We're about to start testing in isolation, so better make sure that each plugin can be tested in isolation.
Http Invoice Request Server plugin
This plugin starts a minimal, rate limited HTTP Server and returns a invoice on the following GET request:
/invoice/<amount>/<description>
$ lightning-cli invoiceserver start
started server successfully on port 8089
$ curl http://localhost:8809/invoice/100000/some-text-here
{"bolt11":"lnbc100000n1p0yr9sxpp50t9rnvw5slcjn6m97fmujpp9xd6w0h26dpvajcv8xwhu42xk5vlqdq8vej8xcgxqyj...","expires_at":1581961350,"payment_hash":"7aca39b1d487f129eb65f277c904253374e7dd5a6859d9618733afcaa8d6a33e", ...}
The webserver is rate-limited, meaning that only a certain amount of request per minute is allowed (to prevent DoS attacks).
The json invoice can be used by other services, for example a service for tipping, donations, PoS devices, ...
Once the plugin is active you can run lightning-cli help invoiceserver to
learn about the command line API:
Commands: start/stop/restart/status.
In the file .lightning/bitcoin/.env the port can be set (default 8089).
Onion routing
Exposing the url using Onion routing is easy. Install tor and
add the service to /etc/tor/torrc
HiddenServiceDir /home/bitcoin/tor/request-invoice-service_v2/
HiddenServicePort 80 127.0.0.1:8809
and restart tor to create the url
$ systemctl stop tor && systemctl start tor
$ cat /home/bitcoin/tor/request-invoice-service_v2/hostname
fkfuvjrbj6cfqppq6xcgfwmp4p23wq2unzlnqmdi6ibqtg2aq7thp2qd.onion
Use tor browser to visit the url and create a invoice (and make a donation?). http://fkfuvjrbj6cfqppq6xcgfwmp4p23wq2unzlnqmdi6ibqtg2aq7thp2qd.onion/invoice/1000/donation