Ruby/Rails: Converting datetime to natural language (e.g. 3/23/2012 to “this Friday”)

问题

Is anyone aware of a gem, method, or code snippet that will convert datetime values into sometime more human-friendly without having to create a series of rules or put a bunch of logic in the view? For example: if today is 3/19/2012, convert:

• 3/23/2012 to “This Friday”
• 3/26/2012 to “Next Monday”
• 3/31/2012 to “Next weekend”
• 4/15/2012 to “Next month”
• 3/15/2012 to “Last Thursday”
• 3/01/2011 to “Last year”

Basically, I’m looking for the opposite of the Chronic gem. Something more similar to the distance_of_time_in_words, but with a twist. Instead of taking dates from the database and displaying them as-is, I’d like to make them more human-friendly and relatable when displayed to the end user.

回答1:

This is a little hack, totally unfinished and inelegant. But Ruby/Rails is so awesome with dates, and ranges are so perfect, maybe if you don't find the gem, something like this will get you started:

module HumanDate
  def date_difference_for_people (from, to)
    seconds_in_day = 24 * 60 * 60
    days_difference = ((to - from)/seconds_in_day).round
    case days_difference
      when -1
        "yesterday"
      when 0
        "today"
      when 1
        "tomorrow"
      when 2..days_left_in_week
        "this #{day_name(difference)}"
      when (days_left_in_week + 1)..(days_left_in_week + 7)
        "next week"
      when (days_left_in_week + 8)..days_left_in_month
        "later this month"
      else
        "later -- how much left to you :-)"
    end
  end

  def day_name(days_from_now)
    days_from_now.days_from_now.strftime("%A")
  end

  def days_left_in_month
    Time.now.end_of_month.day - Time.now.day
  end

  def days_left_in_week
    Time.now.end_of_week.day - Time.now.day
  end
end

回答2:

I modified Tom’s answer to suit my needs and be usable as a standalone module without having to include it anywhere. I placed the file human_date.rb inside my lib directory. I also fixed a tricky issue with the days_difference calculation.

module HumanDate
  include ActionView::Helpers::DateHelper
  extend self

  def date_distance(from, to, long_form = true)
    seconds_in_day = 60 * 60 * 24
    days_difference = ((to.beginning_of_day.to_datetime - from.beginning_of_day.to_datetime)).floor
    case days_difference
      when -2
        "day before yesterday"
      when -1
        "yesterday"
      when 0
        "today"
      when 1
        "tomorrow"
      when 2..6
        "this #{day_name(days_difference)}"
      when 7..13
        "next #{to.strftime("%a")} (#{short_date(days_difference)})"
      else
        if days_difference > 0
          "in #{distance_of_time_in_words(from, to)} (#{short_date(days_difference, long_form)})"
        else
          "#{distance_of_time_in_words(from, to)} ago (#{short_date(days_difference, long_form)})"
        end
    end
  end

  def short_date(this_many, include_day=false)
    format_string = "%-b %-d"
    format_string = "%a, #{format_string}" if include_day
    this_many.days.from_now.strftime(format_string)
  end

  def day_name(this_many)
    this_many.days.from_now.strftime("%A")
  end

  def days_left_in_month
    Time.now.end_of_month.day - Time.now.day
  end

  def days_left_in_week
    Time.now.end_of_week.day - Time.now.day
  end
end

Usage:

1.9.3-p392 :001 > HumanDate. date_distance(Time.now, 2.day.ago)
 => "day before yesterday" 
1.9.3-p392 :002 > HumanDate. date_distance(Time.now, 3.days.from_now)
 => "this Tuesday" 
1.9.3-p392 :003 > HumanDate. date_distance(Time.now, 12.days.from_now)
 => "next Thursday (Aug 1)" 
1.9.3-p392 :004 > HumanDate. date_distance(Time.now, 122.days.from_now)
 => "in 4 months (Tue, Nov 19)" 
1.9.3-p392 :005 > HumanDate. date_distance(Time.now, 122.days.ago)
 => "4 months ago (Wed, Mar 20)" 

回答3:

The goal of the Hublot gem is to solve this problem — to be a "reverse Chronic".

https://github.com/brettshollenberger/hublot

Related question: Ruby/Rails - Convert Date/Time back into Natural Language (2011-02-17 => February 17th, 2011)

来源：https://stackoverflow.com/questions/9779244/ruby-rails-converting-datetime-to-natural-language-e-g-3-23-2012-to-this-fri