🌐 NI Quiz

Multiplayer quiz game — self-hosted, no app install required. Built for the Network Intelligence team's show-and-tell event at LCPR. Players join from their mobile browser, answer questions via a Space Invaders arcade interface, and scores are tracked across sessions.

Live at: https://ni-quiz.carloselugo.com

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Stack

Layer	Tech
Backend	Python · FastAPI · WebSockets
Storage	SQLite (Docker volume)
Frontend	Vanilla HTML/CSS/JS · Canvas 2D
Container	Docker Compose
Reverse proxy	Caddy (shared web_web-net)
Host	labmini-01 · Dell Optiplex · Ubuntu

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Architecture

Player (mobile browser)
    ↓ HTTPS / WSS
Caddy (ni-quiz.carloselugo.com)
    ↓ reverse_proxy :8000
ni-quiz container (FastAPI)
    ↓
SQLite (/data/quiz.db) — Docker volume quiz-data

All game state lives in memory on the server. SQLite persists session scores across restarts.

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File Structure

/opt/ni-quiz/
├── main.py                  # FastAPI app — game logic, WebSockets, SQLite
├── requirements.txt
├── Dockerfile
├── docker-compose.yml
├── templates/
│   ├── player.html          # Mobile arcade game (Space Invaders)
│   ├── host.html            # Projector/host control panel
│   └── scores.html          # Score history — global, by dept, by session
└── static/                  # Static assets (empty — all inline)

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Features

Player (/)

• Language selector — English / Español
• Registration — first name, last name, department
• Space Invaders arcade — 4 lanes, one per answer; ship at bottom fires at the correct invader
• 8-bit sound effects via Web Audio API
• Particle explosions on hit
• Score flash after each answer — points earned + running total
• Podium screen — top 10 with medals at game end
• Exit button — leaves session cleanly from lobby or podium

Host Panel (/host) — projector view

• Password-protected — blocks access before WebSocket connects
• QR code auto-generated with the player join URL
• Live lobby — player count + name chips update in real time
• Live leaderboard during questions — who answered, time taken, correct/wrong
• Full top 10 leaderboard after each question with department
• Game controls — Start, Next Question, Show Results, Reset
• Clear Scores — wipes all SQLite history with confirmation
• Auto-reset — if host disconnects mid-game, server resets automatically after 5 minutes if no host reconnects

Score History (/scores)

• Top 5 cards — all-time best scores across all sessions
• Global tab — full player ranking by best historical score, with department and session count
• By department tab — each department ranked internally, departments sorted by their top player
• Sessions tab — collapsible session list with full rankings and department per player

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Scoring System

points = 200 + 800 × (time_remaining / time_limit)

Condition	Points
Correct, fastest possible	1000
Correct, just before timeout	200
Wrong answer	0
No answer / timeout	0

Time limit: 20 seconds per question.

---

SQLite Schema

CREATE TABLE sessions (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    started_at    TEXT NOT NULL,
    ended_at      TEXT,
    total_players INTEGER DEFAULT 0
);

CREATE TABLE scores (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    session_id    INTEGER NOT NULL REFERENCES sessions(id),
    player        TEXT NOT NULL,
    score         INTEGER NOT NULL DEFAULT 0,
    rank          INTEGER,
    dept          TEXT NOT NULL DEFAULT '',
    finished_at   TEXT NOT NULL
);

Scores are saved when the host advances past the last question. The dept column is added automatically via migration on startup if it doesn't exist (safe for existing DBs).

---

API Endpoints

Method	Path	Description
GET	/	Player game page
GET	/host	Host control panel (password protected)
GET	/scores	Score history page
GET	/api/scores	JSON — all sessions and scores
DELETE	/api/scores/clear	Wipe all sessions and scores
WS	/ws/player/{id}	Player WebSocket
WS	/ws/host	Host WebSocket

---

Docker Compose

services:
  ni-quiz:
    build: .
    volumes:
      - quiz-data:/data
    environment:
      - DB_PATH=/data/quiz.db
    restart: unless-stopped
    networks:
      - web-net

volumes:
  quiz-data:

networks:
  web-net:
    external: true
    name: web_web-net

---

Caddyfile Block

ni-quiz.carloselugo.com {
    import security_headers
    reverse_proxy ni-quiz:8000 {
        header_up Host {host}
        header_up X-Real-IP {remote_host}
    }
    log {
        output file /var/log/caddy/ni-quiz.log
        format json
    }
}

No encode gzip — gzip breaks WebSocket upgrades. No internal_only — players need public access from mobile devices.

---

Deploy

# First deploy
cd /opt/ni-quiz
docker compose up -d --build
docker network connect web_web-net ni-quiz-ni-quiz-1

# Subsequent deploys (network defined in docker-compose.yml)
docker compose down
docker compose up -d --build

# Restart only (no rebuild — e.g. after editing main.py)
docker compose restart ni-quiz

# Backup DB
docker compose cp ni-quiz:/data/quiz.db ./quiz-backup-$(date +%Y%m%d).db

---

Configuration

Host password

Edit in templates/host.html:

const HOST_PASSWORD = 'ni2026';  // ← change this

The password is checked client-side and stored in sessionStorage — valid for the browser tab session only.

Auto-reset timeout

Edit in main.py (ConnectionManager.disconnect_host):

self._reset_task = asyncio.create_task(self._auto_reset(delay=300))  # seconds

Question time limit

Edit in main.py (two places must match):

TIME_LIMIT = 20          # server-side validation
"time_limit": 20,        # sent to client for countdown display

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Known Issues / Notes

• Network on rebuild — docker compose up --build recreates the container and drops it from web_web-net. Fix: define the network in docker-compose.yml (already done), or manually reconnect with docker network connect web_web-net ni-quiz-ni-quiz-1.
• No gzip on WS proxies — Caddy's encode gzip breaks WebSocket upgrades. Always omit for WS-heavy services.
• Host password is client-side — suitable for access control at an internal event. For stricter security, move auth to the backend with fastapi.security.
• Single game instance — all game state is a single global GameState object. Concurrent games are not supported.

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URLs

	URL
Players	https://ni-quiz.carloselugo.com
Host / Projector	https://ni-quiz.carloselugo.com/host
Score History	https://ni-quiz.carloselugo.com/scores