anthumchris

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

	/* This NodeJS script tests IAM Policy Actions for yourself or a specific PolicySourceArn user/role.
	*
	* https://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/configuring-the-jssdk.html
	*/

	import AWS from 'aws-sdk' // $ npm i -D aws-sdk@2

	const iam = new AWS.IAM()
	const sts = new AWS.STS()

	<html>
	<head>
	<style>body { padding: 4rem; text-align: center; }</style>
	<script>
	/* Parentheses may be needed to instantiate: `audioCtx = new (OBJECT)()`<br />
	* Oscillator waveform may need explicit definition: `osc.type = 'sine'`
	*/
	var audioCtx = null
	var isPlaying = false

	// Devs can easily use English strings that will be translated if necessary
	function DeleteButton() {
	function prompt() {
	alert(intl('Are you sure you want to delete gateway?'))
	}

	return(
	<button onclick={prompt}>
	{intl('Delete Gateway')}
	</button>

	#!/bin/bash

	emcc \
	-O0 `# leave uncompressed for example` \
	-s WASM=1 \
	-s EXPORTED_FUNCTIONS="['_hello']" \
	-s EXTRA_EXPORTED_RUNTIME_METHODS="['cwrap']" \
	-o emscripten-module.js \
	--post-js module-post.js \
	hello.c

	/* To test, initiate the fetch() and interrupt your network conneciton
	* (e.g. turn off wireless). The originating ReadableStreamDefaultReader.read()
	* error is lost and unavailable to application's outermost Promise.reject catch()
	*/
	fetch('https://fetch-progress.anthum.com/10kbps/images/sunrise-baseline.jpg')
	.then(response => {
	const reader = response.body.getReader();

	return new Response(
	new ReadableStream({

	fetch('the-best-song-ever.mp3')
	.then(response => {
	if (!response.body) {
	throw Error("ReadableStream is not yet supported in this browser. See https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream")
	return response;
	}

	const reader = response.body.getReader();
	read()

	#/bin/bash

	# This script will push your local repository's latest commit to a remote repository on your server.
	# It's useful for quickly pushing your local changes to deployment servers (Dev, Stage, Prod/Live, etc.)
	#
	# This file should be placed in your remote server's project's git hooks folder and named .git/hooks/post-receive.
	# Security reminder: Your web server should not allow access to the /.git folder URL
	#
	# Ensure that this script is executable:
	# $ chmod +x .git/hooks/post-receive

	server {
	listen 80;
	listen [::]:80;

	server_name ~^(?<subdomain>\w+).dynamic.domain.com;
	root /var/www/vhost/_dynamic/$subdomain;

	access_log /var/log/nginx/dynamic-access.log;
	error_log /var/log/nginx/dynamic-error.log;