Returning players kept getting stale builds: after the /play canvas fix
deployed, the origin served the new play.html (verified — 8/8 cache-busted
requests) but browsers still rendered the old one even after a hard reload.
Cause: the server sets no Cache-Control on the web router. The HTML pages are
include_str!'d into the binary and the wasm-bindgen output (canvas.js,
canvas_bg.wasm, solitaire_wasm.*) uses fixed filenames that change in place on
every deploy, so browsers heuristically cache them indefinitely.
Add `Cache-Control: no-cache` in the security_headers middleware (which wraps
the web router). Browsers now revalidate before using a cached copy; ServeDir
supplies Last-Modified/ETag so unchanged assets still return a cheap 304, while
changed ones (a new deploy) are re-fetched. Stops the stale-build problem for
everyone going forward.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
funman300
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