How to Do Relative Time in Rails

How do I use relative time in Rails?

This is the documentation for time_ago_in_days and here's a few examples.

time_ago_in_words(3.minutes.from_now)                 # => 3 minutes
time_ago_in_words(3.minutes.ago)                      # => 3 minutes
time_ago_in_words(Time.now - 15.hours)                # => about 15 hours
time_ago_in_words(Time.now)                           # => less than a minute
time_ago_in_words(Time.now, include_seconds: true) # => less than 5 seconds

from_time = Time.now - 3.days - 14.minutes - 25.seconds
time_ago_in_words(from_time)      # => 3 days

from_time = (3.days + 14.minutes + 25.seconds).ago
time_ago_in_words(from_time)      # => 3 days

This is a view helper, so it is expected to be called in a view context. It's not gonna work in your model or controller by default.

If you need the same feature elsewhere, for example in a custom class in /lib, then you may want to check the source code and recreate the feature in your code (you can copy/paste the method, but it's likely you will need a less generic method so you may end up with a much smaller implementation).

Using and comparing relative time in Rails

Basic relative time:

# If "time_ago" is more than 1 hour past the current time
if time_ago < 1.hour.ago
  execute_me
end

Comparison:

Use a < to see if time_ago is older than 1.hour.ago, and > to see if time_ago is more recent than 1.hour.ago

Combining times, and using fractional times:

You can combine times, as davidb mentioned, and do:

(1.day + 3.hours + 2500.seconds).ago

You can also do fractional seconds, like:
0.5.seconds.ago

There is no .milliseconds.ago, so if you need millisecond precision, just break it out into a fractional second. That is, 1 millisecond ago is:

0.001.seconds.ago

.ago() in general:

Putting .ago at the end of just about any number will treat the number as a #of seconds.

You can even use fractions in paranthesis:

(1/2.0).hour.ago   # half hour ago
(1/4.0).year.ago   # quarter year ago

NOTE: to use fractions, either the numerator or denominator needs to be a floating point number, otherwise Ruby will automatically cast the answer to an integer, and throw off your math.

Ruby on Rails- Time Condition

To add to the earlier answer

For posts this week

@posts = Post.where("created_at > ?", Time.now.beginning_of_week)

For posts this month:

@posts = Post.where("created_at > ?", Time.now.beginning_of_month)

How to just show minutes or hours or weeks in rails time ago?

You just want it in weeks, hours or minutes? How about this (it would go in a helpers file)

def short_age_string(time)
  diff = Time.now - time #value is seconds (float)
  if diff >= 0
    result = "1-"
  else
    result = "1+"
  end
  diff = diff.abs.to_i
  if diff >= 604800 #seconds in a week
    weeks = diff/604800
    return "#{result}#{weeks}#{"+" if weeks >= 999}W"
  elsif diff > 3600 #seconds in an hour
    return "#{result}#{diff/3600}H"
  else
    return "#{diff/60}#{minutes}M"
  end
end

I took the liberty of making it return "1+..." for times in the future.

Format relative dates

if you have rails, I think ActionView::Helpers::DateHelper#distance_of_time_in_words helps that.

require 'rubygems'
require 'action_view'
include ActionView::Helpers::DateHelper

from_time = Time.now
distance_of_time_in_words(from_time, from_time + 50.minutes)        # => about 1 hour
distance_of_time_in_words(from_time, 50.minutes.from_now)           # => about 1 hour
distance_of_time_in_words(from_time, from_time + 15.seconds)        # => less than a minute
distance_of_time_in_words(from_time, from_time + 15.seconds, true)  # => less than 20 seconds
distance_of_time_in_words(from_time, 3.years.from_now)              # => over 3 years
distance_of_time_in_words(from_time, from_time + 60.hours)          # => about 3 days
distance_of_time_in_words(from_time, from_time + 45.seconds, true)  # => less than a minute
distance_of_time_in_words(from_time, from_time - 45.seconds, true)  # => less than a minute
distance_of_time_in_words(from_time, 76.seconds.from_now)           # => 1 minute
distance_of_time_in_words(from_time, from_time + 1.year + 3.days)   # => about 1 year
distance_of_time_in_words(from_time, from_time + 4.years + 9.days + 30.minutes + 5.seconds) # => over 4 years

to_time = Time.now + 6.years + 19.days
distance_of_time_in_words(from_time, to_time, true)     # => over 6 years
distance_of_time_in_words(to_time, from_time, true)     # => over 6 years
distance_of_time_in_words(Time.now, Time.now)           # => less than a minute

In case of relative to the current time, use distance_of_time_in_words_to_now instead of distance_of_time_in_words.

If your app is rails-based, just use distance_of_time_in_words, distance_of_time_in_words_to_now, time_ago_in_words in view.

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