NullRecord

NullRecord is intended to make using the Null Object pattern with ActiveRecord easier. I initially had all of this logic in a project and decided to rip it out to make it easier to share among projects.

Not sure what the Null Object pattern is all about? Here's some resources to get you started:

Suspicions of nil by Sandi Metz

Null Objects and Falsiness by Advi Grimm

Is there a resource that you find helpful? Submit a Pull Request to add it to this list!

Installation

Add this line to your application's Gemfile:

gem 'null_record'

And then execute:

$ bundle

Or install it yourself as:

$ gem install null_record

If you're including this in a Rails application, create an initializer to include NullRecord in ActiveRecord::Base:

# config/initializers/null_record.rb

ActiveSupport.on_load(:active_record) do
  ActiveRecord::Base.send(:include, NullRecord)
end

Usage

NullRecord patches ActiveRecord finder methods to return a Null Object instead of nil. How neat! Check it out:

Standard ActiveRecord:

User.find(1)
=> ActiveRecord::RecordNotFound: Couldn't find User with 'id'=1

ActiveRecord w/ NullRecord:

User.find(1)
=> <null:User>

In order to take advantage of this patching, you need to call the has_null_record class method in your model:

class User < ActiveRecord::Base
  has_null_record
end

NullRecord uses the awesome Naught gem by Advi Grimm to build Null Objects. You can pass a configuration block to supplement the default configuration:

class User < ActiveRecord::Base
  has_null_record do |config|
    config.impersonate User

    def name
      "Please sign in..."
    end
  end
end

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/alexstophel/null_record. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.