Harnessing Client-Side Caching in Rails: The Power of `expires_in`
In your journey as a software developer, you’ll encounter myriad tools and techniques designed to optimize and streamline web applications. One such tool, often overlooked, is client-side caching. As backend and full-stack engineers, we spend hours crafting complex caching layers on the backend. However, we often overlook the most effective caching technique: having the request never reach the backend! Let’s delve into how requests get cached on the client using the Cache-Control
header.
Cache Control Header
At the core of client-side caching is the HTTP Cache-Control
header. This header offers directives to browsers (and other caching agents) about how they should cache the content and when to consider it stale.
The most common directives include:
- max-age: Specifies the number of seconds the response remains fresh.
- no-cache: Directs caching agents to revalidate with the server before using the cached version.
- public/private:
public
means that any cache, including CDNs, can store the response.private
ensures the response is user-specific and only cached at the end-user level.
By setting the appropriate cache control headers, developers can steer the caching behavior of browsers and intermediaries, thereby optimizing both server load and user experience.