Document reverse proxy with Caddy

Work in progress. Works fine for web browser with basic auth (I'm not yet comfortable running this without basic auth in place).

Problems with basic auth and android app https://github.com/9001/party-up/issues/3

docker-compose.yml

#
# docker-compose up
#

version: '3.3'

# based on:
# * https://www.digitalocean.com/community/tutorials/how-to-install-and-use-docker-compose-on-ubuntu-20-04
# * https://arjunphp.com/windows-server-docker-compose-caddy-server-reverse-proxy/
# * https://github.com/lucaslorentz/caddy-docker-proxy - not actually used

services:
# reverse proxy server
# https://hub.docker.com/_/caddy
caddy:
image: caddy
restart: unless-stopped
hostname: caddy
networks:
- app_net
volumes:
- $PWD/Caddyfile:/etc/caddy/Caddyfile
- $PWD/data:/data
# NOTE only Caddy should be using ports, all others shuld use expose instead
ports:
# NOTE 80 and 443 were needed to get cert. once had cert not needed - looks like http (80) was needed unclear about https (443)
- "80:80"
#- "443:443"
- "2000:2000"

# mkdir -p /home/pi/data/copyparty/cfg /home/pi/data/copyparty/w
# chmod a+rwx /home/pi/data/copyparty/cfg /home/pi/data/copyparty/w
copyparty:
# TODO? -u 1000
container_name: copyparty
image: copyparty/min
hostname: copyparty
restart: unless-stopped
expose:
- 3923
networks:
- app_net
volumes:
- "/home/pi/data/copyparty/cfg:/cfg"
- "/home/pi/data/copyparty/w:/w"

networks:
app_net:
external: false

Caddyfile

https://copyparty.YOUR.DOMAIN.HERE:2000 {
# basicauth works fine for web browsers with CopyParty
# it fails with Party-Up Android sharing app :-(
# not figured out passwords scheme properly yet to want to remove this
basicauth /* {
username hashed_password
}
reverse_proxy copyparty:3923
}

/home/pi/data/copyparty/cfg/config.conf

Disable https, so that reverse proxy certificate is used

[global]
http-only