Hitchhiker's Guide to the Ward by a Codebreaker: Add Google Calendar to Lightning in Thunderbird

One day, I opened up Thunderbird app after an auto upgrade and surprisingly found Google Calendar was not linked anymore in Lightning interface. It happens from time to time while I supposed Mozilla should have fixed it but it doesn't seem to be the case this time.

Searching around the forum, I come across several solutions but none of them is working. Whether it can be problems in the add-on itself or Google has changed API again, I found myself hard to remember what exactly to resolve this over time. This time I need to take a note to keep myself aware of what needs to be done in case the same thing happens again for the ongoing upgrade.

Just a reminder as for what has happened back in September 16th 2013:

Google is changing the Location URL of their CalDAV Calendars

Google has decided to change the authentication mechanism for their CalDAV calendars to OAuth 2.0, which required some changes in Lightning to accommodate.

Due to these changes, the URL to access the calendar has also changed. The old endpoint will stop working after September 16th (today!). This affects only Google calendars using CalDAV protocol.

According to the Mozilla's blog, iCal users with read-only access are not affected.

For iCal way in Lightning, you may receive error message like MODIFICATION_FAILED when adding new gCal event within Lightning Calendar interface, i.e., it becomes write-protected.

What if we really want to view and EDIT our Google Calendar in Lightning? Let's try another protocol like CalDAV. CalDAV provides read and write access to Calendar instance.

You may want to choose this way especially if you cannot make it work for specific option for Google Calendar under Provider for Google Calendar add-on. I found this option is not quite reliable as CalDAV and might not be working from time to time.

Steps as follows:

Download Thunderbird and install Lightning add-on
Open the new calendar dialog (File → New → Calendar)
Add a new remote calendar (On the Network → CalDAV)
As a location enter the following:

https://apidata.googleusercontent.com/caldav/v2/*calendar-id/events

*calendar-id is supposed to be your email address or any other id you have set to your Google Calendar

To enable this, you need to enter Google account login details (supposedly once), along with two way authentication 6 digits password if necessary (depending on whether you have enabled two authentication or not on Google account).

This will enable two way (read, write) communication with your Google Calendar instantly.

For Apple iCal users, they might need to use the following URL: