Joseph Abrahams josephabrahams

Use Lambda to Fix CloudFront/S3 CORS Issues

If you use S3 to serve static assets, you're going to have to configure S3 to deal with CORS issues. Unfortuantly, S3 doesn't return Vary: Origin unless an Origin request header is present. This causes CORS issues for browsers like Chrome since the original cached response from the GET request will get reused for CORS evaluation due to the lack of Vary: Origin.

The solution is to use a Lambda@Edge function to add the correct response headers from S3.

Steps to set up Lambda/CloudFront/S3:

	#!/bin/bash

	sudo apt-get update && \
	sudo apt-get -y upgrade --with-new-pkgs && \
	sudo apt-get -y autoremove && \
	sudo apt-get -y autoclean

	if [ -f /var/run/reboot-required ]; then
	echo "Reboot required."
	fi

	# /etc/lighttpd/external.conf

	$HTTP["host"] == "pi.hole" {
	# Ensure the Pi-hole Block Page knows that this is not a blocked domain
	setenv.add-environment = ("fqdn" => "true")

	# Redirect homepage to "/admin/"
	$HTTP["url"] == "/" {
	url.redirect = ( "" => "/admin/" )
	}

	!/bin/sh

	# only require sudo password once during this script
	sudo -v
	while true; do sudo -n true; sleep 60; kill -0 "$$" \|\| exit; done 2>/dev/null &

	# remove need for typing sudo password in the future
	echo -e "\nubuntu ALL=(ALL) NOPASSWD: ALL" \| sudo tee -a /etc/sudoers

	# allow access to vm shared folders

	<!doctype html>
	<html>
	<head>
	<meta charset="utf-8">
	<title>Child</title>
	</head>
	<body>
	<h1>Child</h1>
	<a href="https://example.com/" target="_top">Link</a>
	</body>

	{
	"repositories":[
	{
	"type":"composer",
	"url":"https://wpackagist.org"
	},
	{
	"type": "vcs",
	"url": "https://github.com/__your_github_org__/acf-pro.git"
	}

	#!/bin/bash

	sudo nginx -t && sudo nginx -s reload && echo "nginx: reload successful"