Page and action caching in Ruby on Rails - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is page caching in Rails?

Page caching saves the entire HTML output of a page as a static file. When a user requests that page, the server serves the static file directly without running Rails code, making it very fast.

intermediate

How does action caching differ from page caching?

Action caching runs Rails filters and code before serving a cached version of the action's output. It allows authentication and other logic to run, unlike page caching which skips Rails entirely.

beginner

Which caching method is better for pages that require user authentication: page caching or action caching?

Action caching is better because it runs Rails filters like authentication before serving cached content. Page caching skips Rails and cannot check user permissions.

beginner

How do you enable page caching for a controller action in Rails?

You use the caches_page :action_name method inside the controller. This tells Rails to save the full HTML output of that action as a static file.

intermediate

What is a common downside of page caching?

Page caching can serve outdated content if the cached file is not expired or deleted after data changes. It also cannot handle dynamic content per user.

What does page caching in Rails do?

A Saves the full HTML output as a static file

B Caches only database queries

C Runs filters before caching

D Caches only JSON responses

Page caching saves the entire HTML output as a static file to serve quickly without running Rails.

Which caching method allows running authentication filters before serving cached content?

A Page caching

B Low-level caching

C Fragment caching

D Action caching

Action caching runs Rails filters like authentication before serving cached content.

How do you enable page caching for an action named 'show'?

A caches_action :show

B caches_page :show

C cache_page :show

D cache_action :show

The correct method is caches_page :show to enable page caching for the 'show' action.

What is a limitation of page caching?

A It is slower than action caching

B It cannot cache static files

C It skips Rails filters and cannot handle dynamic user content

D It requires database queries on every request

Page caching skips Rails filters and cannot handle dynamic content per user.

When is action caching preferred over page caching?

A When you need to run filters like authentication before caching

B When you want to cache static assets

C When you want to cache only partial views

D When you want to cache database queries

Action caching is preferred when filters like authentication must run before serving cached content.

Explain the difference between page caching and action caching in Rails.

Think about when Rails code runs in each caching method.

Describe a scenario where action caching is better than page caching.

Consider pages that show different content to logged-in users.