netchk.rb

#!/usr/bin/env ruby

# Check to see if connected to the internet by checking if the oldest domain is resolveable via DNS
# and if not, restart a WiFi profile.

unless Process.uid.zero?
  puts "ERROR: Must be run as a superuser"

  exit
end

if ARGV[0].nil?
  puts "Usage: netchk PROFILE [SLEEP]", ""
  puts "PROFILE: The name of the WiFi profile in netctl."
  puts "SLEEP:   The number of seconds to sleep between checks. Defaults to `30`"

  exit
end

$profile = ARGV[0]
$sleep   = ARGV[1].to_i
$sleep = 30 if $sleep == 0

# ------------------------------------------------------------------------------------------------ #

require "resolv"

def connected?
  resolver = Resolv::DNS.new
  begin
    resolver.getaddress("symbolics.com") # First domain ever

    true
  rescue
    false
  end
end

loop do
  print "[#{Time.now}] Checking... "

  if connected?
    puts "Connected."
  else
    puts "Disconnected!"
    
    print "Restarting WiFi profile... "
    system("netctl restart #{$profile}")
    puts "Done."
  end

  sleep($sleep)
end