Show the next few events from a Google Calendar on a Kindle Paperwhite
The correct way of doing this depends on the Kindle firmware (and hardware) you are using.
All the methods depend on exploits that are fixed in newer versions of the firmware.
All the documentation is in early 2000s-style phpbb-type forums. The user community is very helpful but it's rather hard to navigate around.
I started here but later worked out that this method didn't support my precise firmware and had to look around the forums for an older method.
Once your Kindle is jailbroken, you can install new software. As the jailbreak threads like the one I linked to above describe, the general installation method is via software called MRPI; you drop binary files in a folder that you can see mounted as a filesystem when you connect your Kindle via a data USB cable to your laptop.
You need to use MRPI to install at least three things: python, KUAL, and USBNetwork. The most up-to-date packages are in this thread at the time of writing. Python is for the scripts in this repo; KUAL is a kind of simple UI toolkit that makes it easy to interact with scripts, via menus; USBNetwork provides an SSHD service on your Kindle so you can get a shell, to debug things.
Once you have a shell (hint: open USBNetwork via KUAL; toggle "allow USBNetwork"; start out by connecting over USB, but for ease of use, then configure for public key auth so you can access over wifi safely).
Now you have a shell, you can install the python libraries required for interacting with Google Calendar API:
python3 -m ensurepip --upgrade
python3 -m pip install google-api-python-client google-auth-httplib2 google-auth-oauthlib requestsI also deleted the Amazon-supplied binaries that provide for remote firmware update, as I don't want to remove access again. These are u/usr/bin/otav3 and /usr/bin/otaupd.
Next, to be sure times are correct, I installed my local timezone info in the right place; that is, I copied /usr/share/zoneinfo/Europe/London from my laptop to the Kindle. Note that I've currently hardcoded my timezone into the script. If you live elsewhere, you'll want to change that.
Finally, to install this software, copy the folder dashboard from the repository to the /extensions folder on the kindle (if that folder is not there
KUAL isn't installed properly).
Set up a local dev environment on your computer, by installing python3 and pip installing the dependencies listed above.
Create a file at bin/calendar.txt whose contents are the calendar id you wish to query. Something like family04215672838001015700@group.calendar.google.com (get it from your calendar's "Sharing" settings).
Generate OAuth credentials: create a new Project in Google Cloud Console; go to APIs and Services and enable the Calendar API; then visit the Credentials section and generate a new OAuth 2.0 Client ID of type "Desktop". Save the resulting credentials.json to dashboard/bin/credentials.json. In the OAuth Consent Screen section, publish the project. It will ask you to go through verification, but you can ignore that, as the project is only for you, and you'll just skip the OAuth warning screen at login, because you trust yourself.
Run the script at bin/cal.py, something like cd bin/; PYTHONPATH=../../ python cal.py. This should run the oauth flow to create token.json, that authorise your script's access. If it succeeds, you'll see some JSON of your upcoming events.
Now copy all three files (calendar.txt, token.json, and credentials.json to the dashboard/bin/ directory on your Kindle). Test by running the same cal.py script from the command line on your Kindle.
Test locally on your computer by running bin/start_once_laptop.sh. This should generate and display the next 8 calendar entries as an SVG.
If that works, test on your Kindle with the "Calendar (debug)" button in KUAL. This should run the script once: it fills the screen with your calendar.
When you're ready, you'll need to roun the start.sh script as a daemon. On my 2015 Kindle, services are managed by the upstart (an Ubuntu system, no longer maintained), so that's what I've provided here. You may need to use a different mechanism.
To use the upstart mechanism, copy bin/calendar.conf to /etc/upstart/ on the Kindle (you'll need to make that partition writeable with mntroot rw first; don't forget to mntroot ro when you're done). Now you should be able to start the service with start calendar; it should also start automatically on system reboot.
Now, when you press the "Calendar (start)" button in KUAL, a flag is set on the filesystem which tells the daemon to write an updated calendar to your Kindle, then set a "wake up" time for an hour, and go into a deep sleep. When it wakes up, it does the same thing again.
It does so after a 30s pause, which gives you time to manually wake the device up, and then press "Calendar (stop)", which will tell the daemon to stop refreshing the screen.
If all that works, consider turning off the Kindle screensaver. If you're going to keep using it as an ebook reader, you'll probably want to leave it running. However, there's a risk that the Kindle may deep sleep before the wakeup timer is set, which would stop the dashboard from refreshing. To do this, type ~ds in the searchbar and hit enter. To re-enable, restart the Kindle by holding the power button for 15-20 seconds and push restart in the menu.
The pragmatic solution I've used is deploy over an sshfs mount.
Toggle USBNetwork so it's running, ensure SSHD is available over wifi, then mount it locally, something like:
sshfs root@192.168.1.82:/ /mnt/kindleUsually I develop it locally, so pushing to the kindle is suitable. However, sometimes, for debugging you need to work directly on the device. So I've been using unison like this:
unison -prefer dashboard/ -fat /mnt/kindle/mnt/base-us/extensions/dashboard/ dashboard/Forked from https://github.com/4dcu-be/kual-dashboard with huge thanks.