WordPress reverse proxy

wp-proxy.sh

#!/usr/bin/env bash

# Requirements
if ! command -v docker &> /dev/null; then
	echo 'Please install docker: https://docs.docker.com/engine/install/'
	exit 1
fi

if ! command -v ngrok &> /dev/null; then
	echo 'Please install ngrok: https://ngrok.com/download'
	exit 1
fi

if [ -z "$1" ]; then
    echo "Usage: wp-proxy.sh <example.altis.dev>"
    exit 1  # Exit with a non-zero status code to indicate an error.
fi

WP_HOST="$1"
PATTERNED_WP_HOST=${WP_HOST//\./%.}
PATTERNED_PARENT=$(echo "$PATTERNED_WP_HOST" | cut -d'.' -f2-)

# Create OpenResty configuration
TMP_PROXY_DIR=/tmp/wp-proxy/conf.d
mkdir -p $TMP_PROXY_DIR
TMP_PROXY_FILE=$(mktemp)
tee "$TMP_PROXY_FILE" <<EOF
upstream backend {
  server ${WP_HOST}:443 max_fails=5 fail_timeout=30;
}

server {
  listen 8181;
  server_name localhost;

  location / {
    more_clear_input_headers "Accept-Encoding";
    more_clear_headers "Content-Security-Policy";
    proxy_pass https://backend;
    proxy_set_header Host            ${WP_HOST};
    proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
    proxy_set_header X-Proxied-By    wp-proxy;
    body_filter_by_lua_block {
      ngx.arg[1] = ngx.arg[1]:gsub("https?://${PATTERNED_WP_HOST}/","/")
      ngx.arg[1] = ngx.arg[1]:gsub("https?://${PATTERNED_PARENT}/","/")
    }
  }
}

EOF
cp "$TMP_PROXY_FILE" "$TMP_PROXY_DIR/wp-proxy.conf"

# Start the reverse proxy and ngrok
docker run -itd -v $TMP_PROXY_DIR:/etc/nginx/conf.d --network host --name wp-proxy-2023-09-08 openresty/openresty:bullseye-fat
ngrok http http://localhost:8181 --host-header=rewrite 
docker rm -f wp-proxy-2023-09-08

Requirements:

1. docker
2. ngrok

Run:

chmod +x *.sh
./wp-proxy.sh my.wordpress.test

It downloads then runs openresty (nginx extended web server) and sets up a reverse proxy by loading a dynamically created configuration file so that the site can be accessed from other hostnames, and then ngrok to make it available to others.
this allows for example zero configuration testing on your iphone, impromptu demos etc.

Notes:

1. it drops the browser content security policy to make loading any scripts work (tradeoff for temporary convenience), but requires no setup
2. needs to have the local wordpress server running beforehand, as this sits in front of it
3. It might work for any local webservice really, it's rewriting any absolute links to relative ones.