A tiny script written in Python 3 for changing cdetype value to "PDOC" in selected e-book formats.
There's a software bug in e-book readers made by most popular company in this area, which results in removing e-books in a very specific situation.
If you put your device into airplane mode for a long time and connect to the Internet afterwards, some e-books are automatically removed from your e-reader. It was discovered that this behaviour depends on cdetype metadata in a file, which is present in certain e-book formats. If a file has EBOK value in cdetype field, then it is deleted from a device in described scenario. Files with PDOC value and without such field at all seem to be safe from removing.
Issue has been known at least since October 2023, but producer of e-book readers hasn't fixed it until now. That's the reason I decided to make this small script for batch changing cdetype value to PDOC.
It updates cdetype metadata to PDOC in each e-book, if this field doesn't have such value yet. Script leaves files without cdetype metadata present untouched as this change seems to be unnecessary for them.
ebook_cdetype_to_pdoc requires Python 3 to run it, that's the basic prerequisite. I'll refer to Python 3 later simply as Python, so keep this in mind.
ebook_cdetype_to_pdoc.py was tested on Python 3.13.1, but it should be fine with any future versions for a while. The same rule applies to mobi_header package and its requirements, so I recommend using all packages in the same versions as in requirements file.
After having Python installed (if you don't have it yet, you can find it there), you need to install extra packages (mobi_header and other packages it requires) from pip. Download requirements.txt file from this repository and install packages listed in this file by typing in cmd/PowerShell/Terminal:
py -m pip install -r requirements.txt
Then you just need to get ebook_cdetype_to_pdoc.py file from this repository.
On most Linux distributions Python is already installed, but it requires a few more steps as pip is not installed along with Python. I will use Ubuntu 22.04.2 as an example there.
Ubuntu has Python installed by default, so start with installing pip, a package installer for Python, by typing in Terminal (with sudo command):
apt-get install -y python3-pip
Then get additional packages from pip, that is mobi_header and other packages needed by it, required for ebook_cdetype_to_pdoc.py to work. In order to do that download requirements.txt file from this repository first, then run the following in Terminal:
python3 -m pip install -r requirements.txt
Then all that is left is to download ebook_cdetype_to_pdoc.py from this repository.
Just place the ebook_cdetype_to_pdoc.py file in the folder with your e-books and run it, that's all.
To see the progress and results of running script, it is advised to start the script from a command line.
For now ebook_cdetype_to_pdoc supports e-book files only with *.mobi and *.azw3 extensions.
This application is based on open source software, including:
Many thanks to authors of all packages and libraries installed along with software mentioned above.
ebook_cdetype_to_pdoc is licensed under the terms of the MIT License.