They say it all started out with a big bang. But, what I wonder is, was it a big bang or did it just seem big because there wasn't anything else drown it out at the time? - Karl Pilkington

When you have a project in which you are not using Mongoid::Timestamps and you want to mock an object's creation time, you have to do some cumbersome operations in order to get those first 4 bytes of the ObjectId to represent the seconds since the Unix epoch that you want for that object.

Particularly, if you want to have two objects with the same creation time, it would not suffice to generate the IDs via the BSON::ObjectId.from_time method, since it would yield the same ID for both objects, and you probably do not want them to be seen as the same object.

This gem solves this little annoying issue by generating a unique ID for the given timestamp by using the other 8 bytes in ObjectId to generate the needed additional entropy.

Add this line to your application's Gemfile:

gem 'mongoid-bigbang'

And then execute:

$ bundle

Or install it yourself as:

$ gem install mongoid-bigbang

Whenever you want to generate a new ObjectId for a given timestamp, just call the Mongoid::Bigbang.id_from_time method, like follows:

# from time as String
Mongoid::Bigbang.id_from_time('18-01-2015 15:53:00 +0000')

# from time as Integer
Mongoid::Bigbang.id_from_time(1421596380)

# from time as Time
time = Time.parse('18-01-2015 15:53:00 +0000')
Mongoid::Bigbang.id_from_time(time)

It is recommended that you add the following to your spec_helper:

RSpec.configure do |config|
  config.before(:each) do
    Mongoid::Bigbang.clean
  end

  # your other configs...
end

1. Fork it ( https://github.com/dnlserrano/mongoid-bigbang/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request