CODEWITHSUNDEEP
ruby-on-railsrubytimetimezone
Zabba
Zabba

Reputation: 65497

DateTime.now or Time.now?

Which of the two should I be using in my Rails application:

DateTime.now or Time.now

Is there any harm in using both in the application?

Can there ever be any differences between the two in case of the above (now) example? (On my current system they are both showing the same time)

Upvotes: 45

Views: 45066

Answers (3)

Yarin
Yarin

Reputation: 183679

Use (Date)Time.current instead of (Date)Time.now

Rails extends the Time and DateTime objects, and includes the current property for retrieving the time the Rails environment is set to (default = UTC), as opposed to the server time (Could be anything).

This is critical- You should always be working in UTC time except when converting between timezones for user input or display- but many production systems are not UTC by default. (e.g. Heroku is set to PST (GMT -8))

See article here

Upvotes: 59

KurtPreston
KurtPreston

Reputation: 1152

If you want to get the time in the application's time zone, you'll need to call Time.zone.now, so that's what I generally use.

Time.now and DateTime.now will both return a time in the system's time, which often is set to UTC.

Upvotes: 8

slandau
slandau

Reputation: 24052

In reference to Time.now (not DateTime.now):

The object created will be created using the resolution available on your system clock, and so may include fractional seconds.

a = Time.new      #=> Wed Apr 09 08:56:03 CDT 2003
b = Time.new      #=> Wed Apr 09 08:56:03 CDT 2003
a == b            #=> false
"%.6f" % a.to_f   #=> "1049896563.230740"
"%.6f" % b.to_f   #=> "1049896563.231466"

Upvotes: 18

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