rails 实现ping功能
##只要传所需参数就可以进行ping
def ping
host = params['hostname'] || 'www.sina.com.cn'
callback = params['jsoncallback'] || params['callback'] # for cross domain ajax jsonp solution
count = params['count'] || 4
file_size = params['file_size'] ||
ping_cmd = is_windows ? 'ping' : 'ping -c 4'

out = ''

IO.popen("#{ping_cmd} #{host} -n #{count} -l #{file_size}") { |f|
while f.gets do
out << $_
end
}

out.gsub!("\n", "<br />")

if callback
render :text => {utput => out}.to_json
else
render :text => out
end
end