unmhtml

Convert MHTML files to standalone HTML with embedded CSS and resources.

Installation

pip install unmhtml

Usage

from unmhtml import MHTMLConverter

# Convert MHTML file to HTML (secure by default)
converter = MHTMLConverter()
html_content = converter.convert_file('saved_page.mhtml')

# Save as standalone HTML
with open('output.html', 'w') as f:
    f.write(html_content)

# Unsafe conversion preserving original content
unsafe_converter = MHTMLConverter(
    remove_javascript=False,
    sanitize_css=False,
    remove_forms=False,
    remove_meta_redirects=False
)
html_content = unsafe_converter.convert_file('trusted_page.mhtml')

Features

• Pure Python - No external dependencies, uses only standard library
• Standalone HTML - Embeds CSS and converts resources to data URIs
• Secure by Default - All security sanitization enabled by default for safe processing
• Graceful degradation - Handles malformed MHTML files
• Memory efficient - Processes large files without excessive memory usage

Security

The library is secure by default - all security features are enabled automatically to safely display untrusted content:

Available Security Options (All Enabled by Default)

• remove_javascript=True - Removes <script> tags, event handlers (onclick, onload, etc.), and converts javascript: URLs to safe # anchors
• sanitize_css=True - Removes external CSS URLs (http://, https://, //, /absolute) while preserving relative URLs (image.png, ../fonts/font.woff) and data URIs
• remove_forms=True - Removes form elements (<form>, <input>, <textarea>, <select>) that could submit data externally
• remove_meta_redirects=True - Removes dangerous meta tags (refresh redirects, set-cookie, dns-prefetch) that could be used maliciously

Requirements

• Python 3.8+

License

MIT