers only)
Estimated milestones
115
Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/5200265459269632
Links to previous Intent discussions
Intent to prototype: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAKfE4f%2Bi4m3rOBF4m-yQVAwau3ghnMS_jkj6Bis5LP5eeYjfzw%40mail.gmail.com