Calibre ebook viewer problem

[phenomshel]

Sorry if this is a duplicate. I did search, (check my profile, I know how the system works) and found a few things that might be related, but nothing exact. It's possible I may have missed it though and if so, my apologies. The suggestion I found for what looked like related issues was that something was locking or blocking the cache files. There is no virus software or filesync apps on the machine that could cause that. See Chris's remarks below.

I'm running a Mac Mini, with Catalina. I can't get any of my ebooks to open in the viewer. A screenshot of the error is below. It appears that the problem is permissions, but even Chris the genius IT husband couldn't figure out why it's happening. I did update to the latest version of calibre, no luck. This has been happening for several versions/updates, it just now got to be a big enough nuisance for me to try to diagnose the problem.

"The metadata.opf goes into Library/Caches/calibre/ev2/t/tmp****** with permissions of 700. Nothing else is accessing it, lsof comes up empty on metadata.opf and everything above it. ps -ef comes up with nothing as well. If it is supposed to have something other than 700 permissions (and that shouldn't matter anyway unless Calibre is running as something other than $USER) why are cache files being created that Calibre itself should be able to access but can't?"

[kovidgoyal]

try setting some other directory as your calibre cache directory via an environment variable as described here: https://manual.calibre-ebook.com/cus...ment-variables

[phenomshel]

Thanks Kovid, I'll give that a try!

[nzzn]

For what its worth, I tried this but no luck. Permissions on the generated .opf file in the cache I specified seem OK but the viewer will still fail in the manner shown above. However, if I click on the cached opf outside of Calibre the viewer opens up and works correctly. Using Catalina 10.15.7 and as the original poster intimated the viewer hasn't worked on Catalina for quite a few versions.

[kovidgoyal]

You tried what?

[nzzn]

Originally Posted by kovidgoyal

You tried what?

I set the cache directory using the appropriate environment variable. That works and I can see subdirectories and files appearing there instead of the in the Catalina default $HOME/Library/Caches/calibre spot.

So when calibre launches the book viewer it generates entries in the cache but then claims that it cannot locate the opf file so it stops.

However, the opf file is there and has reasonable permissions. In fact, when you click on the file outside of calibre the calibre viewer opens up correctly without complaint.

Is it trying to open the file just prior to creating it on the Mac for some reason (buffer flush missing perhaps?)

[kovidgoyal]

No, calibre is written in python and files are written to using context managers, so there is no way a "buffer flush" would be missing. Although a buffer flush missing would not explain a missing directory entry anyway. Look at the path in the error message, compare it to the actual path of the OPF. Are they actually identical, pay special attention to case differences.

[nzzn]

Yes the path is absolutely the same (I can copy the full name from the calibre error detail and then do an 'ls' on that string to see the file exists at that location, has a non-zero size, and has read permissions for everybody).

[kovidgoyal]

Since macOS stupidly uses case insensitive filesystems by default, doing ls proves nothing, that's why I asked you to check the case specifically.

[nzzn]

checked again — they are the exact same letter for letter!

[kovidgoyal]

Then I'm afraid I'm out of ideas, sorry.