Form object pattern in Ruby on Rails - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a form object class inheriting from ActiveModel::Model.

Ruby on Rails

class UserForm
  include [1]

  attr_accessor :name, :email
end

Drag options to blanks, or click blank then click option'

AActiveModel::Model

BActiveRecord::Base

CActionController::Base

DActiveSupport::Concern

Attempts:

3 left

💡 Hint

Common Mistakes

Using ActiveRecord::Base instead of ActiveModel::Model

Forgetting to include any module

The form object pattern uses ActiveModel::Model to get model-like behavior without database persistence.

2fill in blank

medium

Complete the code to add a validation for presence of :email in the form object.

Ruby on Rails

class UserForm
  include ActiveModel::Model

  attr_accessor :name, :email

  validates :email, [1]: true
end

Drag options to blanks, or click blank then click option'

Auniqueness

Bformat

Cpresence

Dlength

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'length' instead of 'presence' for required fields

Using 'uniqueness' which requires database

Use validates :email, presence: true to ensure the email is not blank.

3fill in blank

hard

Fix the error in the save method to return false if the form is invalid.

Ruby on Rails

def save
  return false unless [1]
  # persist data here
  true
end

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Avalidate

Bsave!

Cvalidates

Dvalid?

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'validate' which runs validations but does not return boolean

Using 'save!' which is for ActiveRecord models

The valid? method runs validations and returns true or false.

4fill in blank

hard

Fill both blanks to define an initialize method that sets attributes from params hash.

Ruby on Rails

def initialize(params = {})
  params.each do |key, value|
    [1].send("[2]=", value)
  end
end

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Aself

Bparams

Ckey

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'params.send' instead of 'self.send'

Using 'value' instead of 'key' for method name

Use self.send("key=", value) to assign each attribute dynamically.

5fill in blank

hard

Fill all three blanks to define a save method that validates, creates a User, and returns true if successful.

Ruby on Rails

def save
  return false unless [1]
  user = User.new(name: [2], email: [3])
  user.save
end

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Avalid?

Bname

Cemail

Dsave!

Attempts:

3 left

💡 Hint

Common Mistakes

Calling save! instead of save which raises exceptions

Not checking validity before saving

The save method first checks validity, then creates a User with form attributes, and saves it.