Tealeaf Course 2 Quiz: Lesson 2

course_2_lesson_2_quiz

Lesson 2 Quiz answers 

1. Using the resources keyword exposes the following routes:
  (ex. resources :posts)
  
  GET   /posts   posts#index      posts 
  GET   /posts/:id    posts#show    post
  GET   /posts/new    posts#new     new_post
  POST  /posts        posts#create  
  GET   /posts/:id/edit   posts#edit    edit_post 
  PUT/PATCH    /posts/:id      post#update
  DELETE      /posts/:id        post#destroy
  
2. REST stands for representational state transfer. It is a style of designing web applications where each compenent is viewed as a resource that can either be created, read, updated or deleted. These actions correspond with the CRUD actions for a database and also the 4 main HTTP verbs: POST, GET, PUT/PATCH, & DELETE. 

3. The major difference between model-backed and non model-backed form helpers is flexibility. 
  A model-backed form helper method must adhere to an existing attribute in the model when used and cannot be named
  arbitrarily. However, non model backed form helpers are not constrained this way and can be used to generate any type of element on a   form.

4. The form_for method knows how to build the <form> element based on the object passed to it (ex. form_for @post), and the additional methods called on the form-builder object that form_for uses to create the form ( f.text_field :name, etc).    

5. The general pattern we use in the controller actions that handle form submission is:

  def create
    @object = Class.new(object_params)
    
    if @object.save
      flash[:notice] = "Happy path. It worked."
      redirect_to object_path(@object)
    else
      render 'new'
    end  
  end
   
  def update 
    @object = Class.find(params[:id])
    
    if @object.update(object_params)
      flash[:notice] = "Update successful"
      redirect_to objects_path
    else
      render 'edit'
    end  
  end 

6. Rails validations get triggered at the point a save is attempted on the database. Any errors are saved on the object itself. To show   the validation messages on the UI we would do the following:
  <% if @object.errors.any? %>
    <% @object.errors.full_messages.each do |msg| %>
      <%= msg %>
    <% end %>
  <% end %>  

7. Rails helpers are methods which are used to extract repeated logic (that doesn't pertain to the applications' business logic) from views & controllers into a single location. The helper method can then be called throughout application. This is also used to keep the code DRY and is easier to maintain and make changes. 

8. Rails partials provide us with a way to store common view template code in a single file. The code in this file can then be rendered in a template with one line of code (ex, <%= render 'form' %>). Partials help keep the code DRY.  

9. We use partials when dealing with template code. Helpers are used when defining logic in methods to be reused throughout the application.

10. Non model backed forms are used whenever we don't have to bind a form to a model.