Determines whether an HTTP port is being used by a process.

isPortInUse.swift

import Foundation

func isPortInUse(_ port: Int) -> Bool {
    // Use netstat to find ports in use then grep for one we're interested in.
    // See this solution for piping shell commands: http://stackoverflow.com/a/16650638
    let process = Process()
    process.launchPath = "/bin/sh"
    process.arguments = ["-c", "netstat -an | grep '\\b\(port)\\b' | grep LISTEN"]
    process.standardOutput = Pipe()
    process.launch()
    process.waitUntilExit()

    // No error code suggests something was found.
    // Any other code suggests that no results were available.
    return process.terminationStatus == 0
}