peter
b1086e05dc
Reported from UAT: delete an account, then open its password-reset link. The card drew the full "set
a new password" form — because a `#reset=` fragment was present, and nothing more — and only after
the user had typed a password did the server answer 400. Measured first: no security hole. A user's
tokens cascade away with the row, so nothing can be set on a deleted or a re-created account. What
was left is a dead end of exactly the kind this epic exists to remove, and it is not rare: a reset
link lives one hour, mail is slow or lands in spam, and whoever got two mails clicks the older one.
password-reset/check answers whether a link is still usable WITHOUT spending it, so asking can never
cost the user their one real attempt — the property the tests pin hardest. It gets its own limiter,
because opening a link must not eat the budget for requesting one, and a throttled caller is told
"ok", never "dead": this check may only ever save someone a wasted form, so when it cannot answer it
degrades to the old behaviour instead of declaring a live link finished. The confirm endpoint stays
the authority, and its failure raises the same named screen, since the token can die between the two
calls or the probe itself may have failed.
A too-short password is deliberately NOT that screen. The length check runs before the token is
spent, so a typo costs the link nothing, and the card tells the two 400s apart by `reason` so only
one of them takes the form down.
Both email-link confirmations (verify, password-reset/confirm) now answer in the {code, reason}
shape S4 introduced. They were the last refusals a user meets by simply clicking an old link while
still being answered in hardcoded English under a bilingual UI. The seven remaining bare strings in
this module (register, request-access, the demo guards, set-password) sit behind client-side
validation the UI does first; they are logged as a follow-up rather than swept in silently here.
One bug found by the UAT itself, in the new code: the check went out FOUR times per opened link —
StrictMode double-invokes effects and the shell remounts the card as the session probe settles.
Harmless per request, but against a per-IP limit it would exhaust the budget in two reloads and then
silently fall back to drawing the form unchecked: nothing errors, the feature just stops working.
Deduped in a module-level map holding the in-flight promise (a ref dies with the remount that causes
it); a failed probe drops itself so a blip is never cached as "dead". The test renders the card
twice, because with one render the guard would rot undetected.
UAT on localdev: the reported scenario end to end (delete the account, open the link) shows the named
screen and no form; a live link still opens the form and completes; the CTA lands on the request-a-
link form; one probe per opened link. Throwaway accounts removed.
Backend conventions
The rules below are already followed across backend/app — they lived only in a few module
docstrings (demo.py, userscope.py, routes/_common.py) until this file collected them (E3 S3,
B-core-20). When you add code, match these so the next reader doesn't have to guess "which pattern do
I copy".
Module layering
Three layers, by who runs the code — not by feature:
-
routes/…— request-only. A route module holds HTTP concerns: auth dependencies, request/ response models, status-code mapping, serialization. It owns logic that runs only on a request. Business logic that a request happens to trigger does not live here if anything else runs it too. -
plex/,downloads/,sync/— domain logic shared by more than one caller. Anything the scheduler or the worker runs (not just a request) lives in one of these domain packages, so the route, the worker, and the scheduler share one definition. Examples from this codebase:downloads/service.pyowns enqueue + the job state transitions (routes call it);plex/sync.pyis run by both the admin route and the scheduler;downloads/pipeline.pyis the worker's child pipeline. -
Flat
app/*.pycore modules — cross-cutting primitives.auth,sysconfig,quota,audit,notifications,userscope,realtime,ratelimit,progress, … are single-file primitives many layers import. They depend on nothing above them (a core module must never import aroutes/…module).
Extraction trigger: the SECOND consumer. Keep new logic inline in its first caller. The moment a second caller needs it (a worker as well as a route; a scheduler as well as a route), extract it down a layer — into the relevant domain package, or a flat core module if it's cross-cutting. Don't pre-abstract for a single caller; don't leave shared logic duplicated once there are two.
Transaction ownership
This follows CLAUDE.md's canonical rule verbatim — "the handler/job-wrapper commits; helpers flush
(only quota owns its session)" — so read it that way, not as an exception to it. The commit belongs
to the operation owner; anything called inside another transaction only stages its change
(db.add / flush) and lets the owner commit, so the whole operation is one transaction.
audit.record() is the reference: it adds the audit row and the caller commits it together with the
mutation it records, so an audit entry can never exist without its change (or vice-versa).
- The operation owner is usually the route handler. A
service.*operation the handler delegates a whole transition to (e.g.service.cancel) is that owner and commits its one transition — it isn't a mid-operation helper. A helper that owns its OWN short-lived session (the worker'sjobdbwrites, the same carve-out CLAUDE.md grantsquota) commits that session. Everything else flushes. SessionLocalisexpire_on_commit=False: after a rawUPDATE+ commit, an ORM object you already loaded is stale. Read the fresh value from the row (RETURNING, or a re-SELECT), not the ORM attribute — seeservice.decr_ref_count.
Shared counters and status: do it atomically at the DB
- Never read-modify-write a shared counter in Python (
x.count = x.count + 1). Concurrent sessions lose an update. Use a DB-atomic statement —col = col + 1, orgreatest(col - 1, 0)withRETURNINGso the caller branches on the post-value under the row lock (service.incr_ref_count/decr_ref_count). - Download job status is a
JobStatusStrEnum (downloads/status.py), not bare strings. TheHOLDINGset defines which states hold aMediaAsset(so release accounting stays correct);STOPPED_BY_ROUTEis the route-initiated stop set. A worker child's terminal write goes throughservice.finalize_if_running(an atomicUPDATE … WHERE status='running') so a finishing child can't resurrect a job a route just stopped.
Config: one home per kind
app.config.settings— boot/env config (DB URL, download root, worker concurrency): read once at startup, not user-tunable at runtime.sysconfig.SPECS— the runtime admin knobs (DB-override-or-default). A new admin-tunable value goes inSPECS; don't invent a fourth store. (state.py'smaintenance_batchpredates this and is slated to fold intosysconfig— do not add more like it.)
The gate
Everything below must be green before a change is done (run via siftlode check):
ruff (backend) · tsc ×3 + eslint + prettier + knip (frontend) · vitest · pytest. The
pytest lane runs in backend/docker-compose.test.yml — an ephemeral Postgres + the backend tree
bind-mounted — so the DB-backed integration tests (the db fixture) actually run; SIFTLODE_TEST_ REQUIRE_DB=1 there turns a would-be silent skip into a hard failure. See docs/development.md.