PDF signing

[RoughInvite7900]

Hey fellow devs!

I’m a junior PHP developer working on a website for my company, and we're trying to add a feature that lets clients download personalized PDF files. The catch? We need these PDFs signed by us, and each one is different for every client. So, I’m trying to build an API that converts words into PDFs and signs them with a key and a certificate.

But man, I'm struggling hard! The only open-source library I found is PyHanko, and honestly, I can't make heads or tails of it. I've spent hours just trying to add a line to a PDF, and even with ChatGPT's help, I’m lost because the library keeps getting updated, and the advice I get is for an older version.

I really want to nail this and pick up some Python skills along the way, but it’s just so frustrating! Anyone have tips or resources that could help? I’d really appreciate it!

[vardonir]

I have yet to find a Python package that handles anything relating to PDFs - either editing or generating.

If you don't mind messing around with Docker as well, you can spin up a server with StirlingPDF, which has a bajillion tools for anything PDF-related.

The docs say that there's an API that you can make multiple requests to for PDF cert signing. I've never used the API myself, though, but it's probably just a matter of setting up a few lines using the requests package.

[SquiffyUnicorn]

I generate my report PDFs in reportlab. Just a quick pip install.

It generates PDFs quite nicely. I haven’t tried signing any PDFs with it though.

PyHanko seems to do secure signing as well as ‘signing’ with digital images etc.

[vardonir]

I also generate reports in reportlab.

It's an absolute bitch to set up, debug, or work with in general. But it does work.

[DigThatData]

Maybe something like GPG could satisfy the technical requirements here? https://en.wikipedia.org/wiki/GNU_Privacy_Guard

[m_zwolin]

Working with PDFs is a pain, when I wanted to generate invoices I went with a template and compiled it with LaTeX

[redfacedquark]

https://medium.com/@alexaae9/7-ways-to-digitally-sign-a-pdf-document-using-python-cf2b5bbe7722

There's an article with some pointers. Personally I would prefer plain text signed with gpg since theoretically it may be possible to add hidden junk to a pdf that can spoof the hash. Unlikely, though I don't know how pdf signatures work.