Cloudflare Introduces Cache Response Rules for Enhanced CDN Caching Control

Introducing Cache Response Rules

Cloudflare has announced Cache Response Rules, a new rule type designed to operate after an origin server responds but before Cloudflare caches the content. This feature allows for modifications to HTTP response headers at a critical point in the caching process.

Addressing Caching Inefficiencies

The primary purpose of Cache Response Rules is to resolve common problems that hinder CDN caching efficiency. These include scenarios where headers like `Set-Cookie` or incorrect `Cache-Control` directives prevent content from being cached, even when it should be. Such issues often lead to increased origin bandwidth consumption and reduced performance.

Caching decisions are typically guided by the origin server's response headers. If these headers are misconfigured or contain directives intended for browsers rather than CDNs, the cache may become ineffective, forcing more requests back to the origin than necessary.

Impact on Cache Hit Ratio and Costs

By enabling the modification of response headers at the CDN edge, Cache Response Rules aim to improve cache hit ratios. This can significantly reduce the load on origin servers, decrease infrastructure costs, and enhance content delivery performance. The feature provides a mechanism to correct caching eligibility problems that manifest after the origin has replied, without requiring changes to the origin server itself.