Find an open TCP port

Finds a random available TCP port for listening on, within a specified range of ports. The default range of ports to check is 1024 to 49151, which is the set of TCP User Ports. This function automatically excludes some ports which are considered unsafe by web browsers.

randomPort(min = 1024L, max = 49151L, host = "127.0.0.1", n = 20)

Arguments

min

Minimum port number.

max

Maximum port number.

host

A string that is a valid IPv4 or IPv6 address that is owned by this server, which the application will listen on. "0.0.0.0" represents all IPv4 addresses and "::/0" represents all IPv6 addresses.

n

Number of ports to try before giving up.

Value

A port that is available to listen on.

Examples

if (FALSE) { # \dontrun{
s <- startServer("127.0.0.1", randomPort(), list())
browseURL(paste0("http://127.0.0.1:", s$getPort()))

s$stop()
} # }