🔍 Wayback PDF Diff

Transforming historical PDF archives into meaningful visual insights.

Wayback PDF Diff is a sophisticated prototype designed to extend the Internet Archive's Wayback Machine capabilities. While the Wayback Machine excel at diffing HTML pages, historical PDF comparisons often remain a manual, tedious task. This tool automates that process, providing a side-by-side, highlighted diff of any two PDF versions.

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🌟 Key Features

• 🌐 Wayback Archive Integration: Directly search and pull historical PDF versions using the Wayback Machine CDX API.
• 📄 Precision Extraction: Uses PyMuPDF (fitz) for robust text extraction while preserving document structure.
• 🔍 Granular Comparison: Combines sentence-level and word-level diffing to catch even the smallest changes.
• 📊 Statistical Dashboard: Real-time breakdown of internal changes (Additions, Deletions, and Modifications).
• 🌗 Responsive Web UI: A modern, clean interface for both archive research and local file comparison.

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🛠️ Technical Architecture

This project is built with a focus on modularity and performance:

• Backend: Python / Flask
• PDF Engine: PyMuPDF - Chosen for its speed and accuracy in extracting encoded text.
• Diff Engine: difflib + Custom Regex logic for sentence sanitization.
• API integration: Wayback Machine CDX API for metadata search and playback for content retrieval.

Tip

The tool handles text normalization (whitespace cleaning, line-break reconstruction) to ensure that formatting changes don't clutter the actual content diff.

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📸 Demo & Screenshots

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🚀 Getting Started

Prerequisites

• Python 3.8 or higher
• pip

Installation

1. Clone the repository

   git clone https://github.com/Princeg0210/Wayback-pdf-diff.git
   cd wayback-pdf-diff

2. Install dependencies

   pip install -r requirements.txt

3. Run the application

   python app.py

4. Access the tool Open your browser and navigate to http://127.0.0.1:5001.

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📖 Usage Guide

1. Archive Mode: Enter a URL and browse through historical versions fetched directly from the Internet Archive.
2. Local Mode: Upload two PDF files from your machine.
3. Analyze: Click "Compare" to generate the diff.
4. Insights: Interpret the colors:
   • 🟢 Green : Added Content
   • 🔴 Red : Removed Content
   • 🟡 Yellow : Modified/Changed

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🗺️ Roadmap

• OCR Support: Integrate Tesseract for scanned/image-based PDFs.
• Visual Diff: Image-based (pixel-to-pixel) comparison for layout-heavy documents.
• Batch Processing: Compare multiple versions at once.
• Export Options: Save diff reports as PDF or JSON.

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🤝 Contributing

Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are greatly appreciated.

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

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📄 License

Distributed under the MIT License. See LICENSE for more information.

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✉️ Contact

Prince Gupta - @Princeg0210 Project Link: https://github.com/Princeg0210/Wayback-pdf-diff

_{Built with ❤️ for the Internet Archive Community}