There's a variant of this feature that would be neat to have: Optionally (on command) updating the actual ebook files in the calibre database with the latest metadata available for those files.
Some thoughts along the way:
- Only update book files where the database metadata is newer than the book file.
- Update all available formats of the book with the latest metadata. This should include the OPF file and the separate cover (if any).
- For each book format, update only the meta-data that is supported in that format. (It's obvious, but...)
- Since this would be done only on user command, it doesn't matter if it's a bit on the slow side.
I believe that this would be the moral equivalent of doing a save-to-disk into a temporary directory (with appropriate switches set in Calibre), and then replacing the files in the calibre database directory tree with the newly saved files. Come to think of it, that's probably the simple way to implement it. Right?