copyparty/docs/examples/docker/idp-authelia-caddy/caddy/Caddyfile

fs.example.com {
    tls internal # needed if you don't have an actual domain and use local dns in your network
    forward_auth authelia:9091 {
        uri /api/authz/forward-auth
        copy_headers Remote-User Remote-Groups Remote-Email Remote-Name
    }
    
    route {
        @login query rd=*
        redir @login https://authelia.example.com{uri}
        
        @logout path /logout
        redir @logout https://authelia.example.com{uri}
        
        reverse_proxy copyparty:3923 {
            header_up Cookie "authelia_session=[^;]+" "authelia_session=_"
        }
    }
}

# fs.example.com {
#     tls internal # needed if you don't have an actual domain and use local dns in your network
#     reverse_proxy copyparty:3923
# }

authelia.example.com {
    tls internal # needed if you don't have an actual domain and use local dns in your network
    reverse_proxy authelia:9091
}