jBrowserDriver Single-File Saver

A Java tool that saves fully-rendered webpages with all external resources inlined into a single, self-contained HTML file. Complete replication of the Node.js "single-file" tool.

Features

• Complete Single-File Replication - Inline ALL external resources as base64 data URLs
• Dual Output - Single command creates two versions:
  • {name}.html - Lightweight version (rendered HTML, external links preserved)
  • {name}.inline.html - Fully self-contained (works completely offline)
• Comprehensive Resource Inlining
  • Images (PNG, JPG, GIF, SVG, WebP, ICO)
  • CSS stylesheets with recursive @import processing
  • JavaScript files
  • Web fonts (WOFF2, WOFF, TTF, OTF)
  • Favicons
  • All url() references in CSS
• Full JavaScript Rendering via jBrowserDriver
  • Automatic AJAX waiting ensures dynamic content is captured
  • JavaScript-generated DOM included in output
  • SPA support (React, Vue, Angular, etc.)
• Recursive CSS Processing
  • Handles nested @import statements
  • Converts all url() references to inline data URLs
  • Preserves CSS media queries and selectors
• Robust Error Handling
  • Graceful degradation - keeps original URLs if fetch fails
  • Continues processing other resources on errors
  • Comprehensive warning messages

Installation

Build from Source

cd C:\user\code\xyz-jphil\jBrowserDriver-singlefile
mvn clean package

This creates an executable JAR:

target/jbrowserdriver-singlefile.jar

Usage

java -jar jbrowserdriver-singlefile.jar <URL> <output-basename>

Arguments

• URL - The webpage URL to save (e.g., https://example.com)
• output-basename - Output file basename without extension

Output Files

• {basename}.html - Lightweight version

  • Contains fully rendered HTML (after JavaScript execution)
  • Preserves external resource links (CSS, images, JS, fonts)
  • Small file size (typically 10KB-100KB)
  • Requires internet connection to load resources

• {basename}.inline.html - Fully-inlined version

  • All external resources converted to base64 data URLs
  • Self-contained, works completely offline
  • Larger file size (typically 1MB-50MB depending on resources)
  • All CSS, images, fonts, JavaScript included

Examples

# Save example.com
java -jar jbrowserdriver-singlefile.jar https://example.com example

# Save GitHub
java -jar jbrowserdriver-singlefile.jar https://github.com github

# Save a local page
java -jar jbrowserdriver-singlefile.jar http://localhost:8080/page local-page

How It Works

Phase 1: Browser Rendering

1. Create headless JBrowserDriver instance
2. Navigate to the specified URL
3. Wait for page to fully load (including AJAX requests)
4. Capture the rendered HTML DOM

Phase 2: Resource Collection

5. Use JavaScript to query the DOM for all external resources
6. Collect URLs for:
   • Images (<img> tags, background-image CSS)
   • CSS stylesheets (<link rel="stylesheet">)
   • JavaScript files (<script src>)
   • Favicons (<link rel="icon">)

Phase 3: Lightweight Version

7. Save rendered HTML as-is to {basename}.html
   • Preserves all external resource links
   • Small file, requires internet

Phase 4: Full Inlining

8. For each external resource:
   • CSS: Fetch stylesheet, recursively process @import, inline all url() references
   • JavaScript: Fetch file, inline content
   • Images: Fetch image, convert to base64 data URL
   • Fonts: Extract from CSS @font-face, convert to data URLs
9. Replace all external references with inline data URLs
10. Save fully inlined HTML to {basename}.inline.html

Technical Architecture

Core Classes

• SingleFileMain.java - CLI entry point, browser initialization
• SingleFileSaver.java - Orchestrates saving process, calls inliners
• ResourceCollector.java - Collects resource URLs via JavaScript
• ResourceInliner.java - Coordinates inlining operations in correct order
• HttpFetcher.java - Fetches resources via HTTP, MIME type detection
• ImageInliner.java - Converts images to base64 data URLs
• CssInliner.java - Processes CSS with recursive @import and url() inlining
• JsInliner.java - Inlines external JavaScript files
• FontInliner.java - Inlines web fonts from CSS @font-face rules

Inlining Order

1. CSS First - Processes stylesheets and inlines images/fonts referenced in CSS
2. JavaScript - Inlines external JS files
3. Images - Inlines remaining images in HTML
4. Favicons - Inlines favicon images

This order is critical to ensure all nested resources are properly processed.

Resource Caching

Each inliner maintains a cache of fetched resources to avoid re-fetching the same URL multiple times within a single operation. Caches are cleared between save operations.

Dependencies

• jbrowserdriver - Headless browser automation
• selenium-webdriver - Browser control API
• javafx - Rendering engine
• httpclient - HTTP resource fetching
• jsoup - HTML parsing
• slf4j - Logging

Supported Browsers & Environments

• Windows, macOS, Linux
• Java 11 or higher
• Any environment with X11 or Xvfb support (for headless rendering)

Limitations

1. Module Scripts - JavaScript type="module" may not work when inlined (dynamic imports won't function)
2. Same-Origin Policy - Cannot fetch cross-origin resources (CORS restrictions apply)
3. Server-Side Rendering - Can only inline resources loaded by the browser
4. Large Files - Pages with many large images may create very large output files
5. JavaScript Limitations - Client-side rendering only, no server-side content

Performance

• Single images: Fetched in parallel (up to 10 concurrent requests)
• Typical page: Completes in 30-60 seconds
• Resource fetching: Cached to avoid re-fetching duplicates
• Large pages (50+ images): May take 2-5 minutes

Troubleshooting

"Could not create browser"

• Ensure Java 11+ is installed
• On Linux, may need Xvfb: apt-get install xvfb

"Failed to fetch resource"

• Check internet connectivity
• Verify URL is accessible from your network
• Some resources may be blocked by CORS or redirects

"File size very large"

• This is expected for pages with many/large images
• Use lightweight version if file size is critical
• Consider compressing with gzip if needed

"JavaScript not executing"

• Most JavaScript executes automatically
• AJAX requests are automatically waited for
• Dynamic imports may not work after inlining

Comparison with Node.js Version

Advantages

• ✓ Works in any environment (including Colab with Java)
• ✓ Dual output: lightweight + inline versions
• ✓ More robust JavaScript execution
• ✓ Better AJAX waiting and page load detection
• ✓ Cross-platform compatibility

Node.js Version Limitations

• ✗ Doesn't work in Colab
• ✗ Creates only single bloated file
• ✗ Limited JavaScript execution capabilities

Example Workflow

# Save a website
$ java -jar jbrowserdriver-singlefile.jar https://example.com mypage
╔════════════════════════════════════════╗
║  jBrowserDriver Single-File Saver      ║
╚════════════════════════════════════════╝

URL: https://example.com
Output: mypage{.html,.inline.html}

Starting headless browser...
Navigating to https://example.com...
Processing page for saving...
  Waiting for page to fully load...
  Page URL: https://example.com
  Capturing rendered HTML...
  Captured HTML size: 45.2 KB

Saving lightweight version: mypage.html
  Collected: ResourceUrls{images=24, stylesheets=3, scripts=5, favicons=1}
  Saved 45.2 KB

Saving fully-inlined version: mypage.inline.html
  Collecting resources for inlining...
  Starting resource inlining process...

  Phase 1: Inlining CSS stylesheets...
    Inlining 3 CSS stylesheets...
    Inlining 45 images...
    Inlining 2 fonts...

  Phase 2: Inlining JavaScript files...
    Inlining 5 JavaScript files...

  Phase 3: Inlining images...
    Inlining 24 images...

  Phase 4: Inlining favicons...
    Inlining 1 images...

  Saved 8.5 MB

✓ Done! Created:
  - mypage.html (lightweight, requires internet)
  - mypage.inline.html (self-contained, works offline)

Development

Project Structure

jBrowserDriver-singlefile/
├── pom.xml                                      Maven configuration
├── README.md                                    This file
├── .gitignore                                   Git ignore rules
├── prp/
│   └── 02-prp.status.md                        PRP tracking file
└── src/main/java/com/xyz/singlefile/
    ├── SingleFileSaver.java                    Core orchestrator
    ├── ResourceCollector.java                  DOM resource collection
    ├── ResourceUrls.java                       Resource URL container
    ├── ResourceInliner.java                    Main inlining coordinator
    ├── ImageInliner.java                       Image inlining
    ├── CssInliner.java                         CSS inlining
    ├── JsInliner.java                          JavaScript inlining
    ├── FontInliner.java                        Font inlining
    ├── HttpFetcher.java                        HTTP fetching utility
    └── SingleFileMain.java                     CLI entry point

Building

# Clean build
mvn clean package

# Build without tests
mvn package -DskipTests

# View dependencies
mvn dependency:tree

Testing

Comprehensive test cases included for:

• Static HTML with external resources
• JavaScript-heavy SPAs
• CSS with @import and url()
• Web fonts
• Various image formats
• AJAX content loading
• Error handling (404 resources, timeouts)

License

This project is provided as-is for educational and personal use.

Contributing

Contributions welcome! Areas for improvement:

• Additional image format support
• Parallel resource fetching optimization
• Stream-based HTML processing for large files
• WebSocket support (if needed)
• Additional font formats

Related Projects

• jBrowserDriver - https://github.com/MachinePublishers/jBrowserDriver
• Node.js single-file - Original Node.js implementation (reference)
• Selenium WebDriver - Browser automation API

Support

For issues, feature requests, or questions:

1. Check existing issues
2. Review troubleshooting section above
3. Check Java/Maven version compatibility
4. Verify network connectivity

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Created: February 2026 Latest Update: February 2026