There are a ton of options depending on your tech level.
How are you with basic Python scripts?
I made the script to rip them in bash. I know python, lua, js, bash and powershell, anything using these works.
Surely you can figure out how to use existing libraries for this task, or is there something you’re stuck on?
In a production web app I use Gotenberg. It’s definitely overkill for the task at hand, but if you find yourself doing this often I would highly recommend it. It’s dead easy to convert HTML (and I imagine XHTML) to PDF.
I've used pdfkit to considerable success. It has a few system-level dependencies, but the instructions are pretty straightforward:
Pretty sure calibre makes this easy if you don't wanna reinvent the wheel
came here to say calibre! it works and the converting is super simple. takes a little while for pdf files since its a big file but it works
Oh, I already have that installed. I'll try it.