How do I extend the Time class in a rails app?

Question

Basically I'd like to extend the Time class to add this method:

def round_to_fifteen()
    return Time.at((self.to_i / 900).round * 900)
end

How do I achieve this and where should I put the file that extends the Class?

[This answer](http://stackoverflow.com/a/7491707/877472) seems to have the information you're looking for. — Paul Richter, Dec 28 '13 at 20:20

score 3 · Accepted Answer · answered Dec 28 '13 at 20:26

3

Conventionally, this kind of thing goes in lib/. I'd just have something like lib/time_extensions.rb which is required from an initializer.

You would simply re-open the Time class and add the method desired, like so:

class Time
  def round_to_fifteen()
    return Time.at((self.to_i / 900).round * 900)
  end
end

Then, any Time object will have the #round_to_fifteen method available. You can see this in the console:

2.0.0p247 :004 > class Time
2.0.0p247 :005?>   def round_to_fifteen()
2.0.0p247 :006?>       return Time.at((self.to_i / 900).round * 900)
2.0.0p247 :007?>     end
2.0.0p247 :008?> end
 => nil
2.0.0p247 :009 > Time.now.round_to_fifteen
 => 2013-12-28 13:15:00 -0700

answered Dec 28 '13 at 20:26

Chris Heald

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I'm sorry to be a complete 'Noob' but how do I require it from an initializer? – Sheldon Dec 28 '13 at 20:32
2

Rails has the config/initializers directory. You can create a file in there (I like mine called something like `01_includes.rb` or whatnot), then `require File.join(Rails.root, 'lib/time_extensions')` in there. That'll require your extensions file when Rails boots up, re-open the Time class, and add your method. – Chris Heald Dec 28 '13 at 20:33

score 1 · Answer 2 · edited Dec 28 '13 at 20:45

1

You could literally put this anywhere you want to use it, you could write

    class Time

      def round_to_fifteen
        return Time.at((self.to_i / 900).round * 900)
      end
    end

To use this, you would just write

timestamp_object.round_to_fifteen

edited Dec 28 '13 at 20:45

Sheldon

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answered Dec 28 '13 at 20:19

OneChillDude

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I'm not a Python guy, but I did answer the question, no? – OneChillDude Dec 28 '13 at 20:24
1

This isn't going to work - you have to reopen the Time class if you want to extend it. This code defines a new `UsersHeper::Time` class, which is not the same as the `::Time` class. – Chris Heald Dec 28 '13 at 20:25
1

Ha! you were right, that was very foolish of me. I've edited my answer to improve accuracy – OneChillDude Dec 28 '13 at 20:33

How do I extend the Time class in a rails app?

2 Answers2