🔗 Action Link Checker

A GitHub Action that automatically checks for broken links in your files.

✨ Features

• 🔍 Smart URL Detection: Automatically extracts URLs from markdown links [text](url) and bare URLs
• ⚡ Concurrent Checking: Configurable number of concurrent workers for fast link validation
• ⏱️ Timeout Control: Configurable timeout for each link check
• 🔄 Fallback Strategy: Uses HEAD request first, falls back to GET if needed
• 📊 Clear Reporting: Displays working and broken links with clear visual indicators
• ❌ CI/CD Integration: Fails the workflow when broken links are found

🚀 Usage

Basic Usage

name: Check Links
on: [push, pull_request]

jobs:
  link-check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Check links in README
        uses: yankeexe/action-link-checker@v1
        with:
          file_path: 'README.md'

Advanced Configuration

name: Check Links
on: [push, pull_request]

jobs:
  link-check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Check links with custom settings
        uses: yankeexe/action-link-checker@v1
        with:
          file_path: 'docs/README.md'
          concurrent_workers: '50'
          timeout_seconds: '10'

Multiple Files

name: Check Links
on: [push, pull_request]

jobs:
  link-check:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        file: ['README.md', 'docs/CONTRIBUTING.md', 'docs/API.md']
    steps:
      - uses: actions/checkout@v4
      - name: Check links in ${{ matrix.file }}
        uses: yankeexe/action-link-checker@v1
        with:
          file_path: ${{ matrix.file }}

📋 Inputs

Input	Description	Required	Default
file_path	Path to the file to parse for links	✅ Yes	-
concurrent_workers	Number of concurrent workers for checking links	❌ No	30
timeout_seconds	Timeout in seconds for each link check	❌ No	5

📤 Outputs

This action doesn't produce outputs but will:

• ✅ Pass: When all links are working
• ❌ Fail: When broken links are found (exits with code 1)

📝 Example Output

✅ Working URLs:
- https://github.com/yankeexe/action-link-checker
- https://docs.github.com/en/actions
- https://golang.org/

❌ Invalid URLs:
- https://broken-link-example.com/404
- https://another-broken-link.invalid/

🔗 Supported Link Formats

The action detects and validates:

Markdown Links

[GitHub](https://github.com)
[Documentation](https://docs.example.com)

Bare URLs

Visit https://example.com for more info
Check out https://github.com/user/repo

⚡ Performance Tips

Optimize for Large Files

- name: Check links with higher concurrency
  uses: yankeexe/action-link-checker@v1
  with:
    file_path: 'large-document.md'
    concurrent_workers: '50'
    timeout_seconds: '15'

Handle Slow Links

- name: Check links with extended timeout
  uses: yankeexe/action-link-checker@v1
  with:
    file_path: 'README.md'
    timeout_seconds: '30'

💡 Common Use Cases

Documentation Sites

Perfect for checking links in documentation files, README files, and markdown-based websites.

Blog Posts

Validate external links in blog posts and articles before publishing.

API Documentation

Ensure all API endpoint links and external references are working.

🔧 Troubleshooting

Action Fails with "Error reading file"

• Ensure the file_path is correct and the file exists
• Check that your workflow has checked out the repository (actions/checkout)

Timeout Issues

• Increase timeout_seconds for slow-responding servers
• Some servers may block automated requests; this is expected behavior

Rate Limiting

• Reduce concurrent_workers if you encounter rate limiting
• Some APIs may have strict rate limits for automated tools

🛠️ How It Works

1. The action reads the specified file and extracts URLs using regex pattern matching
2. It identifies both markdown-style links [text](url) and bare URLs
3. For each unique URL, it first attempts a HEAD request (faster, less bandwidth)
4. If the HEAD request fails, it falls back to a GET request
5. Results are collected and reported, with the action failing if any broken links are found

📈 Limitations

• The action currently only checks a single file at a time (use matrix strategy for multiple files)
• Some websites block automated requests, which may result in false negatives

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

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

For major changes, please open an issue first to discuss what you would like to change.

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

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