Intent to Prototype: Timing information for ServiceWorker Static routing API
Keita Suzuki
Contact emails
suzuk...@chromium.org, yyana...@chromium.org
Explainer
https://github.com/WICG/service-worker-static-routing-api/blob/main/resource-timing-api.md
Specification
None
Summary
Adds timing information for ServiceWorker Static Routing API, exposed in navigation timing API and resource timing API for developer use.
Service Worker provides timing information to mark certain points in time. We add two ServiceWorker Static Routing API-relevant timing information: workerRouterEvaluationStart, time to start matching a request with registered router rules, and workerCacheLookupStart, time to start looking up the cache storage if the source is "cache". In addition, we also add two router source information, the matched router source and the final router source.
Blink component
Motivation
Service Worker provides timing information to mark certain points in time. This is exposed and used by the navigation timing API as well as the resource timing API. It currently records two times:
- Start time
- Fetch event dispatch time
However, it currently does not have any fields related to the ServiceWorker Static Routing API. Developers would benefit from having fields that provide information such as:
- the matched route (the route that the Static Routing API evaluated)
- the actual source from which the resource was retrieved
- the time it took to match the route
- the time to look up the cache for the cache source
This information will allow developers to measure the latency incurred by the API such as router evaluation time or time required to conduct cache lookup, or determine if the matched source is the final source used (can find out if the matched source failed to get the resource or not, and which source was used as the alternative).
Initial public proposal
https://github.com/w3c/resource-timing/issues/389
TAG review
None
TAG review status
Pending
Risks
Interoperability and Compatibility
The original ServiceWorker static routing API has received positive signals from Firefox, WebKit and Web developers. We are planning to start requesting signals for the timing information addition soon.
There are no compatibility risks, as this proposal only adds new fields to the timing information and will not modify any of the existing fields.
Gecko: No signal
WebKit: No signal
Web developers: No signals
Other signals:
WebView application risks
Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?
None
Debuggability
None
Is this feature fully tested by web-platform-tests?
We have an in-flight CL which adds wpt tests.(link)
Flag name on chrome://flags
None
Finch feature name
ServiceWorkerStaticRouterTimingInfo
Non-finch justification
None
Requires code in //chrome?
False
Tracking bug
Estimated milestones
No milestones specified
Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/6309742380318720?gate=6008560617259008
This intent message was generated by Chrome Platform Status.
Jonathan Hao
https://chromium.googlesource.com/chromium/src/+/HEAD/docs/security/web-platform-security-guidelines.md#timer-resolution
Keita Suzuki
> Please make sure that this new timing info abide by the Web Platform Security Guildeline:
> https://chromium.googlesource.com/chromium/src/+/HEAD/docs/security/web-platform-security-guidelines.md#timer-resolution
which already abides by the security guideline.
Yoshisato Yanagisawa
Sorry. Forgot to CC blink-dev@, Let me resend the reply.Thanks so much for the input.
> Please make sure that this new timing info abide by the Web Platform Security Guildeline:
> https://chromium.googlesource.com/chromium/src/+/HEAD/docs/security/web-platform-security-guidelines.md#timer-resolution
Our plan is to align the implementation with the existing resource timing implementation,
which already abides by the security guideline.
--
You received this message because you are subscribed to the Google Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+...@chromium.org.
To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAFXMW93NNjJXsaEvZXNCaZC5p23ZqxFF7XYSzyOXOfGjxZZiPg%40mail.gmail.com.