Preview of Office document is again not possible

[SKB-CGN]

Hi,
after upgrading to Nextcloud 22.2.3 - there is again the problem, that no office preview is created.

Following errors are appearing:

Error	core	ImagickException: unable to open image '/tmp//Address.png': No such file or directory @ error/blob.c/OpenBlob/3533

Error	PHP	Error: unlink(/tmp//Address.png): No such file or directory at /usr/local/www/nextcloud/lib/private/Preview/Office.php#66

Seems, that the instance-id or the folder is not returned properly.

[mejo-]

Nextcloud 23 contains PR #26531, which fixes preview generation for office files. The relevant change is this oneliner.

To those who suffer from this bug on Nextcloud 22, could you try patching lib/private/Preview/Office.php the following way and report back whether it fixes the issue for you:

index fef218823e..50c016737e 100644
--- a/lib/private/Preview/Office.php
+++ b/lib/private/Preview/Office.php
@@ -74,7 +74,7 @@ abstract class Office extends ProviderV2 {
                }
 
                $image = new \OC_Image();
-               $image->loadFromData($png);
+               $image->loadFromData((string) $png);
 
                $this->cleanTmpFiles();
                unlink($pngPreview);

[mejo-]

This is already fixed in Nextcloud 23 by #26531 and now also in Nextcloud 22 by #30971 (will be shipped with the upcoming point releases).