How do you do relative time in Rails?

Question

I\'m writing a Rails application, but can\'t seem to find how to do relative time, i.e. if given a certain Time class, it can calculate \"30 seconds ago\" or \"2 days ago\"

Answer 1

I've written a gem that does this for Rails ActiveRecord objects. The example uses created_at, but it will also work on updated_at or anything with the class ActiveSupport::TimeWithZone.

Just gem install and call the 'pretty' method on your TimeWithZone instance.

https://github.com/brettshollenberger/hublot

Answer 2

I've written this, but have to check the existing methods mentioned to see if they are better.

module PrettyDate
  def to_pretty
    a = (Time.now-self).to_i

    case a
      when 0 then 'just now'
      when 1 then 'a second ago'
      when 2..59 then a.to_s+' seconds ago' 
      when 60..119 then 'a minute ago' #120 = 2 minutes
      when 120..3540 then (a/60).to_i.to_s+' minutes ago'
      when 3541..7100 then 'an hour ago' # 3600 = 1 hour
      when 7101..82800 then ((a+99)/3600).to_i.to_s+' hours ago' 
      when 82801..172000 then 'a day ago' # 86400 = 1 day
      when 172001..518400 then ((a+800)/(60*60*24)).to_i.to_s+' days ago'
      when 518400..1036800 then 'a week ago'
      else ((a+180000)/(60*60*24*7)).to_i.to_s+' weeks ago'
    end
  end
end

Time.send :include, PrettyDate

Answer 3

You can use the arithmetic operators to do relative time.

Time.now - 2.days 

Will give you 2 days ago.

Answer 4

What about

30.seconds.ago
2.days.ago

Or something else you were shooting for?

Answer 5

Just to clarify Andrew Marshall's solution for using time_ago_in_words
(For Rails 3.0 and Rails 4.0)

If you are in a view

<%= time_ago_in_words(Date.today - 1) %>

If you are in a controller

include ActionView::Helpers::DateHelper
def index
  @sexy_date = time_ago_in_words(Date.today - 1)
end

Controllers do not have the module ActionView::Helpers::DateHelper imported by default.

N.B. It is not "the rails way" to import helpers into your controllers. Helpers are for helping views. The time_ago_in_words method was decided to be a view entity in the MVC triad. (I don't agree but when in rome...)