spa

Overview ¶

Package spa serves a built single-page app out of an embedded filesystem.

It is the ONE way an app in this repo serves its own UI. Three apps had byte-identical copies of this handler (tasks, research, and meet as it landed); the policy in it is not obvious enough to be worth restating three times, and a policy restated three times drifts:

• a content-addressed asset under assets/ carries an immutable cache hint, because Vite hashes the filename — the bytes at that name never change;
• everything else is no-cache, so a freshly deployed shell replaces the stale one on the next request rather than on the next cache expiry;
• a path that is not a real file rewrites to index.html, which is what lets a deep link survive a reload under a client-side router — EXCEPT under assets/, where a miss is a 404. That subtree holds only content-addressed build output, so a name that is not there is a stale shell asking for a purged chunk, never a client-side route. Answering the shell there hands a <script> tag a document — "Unexpected token '<'", which reads as a corrupt bundle rather than the cache miss it is;
• a DIRECTORY is not a page. http.FileServer lists one, so serving whatever stat succeeds on publishes the whole asset manifest at /<app>/assets/; a directory falls through to the shell (or 404s under assets/) instead;
• a MISSING index.html is 503, not a blank 200. A bundle that failed to sync is then loud in staging instead of being a white page in production.

It is NOT the console at "/" (webui). That one is a different handler on purpose: it owns the root catch-all, so it has to refuse the API namespaces outright and rewrite the document title per white-label host. This one is mounted under its app's own prefix and never sees a path that is not its own.

It is a LEAF — stdlib only — so any app can serve its UI without linking the fleet.