PHP Ping API

gistfile1.php

<?php
if(!empty($_GET["host"])) {
	$host=$_GET["host"];
	if(strpos($host,"/")!==false && ($h=parse_url($host,PHP_URL_HOST))!==false)
		$host=$h;
	$host=preg_replace("/(^\-)?[^0-9a-z\.]/i","",$host);
	$result=shell_exec("ping -nc 1 -W 2000 $host");
	preg_match("/(?<=time=)[0-9\.]+/",$result,$m);
	if(!empty($m[0]))
		$out=array("online"=>true,"host"=>$host,"ping"=>$m[0]."ms");
	else
		$out=array("online"=>false,"host"=>$host);
} else
	$out=array("error"=>"Missing parameter `host`.");
header("Content-type: application/json");
echo json_encode($out);