How to Work With Time Zones in Rails
With different time zones
When dealing with time zones in Rails, there is one key fact to keep in mind:
Rails has configurable time zones, while
Ruby is always in the server's time zone
Thus, using Ruby's time API will give you wrong results for different time zones.
For consistency, you should only use Rails' methods, but the hard thing is to know which method originates from Ruby and which from Rails. To simplify this, adhere to the following suggestion:
Time.zonefor everything time-related
# Example usage of Time.zone Time.zone.now # instead of Time.now, DateTime.now Time.zone.today # instead of Date.today Time.zone.local(...) # instead of Date.new, DateTime.new Time.zone.at(...) # instead of Time.at Time.zone.parse(...) # instead of Time.parse date.beginning_of_day # instead of date.to_time
2.hours.ago work as expected, because they're provided by Rails. Still, prefer using
Time.zone.now + 2.hours as it will leave no doubt about time zones being respected.
In case you should get time objects without time zone information, you can still turn them into zoned times by calling
"Without" time zones
You can not actually "disable" time zones, because their existence is a fact. You can, however, tell Rails the only single time zone you'll need is the server's.
config.time_zone = "Berlin" # Local time zone config.active_record.default_timezone = :local config.active_record.time_zone_aware_attributes = false
Now you may again use both Ruby's and Rails' whole time API.
- The Exhaustive Guide to Rails Time Zones - a quick introduction to how and why things can go wrong when you're using time zones
- Working with time zones in Ruby on Rails - a walk-through of many possible pitfalls when working with time zones in Rails
- How Rails and MySQL are handling time zones - a comparison of two different approaches: a) trying to ignore them, b) fully embracing them