Link and URL helpers in Ruby on Rails - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Rails link_to helper?

Consider the following code in a Rails view:

link_to 'Profile', user_path(42), class: 'btn'

What HTML does this generate?

Ruby on Rails

link_to 'Profile', user_path(42), class: 'btn'

A <button class="btn">Profile</button>

B <a href="/users/42" class="btn">Profile</a>

C <a href="/profile/42" class="btn">Profile</a>

D <a class="btn">Profile</a>

💡 Hint

Remember that user_path(42) generates the URL for user with id 42.

The link_to helper creates an anchor tag with href set to the URL generated by user_path(42). The class attribute is added as specified.

📝 Syntax

intermediate

Which option correctly uses link_to with a block?

Which of the following is the correct syntax to use link_to with a block in Rails?

A

link_to(user_path(5)) do
  'Click here'
end

B link_to(user_path(5)) { 'Click here' }

C link_to do user_path(5) 'Click here' end

D link_to(user_path(5)) do 'Click here' end

💡 Hint

Blocks in Ruby can be written with do...end or curly braces, but link_to with block usually uses do...end with proper indentation.

Option A correctly uses do...end block syntax with link_to, passing the URL as the first argument and the block returning the link text.

🔧 Debug

advanced

Why does this link_to raise an error?

Given this code:

link_to 'Edit', edit_user_path

Why does it raise an error?

Ruby on Rails

link_to 'Edit', edit_user_path

A edit_user_path is not a valid Rails helper

B link_to requires a block when using edit_user_path

C edit_user_path requires an argument for the user id, but none was given

D link_to cannot use path helpers as the second argument

💡 Hint

Check the method signature of edit_user_path in Rails routes.

The edit_user_path helper expects a user id argument to generate the correct URL. Omitting it causes an ArgumentError.

❓ state_output

advanced

What is the value of the generated URL?

Given this route:

resources :articles

and this code:

article_url(10, host: 'example.com')

What is the full URL generated?

Ruby on Rails

article_url(10, host: 'example.com')

A http://example.com/articles/10

B https://example.com/articles/10

C /articles/10

D http://localhost/articles/10

💡 Hint

article_url generates a full URL including protocol and host.

article_url generates a full URL with http by default and the given host 'example.com'.

🧠 Conceptual

expert

Which option correctly explains polymorphic_url usage?

In Rails, what does polymorphic_url(@comment) do if @comment belongs to a Post?

A Generates the URL for the comment nested under its post, like /posts/:post_id/comments/:id

B Generates the URL for the post only, ignoring the comment

C Raises an error because polymorphic_url cannot handle nested resources

D Generates the URL for the comment only, ignoring its parent post

💡 Hint

Polymorphic helpers build URLs based on the object and its associations.

polymorphic_url(@comment) generates the URL for the comment resource based on its class, like /comments/1. It ignores the parent post unless you pass an array like polymorphic_url([@comment.post, @comment]).