When i save a DateTime schedule_time to the DB, it saves according to my local time, but the timestamps (created_at) are saved apparently in UTC (7 hours ahead of my pacific time)
So if i submit the form setting my schedule_time for right now it will be 7 hours different than my created_at.
i need to show many users their times in their own selected zone, and i also need to compare times against each other, so i want all db entries to be in the same zone. Testing on my machine, my user has his zone saved as Pacific (-7:00), but its saving schedule_time in local time, not really UTC, so when i try to display the time back like this:
#item.schedule_time.in_time_zone(#user.time_zone)
it actually takes the stored datetime and subtracts seven hours from it giving me 7 hours before i wanted. i think the best thing is to just store all the datetimes in a uniform way so i can compare them easily.
changing this value config.time_zone = 'UTC' does nothing to change the stored format of my datetime. it stores in my local time regardless, while storing the timepstamps in real UTC.
ive also tried to reformat the datetime before storing it, with in_time_zone(#user.time_zone) but it had no effect on the stored time.
if i can just get schedule_time stored in UTC just like my timestamps are stored i could make this work! any ideas?
If you want to store schedule_time converted to UTC before storing it in the database, you can include a before_save callback in your Item model to convert it as follows:
before_save { |item| item.schedule_time = item.schedule_time.utc }
sorry i was totally on the wrong track.
the issue was with the jquery date picker i was using (will_pickdate). it returns a date and time but with a +0000 time zone offset. by default, the picker autofills with the current local time, but when i submitted that, rails basically thought it was receiving a time in UTC and added it as my local time but with +0000.
in order to store the date properly i have to keep the time and date from the picker intact, but just shift the +0000 part to something appropriate:
my_time.change(offset: user_time_zone_offset)
Related
I have weird situation with my PostgreSQL db date value.
On my web site I have calendar for selecting a date and when I select some future date like "2018-09-23" in PostgreSQL table column it is saved as "2018-09-22 22:00:00"?
Obviously I am missing something. On web site all the time it shows okay time "2018-09-23" but at the table it is minus one day as you see above. Why?
Rails stores DateTime fields in UTC, but without marking their time zone as UTC. This corresponds to the timestamp without time zone type in postgres. So if your time zone is +2, it'll store the time as UTC (+0).
In Rails, Time.zone will return the current local timezone (you can add logic to change this by user, for example). When persisting a datetime, Rails will automatically convert the current Time.zone to UTC. However, it doesn't use the Postgres type that actually includes the time zone data, so it relies on convention to convert back and forth to the user's time zone.
If you really only care about the date, use the date type in your migration instead of Timestamp or DateTime.
Times and dates have a lot of subtle quirks and the "right" behavior depends on your use case. In some applications, you need to deal with "local" time when considering date transitions, and sometimes you need to finesse your application or database logic to think in terms of local time and sometimes you care about UTC time.
I have table which have a datetime field named date. When doing a POST in order to insert a new row, the date sent from the client (browser) looks like 2015-11-20T14:30:00+10:00 which is actually a correct date and timezone.
However, inside Postgres this date has been inserted as 2015-11-20 04:30:00.000000, which as you can see, is not at all the same as above. I know the problem is related to the timezone. But I cannot seems to figure out a fix.
For information, I have configured my app timezone :
class Application < Rails::Application
config.time_zone = 'Brisbane'
end
Ideas?
2015-11-20T14:30:00+10:00 means that the local time of 14:30 is 10 hours ahead of UTC. Your database field reflects the correct UTC value of 04:30. This is often the desired behavior, especially if the value represent a timestamp - the date and time something occured (past tense).
In PostgreSQL, there are two different types of timestamp fields (reference)
The TIMESTAMP WITH TIME ZONE field accepts an input that contains a time zone offset. It then converts the value to UTC for storage. On retrieval, it uses the session's timezone setting.
The TIMESTAMP, or TIMESTAMP WITHOUT TIME ZONE simply stores the date and time given, ignoring any offset, and not converting to UTC.
Most of the time, you should indeed use TIMESTAMP WITH TIME ZONE. You should only use TIMESTAMP WITHOUT TIME ZONE if you need to retain the local date and time value, such as in scheduling of future events and calculation of business hours. And for those scenarios, it often makes more sense to split date and time into separate DATE and TIME fields.
One last thing - if you can avoid it, avoid using Rails time zones and use standard tzdb zones. "Australia/Brisbane" is the full tzdb identifier equivalent to the Rails "Brisbane" time zone. Refer to the section on Rails time zones at the bottom of the timezone tag wiki.
I found this gem to be incredibly useful and easy for correctly setting the time https://github.com/kbaum/browser-timezone-rails
for a while I´m trying to understand how this timezone times will work, and I had a question:
Today in my country, we are in Daylight saving time (GMT-2).
So the user of my application enter a time, like 11:00AM and post the form.
Far as I know, rails will convert this date to UTC and save in the database (mysql in my case), like: 01:00PM UTC.
When I recover that record, I had to convert to local time to display. Ok?
My question is, lets suppose that this date/time represents a date/time in future, when my country gets out from summer time (GMT-3). Rails will save 01:00PM UTC? Today, in Daylight saving time, how will be the local time? And in the future, how will be this local time?
Basically, I always need to display to user 11:00AM.
thanks.
There are several places where timezone can come into play: the operating system (or probably user account) default setting, the database server, Rails environment.rb.
The key is to make sure all dates are stored with UTC time zone, then displayed in whatever your local timezone is. It sounds like you're doing that.
So your question seems to boil down to "if it's Daylight time, I want to offset by -3 hours, else offset by -2 hours". The Rails time extensions let you determine your current offset like Time.zone.now.utc_offset, and Time#dst? tells you if it's Daylight Savings Time with those two you can conditionally subtract the extra hour (3600 hundred seconds).
7 months after you asked, but perhaps skip_time_zone_conversion_for_attributes= will help - it tells AcitveRecord not to convert timezones on storage or retrieval. See ActiveRecord Timestamp which shows the example:
class Topic < ActiveRecord::Base
self.skip_time_zone_conversion_for_attributes = [:written_on]
end
I'm using Rails 3.2.8. When I generate a scaffold with a time field or datetime field. The HTML form field gets pre-populated with the current date/time in UTC. Great that it's pre-populated with the current date/time, but because it's in UTC, we have to change the time back 7 hours every time (which will sometimes require setting the day back 1 also, possibly month and year too). And then it seems the UTC time gets stored in the database, so I'll have issues displaying/editing it as well if I recorded it in our local time.
I looked at the Ruby documentation for the form helpers to deal with local time better, but I don't see anything relevant.
What's the best way to deal with editing and displaying dates and times in Rails?
UPDATE: To clarify, I like the idea that UTC time is stored in the database. I just want the time_select and datetime_select form helpers to edit the times in the user's local timezone. And, of course, I want to easily display the time in the user's local timezone.
You have to set the time zone to display on a per-user basis somewhere in a before/around_filter. This has to be done like:
Time.zone = "Kyiv"
An example can be found in its API: http://api.rubyonrails.org/classes/Time.html#method-c-zone-3D.
Run the rake time:zones:all to see all of them.
All the conversions has to be handled for you behind the scene.
This has helped me in the past. You can do things like:
Time.now.in_time_zone("Central Time (US & Canada)")
See Rails: convert UTC DateTime to another time zone
I have a Rails app that stores time values, and I have set a time zone in config/application.rb.
This works correctly on datetime columns, but time columns show the time in UTC, not the specified time zone.
The time on these two examples are both stored as 20:50 (UTC) in the database, but when I show it in a view the time column shows as UTC and the datetime column is correctly shown in the chosen time zone.
time2: 2000-01-01 20:50:00 UTC
datetime2: 2012-02-09 21:50:00 +0100
Is this expected behavior? Shouldn't time types also use the configured time zone?
ActiveRecord uses TimeWithZone, where methods like localtime, utc, utc? may help you.
Yes, this is expected behavior. Rails (ActiveRecord) stores times in UTC, then coverts them to whatever time zone Time.zone is set to upon rendering in the view.
I give up this, Rails seems to totally ignore config.time_zone with time attributes and just uses it for datetime attributes for reasons I don't understand. And as it seems, not many others understand it as well.
I will change the time attributes to type string and parse it to a time object when I need to work with it as a time object. If this is fixed in a later Rails release I can always change back to using time attributes, but now I need to go on, this has been holding me back for days.
But thanks for trying to help :)