Rails: Converting created_at to PST - ruby-on-rails

I want to convert the created_at to this format January 12, 2:00 PM PST.
The first step I tried was to convert the created_at field to Pacific Standard Time (PST).
However, I'm stuck - I can't even get past this step.
I've tried these, but neither worked:
Time.parse(self.created_at).in_time_zone('Pacific Time (US & Canada)')
time = Time.parse(self.created_at)
time.in_time_zone('Pacific Time (US & Canada)')
I receive no implicit conversion of ActiveSupport::TimeWithZone into String when I do this.
I based it on these questions:
How do you convert the following time from UTC to EST in Ruby (without Rails)?
How to convert time from UTC to PST in rails

Since it is already a datetime, you should be able to just do this to convert it:
self.created_at.in_time_zone('Pacific Time (US & Canada)')
Don't forget to save the new time zone to the record in the database.
Time.parse() is meant to convert strings into datetime(https://apidock.com/ruby/v2_5_5/Time/parse/class).

Related

How to set the timezone to EST throughout the rails app?

I want to use EST throughout the app. I have set the
config.time_zone = 'Eastern Time (US & Canada)'
config.active_record.default_timezone = 'Eastern Time (US & Canada)'
what I want is, I have to get all the time I have used like "DateTime.now" and it now returns time in my local timezone but I want it to return date time in EST. Also I have date time range picker and I get the start date and end date and parse the string to time using
(params[:start_date]).to_time
which also returns the date time in local zone and instead i want all those to return in EST. How can I do this? Any help is appreciated.
Thanks in advance.
DateTime.now and Time.now doesn't respect Time.zone and will always use the server time. If the machine you're using is set to a different timezone, these 2 will use that timezone.
to_time on the other hand defaults to local timezone as mentioned in apidock (although just tried this out and I get utc by default). To get these times in the timezone set, append in_time_zone
DateTime.now.in_time_zone
Time.now.in_time_zone
string.to_time.in_time_zone
There are some shortcuts for these though. The following code will return the timestamps in the current timezone
Time.zone.now
Time.zone.parse(string)
Normally, in database date-time would be saved in UTC format unless you have selected a specific TimeZone for Active Record and it would be easier if you have to meddle with multiple TimeZones. But, while you access the values you will get the values in you selected TimeZone.
config.time_zone = 'Eastern Time (US & Canada)
Now, suppose you have a datetime value in UTC from table as
datetime1 = "2014-08-25 10:25:57 +0000"
You can convert it to the selected timezone 'Eastern Time (US & Canada)' as below,
Time.zone.parse(datetime1) => Mon, 25 Aug 2014 06:25:57 EDT -04:00
Then, if you need it in a proper format, use method strftime.
Time.zone.parse("2014-08-25 10:25:57 +0000").strftime("%d-%m-%Y %H:%M:%S") => "25-08-2014 06:25:57"
Hoep it helps :)

Finding records based on converted timezone?

I have records with a created column whose datetime is stored in UTC.
For instance, this is the datetime stored in one record: 2014-02-01 00:33:25
But if I retrieve that record and confer it to CST, it'd look like this:
Article.find(1).created.in_time_zone('Central Time (US & Canada)') => Fri, 31 Jan 2014 18:33:25 CST -06:00
Which is a different day/month as far as that timezone goes.
The problem I'm having is finding records based on a date. So say I wanted to pull all records for January 31, 2014 (CST). I want to include my example record.
How do I do that in a Rails app? I'm running Rails 4.0.1 and Ruby 2.0.0 with Postgres 9.3.1.0.
Use AT TIME ZONE to change timezone
Article.where("date(created AT TIME ZONE 'UTC' AT TIME ZONE 'CST') = '01/31/2014'")
Got some help outside of SO and got what I was looking for.
Say I wanted to find all records in a date range, this is what it'd be:
Article.where(created: Date.parse("January 1, 2014").in_time_zone('Central Time (US & Canada)').beginning_of_day.utc..Date.parse("January 31, 2014").in_time_zone('Central Time (US & Canada)').end_of_day.utc)

How to preserve timezone when using Time.to_s(:db)?

I'm trying to convert Time object with PST timezone.
zone = ActiveSupport::TimeZone.new("Pacific Time (US & Canada)")
now = Time.now.in_time_zone(zone)
when I output now, it's correct. when I do Time.now.in_time_zone(zone).to_s(:db), it outputs GMT (original date).
How do I fix it?
Update: Looks like..the following code works
zone = ActiveSupport::TimeZone.new("Pacific Time (US & Canada)")
now = Time.now.in_time_zone(zone).strftime("%Y-%m-%d %H:%M:%S")
Database dates are usually stored in utc time format..
ActiveSupport is returning UTC, not GMT on to_s(:db),
see http://apidock.com/rails/ActiveSupport/TimeWithZone/to_s
EDIT: Maybe this helps you?
http://chris.finne.us/2011/09/23/rails-3-tosdb-when-database-time-is-not-utc/

Rails: How to parse date-time string into a specific time zone

I'm using Rails 3.2 and ruby 1.9.3 on Debian. I have an app that collects a date, time, and timezone in the form of strings via an HTML form. Something like this:
start_date: "04-15-2010",
start_time: "10:00:00",
timezone: "Central Time (US & Canada)"
What I'd like to do is parse these 3 elements into a single date that is saved into my database as UTC, which in this case would add 7 hours to the start time, once it's in the UTC time zone.
So the stored time would be 17:00 once it's in the DB as UTC instead of the received Central time.
I have tried something like this to parse the date:
ActiveSupport::TimeZone[timezone].at DateTime.strptime("{ 2012-04-09 20:00:00 }", "{ %Y-%m-%d %H:%M:%S }").to_i
However, I'm not able to incorporate the time zone into the resulting time with %Z. It either doesn't parse or the time is interpreted as UTC not Central time. So my question is, how to coerce a date string into a certain time zone without changing the value of the actual date/time stored. I'd like to be able to parse the string into a date/time object that includes the correct time zone with it at that time so that future time zone conversions are accurate. I've looked all over and can't find a way to do this. It's strange, since this seems like something common one does with dates inputted from HTML forms. Thank you for any help.
Try this:
zone = "Central Time (US & Canada)"
ActiveSupport::TimeZone[zone].parse("2013-04-03 17:47:00")
Use String#in_time_zone (Rails 4+)
I personally prefer using String#in_time_zone:
>> '22.09.1986 10:30'.in_time_zone('Central Time (US & Canada)')
# => Mon, 22 Sep 1986 10:30:00 CDT -05:00
This parses the date and time in the String into the time zone provided.
%Z is the correct way to specify a Time zone name. Have you tried the following ?
date_and_time = '%m-%d-%Y %H:%M:%S %Z'
DateTime.strptime("04-15-2010 10:00:00 Central Time (US & Canada)",date_and_time)
This is the method that I came up with. Not the prettiest, but it works. Allows parsing the string using a specified format, and then turning it into the format that I know Time.zone.parse requires.
class ActiveSupport::TimeZone
def strptime(time, format='%m/%d/%Y')
formatted = Time.strptime(time, format).strftime('%Y-%m-%d %T')
parse(formatted)
end
end
Then you can do something like what was mentioned in another question, but with a specified format:
zone = "Central Time (US & Canada)"
ActiveSupport::TimeZone[zone].strptime('2013-04-03', '%Y-%m-%d')
Or if you already have a time zone set:
Time.zone = "Central Time (US & Canada)"
Time.zone.strptime('01/13/2006')
I used a default format of %m/%d/%Y because that's what my user input is most of the time. You can customize this to your needs, or use the default format DateTime uses which is believe is iso8601 (%FT%T%z)
I've finally found the dirty, yet definitive way to do this.
First, parse the string using plain Ruby Time.strptime like this:
time = Time.strptime('12 : 00 : PM', '%I : %M : %p')
This way you get the parsed Time, but not yet in correct timezone. To fix that, let's convert the time to string form and parse it with the standard ActiveSupport::TimeZone#parse
Time.zone.parse(time.to_s)
The result is the ActiveSupport::TimeWithZone with our time parsed into the correct timezone.
The reason why we have to do it this way is that neither ActiveSupport::TimeZone nor ActiveSupport::TimeWithZone support the strptime method. So we have to parse the Time with core Ruby strptime that does not have timezone information, convert it to format acceptable in ActiveSupport objects and then parse it yet again.
To have DateTime take the date string and attach a timezone other than UTC without changing the values of the date string , use this, its easy , doesnt break on leap day :)
xx = DateTime.strptime("9/1/15 #{object.time_zone}", "%m/%d/%Y %Z")
Convert specific date format in UTC.
ActiveSupport::TimeZone['UTC'].parse(Time.strptime('01/24/2019T16:10:16', "%m/%d/%YT%H:%M:%S").asctime)

How to parse date such that it is in EST

I am using Rails 3.1. Here is my configuration
config.time_zone = "Eastern Time (US & Canada)"
Now user enters Nov 30, 2011 at 7:00 PM. How do I parse this text so that after parsing I get the result in EST?
You can do so by calling time = ActiveSupport::TimeZone.new('EST').parse('Nov 30, 2011 at 7:00 PM'). Also you can parse the time string as being in user-specific or default timezone by calling Time.zone.parse. You can convert the result time into any timezone thanm i.e. Time.zone.now.in_time_zone('Asia/Yekaterinburg')
Also there is no need in do any manual conversions of timezones before storing the time to database as Rails does is automatically.
You should store all values in UTC and render them in user's local time. "Eastern Time" is a loose concept at best and changes on a fairly regular basis as politicians decide to extend or contract Daylight Saving Time.
Generally you can do this with the ActiveSupport::TimeZone methods local_to_utc and utc_to_local conversion methods.

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