PDF.js not rendering PDFs in wpe-webkit-mir-kiosk (works in Firefox)

[j-engels]

Hi everyone,

I'm developing a web application that is intended to run in kiosk mode using the snaps ubuntu-frame and wpe-webkit-mir-kiosk. The app includes a PDF viewer implemented with PDF.js.

Everything works as expected in standard browsers like Firefox — the PDF is rendered correctly. However, when running the same application in wpe-webkit-mir-kiosk, the PDF usually fails to render. Occasionally it does render, but most of the time it doesn't.

I also tested the official PDF.js demo (https://mozilla.github.io/pdf.js/web/viewer.html) directly in wpe-webkit-mir-kiosk, and the issue persists there as well.

While debugging, I encountered the following error in the console:

SyntaxError: Unexpected token '{' (pdf.mjs: 12306)

This issue seems specific to wpe-webkit-mir-kiosk, as everything works fine in Firefox.

Has anyone experienced a similar issue or found a workaround?
Any help or suggestions would be greatly appreciated. If more information is needed, I’m happy to provide it.

Thanks in advance!

[calixteman]

Epiphany which is webkit-based is using pdf.js:
https://bugs.webkit.org/show_bug.cgi?id=237513
The screenshot is showing a syntax error which is maybe due to the fact pdf.mjs is a module... I don't know. It's very strange that it works intermittently.

[j-engels]

Thank you for your answer! Does this mean it should be possible to get it working properly with the wpe-webkit-mir-kiosk snap? Do you have any further suggestions on what I could try to fix it?