nginx on the server also answers on its own IP. A direct request with a fresh
X-Forwarded-For each time got a new throttle identity every time and skipped
every per-IP limit (OTP request/login, admin login): reproduced on the server
2026-10-13, 65 of 65 health requests with rotating XFF got 200.
TrustedProxyMiddleware reads X-Real-IP (set by nginx from the TCP peer) and,
when the peer is not in TRUSTED_PROXY_NETWORKS (default: ArvanCloud's
published list), replaces XFF with the peer address. Logs a WARNING once an
hour per untrusted peer that sent a proxied XFF, so a new Arvan range shows up.
Also ignore the parallel test DB clones (.test-db_N.sqlite3).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Postgres here allows 60 connections, but each of the 96 gunicorn threads held its
own persistent one: at 100 concurrent users (local Postgres with the same limit)
21% of requests were 500 "remaining connection slots are reserved". Now each worker
has a psycopg pool (8), so the same load gives 0 errors and 714 req/s (was 460).
- A full pool answers 503 + Retry-After (DRF handler and middleware), not 500.
- The AI tutor and the OTP SMS call return their connection before the network wait.
- statement_timeout 30 s, idle-in-transaction 60 s; bad pool settings and the old
DB_CONN_MAX_AGE stop startup instead of failing every request.
- /api/health dbPool: per-worker pool stats and workers x pool + 6 vs max_connections.
- Indexes on the columns global counters filter by time (weekly leaderboard,
global SMS cap, global AI cap); the leaderboard recomputes once per expiry.
- Worker count moves into gunicorn.conf.py (4 on a shared 8-core box).
- security doc: Redis item closed (server uses our own Redis since 2026-10-08).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Tutor (prompt tutor-v3-stepwise-plain): plain text instead of LaTeX/markdown,
with rag/services/mathtext.py converting whatever still slips through; full
step-by-step solutions with a check before the final answer; three tones by
grade; the last 6 messages of the conversation go to the model and follow-ups
are no longer served from another user's cache; book solutions the checker
disputes are kept out of the context; a questionId gives the tutor the
practice question and the student's wrong answer. /api/health reports when
the AI credit runs out. rag_model_benchmark compares chat models on verified
book problems (run on the server; credit ran out mid-run).
Map: only lessons that have questions count toward finishing an island,
lessonIds[0] / nextLessonId is always the next lesson to play, and a finished
island stays finished. The Seyar characters (sigma/delta/pi) are seeded.
Audit fixes, each reproduced before fixing:
- the plan is stored on the order, so paying a monthly order after starting
a yearly checkout no longer grants a year
- opening checkout no longer demotes an active subscription; renewals extend
from the current expiry; expired subscriptions are not reported active
- one discount code per order and only before the gateway; a 100% code
completes the purchase; lost Zarinpal confirmations are re-verified
- the unused /api/payment/webhook "mark paid" endpoint is removed
- XP counts only answers recorded on the server
- 6-digit OTP, each code dies after 5 wrong guesses; POST /api/auth/logout
- a guest who signs up keeps their account and progress (test phones excluded)
- affiliate commission on the first real payment; guests excluded
- parents with several children no longer get a 500
- SQLite runs transactions IMMEDIATE, since it ignores select_for_update
- admin login is rate-limited; display names drop phone numbers and links;
userQuestion is capped at 2000 characters
- server-side heart enforcement exists behind HEARTS_ENFORCED (off until the
frontend handles 403 no_hearts)
Not done on purpose: rotating the server's secret key and moving to Postgres.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Found in a deeper pass over what the frontend's flow actually touches:
- Nothing in the app ever wrote StreakRecord: "days in a row" was 0 forever
for every real user. Answers and lesson/island completions now record the
day (Tehran time); a broken chain shows 0. A streak error never fails the
answer itself.
- /api/leaderboard only changed when someone ran rebuild_leaderboard by
hand. It is now computed live (60s cache); weekly counts island XP too.
- gunicorn ran 3 sync workers with a 30s timeout, so every "ask Pi" stream
pinned a whole worker (~10s, GapGPT buffers the answer) and three at once
queued the entire API. gunicorn.conf.py (read automatically from the
working directory) switches to gthread, 8 threads, 120s timeout.
- Every /api/ response now says Cache-Control: private, no-store, so turning
on caching in the ArvanCloud panel can never serve one student another's data.
- /api/user/summary named no active plan ever ("subscription app not
implemented yet" had long stopped being true).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
