ameer 9ea0a8b039 feat: anti-cheat + presence panel + projector view
Refinement pass on top of the validated v1.2 base.

Hardening / quick fixes
- Caddyfile.tpl: CSP / HSTS / X-Frame / Referrer-Policy / Permissions-Policy,
  1 MiB request body cap, X-Forwarded-For pass-through; stock-Caddy compatible.
- auth.py: STUDENT_MAX_AGE 1y -> 30d.
- bootstrap.sh: stage 5 prepends `git config --add safe.directory` so the
  re-bootstrap path no longer 'detected dubious ownership' faults.
- admin.js: drop the misleading `closedPayload?.state || session.state`
  shim; state derives from session only.

Anti-cheat
- New `student_events` audit table; new POST /api/session/{sid}/event for
  blur / visibility_hidden / focus / visibility_visible. quiz.js debounces
  events at 1.5s and uses sendBeacon for visibility_hidden so the event
  survives a navigation. Counts surface in admin presence + CSV export.
- First-claim-wins on join: add_participant raises DuplicateStudentId on
  PK violation; route returns 409 + records a duplicate_join audit event
  with attempted name + IP + UA. Admin dashboard surfaces a per-row red
  badge for hits on real participants and a top-of-page alert for orphan
  attempts.
- DELETE /admin/api/students/{id} as the recovery hatch: clears the
  participant + submissions, kicks active WS sockets so a stale cookie
  cannot continue submitting. quiz.js surfaces the FastAPI detail message
  in the join form so users see the 'already in use' guidance.

Presence panel
- New presence_update WS message; in-process presence map keyed on
  student_id tracks ws_count + last_seen_ms. Admin dashboard renders
  per-student rows: connected/idle/dropped dot, blur+hidden+duplicate
  badges, 'answered current Q' tick, and a clear-student button.

Projector view (public, read-only)
- /projector/?sid=..., GET /api/session/{sid}/projector, WS
  /ws/projector/{sid}. Single self-contained projector_state snapshot
  pushed on every state change. Public leaderboard strips student_id;
  QR rendered server-side as data: URL (CSP-compliant).
- Includes per-Q answer histogram, 8-bucket response-time distribution,
  10-bucket score distribution.
- static/projector.{html,css,js}: editorial-broadside design — masthead,
  registration crosses, conic-gradient countdown ring, SVG stepped-area
  score distribution with median tick, leaderboard row-stagger. Inherits
  light/dark tokens from style.css; honours prefers-reduced-motion. No
  scroll at 1366x768 / 1920x1080 / 3440x1440.

Tests
- tests/test_anti_cheat.py: blur logging + CSV count, unknown-kind 422,
  unauthenticated event 401, duplicate-join 409 + audit, admin
  clear-student happy + 404, server-side submit lockout regression.
- tests/test_projector.py: snapshot shape, leaderboard student_id
  redaction, WS push on state change, 404 for unknown sid, page redirect
  when no sid.
- Existing tests updated for the new presence_update snapshot frame +
  CSV header columns + first-claim-wins refusal of re-key.

57/57 pytest green; smoke-tested locally end-to-end.
2026-05-04 16:08:59 +08:00
2026-05-02 02:54:34 +08:00

Live in-lecture quiz portal

FastAPI + WebSocket + SQLite quiz portal designed for ~40 students per class session. Single-process, in-memory room manager, vanilla HTML/JS front-end, Caddy in front for TLS.

Quick local run

python3 -m venv .venv
. .venv/bin/activate
pip install -e '.[dev]'
cp .env.example .env  # edit QUIZ_SECRET_KEY + QUIZ_ADMIN_PASSWORD
uvicorn app.main:app --host 127.0.0.1 --port 8001 --reload

Open http://127.0.0.1:8001/admin/, log in, create a quiz pool from a JSON pool file (see examples/pool_example.json for the schema), create a session, and share the join URL.

VPS deploy (one-shot)

On a fresh Ubuntu 24.04 LTS root SSH:

curl -fsSL https://gitea.ahkhan.me/apps/quiz/raw/branch/master/deploy/bootstrap.sh | bash

The bootstrap:

  1. apt-installs Caddy + Python venv tooling
  2. Creates a quiz system user (no shell, no SSH)
  3. Clones this repo to /opt/quiz
  4. Builds the venv and installs the app
  5. Generates QUIZ_SECRET_KEY, prompts for QUIZ_ADMIN_PASSWORD
  6. Drops the systemd unit and Caddyfile
  7. Starts both services
  8. Curl-checks 127.0.0.1:8001/healthz

After: quiz.ahkhan.me is live with auto-Let's-Encrypt cert. To override the domain or repo URL, set DOMAIN= or REPO_URL= in the environment before running the script.

Class-day workflow

  1. Provision Aliyun Intl HK ECS pay-as-you-go (ecs.t6-c2m1.large, Ubuntu 24.04 LTS).
  2. Point DNS A-record quiz.ahkhan.me at the new IP.
  3. SSH in as root, run the curl|bash one-liner above.
  4. Open quiz.ahkhan.me/admin/, log in, upload the week's pool JSON, create a session.
  5. Share the QR / join URL with the class.
  6. After class: scp root@<ip>:/opt/quiz/quiz.db ./backups/quiz-YYYY-MM-DD.db
  7. Destroy the instance.

Quiz pool files

Real pool JSON files contain answer keys and must not be committed to this repo. .gitignore excludes examples/*_pool.json (only examples/pool_example.json may be tracked). Author pools elsewhere (e.g., your course-material directory) and upload at runtime via the admin UI.

Tests

pytest -q
pytest --cov=app

For the WebSocket adversarial stress harness (Node.js + Playwright, runs in a tmux loop), see tests/stress/README.md.

Spec

SPEC.md documents the locked v1.0 design (state machine, scoring, identity flow, all WS message types).

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