Sending emails from controllers in Ruby on Rails - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to send a welcome email from the controller.

Ruby on Rails

UserMailer.[1](user).deliver_now

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

Awelcome_email

Bsend_email

Cemail_user

Dnotify_user

Attempts:

3 left

💡 Hint

Common Mistakes

Using a method name that does not exist in the mailer.

Forgetting to call deliver_now or deliver_later to send the email.

The mailer method welcome_email is called to send the email immediately with deliver_now.

2fill in blank

medium

Complete the code to pass the user object to the mailer method.

Ruby on Rails

UserMailer.welcome_email([1]).deliver_now

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

Acurrent_user

Bemail

Cparams

Duser

Attempts:

3 left

💡 Hint

Common Mistakes

Passing incorrect variables like params or email string instead of the user object.

The user object is passed to the mailer method to personalize the email.

3fill in blank

hard

Fix the error in sending the email asynchronously.

Ruby on Rails

UserMailer.welcome_email(user).[1]

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

Asend_later

Bsend_now

Cdeliver_later

Ddeliver_now

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'deliver_now' sends the email immediately, not asynchronously.

Using 'send_later' or 'send_now' are not valid Rails mailer methods.

To send emails asynchronously in Rails, use deliver_later.

4fill in blank

hard

Fill both blanks to create and send a password reset email asynchronously.

Ruby on Rails

UserMailer.[1]([2]).deliver_later

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

Apassword_reset

Buser

Creset_password

Dcurrent_user

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect method names like 'reset_password'.

Passing wrong variables like 'current_user' if not defined.

The mailer method password_reset is called with the user object, then sent asynchronously with deliver_later.

5fill in blank

hard

Fill all three blanks to send a notification email with a custom subject and recipient.

Ruby on Rails

UserMailer.[1]([2]).with(subject: [3]).deliver_now

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

Anotification_email

Buser

C"Account Update"

Dadmin

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the subject as a symbol instead of a string.

Using wrong variable names for the user or subject.

The notification_email method is called with the user object, a custom subject "Account Update" is passed via with, then sent immediately.

Practice

1. What is the main role of a controller when sending emails in Rails?

easy

A. To call the mailer method and trigger the email sending

B. To write the email content and layout

C. To configure the SMTP settings

D. To store email templates in the database

Solution

1. Step 1: Understand controller responsibility

   Controllers handle user requests and trigger actions like sending emails by calling mailer methods.

2. Step 2: Identify mailer role

   Mailers contain email content and setup, not controllers.

3. Final Answer:

   To call the mailer method and trigger the email sending -> Option A

4. Quick Check:

   Controllers trigger mailers [OK]

Hint: Controllers trigger mailers, mailers build emails [OK]

Common Mistakes:

• Writing email content in controllers
• Configuring SMTP in controllers
• Storing templates in controllers

2. Which of the following is the correct syntax to send an email immediately from a controller using a mailer named UserMailer and a method welcome_email?

easy

A. UserMailer.welcome_email.deliver_later(params[:user])

B. UserMailer.welcome_email(params[:user]).deliver_now

C. UserMailer.deliver_now.welcome_email(params[:user])

D. UserMailer.welcome_email(params[:user]).send_now

Solution

1. Step 1: Identify mailer method call

   The mailer method is called with parameters: UserMailer.welcome_email(params[:user]).

2. Step 2: Use correct delivery method

   To send immediately, use deliver_now after the mailer method call.

3. Final Answer:

   UserMailer.welcome_email(params[:user]).deliver_now -> Option B

4. Quick Check:

   Immediate send = deliver_now after mailer call [OK]

Hint: Call mailer method then add .deliver_now for immediate send [OK]

Common Mistakes:

• Using deliver_later for immediate send
• Calling deliver_now before mailer method
• Using non-existent send_now method

3. Given this controller code snippet:

def create
  @user = User.new(user_params)
  if @user.save
    UserMailer.welcome_email(@user).deliver_later
    redirect_to root_path, notice: 'User created!'

What happens when this code runs successfully?

medium

A. The welcome email is sent immediately before redirecting

B. The redirect happens only after the email is sent

C. The welcome email is queued to be sent later, then redirect happens

D. The email is never sent because deliver_later is incorrect here

Solution

1. Step 1: Understand deliver_later behavior

   Calling deliver_later queues the email to be sent asynchronously in the background.

2. Step 2: Analyze controller flow

   The redirect happens immediately after queuing the email, not waiting for sending.

3. Final Answer:

   The welcome email is queued to be sent later, then redirect happens -> Option C

4. Quick Check:

   deliver_later queues email, redirect immediate [OK]

Hint: deliver_later queues email, does not block controller [OK]

Common Mistakes:

• Thinking deliver_later sends email immediately
• Assuming redirect waits for email sending
• Believing deliver_later is invalid syntax

4. Identify the error in this controller code snippet:

def notify
  UserMailer.notify_user.deliver_now(user)
  redirect_to dashboard_path
end

medium

A. deliver_now is not a valid method for sending emails

B. redirect_to should be called before sending email

C. notify_user method cannot be called without parentheses

D. deliver_now should be called after passing user argument to notify_user

Solution

1. Step 1: Check method call order

   The user argument must be passed to notify_user before calling deliver_now.

2. Step 2: Correct syntax

   Correct call: UserMailer.notify_user(user).deliver_now.

3. Final Answer:

   deliver_now should be called after passing user argument to notify_user -> Option D

4. Quick Check:

   Pass args before deliver_now [OK]

Hint: Pass arguments inside mailer method, then call deliver_now [OK]

Common Mistakes:

• Calling deliver_now with arguments
• Calling redirect_to before email
• Misusing parentheses in method calls

5. You want to send a confirmation email from a controller only if the user has a verified email address. Which is the best way to implement this?

hard

A. In the controller, check if user.verified? then call UserMailer.confirmation_email(user).deliver_now

B. Always call UserMailer.confirmation_email(user).deliver_now and check verification inside the mailer

C. Send the email unconditionally and add a condition in the email template

D. Call UserMailer.confirmation_email.deliver_now(user) without any condition

Solution

1. Step 1: Decide where to check condition

   Controller should decide if email should be sent based on user verification status.

2. Step 2: Call mailer only when condition is true

   Call UserMailer.confirmation_email(user).deliver_now only if user.verified? is true.

3. Final Answer:

   In the controller, check if user.verified? then call UserMailer.confirmation_email(user).deliver_now -> Option A

4. Quick Check:

   Check condition in controller before sending email [OK]

Hint: Check conditions in controller before calling mailer [OK]

Common Mistakes:

• Checking conditions inside mailer or template
• Sending emails unconditionally
• Passing arguments after deliver_now