PDF Metadata Editor & Linearizer

A web-based tool for editing PDF metadata and linearizing PDFs for faster web viewing using QPDF WebAssembly.

Features

✅ Working Features

• PDF File Upload: Browse or drag-and-drop PDF files
• PDF Viewer: View PDF pages with zoom and navigation controls
• Metadata Editing: Edit title, author, subject, keywords, creator, producer, and dates
• Custom Metadata Fields: Add custom metadata fields
• File Download: Download PDFs with updated metadata

⚠️ Linearization Status

• QPDF WASM Integration: Attempts to load QPDF WebAssembly for real PDF linearization
• Current Status: QPDF WASM packages have CDN distribution issues
• Fallback: Shows clear warnings when linearization is unavailable
• Metadata Only: App works perfectly for metadata editing without linearization

How to Use

1. Upload PDF: Click "Browse Files" or drag-and-drop a PDF file
2. Edit Metadata: Fill in the metadata fields as desired
3. Process:
   • If QPDF WASM loads: Get real linearization + metadata updates
   • If QPDF unavailable: Get metadata updates only
4. Download: Save your updated PDF

Getting QPDF Linearization Working

Option 1: Host QPDF WASM Locally

1. Download a working QPDF WASM build
2. Place it in the project directory as qpdf-wasm-local.js
3. Update the global variable to match the QPDF API

Option 2: Use Reliable CDN

1. Find a working QPDF WASM CDN source
2. Update qpdf-loader.js with the correct URL and global variable
3. Test that the WASM file loads and provides the expected API

Option 3: Server-Side Implementation

1. Install QPDF on your server: sudo apt-get install qpdf
2. Create an API endpoint that accepts PDF files
3. Use QPDF command-line: qpdf --linearize input.pdf output.pdf
4. Return the linearized PDF to the client

QPDF WASM Packages Tested

The app attempts to load from these sources:

• @neslinesli93/qpdf-wasm (GitHub: neslinesli93/qpdf-wasm)
• qpdf-wasm-esm-embedded
• Local implementation placeholder

Usage

Running Locally (Jekyll)

1. Install Dependencies: bundle install
2. Run Server: bundle exec jekyll serve
3. Open: Navigate to http://localhost:4000

Files Structure

├── _config.yml         # Jekyll configuration
├── Gemfile            # Ruby dependencies
├── _layouts
│   └── default.html   # Main layout
├── index.html         # Main application page
├── app.js             # Main application logic
├── helper.js          # Helper scripts (QPDF loader, etc)
├── style.css          # Application styles
└── README.md          # This file

Development Notes

• No Simulation: Removed all fake/simulated linearization
• Real QPDF Only: Only uses actual QPDF WASM when available
• Clear Feedback: Users know exactly what features are available
• Graceful Degradation: Works perfectly for metadata editing alone

Browser Compatibility

• Chrome/Edge: ✅ Full support
• Firefox: ✅ Full support
• Safari: ✅ Full support
• Requires: Modern browser with WebAssembly support

License

This project demonstrates PDF processing in the browser and is intended for educational/development purposes.