Kobo File and DB Manager

Purpose

To be able to remove damaged, large or old books from my Kobo ereader device programmatically. As my Kobo (Kobo Wifi) only has a D-pad and poor software interface, I wanted more efficiency and accuracy. (Similarly, the Desktop app doesn't seem to communicate with it well about deleting things either.)

Basic Start

I did a fair amount of reading on mobileread.com about my model of Kobo (Kobo Wifi, Model N647, circa 2010) and on Kobo systems in general. I found a very helpful dive at kobodb-schema.sourceforge.net where someone had dissected their kobo device db and determined the schema and relations. I took that a step further and used a tool called sqlacodegen to generate a sqlalchemy mapping of my personal device db. Now I can start using object oriented mappings to manuplate and update the data in my db.

(For those of you wondering why I didn't just SQL this jazz, my SQL foo is poor and rusty. My Python foo is much better. And its easier to share a project if its got code associated with it :D )

Tidbits of Discovery

The database has funny connections to other tables. Many not sharing names...

• content.ContentID --> content_keys.volumeId
• Shelf.InternalName --> ShelfContent.ShelfName
• user.UserID --> content.___UserID

There is also a quirk in that, chapter markers are stored in the content table, in addition to the books. So, a book is denoted by having a NULL BookTitle and NULL BookID. While a chapter in that book uses the Title and ContentID of its parent in the BookTitle and BookID.

• book.ContentID = chapter.BookID; chapter.ContentID = book.adobe_location; chapter.adobe_location maps to a location within the file location as best I can tell
• book.Title = chapter.BookTitle; chapter.Title then becomes the chapter title
• book.ContentType = 6; chapter.ContentType = 9

Unknowns....

• what is content.ContentType = 899 ???

Mappings

• content.ContentID (for the book type) maps to .kobo/kepub; also content.adobe_location shows a mounted path to the same file
• content.ImageID maps to .kobo/images
• content.___FileSize is the size in bytes
• content.___UserID = 'removed' is related to previews or collections not stored on the device...?