Using abandoned QR code generator

[MakisH]

We are currently prepending a QR code on every printed page, but the service no longer exists:

precice.github.io/_includes/head.html

Lines 93 to 102 in da79df0

	<!-- QR code to retrieve printed page -->
	<style>
	@media print {
	div.post-header:before {
	content: url('https://chart.googleapis.com/chart?cht=qr&chs=100x100&chl=https://precice.org{{page.url}}&choe=UTF-8');
	margin-top: -25px;
	float: right;
	}
	}
	</style>

This is also being reported in a dead URL checker, polluting the actual results.

Discussion and some alternatives: https://stackoverflow.com/q/77757225/2254346

[swayamagrawal]

I checked the codebase and it seems the chart.googleapis.com reference has already been removed from head.html. Could you confirm if this issue is still valid or can be closed?

[MakisH]

I removed that in #655 but kept this issue open since the feature is, in any case, nice to have.

Note that we are planning a migration to Hugo #472, which might need a different implementation.

[swayamagrawal]

Thank you for the context! I am currently applying for GSoC 2026 for the Website Modernization project. I will keep the Hugo migration in mind and implement the QR code feature in a Hugo compatible way.

[Wdhanashri]

Hi! I've submitted a PR #730 to re-implement the QR code feature using the qrcode-generator JS library (client-side, no external API dependency). It generates the QR code on page load and only displays it in print via @media print CSS. Happy to adjust the approach based on feedback.

[Aayushman-nvm]

I saw the PR and @MakisH I had a small suggestion...
Have you considered using the vendoring approach instead of loading the QR library from a CDN?
The current approach (which is already good) works like this:

user visits page -> browser requests CDN -> CDN serves file -> QR works

However, if the CDN goes down, the URL changes, the package gets deprecated, or the file is removed, the QR functionality would stop working.
A slightly more robust setup could be:

user visits page -> browser requests js/qrcode.min.js from our server -> QR works

In this case, js/qrcode.min.js (or whichever library we choose) would be stored locally in the repository. That way, the QR functionality would only break if the preCICE website itself is down,

I initially considered opening a PR for this, but since the issue is already closed, I’m sharing the idea here instead.
Just a minor improvement idea, the current implementation is totally fine as well

[MakisH]

Thanks for the idea, but I think there is no need to invest any more effort on this at the moment:

Note that we are planning a migration to Hugo #472, which might need a different implementation.