Small script to parse nginx access log file, and find out from what organisation (AS) was visiting your website

nginx_access_to_as.rb

#!/usr/bin/env ruby

require 'teamcymru'
require 'ipaddr'

c = TeamCymru::ASNClient.new

ips = Array.new
ARGF.each do |line|
        ip = IPAddr.new(line.split()[0])
        # rewrite ::ffff:v4inv6-notation to native v4
        ips << ip.native.to_s
end

# group and count IPs
grouped_ips = ips.inject(Hash.new(0)) { |h, ip| h[ip] += 1; h}

grouped_ips.sort_by{|k,v| v}.reverse.each do |ip, num|
        as_info = c.lookup(ip)
        printf "%5.d%55.50s %s\n", num, as_info.org, ip 
end
puts "-"*80
printf "%5.d\n", ips.length