ActiveModel::Niceties

My presentation at Codeminer 42 Tech Talk on 08/28/2012

Transcript

1. ActiveModel::Niceties Tuesday, August 28, 12
2. $ whoami Cainã Costa @cfcosta_ Developer at Codeminer42 $ Tuesday, August 28, 12
3. Let’s say we have a form... Tuesday, August 28, 12
4. <%= form_for @contact do |f| %> <%= f.label :name %> <%= f.text_field :name %> <%= f.label :email %> <%= f.text_field :email %> <%= f.label :body %> <%= f.text_area :body %> <%= f.submit %> <% end %> Tuesday, August 28, 12
5. class ContactController < ApplicationController def new @contact = Contact.new end def create @contact = Contact.new(params[:contact]) if @contact.valid? # Code to send the contact mail else render 'new' end end end Tuesday, August 28, 12
6. class Contact end Tuesday, August 28, 12
7. Does that work? Tuesday, August 28, 12
8. Nope! Tuesday, August 28, 12
9. ActiveModel::Naming to the rescue! Tuesday, August 28, 12
10. class ContactForm extend ActiveModel::Naming end Tuesday, August 28, 12
11. Not yet... Tuesday, August 28, 12
12. class ContactForm extend ActiveModel::Naming include ActiveModel::Conversion end Tuesday, August 28, 12
13. What now? Tuesday, August 28, 12
14. class ContactForm extend ActiveModel::Naming include ActiveModel::Conversion def persisted? false end end Tuesday, August 28, 12
15. Looks like the problem is on our code now... Tuesday, August 28, 12
16. class ContactForm extend ActiveModel::Naming include ActiveModel::Conversion attr_accessor :name, :email, :body def initialize(attributes = {}) attributes.each_pair do |k,v| send(:”#{k}=”, v) end end def persisted? false end end Tuesday, August 28, 12
17. But when we try to save it... Tuesday, August 28, 12
18. Ok, Let’s add some validations to it! Tuesday, August 28, 12
19. FactoryGirl.define do factory :contact_form do name { Faker::Name.name } email { Faker::Internet.email } body { Faker::Lorem.paragraphs(3).join("\n") } end end But some tests first... Tuesday, August 28, 12
20. Factories are not only for database models! Tuesday, August 28, 12
21. require 'spec_helper' describe Contact do subject { build :contact } it "is valid with valid attributes" do should be_valid end it "is not valid without name" do subject.name = nil should_not be_valid end it "is not valid without (or with invalid) email" do subject.email = nil should_not be_valid subject.email = "invalid email" should_not be_valid end it "is not valid without body" do subject.body = nil should_not be_valid end end Tuesday, August 28, 12
22. class Contact extend ActiveModel::Naming include ActiveModel::Conversion include ActiveModel::Validations attr_accessor :name, :email, :subject, :body validates :name, :email, :body, presence: true validates :email, format: { with: %r{.+@.+\..+} }, allow_blank: true def initialize(attributes = {}) attributes.each do |k, v| send("#{k}=", v) end end def persisted? false end end Tuesday, August 28, 12
23. Does it work? You can bet your sorry ass that it does. Tuesday, August 28, 12
24. But what about Mass- assignment Security? Tuesday, August 28, 12
25. Let’s do it on the right place! THE CONTROLLER! Tuesday, August 28, 12
26. class ContactsController < ApplicationController include ActiveModel::MassAssignmentSecurity attr_accessible :name, :email, :password # #new removed for briefness def create @contact = Contact.new(contact_params) if @contact.valid? # blabla else render 'new' end end private def contact_params params[:contact] ||= {} sanitize_for_mass_assignment(params[:contact]) end end Tuesday, August 28, 12
27. What about roles? def contact_params role = current_user.admin? ? :user : :admin params[:contact] ||= {} sanitize_for_mass_assignment(params[:contact], as: role) end Tuesday, August 28, 12
28. Rails have a lot of things ready for use. Just use them. Tuesday, August 28, 12
29. Questions? Tuesday, August 28, 12