twital: automate lab weekly newsletter

twital stands for "This Week in the Aranda Lab", by the way. Creative naming is not my forte.

TL;DR: check out email_contents.txt for a sample output.

Note: for security concerns, I have modified the script to remove several addresses. These addresses appears as "REDACTED", so you'll have to plug your own details to get it to work. I have also excluded client_secret.json, which is required for task #1.

Overview of process

There's basically three tasks:

Parse lab Google Calendar.
Find a way to email the text out.
Set a timer to do it once every week.

Parsing Google Calendar

Surprisingly NOT the hardest part of the project. #2 was a bigger PITA.

Google has provided sample code to parse one's personal calendar.

https://developers.google.com/google-apps/calendar/quickstart/python

It's supposed to generate two files: .credentials and client_secret.json if it is unable to find these files on your system.

Note: I was unable to generate them on Bash: The text-mode authentication did not work for some reason. I had to run the code on Windows to authenticate via my browser to generate these two files, then move them over to my Debian system. -__-"

Once parsed, there's a lot of unexplained mojo in the script to deal with parsing dates and times. I've standardised the script to use a specific timezone (GMT+3) to properly output event start and end times.

Emailing the text out

Again, RTFM and follow instructions.

https://wiki.debian.org/GmailAndExim4

I tried using Yahoo Mail and it didn't work. I guess there's a reason why Gmail is dominating the free email space.

Setting up the weekly trigger

$ crontab -e

0 9 * * 0 cd /home/liewy/kaust/twital/ && ./mail_twital.sh

(cron, by default, runs from ~, so one needs to cd into the folder containing the script.)

Postscript

A few explanations of why I did certain things:

Why wrap the email body with <pre> </pre> before sending it out?

It's because Outlook defaults to viewing emails in HTML mode, which badly mangles the "Aranda Lab" header. The <pre> protects multiple space characters from getting merged into one. Blame HTML for this silliness.
Why use command-line mail command (i.e. exim4) to do the emailing, instead of writing a script to do it?

Laziness, and also because having the mail command set up properly on my own system allows me to email myself notifications (e.g. if I'm monitoring a script's output, I can get the output sent to me via email).