Caching is an essential technique in web development to improve the performance of web applications. Rails provides a built-in caching framework that enables developers to cache the results of expensive operations to improve application performance. In this blog post, we will discuss the basics of caching in Rails and how to use Rails Cache.
What is Caching?
Caching is the process of storing frequently accessed data in memory or on disk to reduce the time it takes to retrieve the data again. When a web application receives a request, it may perform expensive operations, such as querying a database or rendering a view. Caching allows these results to be stored and retrieved quickly, reducing the overhead of these operations.
Caching in Rails:
Rails provides a built-in caching framework that supports different caching strategies such as page caching, action caching, fragment caching, and low-level caching. The Rails cache store is an interface that allows developers to store and retrieve cached data. Rails supports several cache stores, including file store, memory store, and Redis.
The Rails cache store interface provides the following methods:
- fetch: retrieves the value of a given key from the cache. If the key is not present in the cache, the provided block is executed, and its result is stored in the cache.
- read: retrieves the value of a given key from the cache. If the key is not present in the cache, nil is returned.
- write: stores the value of a given key in the cache.
- delete: removes the value of a given key from the cache.
Stup by Stup guide to use Rails cache
Caching is a mechanism that helps to speed up the web application by storing frequently used data in memory for faster access. Rails, being a web development framework, also provides support for caching through various caching mechanisms like page caching, action caching, fragment caching, and more.
In this guide, we will explore the steps involved in using the Rails cache.
Step 1: Configure Rails Cache
Rails comes with a built-in caching mechanism that can be configured in the config/application.rb file. You can choose to configure any caching store according to your requirements, such as memcached, Redis, or file store.
Here's an example of configuring the Rails cache using memcached:
config.cache_store = :mem_cache_store, "localhost:11211", { :namespace => "myapp" }
Step 2: Set up Cache Keys
Cache keys are unique identifiers that help to store and retrieve data from the cache. The best practice is to use a unique cache key for each cached item
def cache_key
"#{self.class.name}/#{id}-#{updated_at.to_i}"
end
Step 3: Using Rails Cache
Rails cache can be used in various ways, such as caching views, caching database queries, and caching API responses. Let's take a look at a few examples:
Example 1: Caching Views
Rails allows you to cache entire views or partials using the cache helper method. Here's an example of caching a view:
<% cache("homepage") do %>
<div id="posts">
<% @posts.each do |post| %>
<%= render partial: "post", locals: { post: post } %>
<% end %>
</div>
<% end %>
In the above code, the cache method will store the rendered HTML of the view in the cache with the key "homepage". If the view is requested again, the cached HTML will be returned instead of rendering the view again.
Example 2: Caching Database Queries
Rails also provides support for caching database queries using the Rails.cache.fetch method. Here's an example of caching a database query:
@posts = Rails.cache.fetch("all_posts", expires_in: 1.hour) do
Post.all
end
In the above code, the Rails.cache.fetch method will store the result of the database query in the cache with the key "all_posts". If the same query is requested again within one hour, the cached result will be returned instead of querying the database again.
Example 3: Caching API Responses
Rails also allows you to cache API responses using the Rails.cache.fetch method. Here's an example of caching an API response:
response = Rails.cache.fetch("api_response", expires_in: 1.hour) do
RestClient.get("http://api.example.com/posts")
end
In the above code, the Rails.cache.fetch method will store the API response in the cache with the key "api_response". If the same API is requested again within one hour, the cached response will be returned instead of making the API call again.
Rails Cache in Controller
class ProductsController < ApplicationController
def index
@products = Rails.cache.fetch("products") do
Product.all
end
end
end
In the above example, the fetch method retrieves the value of the "products" key from the cache. If the key is not present in the cache, the block is executed, and the result is stored in the cache with the given key.
Conclusion
Caching is an essential aspect of web development that helps to speed up the web application by storing frequently used data in memory. In this guide, we explored how to use the Rails cache by configuring the cache store, setting up cache keys, and caching views, database queries, and API responses. By using caching mechanisms in Rails, we can significantly improve the performance of our web applications.
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