How to Increase Performance in Rails: the stale? method

Fernando Tinoco
Fernando Tinoco
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On his last appearance on Talk With the Experts, SitePoint’s developer Mal Curtis was asked about performance issues on Ruby on Rails apps and ways to increase speed. One of his suggestion was to use the stale? method, a sometimes underused function in Rails that can, out of the box, do a very good job of automatically reducing perceived latency. In a nutshell, the stale? method prevents rendering of an entire template when there is no need to. Rails and the browser handle everything correctly for you as a status 304 (not modified) is returned instead a normal status 200. Mal has put the video below together to show, in 3 minutes, how to use the stale? method on its most basic form to increase speed on a Ruby on Rails app. Great tip. [youtube fzp14eDwJns]

Frequently Asked Questions (FAQs) about Increasing Performance in Rails

What is the role of ActionController::Base.stale? in Rails?

ActionController::Base.stale? is a method in Rails that is used to manage the freshness of a particular resource. It checks if the request is stale, meaning if the resource has been modified since the last request. If it is stale, it means the resource has been updated and the server needs to send a new copy to the client. This method is crucial in improving the performance of Rails applications as it helps to avoid unnecessary data transfer and processing.

How does stale? method improve Rails performance?

The stale? method improves Rails performance by reducing unnecessary data transfer and processing. It does this by checking if a resource has been modified since the last request. If it hasn’t, the server can send a 304 Not Modified response, instead of sending the entire resource again. This saves bandwidth and processing power, leading to faster response times and a more efficient application.

What is ActionController::ConditionalGet?

ActionController::ConditionalGet is a module in Rails that provides methods to handle conditional GET requests. These are requests where the server responds differently based on the state of the resource. The methods provided by this module, including stale?, help to improve the performance of Rails applications by reducing unnecessary data transfer and processing.

How does Rails 5 support passing a collection of records to fresh_when and stale?

In Rails 5, you can pass a collection of records to the fresh_when and stale? methods. These methods will then check the freshness of the entire collection, rather than just a single record. This can improve performance when dealing with large collections, as it reduces the number of requests needed to check the freshness of each individual record.

How can I use the stale? method in my Rails application?

To use the stale? method in your Rails application, you need to call it in your controller action, passing in the resource you want to check. If the resource is stale, the method will yield to the block provided, allowing you to update the resource. If the resource is not stale, the method will automatically send a 304 Not Modified response.

What is the difference between fresh_when and stale? methods in Rails?

Both fresh_when and stale? methods in Rails are used to manage the freshness of a resource. The main difference is how they respond when the resource is not fresh. The fresh_when method sets the ETag and Last-Modified headers in the response, while the stale? method also checks these headers in the request and sends a 304 Not Modified response if the resource is not stale.

How does Rails handle conditional GET requests?

Rails handles conditional GET requests using the methods provided by the ActionController::ConditionalGet module. These methods, including stale?, check the ETag and Last-Modified headers in the request against the current state of the resource. If the resource has not been modified, a 304 Not Modified response is sent, otherwise, the updated resource is sent.

What is a 304 Not Modified response in Rails?

A 304 Not Modified response in Rails is sent when a client makes a conditional GET request for a resource that has not been modified since the last request. This response tells the client that the cached version of the resource is still valid, so there is no need to download the resource again. This saves bandwidth and improves the performance of the application.

How can I improve the performance of my Rails application?

There are many ways to improve the performance of your Rails application. One way is to use the stale? method to manage the freshness of your resources, reducing unnecessary data transfer and processing. Other ways include optimizing your database queries, using caching, and reducing the number of HTTP requests.

What is ETag in Rails?

ETag is a header in HTTP that is used for web cache validation. It is a unique identifier assigned to a specific version of a resource. When a client makes a request, it can include the ETag of the cached version of the resource. The server can then compare this ETag with the current ETag of the resource to determine if the resource has been modified. If not, a 304 Not Modified response is sent, saving bandwidth and improving performance.