Clearing Nginx's HTTP Cache
I recently implemented Nginx HTTP content caching on our WordPress web servers to improve page load speeds and eliminate redundant, unneeded server-side page rendering. Caching the pages was relatively straightforward, but clearing the cache required a custom workaround.
Nginx comes in two versions: free and “Nginx Plus” at $2,500/year. The free version of Nginx does not offer the needed cache-clearing features of Nginx Plus, and I wasn’t comfortable paying $20,000 for 8 instances without trying to build my own solution.
Our Nginx servers run as an HTTP proxy for multiple PHP/MySQL-backed WordPress sites. The goal was to cache the dynamic PHP HTML responses in Nginx and serve the HTML pages from Nginx to avoid redundant, CPU-intensive PHP renders.
Site Cache Configuration
The example below shows how PHP response caching is configured for a site (other nginx configuration details are excluded for brevity). A cache named
cachedemo-prod is defined to store cached HTML f