PDF Thumbnail Generation Broken

[WebbleVince]

Hi there,

Lately, there seems to be a swath of people (outside of Cloudron, at least) reporting their PDFs no longer get thumbnails generated. I recently had to force regenerate all thumbnails on one of my WP sites on Cloudron, and faced the same issue: PDFs no longer get thumbnails.

While investigating, it seems that ImageMagick could be the culprit here. I think WordPress uses ImageMagick to do the conversion. Using wp media regenerate outputs lines like:

Warning: attempt to perform an operation not allowed by the security policy `PDF' @ error/constitute.c/IsCoderAuthorized/408 (ID 5110)
Warning: No metadata. (ID 5110)
3/558 Couldn't regenerate thumbnails for "<redacted>" (ID 5110).

I traced it to the /etc/ImageMagick-6/policy.xml file that must've changed recently in the base image used by Cloudron. Could you perhaps look into it? I'm using PDF thumbnails heavily on one of my hosted sites and it used to work just fine

Thanks in advance!

All the best,
Vince.

[nebulon]

@webblevince well spotted! I have pushed a new app package which hopefully fixes the issue. I think there are several other apps also being affected by this.

Please check for updates on your instance and apply the update and let us know if this has fixed it for you, then we can go through the other apps to see which one also needs this.

[necrevistonnezr]

@nebulon will this fix heic/heif previews via imagemagick as well?

[nebulon]

@necrevistonnezr not really, this will just not forbid to create PDF thumbnails.

[coniunctio]

Must we install ImageMagick/Imagick on our server hosting Cloudron in order to have PDF previews function correctly or are ImageMagick/Imagick installed as part of the initial Cloudron installation script during the original setup? I am using Ubuntu 20.04 and Cloudron installed on a VM located on my home NAS.

With gratitude,
James

[girish]

@coniunctio That shouldn't be required. imagemagick is already installed in the WP app container. Are you seeing any failure? If so, can you tell me how to reproduce this?