Drouot Monitor - Chrome Extension

Automated auction monitoring tool for Drouot.com - Never miss a deal again!

Features

• Passive Scraping: Automatically extracts lots from Drouot pages you visit
• Advanced Filtering: Filter by category, keywords, price, date, and auction house
• NEW/SEEN State Tracking: Track which items you've viewed
• Visual Indicators: Badges and highlights on Drouot pages
• Smart Scoring: Prioritizes items based on match quality
• Local Storage: All data stays on your device
• React-powered UI: Beautiful, responsive popup interface

Setup

Prerequisites

• Node.js 16+ and npm
• Chrome/Chromium browser

Installation

1. Install dependencies:

   npm install

2. Build the extension:

   npm run build

3. Load in Chrome:

   • Open chrome://extensions/
   • Enable "Developer mode" (top right)
   • Click "Load unpacked"
   • Select the dist/ folder

Development Mode

For active development with auto-rebuild:

npm run dev

Then reload the extension in Chrome after changes.

Usage

First Time Setup

1. Click the extension icon
2. Go to Settings (⚙️)
3. Configure your filters:
   • Select categories (e.g., Mobilier, Art Contemporain)
   • Add include keywords (e.g., "louis xvi", "empire")
   • Add exclude keywords (e.g., "reproduction", "style de")
   • Set price range
   • Select auction houses (e.g., Artcurial, Drouot Estimations)
4. Save

Daily Usage

1. Browse Drouot.com naturally - The extension works passively
2. Extension scrapes lots as you visit pages
3. Badge shows NEW count - Click to view
4. Review matches in popup
5. Mark as seen or favorite items
6. Click item to open on Drouot.com

Visual Indicators

On Drouot pages, you'll see:

• 🆕 NEW badges - Unviewed matching items
• ⭐ FAVORITE badges - Items you starred
• 👀 SEEN badges - Previously viewed items
• Highlighting - Color-coded borders around matching items

Architecture

See ARCHITECTURE.md for detailed system design.

Key Components

• Content Script (content/content.js): Scrapes DOM, adds badges
• Background Worker (background.js): Processes lots, manages state
• Popup UI (popup/): React app for viewing and managing items
• Storage Service (src/services/storage.js): chrome.storage wrapper
• Filter Engine (src/services/filter.js): Matching algorithm

Data Storage

All data is stored locally using chrome.storage.local:

• Lots: Scraped auction items
• User States: NEW/SEEN/FAVORITE/IGNORED per item
• Filters: Your configured filters
• Preferences: UI settings

See STORAGE_SCHEMA.md for detailed schema.

Filtering Logic

The extension matches lots against your filters using:

1. Category matching - Must be in selected categories
2. Keyword inclusion - Must contain at least one include keyword
3. Keyword exclusion - Must not contain any exclude keywords
4. Price range - Estimate must be within min/max
5. Date range - Auction date must be within range
6. Auction house - Must be from selected auction houses

See SCRAPING_STRATEGY.md for scraping details.

Scoring System

Each matching lot receives a score (0-100) based on:

• Category match: +15
• Keyword matches: +10 per keyword
• Title matches: +5 bonus
• Price proximity: up to +15
• Recency: up to +10
• Auction urgency: up to +15
• Has image: +5
• Auction house match: +10

Higher scores appear first in the popup.

File Structure

drouot-monitor/
├── manifest.json              # Extension manifest
├── background.js              # Service worker
├── content/
│   ├── content.js             # Content script
│   └── content.css            # Page styling
├── popup/
│   ├── popup.html             # Popup HTML
│   └── popup.jsx              # React entry
├── src/
│   ├── components/            # React components
│   │   ├── App.jsx
│   │   ├── ItemCard.jsx
│   │   ├── ItemList.jsx
│   │   ├── TabNavigation.jsx
│   │   └── Settings.jsx
│   ├── services/              # Business logic
│   │   ├── storage.js
│   │   ├── scraper.js
│   │   ├── filter.js
│   │   └── messaging.js
│   ├── utils/                 # Utilities
│   │   ├── date.js
│   │   └── price.js
│   └── constants.js           # Constants
├── assets/                    # Icons
├── package.json
├── webpack.config.js
└── README.md

Development

Adding New Features

1. New filter type: Add to DEFAULT_FILTERS in constants.js, update matchesFilters() in filter.js, add UI in Settings.jsx
2. New item state: Add to ItemState enum, update storage.js indexes
3. New scraping pattern: Add selectors to SCRAPING_PATTERNS in scraper.js

Testing

Test on real Drouot pages:

• Listing pages: https://www.drouot.com/ventes
• Search results: https://www.drouot.com/recherche
• Lot details: https://www.drouot.com/l/*

Debugging

• Check console logs in:
  • Content script: Page console (F12)
  • Background: Extension service worker (chrome://extensions → Details → Inspect)
  • Popup: Right-click popup → Inspect

Troubleshooting

No lots scraped

• Check console for errors
• Verify Drouot page structure hasn't changed
• Click 🔄 button on page to manually re-scrape

Filters not working

• Ensure filters are enabled in Settings
• Check filter criteria aren't too restrictive
• Re-save filters to trigger re-evaluation

Badge not updating

• Reload extension
• Check background service worker for errors
• Verify storage isn't corrupted: chrome://extensions → Developer tools

Performance

• Scraping: <100ms per page
• Filter matching: <10ms per lot
• Storage: Unlimited (uses chrome.storage.local)
• Memory: ~20MB for 10,000 lots

Privacy

• No tracking: Zero analytics or telemetry
• Local-first: All data stays on your device
• No external requests: Only scrapes pages you visit
• Open source: Inspect all code

Legal

This extension:

• ✅ Only scrapes pages the user actively visits
• ✅ Does not make automated requests to Drouot
• ✅ Respects robots.txt (implicitly via browser)
• ✅ Is for personal use only
• ❌ Does not resell or share data

Not affiliated with Drouot.com

Roadmap

See MVP_ROADMAP.md for detailed roadmap.

MVP (Current)

• Scraping engine
• Filter matching
• State tracking (NEW/SEEN/FAVORITE)
• Popup UI
• Content script badges

Post-MVP

• Multi-device sync (Firebase/Supabase)
• Email notifications
• Price tracking & alerts
• Export to CSV
• Browser extension for other auction sites

Contributing

1. Fork the repo
2. Create feature branch (git checkout -b feature/amazing)
3. Commit changes (git commit -m 'Add amazing feature')
4. Push to branch (git push origin feature/amazing)
5. Open Pull Request

License

MIT License - See LICENSE file for details

Support

For issues or questions:

1. Check ARCHITECTURE.md for technical details
2. Check SCRAPING_STRATEGY.md for scraping info
3. Open an issue on GitHub

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Made with ❤️ for auction enthusiasts