Simon Willison’s Weblog

monolith (via) Neat CLI tool built in Rust that can create a single packaged HTML file of a web page plus all of its dependencies.

cargo install monolith # or brew install
monolith https://simonwillison.net/ > simonwillison.html

That command produced this 1.5MB single file result. All of the linked images, CSS and JavaScript assets have had their contents inlined into base64 URIs in their src= and href= attributes.

I was intrigued as to how it works, so I dumped the whole repository into Gemini 2.0 Pro and asked for an architectural summary:

cd /tmp
git clone https://github.com/Y2Z/monolith
cd monolith
files-to-prompt . -c | llm -m gemini-2.0-pro-exp-02-05 \
  -s 'architectural overview as markdown'

Here's what I got. Short version: it uses the reqwest, html5ever, markup5ever_rcdom and cssparser crates to fetch and parse HTML and CSS and extract, combine and rewrite the assets. It doesn't currently attempt to run any JavaScript.