For date and time validation in Ruby on Rails, I recommend the ValidatesTimeliness gem.

It seems to work with not only ActiveRecord but also Mongoid.

・adzap/validates_timeliness · GitHub

After installing the validates_timeliness gem, set up minimum Japanese error messages.

# config/locales/model.ja.yml
ja:
  activerecord:
    errors:
      messages:
        invalid_date: は正しい形式で入力してください。
        invalid_time: は正しい形式で入力してください。
        invalid_datetime: は正しい形式で入力してください。

Basic setup is just this, then you can set validation with validates_datetime etc. in the model.

# app/models/article.rb
class Article < ActiveRecord::Base
  validates_datetime :published_at
  validates_date :published_date
  validates_time :published_time
end

If the default date and time validation formats aren’t sufficient, you can add your own custom defined formats.

Turn on Plugin Parser with config.use_plugin_parser = true and add formats with config.parser.add_formats.

# config/initializers/validates_timeliness.rb
ValidatesTimeliness.setup do |config|

  config.use_plugin_parser = true
  config.parser.add_formats(:time, "%H:%M")

end

The above setting allows Time formats like “01:23”.

For more detailed information, check the Wiki.

・Plugin Parser · adzap/validates_timeliness Wiki

ValidatesTimeliness uses timeliness for Date/time parser, so you can check default formats from the timeliness page.

・timeliness/README.rdoc at master · adzap/timeliness · GitHub

ValidatesTimeliness is very convenient.

I think date and time formats are universal, so it would be nice if they were included by default in Rails. I wonder why they’re not?

That’s all from the Gemba.