Why structure conventions matter in Ruby on Rails - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a Rails controller named PostsController.

Ruby on Rails

class PostsController < [1]
  def index
    @posts = Post.all
  end
end

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AActiveRecord

BApplicationRecord

CActionView

DApplicationController

Attempts:

3 left

💡 Hint

Common Mistakes

Using ActiveRecord as a parent class for controllers.

Confusing ApplicationRecord with ApplicationController.

In Rails, controllers inherit from ApplicationController to get the basic controller behavior.

2fill in blank

medium

Complete the code to render the 'show' view in the controller action.

Ruby on Rails

def show
  @post = Post.find(params[:id])
  [1]
end

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Arender json: @post

Bredirect_to posts_path

Crender :show

Dredirect_to @post

Attempts:

3 left

💡 Hint

Common Mistakes

Using redirect instead of render when you want to display a view.

Rendering JSON when the goal is to show an HTML page.

The render :show command tells Rails to display the 'show' template for the current action.

3fill in blank

hard

Fix the error in the model by completing the validation syntax.

Ruby on Rails

class Post < ApplicationRecord
  validates :title, [1]: true
end

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Apresence

Bexistence

Cvalid

Drequired

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'existence' which is not a valid Rails validator.

Confusing 'required' with the correct validator keyword.

The correct validation to ensure a field is not empty is presence: true.

4fill in blank

hard

Fill both blanks to complete the route definition for posts resource.

Ruby on Rails

Rails.application.routes.draw do
  [1] :posts, only: [:index, [2]]
end

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Aresources

Bshow

Cget

Dpost

Attempts:

3 left

💡 Hint

Common Mistakes

Using get instead of resources for multiple routes.

Including HTTP verbs instead of action names in the only array.

The resources method defines RESTful routes, and show is one of the common actions.

5fill in blank

hard

Fill all three blanks to complete the migration creating a posts table with title and body.

Ruby on Rails

class CreatePosts < ActiveRecord::Migration[6.1]
  def change
    create_table :posts do |[1]|
      [2].string :title
      [3].text :body
    end
  end
end

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At

Btable

Ccolumn

Drecord

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently inside the block.

Trying to use table or column as the block variable.

In migrations, the block variable (commonly t) is used to define columns like t.string and t.text.