A Node.js Express server that acts as an intelligent proxy to block advertisements, trackers, and malicious content. This lightweight solution provides enterprise-grade ad blocking capabilities with comprehensive APIs for management and monitoring.

• Intelligent Ad Blocking: Blocks ads using domain blacklists and pattern matching
• Real-time Proxy: Acts as a transparent proxy for web requests
• Multiple Blocklist Sources: Integrates with EasyList and custom blocklists
• Whitelist Support: Allow specific domains to bypass blocking
• Statistics & Analytics: Track blocked vs allowed requests with detailed metrics
• RESTful API: Complete API for blocklist management and monitoring
• Production Ready: Includes logging, rate limiting, and error handling
• Performance Optimized: In-memory caching for fast blocklist lookups

graph TD
    A[Client Request] --> B[Express Server]
    B --> C[Rate Limiting]
    C --> D[Ad Blocker Middleware]
    D --> E{Check Blocklists}
    E -->|Blocked| F[Return 204 No Content]
    E -->|Allowed| G[Proxy Middleware]
    G --> H[Forward to Target]
    H --> I[Return Response]

    J[Blocklist Manager] --> K[Local Blocklists]
    J --> L[Remote Sources - EasyList]
    J --> M[Whitelist]
    J --> E

1. Request Flow:

   • Client sends request with target URL
   • Server applies rate limiting and security checks
   • Ad blocker middleware checks URL against blocklists
   • If blocked: returns 204 No Content
   • If allowed: proxies request to target and returns response

2. Blocklist Management:

   • Loads local blocklists on startup
   • Periodically updates from remote sources (EasyList)
   • Maintains in-memory cache for performance
   • Supports custom domain and pattern rules

3. Statistics Tracking:

   • Real-time counters for blocked/allowed requests
   • Daily statistics with historical data
   • Top blocked domains tracking
   • Performance metrics and uptime

• Node.js 16+
• npm or yarn

# Clone the repository
git clone https://github.com/drealdumore/ads-blocker.git

cd ads-blocker

# Install dependencies
npm install

# Copy environment configuration
cp .env.example .env

# Start the server
npm start

# For development with auto-reload
npm run dev

Create a .env file based on .env.example:

PORT=3000
NODE_ENV=production
ALLOWED_ORIGINS=*
LOG_LEVEL=info
RATE_LIMIT_WINDOW_MS=900000
RATE_LIMIT_MAX_REQUESTS=1000
BLOCKLIST_UPDATE_INTERVAL=24
PROXY_TIMEOUT=30000

Place custom blocklists in src/data/blocklists/:

• domains.txt - Domain-based blocking rules
• patterns.txt - Regex patterns for URL matching
• whitelist.txt - Domains to never block

Send requests through the proxy by providing the target URL:

# Using query parameter
curl "http://localhost:3000/?url=https://example.com"

# Using header
curl -H "X-Target-URL: https://example.com" http://localhost:3000/

# Check blocklist status
GET /api/blocklist/status

# Check if URL would be blocked
POST /api/blocklist/check
{
  "url": "https://example.com",
  "userAgent": "Mozilla/5.0...",
  "referer": "https://source.com"
}

# Add domain to blocklist
POST /api/blocklist/domain
{
  "domain": "ads.example.com"
}

# Remove domain from blocklist
DELETE /api/blocklist/domain
{
  "domain": "ads.example.com"
}

# Add domain to whitelist
POST /api/blocklist/whitelist
{
  "domain": "trusted.com"
}

# Update remote blocklists
POST /api/blocklist/update

# Get overall statistics
GET /api/stats

# Get daily statistics (last 7 days)
GET /api/stats/daily?days=7

# Get top blocked domains
GET /api/stats/top-blocked?limit=10

# Get recent blocked requests
GET /api/stats/recent?limit=50

# Reset statistics
POST /api/stats/reset

# Server health status
GET /health

{
  "success": true,
  "data": {
    "blocked": 1250,
    "allowed": 8750,
    "totalRequests": 10000,
    "blockRate": "12.50%",
    "uptime": 86400000,
    "requestsPerMinute": 6.94,
    "topBlockedDomains": [
      { "domain": "doubleclick.net", "count": 342 },
      { "domain": "googlesyndication.com", "count": 201 }
    ]
  }
}

{
  "success": true,
  "data": {
    "url": "https://ads.example.com/banner.js",
    "blocked": true,
    "reason": "Matches blocklist criteria"
  }
}

• Rate Limiting: Configurable request limits per IP
• CORS Protection: Configurable origin restrictions
• Header Security: Helmet.js for security headers
• Input Validation: URL validation and sanitization
• Error Handling: Graceful error responses
• Logging: Comprehensive request and error logging

• logs/combined.log - All application logs
• logs/error.log - Error-level logs only

• error - Critical errors
• warn - Warning messages
• info - General information
• debug - Detailed debugging (development)

• Request counts (blocked/allowed)
• Response times
• Top blocked domains
• Daily/hourly statistics
• Error rates
• Uptime statistics

## 🧪 Testing

```bash
# Run tests
npm test

# Run linting
npm run lint

# Fix linting issues
npm run lint:fix

• Memory Usage: ~50MB baseline + blocklist size
• Response Time: <10ms for blocklist checks
• Throughput: 1000+ requests/second
• Blocklist Size: 50,000+ domains from EasyList

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests if applicable
5. Run linting and tests
6. Submit a pull request

• Documentation: Check this README
• Issues: GitHub Issues
• Performance: Check /health and /api/stats endpoints