Link and URL helpers in Ruby on Rails - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the link_to helper do in Rails?

The link_to helper creates an HTML anchor (<a>) tag that links to a specified URL or path. It helps generate clickable links easily in views.

beginner

How do you generate a URL for a named route in Rails?

You use URL helpers that Rails creates from your routes, like posts_path or post_url(@post). These helpers return the path or full URL for the route.

intermediate

What is the difference between _path and _url helpers in Rails?

_path helpers return a relative path (like /posts/1), while _url helpers return the full URL including the domain (like http://example.com/posts/1).

intermediate

How can you add HTML options like CSS classes or data attributes to a link_to helper?

You pass a hash of HTML options as the last argument to <code>link_to</code>. For example, <code>link_to 'Home', root_path, class: 'nav-link', data: { toggle: 'dropdown' }</code> adds a class and data attribute.

intermediate

What helper would you use to create a link that submits a DELETE request in Rails?

Use link_to with the method: :delete option. Rails uses JavaScript to convert the link click into a DELETE HTTP request.

Which helper generates a clickable link in Rails?

A link_to

B url_for

C form_for

D button_to

link_to creates clickable links. url_for generates URLs but not links.

What does posts_path return?

A Full URL including domain

B JavaScript code

C Relative path like '/posts'

D HTML anchor tag

posts_path returns the relative path for posts.

How do you add a CSS class to a link_to helper?

A Use <code>class</code> key in options hash

B Pass class name as second argument

C Wrap link_to in a <code>&lt;div&gt;</code>

D Add class in controller

You add HTML options like class using a hash as the last argument.

Which option makes link_to send a DELETE request?

A method: :get

B method: :delete

C method: :post

D method: :put

method: :delete tells Rails to send a DELETE HTTP request.

What is the difference between post_path(@post) and post_url(@post)?

A No difference

B <code>post_path</code> returns full URL, <code>post_url</code> returns path

C One is for GET, other for POST

D <code>post_path</code> returns path, <code>post_url</code> returns full URL

post_path returns relative path; post_url returns full URL with domain.

Explain how to create a link in Rails that looks like a button and sends a DELETE request when clicked.

Think about link_to options and styling.

Describe the difference between URL helpers ending with _path and those ending with _url in Rails.

Consider what the browser needs to navigate.