AGAS Backend (Hackathon Demo)

Real-time gas monitoring backend using Node.js, Express, Socket.IO, and PostgreSQL.

This version is configured for demo use:

• no authentication required
• CO2 and gas level only
• default demo user created automatically

Current Features

• Arduino data ingestion via REST
• Real-time WebSocket broadcast to frontend
• PostgreSQL persistence for readings, alerts, and control state
• Alert generation based on thresholds
• Manual control endpoints (fan, valve, alarm)
• Metrics endpoints for current and historical data

Tech Stack

• express
• socket.io
• pg
• axios
• cors
• dotenv

Project Structure

backend/
  config/database.js
  db/schema.sql
  db.js
  middlewares/
  routes/
  services/
  sockets/
  server.js

Setup

1. Install dependencies:

npm install

2. Create .env in the project root:

PORT=3000
HOST=0.0.0.0
DATABASE_URL=postgresql://postgres:YOUR_PASSWORD@localhost:5433/smart_safety
DB_SSL=false
DEFAULT_USER_ID=AGAS-2026-001

3. Start server:

npm start

Server URL: http://localhost:3000

☁️ Cloud Deployment

DigitalOcean (Recommended for Students)

Quick Start:

1. Sign up at digitalocean.com
2. Get $200 free credit: GitHub Student Pack
3. Deploy: cloud.digitalocean.com/apps/new

📖 See DIGITALOCEAN_QUICK_START.md - 5-minute setup! 📖 See DIGITALOCEAN_DEPLOYMENT.md - Full guide

Cost: ~$12/month (FREE for 16+ months with student credits!)

---

Azure (Alternative)

Quick Start:

azd auth login
azd env set DATABASE_ADMIN_PASSWORD "YourSecurePassword123!"
azd up

📖 See AZURE_QUICK_START.md for a 5-minute deployment guide. 📖 See AZURE_DEPLOYMENT.md for complete documentation.

Note: Azure for Students may have region restrictions. See AZURE_REGIONS.md.

Data Model (Sensor Input)

Only these sensor fields are used now:

{
  "sensorId": "SENSOR-001",
  "co2": 920,
  "gas_level": 6
}

Supported payload styles:

• flat payload: co2, gas_level
• nested payload: { readings: { co2, gas_level } }

Alert Thresholds

• danger when co2 >= 1500 or gas_level >= 20
• warning when co2 >= 1000 or gas_level >= 10
• otherwise safe

REST API

Base

• GET / -> health text response

Arduino / Hardware

• POST /api/gas-data
• GET /api/fetch-gas-data?apiUrl=...

Example:

curl -X POST http://localhost:3000/api/gas-data \
  -H "Content-Type: application/json" \
  -d '{"sensorId":"SENSOR-001","co2":920,"gas_level":6}'

Frontend (/v1)

• GET /v1/metrics/current
• GET /v1/metrics/history?period=24h&interval=5m
• GET /v1/control/state
• POST /v1/control/toggle
• GET /v1/alerts?status=all&limit=50
• POST /v1/alerts/:id/resolve

Toggle body example:

{
  "device": "fan",
  "state": true
}

WebSocket Events

Connect client:

const socket = io('http://localhost:3000');

Events from server:

• connected
• gas-data-update
• sensor_update
• fetch-success
• fetch-error

Quick Smoke Test

1. Send sample reading:

curl -X POST http://localhost:3000/api/gas-data \
  -H "Content-Type: application/json" \
  -d '{"sensorId":"SENSOR-001","co2":920,"gas_level":6}'

2. Fetch latest metrics:

curl http://localhost:3000/v1/metrics/current

Expected readings includes only:

• co2
• gas_level

Demo Mode Notes

• Authentication is disabled intentionally for hackathon demo.
• Default user code seeded: AGAS-2026-001.
• v1 routes require database availability.

Additional Docs

• HACKATHON_QUICK_START.md
• ARDUINO_API_SPEC.md
• FRONTEND_API_SPEC.md
• DATABASE_SETUP.md
• DOCUMENTATION_INDEX.md

License

ISC