After an update, a tab or a device whose service worker still serves the
previous build asks for chunks the update removed. The server answered those
requests with index.html and a 200, so the import failed with a MIME error,
and everything caching in between was free to keep the HTML as the chunk. A
precache install that met a missing file stored it, and Workbox reuses hashed
entries by URL, so the device showed "A new version is available" on every
load, whatever the reload or the cleared browser cache, and carried the broken
entry into every later release that keeps the file's name.
The SPA fallback now answers a GET for a build file that is not on disk with
a plain 404 (no-store) instead of index.html. A precache install refuses it,
so the worker whose cache is complete stays in charge until the new build is.
index.html is sent relative to the public dir, which also stops an install
living under a dot directory from answering every deep link with a 404.
On the client, the reload after a dead chunk (the automatic one and the
button on the update screen) no longer goes straight back to the worker that
served the broken shell. When that same worker is still in charge and the
server answers, its precache and registration are dropped first, so the
reload reaches the build the server runs now. Offline, and in offline mode,
the shell is kept. Every recovery reload, and the reload of the version
handover, asks for the page under a one-off query parameter, so a proxy or
CDN that keeps index.html against its headers cannot hand back the stale
shell either.
A chunk the entry imports statically fails before any of that code runs.
shell-guard.js, a small classic script loaded ahead of the entry, watches for
exactly that failure and runs the same recovery, once per session.
A stylesheet, font or icon that holds a page raises no error at all, so once
the app has started and the browser is idle, it looks through the precache
for entries that hold a page under a build file's name, fetches each from
the server past every cache and puts it back in place. A repaired stylesheet
is loaded again, and so are the app's stylesheets when a font was repaired,
since the browser does not try a face that failed again in the same
document. Only the headers are read, a precache found sound is not looked at
again until its entries change, nothing is fetched while nothing is broken,
and nothing happens offline, in offline mode or without storage. An answer
that is not the file (an auth wall, its login page, a server error) leaves
the entry for the next launch.
A page the recovery loaded from the network already runs the version the
server reports, so the version handover now records it instead of reloading
it a second time once the new worker takes over. A page loaded past an older
worker that is still in charge, as a hard reload does, still asks for the new
worker and records the version only once that has taken over, so the next
tab or launch cannot get the old shell without a handover.
Dropping the worker ends a Web Push subscription with it, so on such a device
the settings card shows push as off until it is switched on again. A missing
sw-push.js now fails the worker install with a 404 rather than index.html; the
comments that described the old answer say so.
A fourth built-in channel next to email, webhook and ntfy. Browsers
register per device, the server encrypts per RFC 8291 and signs per RFC
8292 with node:crypto and sends only to known push services through the
SSRF guard. The event matrix decides per category what arrives by push;
admins switch the channel on under Notifications.
VAPID keys come from the environment or are generated once, only while
neither stored row exists, and kept encrypted. A pair that does not
decrypt or match is never overwritten and never swapped for another one:
push stays off with an error in the log and every device stays
registered until the key is fixed. The subject is VAPID_SUBJECT, then an
https APP_URL, then the project URL.
Only chat messages collapse into one notification per trip, and a
replacement still alerts. A 403 removes a device only after three
failures in a row; 404 and 410 remove it at once. Password change, reset
and an admin setting a password drop the user's devices with the other
credentials. The request log redacts subscriptions and endpoints, boot
errors print *** for every secret variable, and logout forgets the
device with a plain fetch so an expired session cannot redirect midway.
Addresses discussion #894.
Maurice