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Use Time.current / Date.current / DateTime.current on projects that have a time zone

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Arne Hartherz
January 04, 2012Software engineer at makandra GmbH

Basically, you now need to know if your project uses a "real" time zone or :local, and if config.active_record.time_zone_aware_attributes is set to false or not.

  • With time zones configured, always use .current for Time, Date, and DateTime.

    ActiveRecord attributes will be time-zoned, and .current values will be converted properly when written to the database.
    Do not use Time.now and friends. Timezone-less objects will not be converted properly when written to the database.

  • With no/local time zone use Time.now, Date.today, or DateTime.now.

    ActiveRecord attributes will not be time-zoned.
    Using .current would hand you UTC objects whose to_s(:db) may not convert properly.


Legacy behavior in Rails 2.3

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It's been briefly mentioned in the random list of ActiveSupport goodies, but please do remember to always use Time.current instead of Time.now, etc.

Why?

Because of the way Rails and MySQL deal with time zones you would need to take care to use Time.zone.now in projects which hold time zone information and Time.now only in those that run with the server's time. If you don't, bad things can and will happen. More information can be found that card.

Prefer "current"

Time.current decides if it wants to be a Time.zone.now or a Time.now depending on the project settings. Using it keeps you sane and happy.

That logic is available for Time.current, Date.current and DateTime.current.

Posted by Arne Hartherz to makandra dev (2012-01-04 12:11)