hexarch in rails

01_original.rb

# Original Rails controller and action
class EmployeesController < ApplicationController
  def create
    @employee = Employee.new(employee_params)
    
    if @employee.save
      redirect_to @employee, notice: "Employee #{@employee.name} created"
    else
      render :new
    end
  end
end

02_protocols.rb

describe 'persistence_adapter', shared: true do
  describe '.new(options)' do
    it 'returns a saveable object' do
      expect(described_type.new({})).to respond_to(:save)
    end
  end

  describe '#save' do
    it 'sets the id' do
      described_type.new({}).tap do |s| 
        expect(s.id).to be_nil
        s.save
        expect(s.id).to_not be_nil
      end
    end
  end

  describe '#name' do
    it 'returns the name passed to initialize' do
      expect(described_type.new(name: 'Pat').name).to eq('Pat')
    end
  end
end

describe 'view_adapter', shared: true do
  describe '#redirect_to(employee, options)' do
    let(:employee) { double('employee', id: 123, name: 'Pat Maddox') }

    it 'accepts an employee with a notice: option' do
      subject.redirect_to employee, notice: "yer on notice"
    end
  end

  describe '#render(page)' do
    it 'accepts :new' do
      subject.render :new
    end
  end

  describe '#employee_params' do
    it 'returns a hash with :name' do
      expect(subject.employee_params[:name]).to be_present
    end
  end
end

03_persistence.rb

class PersistableInMemory
  attr_reader :id, :name

  def initialize(attributes)
    @name = attributes[:name]
  end

  def save
    @id = [Time.now, rand(1_000_000_000_000)].join
  end
end

04_io.rb

class TerminalAdapter
  def redirect_to(employee, options)
    puts "[LOG] redirecting to #{employee}"
    puts options[:notice]
  end

  def render(page)
    puts "Press return to create a new employee" if page == :new
  end

  def employee_params
    print "Name? "
    { name: gets.chomp }
  end
end

05_rewire.rb

ApplicationController = TerminalAdapter
Employee = PersistableInMemory

06_full_example.rb

class PersistableInMemory
  attr_reader :id, :name

  def initialize(attributes)
    @name = attributes[:name]
  end

  def save
    @id = [Time.now, rand(1_000_000_000_000)].join
  end
end

class TerminalAdapter
  def redirect_to(employee, options)
    puts "[LOG] redirecting to #{employee}"
    puts options[:notice]
  end

  def render(page)
    puts "Press return to create a new employee" if page == :new
  end

  def employee_params
    print "Name? "
    { name: gets.chomp }
  end
end

ApplicationController = TerminalAdapter
Employee = PersistableInMemory

# Original Rails controller and action
class EmployeesController < ApplicationController
  def create
    @employee = Employee.new(employee_params)
    
    if @employee.save
      redirect_to @employee, notice: "Employee #{@employee.name} created"
    else
      render :new
    end
  end
end

app = EmployeesController.new
app.create
app

07_hexy.rb

# Original Rails controller and action with dependencies inverted
class EmployeesController
  def initialize(io, db)
    @io, @db = io, db
  end

  def create
    @employee = @db.new(@io.employee_params)
    
    if @employee.save
      @io.redirect_to @employee, notice: "Employee #{@employee.name} created"
    else
      @io.render :new
    end
  end
end

class PersistableInMemory
  attr_reader :name

  def initialize(attributes)
    @name = attributes[:name]
  end

  def save
    @id = [Time.now, rand(1_000_000_000_000)].join
  end
end

class TerminalAdapter
  def redirect_to(employee, options)
    puts "[LOG] redirecting to #{employee}"
    puts options[:notice]
  end

  def render(page)
    puts "Press return to create a new employee" if page == :new
  end

  def employee_params
    print "Name? "
    { name: gets.chomp }
  end
end

app = EmployeesController.new TerminalAdapter.new, PersistableInMemory
app.create
app