Reporting URL for SW update failures

[jakearchibald]

Like CSP reporting, something to report update failures to. Probably particular kinds of failures.

[mkruisselbrink]

See https://w3c.github.io/reporting/ for a possible generic reporting mechanism we could use for this,

[jakearchibald]

F2F:

• Things we might want to report
  • Failed installs
  • Error page served to browser
  • Browser bypassed your SW because it doesn't like it (?)
• Could respondWith return something to indicate if fetch accepted the response - but would you have to use waitUntil to keep alive for this?
• Could we have a fetcherror event which fires if a response returned from fetch was rejected - it would allow you to fall back to default browser behaviour

[wheresrhys]

This would be very useful. Is there some reason this could not also trigger an event sent to one/all the current sw clients. My use case is that users with a cookie longer than 4096 bytes get a 400 when requesting our sw (I'm working on a fix for this elsewhere too), and for each of those users I would like an API to detect this and unregister the service worker.

In a similar vein, an interface for handling failed registrations would be useful: am I right in thinking navigator.serviceWorker.register() doesn't reject if the request for the service worker fails?

[jakearchibald]

am I right in thinking navigator.serviceWorker.register() doesn't reject if the request for the service worker fails?

It'll reject if it's the first call to register(), as it's a failure to register. After registration, calling register doesn't trigger updates, so it doesn't reject on update failure.

[jakearchibald]

F2F: Lukewarm to this. We can look again if people ask for it.