ServiceAuthenticator

This is a lightweight gem built for the purposes of creating consistent configuration between services. Using this gem, you can store all service keys used for transactions between services on the ServiceAuthenticator::KeyChain and validate that any incoming requests to a service are using a valid key using ServiceAuthenticator::KeyValidator.

Add this line to your application's Gemfile:

gem 'service_authenticator'

And then execute:

$ bundle

Or install it yourself as:

$ gem install service_authenticator

ServiceAuthenticator was built to make the actual implementation of the gem as flexible as possible. With that in mind, here are a few examples of how ServiceAuthenticator can be used in an application:

1. Configuration of environment variables in a Rails initializer

#config/initializers/client_keys.rb

keychain_config = YAML.load(File.read(Rails.root.join('config', 'client_keys.yml')))[Rails.env].try(:deep_symbolize_keys!) || {
  example_service_one: [ENV['EXAMPLE_SERVICE_ONE_CLIENT_KEY']],
  example_service_two: [ENV['EXAMPLE_SERVICE_TWO_CLIENT_KEY']],
}

ServiceAuthenticator::KeyChain.add_keys do |keys|
  keys.example_service_one = keychain_config[:example_service_one]
  keys.example_service_two = keychain_config[:example_service_two]
end

Those keys can later be accessed using

ServiceAuthenticator::KeyChain.keys

2. Creating a controller concern to handle incoming client requests

#app/controllers/concerns/client_key_validator.rb

module ClientKeyValidator
  def validate_client_key(client_service)
    unless key_validator(client_service).valid_key?(key)
      render json: { message: 'invalid client key' }, status: 401
    end
  end

  private

  def key
    @key ||= request.env["HTTP_CLIENT_KEY"] || params[:client_key]
  end

  def key_validator(client_service)
    @key_validator ||= ServiceAuthenticator::KeyValidator.new(client_service)
  end
end

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.

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/service_authenticator. 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.

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