Test a series of random TCP ports from 3000 to 8000 (excluding a few that are considered unsafe by Chrome) and return the first available one. A web server can be later started on this port.
random_port(port = 4321L, host = "127.0.0.1", n = 20)
The preferred port(s).
A string that is a valid IPv4 address that is owned by this
server, or "0.0.0.0"
to listen on all IP addresses.
The maximum number of random ports to be tested.
A port number, or an error if no ports are available.