ADR0001: Consistent Date/Time Formats

[kimadactyl]

• Status: proposed
• Deciders: Kim, Alice
• Date: 2020-05-06

Context and Problem Statement

We want to use consistent date/time formats and methods of rendering them across the whole of imok, but there are a number of options for how we do that. There are pros and cons to all of them.

Considered Options

• Use strftime('%x') and strftime('%X') (long form dates and times in member's locale)
• Use strftime('%Y-%m-%d') and strftime('%H:%M') (ISO-8601 24hour times)
• Use time_format(time_obj, format='SHORT_TIME_FORMAT', use_l10n=True) and date_format(date_obj, format='SHORT_DATE_FORMAT', use_l10n=True) (short form dates and times in member's locale)
• Use Babel and standard dates and short-form times with the member's locale

As we are discussing both time and date formats, there is of course the option to mix and match.

Decision Outcome

Chosen option: Do nothing. The current mixture of formats we have are working, and this decision is not one we want to make without consultation. We will raise a GitHub issue to discuss this in more depth.

Pros and Cons of the Options

Long form dates and times in member's locale

This is the method we have been mostly using up until now. It displays a long form of the date and time in a way that the member's locale describes (en_GB for admins)

Examples:

locale	date	time
*	05/04/21	18:25:27

• Good, because it is mostly what we have been using already
• Good, because it plays well with timezones
• Bad, because the long times with seconds are ugly and unhelpful
• Bad, because it doesn't actually use the correct locale

ISO-8601 24hour times

Display dates in ISO-8601 and times using the 24 hour clock.

Examples:

locale	date	time
*	2021-05-04	18:25

• Good, because it is a standard format
• Good, because the seconds are not displayed
• Good, because dates cannot be confused once you know ISO-8601 (2020-03-02)
• Bad, because some people struggle with the 24 hour clock
• Bad, because some people struggle with ISO-8601
• Bad, because timezone support needs further testing

Short form dates and times in member's locale

Use time_format and date_format with the SHORT formats.

Examples:

locale	date	time
en_GB	4 May 2021	6:46 p.m.
cy_GB	4 Mai 2021	6:46 y.h.
sq_AL	04 Maj 2021	6.46.PM
ti_ER	May 4, 2021	6:57 p.m.

• Good, because the seconds are not displayed
• Good, because we assume it will be familiar to members
• Good, because it should work well with timezone support
• Bad, because developers don't read/write the supported locales so don't know if they are displayed correctly
• Bad, because coverage of locales is relatively small and it appears to fall back to en_US

Babel and short form dates and times in member's locale

Add an additional Python module Babel to display the times in the member's locale but with greater language support than Django's own formats.

Examples:

locale	date	time
en_GB	4 May 2021	18:46
cy_GB	4 Mai 2021	18:46
sq_AL	4 Maj 2021	6:46 e pasdites
ti_ER	04-ግን-2021	6:46 ድሕር ሰዓት

• Good, because the dates and times are truly localised
• Good, because we assume it will be familiar to members
• Bad, because it requires an extra module
• Bad, because we don't know how well it will work with timezones
• Bad, because the times are potentially verbose
• Bad, because developers don't read/write the supported locales so don't know if they are displayed correctly