A web application that monitors product availability on websites by regularly checking if specific text (indicating out-of-stock status) is present on a webpage.

• Automated Monitoring: Regularly checks target URLs for stock availability
• Web Dashboard: Beautiful, responsive web interface to monitor status
• Real-time Updates: Live status updates and check history
• Configurable: Easy configuration of target URL, check intervals, and stock indicators
• Azure Ready: Designed for deployment on Azure Container Apps
• Logging: Comprehensive logging with Winston
• Error Handling: Robust error handling with retry logic
• Security: Helmet.js security headers and CORS configuration

• Backend: Node.js with TypeScript and Express
• Frontend: Vanilla JavaScript with Tailwind CSS
• Monitoring: Cheerio for web scraping, Axios for HTTP requests
• Scheduling: Node-cron for automated checks
• Deployment: Docker containerization with Azure Container Apps

• Node.js 18 or higher
• npm or yarn
• Docker (for containerization)
• Azure CLI (for deployment)

1. Clone and setup:

   cd d:\AIApps\Projects\InstockDetector
   npm install

2. Configure environment:

   cp .env.example .env

   Edit .env file with your settings:

   TARGET_URL=https://your-target-website.com/product
   CHECK_INTERVAL_MINUTES=5
   OUT_OF_STOCK_TEXT=No products available yet
   

3. Start development server:

   npm run dev

4. Open browser: Navigate to http://localhost:3000

npm run build
npm start

You can also update configuration through the web interface:

• Click the "Settings" button in the top right
• Update Target URL, Check Interval, or Out of Stock Text
• Changes take effect immediately

1. Build and push container:

   # Build the container
   docker build -t instock-detector .
   # Tag for Azure Container Registry
   docker tag instock-detector <your-acr>.azurecr.io/instock-detector:latest
   # Push to registry
   docker push <your-acr>.azurecr.io/instock-detector:latest

2. Deploy with Azure Developer CLI:

   azd auth login
   azd init
   azd up

3. Or deploy with Bicep:

   az deployment group create \
    --resource-group <your-rg> \
    --template-file infra/main.bicep \
    --parameters targetUrl="https://your-site.com" \
    --parameters containerImage="<your-acr>.azurecr.io/instock-detector:latest"

# Build
docker build -t instock-detector .
# Run
docker run -p 3000:3000 \
 -e TARGET_URL="https://your-site.com" \
 -e CHECK_INTERVAL_MINUTES="5" \
 -e OUT_OF_STOCK_TEXT="No products available yet" \
 instock-detector

1. Amazon Product Page:

   • URL: https://amazon.com/product-page
   • Out of Stock Text: Currently unavailable

2. Custom Store:

   • URL: https://store.com/limited-edition-item
   • Out of Stock Text: Sold out

3. Shopify Store:

   • URL: https://store.shopify.com/products/item
   • Out of Stock Text: Sorry, this item is out of stock

// Check stock manually
const response = await fetch('/api/check', { method: 'POST' });
const result = await response.json();
// Update configuration
await fetch('/api/config', {
 method: 'POST',
 headers: { 'Content-Type': 'application/json' },
 body: JSON.stringify({
 targetUrl: 'https://new-site.com',
 checkIntervalMinutes: 10,
 outOfStockText: 'Out of stock'
 })
});

The application provides comprehensive logging and monitoring:

• Health Endpoint: /health for load balancer checks
• Structured Logging: JSON formatted logs with Winston
• Azure Integration: Logs automatically sent to Azure Log Analytics
• Error Tracking: Failed requests and network errors are logged
• Performance Metrics: Response times and success rates tracked

• No Credentials Stored: Uses managed identity for Azure resources
• Security Headers: Helmet.js provides security headers
• CORS Configuration: Configurable cross-origin requests
• Input Validation: All user inputs are validated
• Rate Limiting: Built-in protection against abuse
• Container Security: Runs as non-root user

1. Connection Refused:

   • Check if target website blocks automated requests
   • Verify URL is accessible
   • Check firewall settings

2. False Positives:

   • Adjust the "Out of Stock Text" to be more specific
   • Check if website structure changed

3. High Memory Usage:

   • Reduce check interval
   • Clear browser cache
   • Monitor for memory leaks

View logs in different ways:

# Local development
tail -f logs/combined.log
# Docker container
docker logs <container-id>
# Azure Container Apps
az containerapp logs show --name instock-detector --resource-group <rg>

├── src/ # TypeScript source code
│ ├── app.ts # Main Express application
│ ├── stockMonitor.ts # Core monitoring logic
│ ├── scheduler.ts # Cron job scheduling
│ ├── statusManager.ts # Status tracking
│ ├── logger.ts # Winston logging setup
│ └── types.ts # TypeScript type definitions
├── public/ # Static web assets
│ ├── index.html # Web dashboard
│ └── app.js # Frontend JavaScript
├── infra/ # Azure infrastructure as code
│ └── main.bicep # Bicep template
├── Dockerfile # Container configuration
└── azure.yaml # Azure Developer CLI config

# Run tests
npm test
# Run with coverage
npm run test:coverage
# Lint code
npm run lint

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests
5. Submit a pull request

MIT License - see LICENSE file for details.

For issues and questions:

• Create an issue in the repository
• Check the troubleshooting section
• Review Azure Container Apps documentation