Date and Time localization based on Rails' i18n functionalities
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The localized_dates plugin takes away some of the pain of localizing dates and times. It leverages the power of the
Rails i18n plugin ( to facilitate localization of dates and times.


To install the plugin, change into an existing Rails application and run

  ruby script/plugin install git://

This will download the plugin and store it in vendor/plugins/localized_dates. It will also create a directory named
config/locales and copy three locale files, en.rb, en.yml, and de.yml into this directory. While the "en"
locale files mimic current Rails formats, "de" serves as a demo on how date and time formats can be customized.

Adding a new locale

To add a new locale, simply create a new file in config/locales. You can make your life easier by copying an existing
locale and basing your new locale on it.

Adding new date and time formats

Adding new date and time formats is easy. Take a look at the basic structure of the locale file en.yml:

        default: "%Y-%m-%d"
        short: "%e %b"
        long: "%B %e, %Y"
        only_day: "%e"

        default: "%a %b %d %H:%M:%S %Z %Y"
        time: "%H:%M"
        short: "%d %b %H:%M"
        long: "%B %d, %Y %H:%M"
        only_second: "%S"

            default: "%Y-%m-%dT%H:%M:%S%Z"

        am: 'am'
        pm: 'pm'

As you can see, there are two basic entites: date and time. time also has two children, datetime and time_with_zone
that both inherit from :time so you usually don't even need to define them (the "de" locale, for, example doesn't).

If you need more complex Ruby constructs such as lambdas, you still need to define them in a separate Ruby file. Take
a look at the following default formats of en.rb:

    :en => {
      :date => {
        :formats => {
          :long_ordinal => lambda { |date| "%B #{}, %Y" }
      :time => {
        :formats => {
          :long_ordinal => lambda { |time| "%B #{}, %Y %H:%M" }
        :time_with_zone => {
          :formats => {
            :default => lambda { |time| "%Y-%m-%d %H:%M:%S #{time.formatted_offset(false, 'UTC')}" }

For example, if you define a time format named release_date, you can use in your views.
You should always define a format named default for both, date and time, that serves as the default format. You can use
the default format by simply writing without passing an additional parameter.

You can either use a strftime compatible formatting string or a Proc that returns a strftime formatting string as a
date/time format. Take a look at the following examples:

  :short => "%d %B, %H:%M" # => "03 August, 22:49"
  :long => lambda { |time| "%A, #{}. %B %Y, %H:%M" } # => "Samstag, 3. August 2008, 22:49"
Please note that the use of Procs is slightly different from Rails' original behavior:

  old: :long => lambda { |time| time.strftime("%A, #{}. %B %Y, %H:%M") }
  new: :long => lambda { |time| "%A, #{}. %B %Y, %H:%M" }
The old way should still work without throwing error messages, however, the dates and times will not be localized.

For further information on strftime formatting, see

Check installed locales

To display a list of all locales installed in config/locales, you can use the following rake command:

  rake locales

Customizing day and month names

If you localize your application for a language other than English, you most likely want to change the default month
and day names to your own countries' names. Here's how it's done:

      day_names: [Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday]
      abbr_day_names: [Sun, Mon, Tue, Wed, Thu, Fri, Sat]
      month_names: [~, January, February, March, April, May, June, July, August, September, October, November, December]
      abbr_month_names: [~, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec]
      order: [ :year, :month, :day ]

The only caveat here is that month_names and abbr_month_names *need* nil as their respective first elements. If you
don't use nil as the first element you'll end up with wrong dates (August will become September, etc.). Also note that
the definition of day names starts with Sunday (not Monday).

Changing the default locale

If you want to use a default locale other than "en", you have to tell the i18n plugin the locale you want to use by
default. Simply put the following line in an initializer in config/initializers or include it in your environment.rb:

    I18n.default_locale = :de


* Aslak Hellesøy (
* Andreas Korth
* Andreas Neuhaus

Bugs and Feedback

If you discover any bugs I'd appreciate if you sent me an e-mail to Please include a detailed
description of your problem if you want me to help you.

If you have positive feedback and want to drop me a line that's fine, too! :-)

Copyright (c) 2008 Clemens Kofler <>, released under the MIT license