[GUI Plugin] Extract ISBN

[kiwidude]

There are PDFs where the text is behind an image - you can select it but as far as Calibre's PDF conversion is concerned it cannot see it as anything but an image. If you find a book where you can convert it to PDF and select the ISBN as text in Calibre's ebook viewer then it might be a case the plugin should be catching. As I said above, click on the View log button to see what numbers it found if any, it might be rejecting them as invalid ISBNs or it may not be finding the numbers at all. It would be fairly unlikely that you have found another valid ISBN combination that is being rejected by the plugin due to something I can control (such as variations of emdash) but anything is possible.

As for djvu's, I don't own any so perhaps someone else can comment, but I think I read somewhere that Calibre didn't use to convert them anyways. If Calibre cannot convert a format to epub, then this plugin will not work with it.

[pegasusses]

great plugin, thanks

[kiwidude]

Changes in this release:

• Upgrade to support the centralised keyboard shortcut management in Calibre

Requires Calibre 0.8.18.

[maartencoertjens]

Hi

Thanks a lot for this plugin, my metadata searches are a lot more effective now
I have one small polite request: would it be possible to have an option where if the extract process doesn't find isbn, that it adds 'not found' in the ISBN column. I keep forgetting which ones I have run the search on and which ones not.
In case this is already an option that I didn't find, my apologies and please be so kind as to point me in the right direction

Thanks a lot
Maarten

[kiwidude]

@Maarten - glad you found it useful. If you just do a search for isbn:false that will tell you which books do not have isbns.

[maartencoertjens]

Thanks a lot. However I am not clear what it shows: the books that don't have isbn, or the ones where isbn has not been extracted yet.
As my library changes all the time with new books, books moved to other libraries, etc I never can remember for which books I already did the extract isbn. So I think I keeping on trying to extract isbn of books that I already tried before.
If an unsuccesful search would put something like 'not found' in the ISBN column, then I could do the search only for the books for which I never did a search.

I hope I managed to explain?

Thanks a lot!
Maarten

[capnm]

Originally Posted by maartencoertjens

If an unsuccesful search would put something like 'not found' in the ISBN column, then I could do the search only for the books for which I never did a search.
Maarten

Create a custom column "ISBN extracted" and set it to 'true' on the books when you run the extraction.

If you only want to use extracted ISBNs you'll have to clear the ISBN field before you run the extraction -- it's not going to blank out an existing ISBN in the metadata if it doesn't find one in the text.

[kiwidude]

Yeah it would have to be a whole new piece of functionality. And to cater for all the scenarios above it would have to be an options dropdown, something like:

If no ISBN is found then:

• Do nothing (default),
• Set ISBN to 'NotFound' if no existing ISBN
• Set ISBN to 'NotFound' always

I leave it to others to comment whether anyone else would find it useful enough to justify the effort.

There is another option. There is already a dropdown option for this plugin which lets it display a search for books that have new or updated ISBNs after an extract completes. I could add another option to this which would allow you to display books for which no ISBNs were extracted. If you want that result to be more "permanent" (as it will get reset when you run another extract) you could select those books and assign some value to a custom column or tag using the bulk metadata screen.

That latter option would certainly be trivial to add if it would be useful.

[kovidgoyal]

@kiwidude: Do not set an isbn to something that is not valid as an ISBN. Instead use a tag or an extra identifier.

[kiwidude]

@Kovid - I did wonder if it was even technically possible (whether you had some sort of validation preventing it), but I found that I could indeed in the edit metadata dialog set it to whatever I like.

I completely agree it isn't very desirable from a data integrity point of view.

[kovidgoyal]

There is validation in place whenever it is used (for example in the metadata download plugins, but not when it is set).

[indigene]

Hello Kiwidude - Why is that I am not able to install all the plugins you have created? I am on 0.8.8 and for each of your plugin the status mentions "Calibre upgrade required".

Funny thing is I have used many of your plugins, like ISBN extract, but after the few recent Calibre upgrades these plugins have stopped working.

[kiwidude]

I am guessing you are being fooled by the fact that 0.8.8 is "really" a version number of 0.8.08, which is less than the minimum requirement of most of my UI plugins of 0.8.18. The majority of the plugins were upgraded to support customisable keyboard shortcuts via calibre's new centralised keyboard management (which is wonderful btw).

So just follow the instructions - upgrade your calibre to the latest build, and all should be good.

[jlutes]

First, thanks for the plugin - it's saved me many an hour. I do have a suggestion though. It's not unusual for me to get a new book with the ISBN in the tags section or file name. Any chance of searching those as well?

[kiwidude]

@jlutes - extracting from the filename is not at all possible - the original filename is lost the moment you add the book to calibre. However you could setup a regex to extract it from the filename as part of the adding books preferences - if it is something you want to toggle between for different filename formats I would suggest my Quick Preferences plugin.

As for the "tags" section, do you mean inside the metadata of the book? Again you "could" use the "Read metadata from file" option when adding the book to obtain this.

If like me you prefer not to have that option enabled (since the title/author are far too often garbage for my taste and I prefer getting from the filename), then I can see a case for wanting the Extract ISBN plugin to attempt to read it from metadata. I guess my hesitation is the complication of what "priority" any ISBN there should have. Bear in mind that every time a conversion is done on a book (or the Update metadata feature in the Modify ePub plugin is used) it is overwriting that book metadata with the contents of whatever is set in your library. There are cases where:
- an ISBN can be found in the book content and that is the preferred one
- the ISBN extracted from the book is for a different book (such as an advertisement for a related book for the publisher), but there is one set in metadata
- no ISBN can be found in the book content, but one is present in the metadata.

So I don't know which preference should be given if I were to include scanning the metadata