__main__ built a plain HTTPServer (single-threaded): during a RAM install
POST every other request waited in the accept queue, including the 2 s
/api/status poll that feeds the operation modal - its bar and step
headline never moved and the whole result appeared only at the end (live
2026-09-29).
_build_http_server() now returns a ThreadingHTTPServer (daemon threads).
Card access is unchanged: it is serialized by _CARD_LOCK, not by the
server - every POST is blanket-wrapped in do_POST, every /api/ GET except
/api/status and /api/test/status is wrapped in do_GET, and the background
threads (STATUS poll, _bip_data_available, test runner) take the lock;
the audit found no card-access holes. do_GET also lets non-/api (static
PWA) paths bypass the lock, so page assets stay answerable during long
operations.
Regression test tests/test_http_concurrency.py: a fast request must
complete while a slow one is in flight (fails on HTTPServer with exactly
the reported symptom: 1.01 s vs 0.20 s); test_startup_cardless patches
the new factory.
sw cache simple-v312; tests: 519 Python / 674 Node.
catarrh
f942056d21