JSON rendering in Ruby on Rails - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is JSON rendering in Rails?

JSON rendering in Rails means sending data from the server to the client in JSON format, which is easy for web apps to use and understand.

beginner

How do you render JSON in a Rails controller?

Use render json: @object inside a controller action to send the object as JSON to the client.

intermediate

What does render json: @user, only: [:id, :name] do?

It sends only the id and name fields of the @user object as JSON, hiding other data.

beginner

Why use JSON rendering instead of HTML in Rails APIs?

JSON is lightweight and easy for apps and JavaScript to read, making it perfect for APIs that send data, not full web pages.

intermediate

How can you customize JSON output in Rails?

You can use options like only, except, or methods in render json: or create custom serializers.

Which Rails method sends data as JSON to the client?

A redirect_to @data

B render json: @data

C send_data @data

D render html: @data

Use render json: @data to send JSON data from a Rails controller.

How do you exclude fields from JSON output in Rails?

A render json: @obj, only: [:field1]

B render json: @obj, hide: [:field4]

C render json: @obj, except: [:field2]

D render json: @obj, include: [:field3]

The except option excludes specified fields from the JSON output.

What format does Rails use when you write render json: @user?

A JSON

B HTML

C XML

D Plain text

The render json: method sends data in JSON format.

Which option adds extra methods to JSON output in Rails?

A methods

B only

C except

D include

The methods option adds custom methods to the JSON output.

Why is JSON preferred for APIs over HTML?

A JSON cannot be parsed by JavaScript

B JSON is heavier than HTML

C HTML is not supported by browsers

D JSON is easier for apps to read and use

JSON is lightweight and easy for apps and JavaScript to read, making it ideal for APIs.

Explain how to render JSON in a Rails controller and how to control which fields are included.

Think about how you send data and filter fields.

Describe why JSON rendering is important for building APIs in Rails.

Consider how apps use data from servers.