Monthly Shaarli

All links of one month in a single page.

July, 2021

Finding, managing and reading e-books

Where to find e-books

Managing your ebook collection

  • Calibre, the software for managing all aspects of your ebook library. Created by Kovid Goyal, maintained by hundreds of contributors. Project repo.
  • For a full-fledged web interface to your Calibre library, look no further than Calibre-web. Just like Calibre's built-in server, Calibre-web also supports OPDS, which makes it easy to integrate with mobile apps such as Librera Reader.
  • COPS, a Calibre PHP OPDS server. A less-powerful alternative to Calibre-web, in my opinion. But it served me well for some time before I discovered Calibre-web.

Tools for finding e-books

Reading e-books

Recently discovered Thorium Reader. Works very nicely on the Linux desktop and connects to our Calibre-Web OPDS server. My Ansible role.

Foliate is another nice desktop ebook reader. My Ansible role.

For reading on Android I use Librera Reader.

More links

Batteries aren't the only way to store energy.
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Any reversible physical process is an energy storage technology.

An interesting take from Technology Connections.
In this one, he reminds us that simple management of heat in our homes can amount to a simple and immediately available method to distribute energy use from the hours of peak demand.

Crooked Timber says: "energy storage is a solvable problem [...] concerns about the variability of wind and solar power will come to nothing in the end".

Moving rocks up and down former mine shafts could be a workable energy storage system.

Materials Project

The Materials Project's mission is to accelerate the the discovery of new technological materials through advanced scientific computing and innovative design tools.

To use Materials Project's API, pymatgen may be easiest.
I am not aware of a similar API wrapper for R.

Taylor Sparks has produced a number of videos related to the Materials Project, such as Materials Project API example using pymatgen and Materials data repositories.

What's Inside the EU Green Pass QR Code?

I recently got a copy of my "digital covid certificate". (You can get yours at covidbevis.se).
The certificate contains a rather dense-looking QR code, so naturally I was curious as to what data it contained.

With the help of Binary Eye, I could see that whatever the QR code encoded was not stored in clear-text.

Searching the web, I encountered this blog post by Austrian hacker Tobias Girstmair.
He has written a Python script that deconstructs the QR code into its data fields.

I installed it and used it to read out the values from a JPG screenshot of my QR code (I have randomised or hidden some data to protect privacy):

$ git clone https://git.gir.st/greenpass.git/
$ cd greenpass
$ python3.8 -m venv venv,
$ source venv/bin/activate
$ pip3 install flynn base45 PyPDF2 pyzbar Pillow
$ sudo apt install libzbar0 
$ python3 greenpass.py myqrcode-screenshot.jpg
QR Code Issuer : SE
QR Code Expiry : 2021-09-29 15:00:00
QR Code Generated : 2021-07-01 15:00:00
 Vaccination Group
   Unique Certificate Identifier: UVCI : URN:UVCI:01:SE:EHM/V10050020P8X
   Country of Vaccination : SE
   Dose Number : 1
   ISO8601 complete date: Date of Vaccination : 2021-06-01
   Certificate Issuer : Swedish eHealth Agency
   Marketing Authorization Holder : ORG-100030215
   vaccine medicinal product : EU/1/20/1528
   Total Series of Doses : 2
   disease or agent targeted : 840539006
   vaccine or prophylaxis : J07BX03
 Date of birth : 1982-02-01
 Surname(s), forename(s)
   Surname : <>
   Forename : <>
   Standardised surname : <>
   Standardised forename : <>
 Schema version : 1.3.0

The script worked when supplying a screenshot, but threw an error when I tried supplying the HC1 hash itself. In any case, I congratulate Tobias on a very nice piece of investigative work, allowing citizens all over the EU to inspect the data they share when using their COVID vaccination certificate.