def calculate_ip
client_ip = @env['HTTP_CLIENT_IP']
forwarded_ips = ips_from('HTTP_X_FORWARDED_FOR')
remote_addrs = ips_from('REMOTE_ADDR')
check_ip = client_ip && @middleware.check_ip
if check_ip && !forwarded_ips.include?(client_ip)
raise IpSpoofAttackError, "IP spoofing attack?!" \
"HTTP_CLIENT_IP=#{@env['HTTP_CLIENT_IP'].inspect}" \
"HTTP_X_FORWARDED_FOR=#{@env['HTTP_X_FORWARDED_FOR'].inspect}"
end
not_proxy = client_ip || forwarded_ips.last || remote_addrs.first
not_proxy || ips_from('REMOTE_ADDR', :allow_proxies).first
end