Root route in Ruby on Rails - Cheat Sheet & Quick Revision

Recall & Review

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What is the purpose of the root route in a Rails application?

The root route defines the default page users see when they visit the base URL of the app, like visiting www.example.com without any extra path.

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How do you set the root route in Rails?

You set it in the config/routes.rb file using root 'controller#action'. For example, root 'home#index' makes the home controller's index action the homepage.

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What happens if you don't define a root route in a Rails app?

Visiting the base URL will cause an error because Rails won't know which page to show by default.

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Can the root route point to any controller and action?

Yes, the root route can point to any controller and action you want to be the homepage, as long as that action exists and can render a view.

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Example: What does this line do? root 'dashboard#main'

It sets the root URL to show the main action inside the dashboard controller. So visiting the base URL loads that page.

Where do you define the root route in a Rails app?

A app/controllers/application_controller.rb

B config/routes.rb

C config/database.yml

D app/views/layouts/application.html.erb

The root route is set in the config/routes.rb file.

What does this line do? root 'welcome#home'

A Redirects all routes to welcome#home

B Creates a new controller named welcome

C Sets the homepage to the home action in welcome controller

D Deletes the welcome controller

It sets the root URL to show the home action inside the welcome controller.

What happens if you visit the base URL without a root route defined?

A You get an error page

B Rails shows a default homepage

C Rails redirects to /index

D Rails shows a blank page

Without a root route, Rails does not know which page to show and returns an error.

Can the root route point to a non-existent action?

A No, it must point to a view file

B Yes, Rails creates the action automatically

C Yes, but it shows a blank page

D No, it must point to an existing action

The root route must point to an existing controller action to work properly.

Which of these is a valid root route declaration?

A root 'pages#about'

B root to: 'pages#about'

C root pages#about

D root: 'pages#about'

The correct syntax is root 'controller#action'.

Explain how to set a root route in a Rails app and why it is important.

Think about the file where routes live and what the root route controls.

Describe what happens if a Rails app does not have a root route defined and a user visits the base URL.

Consider what Rails needs to know to show a page at the main URL.