TemporalScopes

Providing temporal scopes for an ActiveRecord model to allow queries by time. For example, MyModel.now.where(...), my_model.archive, MyModel.past.where(...).

This is done by adding the database columns valid_from and valid_to to the model's table.

Usage

Make an `ActiveRecord` have temporal scopes

class Article < ActiveRecord::Base
  has_temporal_scopes

end

Archive an object

current_article = Article.create(title: 'My new article', body: 'Lorem ipsum')

past_article = Article.create(title: 'My new article', body: 'Lorem ipsum')
past_article.archive

# or provide a datetime:
past_article.archive at: 1.hour.ago

Use temporal scopes for filtering

Article.now                          #  => [current_article]
Article.past                         #  => [past_article]
Article.with_past                    #  => [current_article, past_article]

Note that the default scope is set to now.

Article.all                          #  => [current_article]
Article.now                          #  => [current_article]
Article.with_past                    #  => [current_article, past_article]
Article.without_temporal_condition   #  => [current_article, past_article]

Documentation

Further documentation can be found on rubydoc.info.

Caveats

This gem requires Rails 4.
There is only one valid_from and one valid_to time per object. Therefore, you can't keep track of first archiving an object and later un-archiving it. Un-archiving an object loses the information of first archiving it.
Currently, the future is not handled (Article.future and article.archive at: 1.hour.from.now do not work.) But this is planned to be implemented in the future.

Installation

Installing the Gem

Add the gem to your Gemfile:

# Gemfile
# ...
gem 'temporal_scopes'

Then, run bundle install.

Database

Add the columns valid_from and valid_to to the model you would like to have temporal scopes.

bundle exec rails generate migration add_validity_period_to_articles valid_from:datetime:index valid_to:datetime:index
bundle exec rake db:migrate

Author and License

Released under the MIT License.