Ruby on Rails Technology & Digital Applications 5

Question 1

In a Rails app, which approach lets you serve a Vue.js or React SPA while still using Rails for the API?

Accepted Answer

Serve the SPA separately (e.g., Vercel/Netlify) and point it at a Rails API-only app

Answer

A decoupled architecture serves the SPA via a CDN or static host while the Rails API-only app handles data requests, enabling independent deployment.

Question 2

Which Rails helper method generates a `<meta>` CSRF token tag used by JavaScript fetch requests?

Accepted Answer

csrf_meta_tags

Answer

`csrf_meta_tags` renders `` and `` tags that JS can read to include the token in AJAX requests.

Question 3

What does the `jbuilder` gem enable in Rails views?

Accepted Answer

A DSL for building JSON responses in `.json.jbuilder` view templates

Answer

Jbuilder provides a Ruby DSL in `.json.jbuilder` templates to construct JSON responses with conditional logic and partials.

Question 4

Which Active Record method efficiently loads associated records to prevent N+1 queries in a Rails API response?

Accepted Answer

preload, eager_load, or includes

Answer

`includes`, `preload`, and `eager_load` all solve N+1 by loading associations in separate or joined queries before iteration.

Question 5

When configuring Rails to send emails via SendGrid in production, which setting specifies the SMTP delivery method?

Accepted Answer

config.action_mailer.delivery_method = :smtp with smtp_settings

Answer

ActionMailer uses `delivery_method: :smtp` with host/port/credentials in `smtp_settings` to route mail through SendGrid's SMTP relay.

Ruby on Rails Practice Test