First commit

Adding code samples from blog post. Basic Gemfile and Rakefile

Author: brynary

1-value-objects/rating.rb

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+class Rating
+  include Comparable
+
+  def self.from_cost(cost)
+    if cost <= 2
+      new("A")
+    elsif cost <= 4
+      new("B")
+    elsif cost <= 8
+      new("C")
+    elsif cost <= 16
+      new("D")
+    else
+      new("F")
+    end
+  end
+
+  def initialize(letter)
+    @letter = letter
+  end
+
+  def better_than?(other)
+    self > other
+  end
+
+  def <=>(other)
+    other.to_s <=> to_s
+  end
+
+  def hash
+    @letter.hash
+  end
+
+  def eql?(other)
+    to_s == other.to_s
+  end
+
+  def to_s
+    @letter.to_s
+  end
+end

2-service-objects/sessions_controller.rb

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+class SessionsController < ApplicationController
+  def create
+    user = User.where(email: params[:email]).first
+
+    if UserAuthenticator.new(user).authenticate(params[:password])
+      self.current_user = user
+      redirect_to dashboard_path
+    else
+      flash[:alert] = "Login failed."
+      render "new"
+    end
+  end
+end

2-service-objects/user_authenticator.rb

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+class UserAuthenticator
+  def initialize(user)
+    @user = user
+  end
+
+  def authenticate(unencrypted_password)
+    return false unless @user
+
+    if BCrypt::Password.new(@user.password_digest) == unencrypted_password
+      @user
+    else
+      false
+    end
+  end
+end

3-form-objects/signup.rb

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+class Signup
+  include Virtus
+
+  extend ActiveModel::Naming
+  include ActiveModel::Conversion
+  include ActiveModel::Validations
+
+  attr_reader :user
+  attr_reader :company
+
+  attribute :name, String
+  attribute :company_name, String
+  attribute :email, String
+
+  validates :email, presence: true
+  # … more validations …
+
+  # Forms are never themselves persisted
+  def persisted?
+    false
+  end
+
+  def save
+    if valid?
+      persist!
+      true
+    else
+      false
+    end
+  end
+
+private
+
+  def persist!
+    @company = Company.create!(name: company_name)
+    @user = @company.users.create!(name: name, email: email)
+  end
+end

3-form-objects/signups_controller.rb

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+class SignupsController < ApplicationController
+  def create
+    @signup = Signup.new(params[:signup])
+
+    if @signup.save
+      redirect_to dashboard_path
+    else
+      render "new"
+    end
+  end
+end

4-query-objects/abandoned_trial_query.rb

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+class AbandonedTrialQuery
+  def initialize(relation = Account.scoped)
+    @relation = relation
+  end
+
+  def find_each(&block)
+    @relation.
+      where(plan: nil, invites_count: 0).
+      find_each(&block)
+  end
+end

4-query-objects/notify_abandoned_trials.rb

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+class NotifyAbandonedTrials < Job
+  def run
+    AbandonedTrialQuery.new.find_each do |account|
+      account.send_offer_for_support
+    end
+  end
+end

4-query-objects/relation_composition.rb

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+old_accounts = Account.where("created_at < ?", 1.month.ago)
+old_abandoned_trials = AbandonedTrialQuery.new(old_accounts)

5-view-objects/donut_chart.rb

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+class DonutChart
+  def initialize(snapshot)
+    @snapshot = snapshot
+  end
+
+  def cache_key
+    @snapshot.id.to_s
+  end
+
+  def data
+    # pull data from @snapshot and turn it into a JSON structure
+  end
+end

6-policy-objects/active_user_policy.rb

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+class ActiveUserPolicy
+  def initialize(user)
+    @user = user
+  end
+
+  def active?
+    @user.email_confirmed? &&
+    @user.last_login_at > 14.days.ago
+  end
+end

7-decorators/comments_controller.rb

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+class CommentsController < ApplicationController
+  def create
+    @comment = FacebookCommentNotifier.new(Comment.new(params[:comment]))
+
+    if @comment.save
+      redirect_to blog_path, notice: "Your comment was posted."
+    else
+      render "new"
+    end
+  end
+end

7-decorators/facebook_comment_notifier.rb

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+class FacebookCommentNotifier
+  def initialize(comment)
+    @comment = comment
+  end
+
+  def save
+    @comment.save && post_to_wall
+  end
+
+private
+
+  def post_to_wall
+    Facebook.post(title: @comment.title, user: @comment.author)
+  end
+end

Gemfile

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+source "https://rubygems.org"
+
+gem "rspec"
+gem "rake"

Gemfile.lock

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+GEM
+  remote: https://rubygems.org/
+  specs:
+    diff-lcs (1.1.3)
+    rake (10.0.3)
+    rspec (2.12.0)
+      rspec-core (~> 2.12.0)
+      rspec-expectations (~> 2.12.0)
+      rspec-mocks (~> 2.12.0)
+    rspec-core (2.12.2)
+    rspec-expectations (2.12.1)
+      diff-lcs (~> 1.1.3)
+    rspec-mocks (2.12.2)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  rake
+  rspec

Rakefile

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+require 'rspec/core/rake_task'
+
+RSpec::Core::RakeTask.new(:spec)
+
+task default: :spec