in_memory_repo.rb

class MemoryRepo < Chassis:MemoryRepo
  def find(klass, id)
    super klass, id.to_i
  end

  def query_auth_token_with_code(klass, q)
    all(klass).find do |auth_token|
      auth_token.code == q.code
    end
  end

  # Implement a method to handle the specific selector
  # It's simple enough to just load all records then make
  # find/select calls to get the right stuff.
  def query_user_with_token(klass, q)
    all(klass).find do |user|
      user.token == q.token
    end
  end

  def query_user_with_phone_number(klass, q)
    all(klass).find do |user|
      user.phone_number == q.phone_number
    end
  end

  def query_groups_for_user(klass, q)
    set = all(klass).select do |group|
      group.users.include? q.user
    end

    if q.updated_after
      set.select! do |group|
        group.updated_at.utc >= q.updated_after.utc
      end
    end

    set
  end
end

user.rb

class User
  # Connect this class to the UserRepo
  include Chassis::Persistence

  attr_accessor :name, :phone_number, :token, :device

  def push?
    !!device.push_token
  end

  def save
    raise "Users must have tokens!" unless token
    super
  end
end

user_repo.rb

class UserRepo
  # Delegate operations to the default Repo with the correct
  # object_class
  extend Chassis::Repo::Delegation

  class UnknownTokenError < StandardError
    def initialize(token)
      @token = token
    end

    def to_s
      "Could not identifiy user with token: #{@token}"
    end
  end

  class UnknownPhoneNumber < StandardError
    def initialize(phone_number)
      @phone_number = phone_number
    end

    def to_s
      "Could not identifiy user with phone number: #{@phone_number}"
    end
  end

  # Define application specific methods used to access the objects
  # in a meaningful way
  class << self
    def find_by_token!(token)
      user = query UserWithToken.new(token)
      raise UnknownTokenError, token if user.nil?
      user
    end

    def find_by_phone_number!(phone_number)
      user = query UserWithPhoneNumber.new(phone_number)
      raise UnknownPhoneNumber, phone_number if user.nil?
      user
    end
  end
end

# Define selectors which are passed when querying the repo
UserWithToken = Struct.new :token
UserWithPhoneNumber = Struct.new :phone_number