Using constants in environment.rb in Ruby on Rails

Posted on 29 March 2007

Constants help with consistency, they easily allow you to keep your code DRY.

One of the ways I utitilise constants is to standardise the date formatting I use across an app.

For example, in environment.rb I will create a module to contain my date format constants:

module Dates
  DATE_FORMAT = "%d% %b %Y"
  DATE_TIME_FORMAT = "#{DATE_FORMAT} %H:%M"
end

The module just groups them nicely together. To use the constants I will write the following:

@object.created_at.strftime(Dates::DATE_FORMAT)
@object.created_at.strftime(Dates::DATE_TIME_FORMAT)

Remember you will need to restart your server after making any changes to environment.rb

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Comments...

• Constants in environment.rb are good. But if you're going to bother with date formats, you should define them so that they work with Date's to_s(format) method.

  ActiveSupport::CoreExtensions::Time::Conversions::DATE_FORMATS.merge!(:my_date => "%d% %b %Y", :my_date_time => "%d% %b %Y %H:%M")

  Then you can do @object.created_at.to_s(:my_date)
  

  josh at 30 Mar 07 at 00:34

• Nice trick especially the module part :)

  Ed at 30 Mar 07 at 02:39

• thanks guys.

  sal at 19 Jul 07 at 21:25