Class WebEngineRefresher

What it refreshes: chromium.firstStable only, the day each Chrome major was first served on Android's stable channel. The Android and iOS "ended" facts never come from here: they ship with the server's releases and the override file (design D-7).

How: one request for the newest major Google serves on android/stable, then one request per major newer than the bundled table's newest, each asking for that major's first release served to a non-zero fraction of devices - the rule that dates the bundled table (BuildUtil/scripts/Update-WebEngineTable.ps1). A weekly run therefore costs two or three small requests. The days fetched are added to the BUNDLED table's days, never to an earlier cache, so that nothing an older run wrote is carried on; the result is checked against every bound the table applies on load (WebEngineSupportTable) and written to the cache file "webengine"/"webengine-cache.json" in the server's current directory, through a temporary file and a move. The table in use is then loaded again (WebEngineAdvisor.loadTable(ServerSettings,Path)), with the cache as its second source.

Bounds: an answer that is not HTTP 200, is larger than 65536 bytes, ends early, takes longer than its timeouts, is not JSON or not the service's shape, names a major outside 50..999 or more than 100 majors past the bundled table, answers a request for one major with a release of another, a release served to nobody, or a day the table's bounds refuse, fails the WHOLE run: nothing is written, the table in use and the cache stay as they were, and the next attempt comes a day later (RETRY). Nothing here ever throws into the server.

The request carries nothing of the server, its sessions or its users: a GET of a public, anonymous URL through HttpClient, with a connect timeout and a request timeout of 10 s each and the whole exchange, body included, bounded by their sum; no cookie handler; no redirect followed; the system proxy selector, as IP2Location's downloads use; and no header beyond the client's own (its User-Agent is Java's default).

The log: one INFO line when the server starts, naming the URL and the cache file, or saying why nothing is refreshed; one WARNING for the first failure of a streak, FINE for the failures after it, and one INFO when a refresh succeeds after a streak. Every successful refresh shows as the advisor's "Web engine support table loaded" line.

When: FIRST_DELAY after the server starts when the cache is missing or at least INTERVAL old, otherwise when it reaches that age; then INTERVAL after a success and RETRY after a failure. The work runs on one virtual thread of a single-thread scheduler, as IP2Location's update checks do (co.mindus.ip2location). stop() interrupts a run in progress; a stopped run loads nothing and warns nothing.

Switches: the server setting ServerSettings.WEB_ENGINE_REFRESH (default on), read when the server starts. Nothing is refreshed while ServerSettings.WEB_ENGINE_DATA_FILE names a file: that file replaces the whole table, cache included.