1129963 - Use system timezone database where available (linux,mac)

Status: NEW

(Calendar :: General, enhancement)

Description

[Eugene Crosser]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0
Build ID: 20150125222008

Steps to reproduce:

As of the version currently in production, Lightling uses private timezone database that is distributed as part of the package, and can be updated only when a new version of the package is published.


Actual results:

When timezone definition for some counties change, it takes significant time for the updated database to be published with the next version of Lightning. Furthermore, if Lightning is a package in an OS distribution (like in Ubuntu), it is not updated until the next version of the OS distribution. This may lead, in the case of "long term support" distribution, to users having timezone database that is out of date by years. Many bugs in this tracker (search for "timezone") prove that this is a significant problem for many users.


Expected results:

Most operating systems come with system-wide timezone database that is typically updated automatically (between releases of the OS distribution) and is up to date most of the time. Lightling could abandon its private timezone database and use system-wide database instead. Alternatively, a method could be introduced to dynamically update LIghtning's private timezone database "in the filed", in a user-friendly manner.

I am filing this bug as a followup to discussion in Bug 1009894, comments 25 - 29.

Comment 1

[Philipp Kewisch [:Fallen] [:📆][:🧩]]

Attachment: vzic.js

Thanks for the report. Extra notes:

The files in /usr/share/zoneinfo are binary data that follow a format like this: <http://www.cstdbill.com/tzdb/tzfile-format.html>. Getting that data does not yet give us .ics timezone data, we essentially need to run vzic on it. I've attached some wip code that at least parses the binary files. It also creates something like ICS, but its not correct yet.

Windows, where most of our users are, does not have Olson timezone information available. The OS provides only the TimeZoneInfo Database, which does not have an 1:1 mapping with Olson.

Comment 2

[Dmitry Monakhov]

There is another method to make automatic time zone  update.
ICAL has a special field TZURL like this
TZURL:http://tzurl.org/zoneinfo/Africa/Abidjan

So the update procedure can be platform/OS independent.

Comment 3

[Philipp Kewisch [:Fallen] [:📆][:🧩]]

I don't think we should be depending on tzurl.org, first of all to save their bandwidth and also for user privacy concerns. The future is actually this draft, possibly at some point after that is standard we can get ntp servers to also have timezone info and then just use them.

https://tools.ietf.org/html/draft-douglass-timezone-service-11

Comment 4

[Nick]

Xubuntu 15.04-64 Ru
Thunderbird 38.1.0 from Ubuntuzilla (mozilla-build)
Lightning 4.0.1.2 (integrating now)
I cannot set right timezone for Europe/Moscow

Comment 6

[Magnus Melin [:mkmelin]]

Maybe obsoleted by bug 1158733 and the detection that should take care of.