I am trying to check if a time submitted by the user in a datetime_field in a form is less than the current time.
My current issue is that the submitted date is that exact date in UTC, is Mon, 13 Apr 2020 23:00:00 UTC +00:00, however, DateTime.now.utc is 2020-04-14 03:14:00.694513 UTC.
I would like to be able to compare just the dates and the times to compare them, regardless of the timezone they are in.
Related
I have an integer that represents a unix epoch time in millisecond precision and a time zone string. I need to create a TimeWithZone object with them.
epoch_ms_integer = 1586653140000
time_zone = "America/Los_Angeles"
Trying to convert to:
Sat, 11 Apr 2020 20:59:00 PDT -07:00
I was able to accomplish this by doing:
Time.at(epoch_ms_integer/1000).asctime.in_time_zone("America/Los_Angeles")
but was wondering if this is the best way to achieve this. The app I'm working on is configured to EST/EDT time zone so Time.at(epoch_ms_integer/1000) returns 2020-04-11 20:59:00 -0400.
I was able to find the asctime solution in one of the answers here Ruby / Rails - Change the timezone of a Time, without changing the value
the same question was asked here but no answer converting epoch time with milliseconds to datetime.
Assuming that the timestamp is in milliseconds, then 1586653140000 is
Epoch: 1586653140
GMT: Sunday, April 12, 2020 12:59:00 AM
PDT: Saturday, April 11, 2020 17:59:00 PM -in time zone America/Los Angeles
These are just 3 different ways to refer to a specific point in time around the world.
Sat, 11 Apr 2020 20:59:00 PDT -07:00 and 2020-04-11 20:59:00 -0400 each refer to different points in time and not the same as epoch(1586653140)
Since the Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970 (midnight UTC/GMT), it wouldn't make sense to take 1586653140 and only change the time zone without adding the zone's offset because now you are talking about another point in time.
To get the right "translation" from the epoch to any time zone you could just do
Time.zone = "GMT"
Time.zone.at(1586653140)
=> Sun, 12 Apr 2020 00:59:00 GMT +00:00
Time.zone = "America/Los_Angeles"
Time.zone.at(1586653140)
=> Sat, 11 Apr 2020 17:59:00 PDT -07:00
When working with dates in time zones in rails it is important to only use functions that take the set time zone into account:
DON’T USE
Time.now
Date.today
Date.today.to_time
Time.parse("2015-07-04 17:05:37")
Time.strptime(string, "%Y-%m-%dT%H:%M:%S%z")
DO USE
Time.current
2.hours.ago
Time.zone.today
Date.current
1.day.from_now
Time.zone.parse("2015-07-04 17:05:37")
Time.strptime(string, "%Y-%m-%dT%H:%M:%S%z").in_time_zone
Also keep in mind that in a Rails app, we have three different time zones:
system time,
application time, and
database time.
This post by thoughtbot explains things clearly.
For eg. If today = 'Wed, 12 Feb 2020' then,
The condition to write paste date, should return false as today's date is 12th feb. It should return true for all the date before today.
I need a condition in which today's date is not considered in past date in utc.
Wed, 12 Feb 2020 00:00:00 UTC +00:00 is DateTime, what you can do is convert it to_date and then call past? on it.
DateTime.now.to_date.past?
It will give you false
I'm working with a Grails application and I can't find a clear way to translate a date from one TimeZone to the next/previous TimeZone available (I will define what I consider the next/previous Timezone below).
The facts:
I'm working with date filters in a Grails Application so we can retrieve information based on those filters. The application supports TimeZone so the logged user can set his profile to a particular Timezone.
The dates of the filter are on UTC format and the information on the database is stored also on UTC.
The question:
The user logged has his profile on Timezone UTC+00.
There is a predefined date filter called "This Week", when a user clicks on it generate a period of dates corresponding to the current week in UTC so we can bring all the information on the database from the current week.
If we are on the current day (Thu 19 Nov 2015) the dates the filter will generate for "This Week" to look on the database would be:
Sun Nov 15 00:00:00 UTC 2015 to Sun Nov 22 23:59:59 UTC 2015
This is correct and will bring all the information on the database on that period.
Now, suppose the user doing this has set a Timezone UTC +01.
If we are on the current day (Thu 19 Nov 2015) the dates the filter will generate to look on the database would be the same period:
Sun Nov 15 00:00:00 UTC 2015 to Sun Nov 22 23:59:59 UTC 2015
But in this case I need to translate them to a correct TimeZone because the "This Week" for the current user won't be the same for a user on UTC +01 this is because for this user the date Sun Nov 15 00:00:00 would correspond to the date
Sun Nov 14 23:00:00 on the UTC time (since he/she is one hour ahead) and therefore when filter by "This Week" I should search on the database by the dates:
Sun Nov 14 23:00:00 UTC 2015 to Sun Nov 22 22:59:59 UTC 2015
The thing is I have created a method utcDateToUserTZ(date) to translate from an UTCDate to LocalTimeZone date but this would convert the UTC dates:
Sun Nov 15 00:00:00 UTC 2015 to Sun Nov 22 23:59:59 UTC 2015
into
Sun Nov 15 01:00:00 UTC 2015 to Sun Nov 23 00:59:59 UTC 2015
And that is not what I'm looking for. I need those dates to be translated to the previous TimeZone.
I hope no to be walking around with an issue that has a simpler solution, in which case I hope you can tell me if there exist something easier to solve this.
Thanks,
The method commented before is:
public DateTime utcDateToUserTZ(Date date) {
TimeZone profileTimeZone = getCurrentUserProfile().timeZone
DateTimeZone dateTimeZone = DateTimeZone.forTimeZone(profileTimeZone)
return new DateTime(date, dateTimeZone).withZone(dateTimeZone)
}
Rails 4.2 and PostgreSQL 9.4.
I have events with starts_at and time_zone columns.
I'd like a SQL query to return all events that start, in their local time zone, on a specified date.
I.e. if an event starts at 11pm in Hawaii on Jan 24th:
t1 = ActiveSupport::TimeZone['Hawaii'].parse("2015-01-24 23:00:00")
=> Sat, 24 Jan 2015 23:00:00 HST -10:00
t1.in_time_zone('UTC')
=> Sun, 25 Jan 2015 09:00:00 UTC +00:00
And if an event starts at 1am in Hong Kong on Jan 24th:
t2 = ActiveSupport::TimeZone['Hong Kong'].parse("2015-01-24 01:00:00")
=> Sat, 24 Jan 2015 01:00:00 HKT +08:00
t2.in_time_zone('UTC')
=> Fri, 23 Jan 2015 17:00:00 UTC +00:00
The events occur on the 25th and 23rd of Jan in Rails' implicit UTC database zone, but both events occur on the 24th in their own time zone.
I'd like to write a SQL query akin to:
SELECT * FROM events WHERE (events.starts_at at time zone 'UTC' at time zone events.time_zone)::date = '2015-01-24';
(The initial conversion to UTC is required for a timestamp I believe)
However I get an error ERROR: time zone "Hawaii" not recognized
This is because PostgreSQL time zone names do not match with that of Rails (SELECT * FROM pg_timezone_names; for a list.)
Is there an alternative method where I can still do the query in SQL but not have this problem? I don't want to load the entire events set into Rails and process it there as it is very large and this is a frequent query.
As a small context as to why I need this query: I have a membership pass valid over a certain date range which gives you access to events which can occur in different time zones.
If there is no other way to do this, is there any tool that converts between the Rails names for time zones and that used by PostgreSQL so that I can save both the Rails zone and the PostgreSQL zone in the database record?
Using time zone abbreviations such as PDT instead (I don't even know if these are consistent between Rails and PostgreSQL either) doesn't deal with daylight savings time (which, granted, may not be an issue here but is not satisfactory).
I have an app where different users are in different parts of the globe (I know their timezone), and they can enter dates and times, and I need to store everything in UTC on the DB.
Normally to instance my Time variable, I'm doing:
DateTime.new(date.year, date.month, date.day, hours, minutes, 0)
This is already in UTC, but without converting.
If I add a 7th parameter to that string with the time_zone (ie. "Melbourne"), then it will interpret it as a a date in Australia, and the resulting DateTime, when converted to UTC, is 10-ish hours behind, and that works.
However, that's not taking into account Daylight Saving.
What I need is to do exactly that (instance a DateTime from the components of a date/time), such that (in the case of Australia, for example), using the same hours/minutes for April 9th will give me a different offset when converted to UTC than if I used April 5th.
Any ideas?
Thanks!
Daniel
Have a look at tzinfo
irb(main):002:0> require 'tzinfo'
=> true
irb(main):003:0> tz = TZInfo::Timezone.get("Australia/Melbourne")
=> #<TZInfo::DataTimezone: Australia/Melbourne>
irb(main):004:0> tz.utc_to_local(Time.parse("2013-04-05 00:00:00"))
=> Fri Apr 05 11:00:00 UTC 2013
irb(main):005:0> tz.utc_to_local(Time.parse("2013-04-09 00:00:00"))
=> Tue Apr 09 10:00:00 UTC 2013
irb(main):015:0> tz.local_to_utc(Time.parse("2013-04-09 00:00:00"))
=> Mon Apr 08 14:00:00 UTC 2013
irb(main):016:0> tz.local_to_utc(Time.parse("2013-04-05 00:00:00"))
=> Thu Apr 04 13:00:00 UTC 2013