Caddyfile v2 for Ruby on Rails application

bash

# save Caddyfile in rails app root folder

# run rails server with port 4000 in one terminal
$ bundel exec rails server -p 4000 -b 127.0.0.1

# run caddy in another terminal
CADDY_HOST=localhost CADDY_PORT=3000 CADDY_BACKEND_PORT=4000 caddy run -config Caddyfile

Caddyfile

http://{$CADDY_HOST}:{$CADDY_PORT} {
  root * ./public
  @notStatic {
    not {
      file {
        try_files {path}
      }
    }
  }

  reverse_proxy @notStatic {
    to localhost:{$CADDY_BACKEND_PORT}

    header_up X-Real-IP {remote_host}
    header_up X-Forwarded-Proto {scheme}
    header_up Access-Control-Allow-Origin *
    header_up Access-Control-Allow-Credentials true
    header_up Access-Control-Allow-Headers Cache-Control,Content-Type
    transport http {
      read_buffer 8192
    }
  }
  file_server
}

Adapt most of the config from this URL

for Caddyfile v1, check this out