{id} as template in Generate Cover

[msel]

Hello,

i want to add the ID (the integer value) of a book to the cover. The lookup name is {id}. But when I add this value in a cover template I'll get an error:
EXCEPTION: Value: unknown field id

My template and the error message is attached.

Greetings, Maria

[BetterRed]

I had problems with using {id}… can't recall exactly where, might have been in the book jacket. I never liked the column name 'id' anyway, so I created a virtual column called book_row/Book # and when I used it the problem went away.



BR

[kovidgoyal]

Yes database fields like id are not available for covers as covers need to be generated for standalone books as well, for example, when generating a cover for an epub without one on the command line.

[kjdavies]

Originally Posted by msel

Hello,

i want to add the ID (the integer value) of a book to the cover. The lookup name is {id}. But when I add this value in a cover template I'll get an error:
EXCEPTION: Value: unknown field id

My template and the error message is attached.

Greetings, Maria

There appears to be a workaround.

Create a custom column (I called mine 'fakeid'), 'Column built from other columns', with the template '{id}'.

Then use {#fakeid} in your cover template.

I'm using calibre 6.29 in Windows 10, 'Generate Cover' plugin is current.

[BetterRed]

Originally Posted by kjdavies

There appears to be a workaround.

Create a custom column (I called mine 'fakeid'), 'Column built from other columns', with the template '{id}'.

Then use {#fakeid} in your cover template.

I'm using calibre 6.29 in Windows 10, 'Generate Cover' plugin is current.

The OP is using the built in Generate Cover tool… look at screenshots in post #1.

BR

[theducks]

FWIW I think this {id} on cover is a real bad idea.

There are things that trigger an ID change.
I used to include {id} in my file name, when all of a sudden updating a book got a different file ID than before and I had multiples of the (supposed) same book on my device.

[kjdavies]

Originally Posted by BetterRed

The OP is using the built in Generate Cover tool… look at screenshots in post #1.

BR

Indeed, I did as well (but didn't say so, oops).

[kjdavies]

Originally Posted by theducks

FWIW I think this {id} on cover is a real bad idea.

There are things that trigger an ID change.
I used to include {id} in my file name, when all of a sudden updating a book got a different file ID than before and I had multiples of the (supposed) same book on my device.

I concur. I move files between libraries fairly frequently (faster to move a thousand files to a working library for cleanup and move them back to my bigger library when done than it is to do cleanup in place) and get new IDs all the time. For similar reasons I don't link books, either.

However, we were asked 'is this a good idea?', but 'how can I do this?'.

"I didn't ask 'how big is the room?', I said 'I cast fireball'."

People who pay me ignore my advice on best practice (and I have been paid a lot fixing these situations), so I no longer judge... besides, I have enough weird questions of my own to try to talk someone else out of theirs.