php验证URL是否合法的函数

<?php
function isValidUrl($url) {

$patern = '/^http[s]?:＼/＼/'.
'(([0-9]{1,3}＼.){3}[0-9]{1,3}'. // IP形式的URL- 199.194.52.184
'|'. // 允许IP和DOMAIN（域名）
'([0-9a-z_!~*＼'()-]+＼.)*'. // 三级域验证- www.
'([0-9a-z][0-9a-z-]{0,61})?[0-9a-z]＼.'. // 二级域验证
'[a-z]{2,6})'. // 顶级域验证.com or .museum
'(:[0-9]{1,4})?'. // 端口- :80
'((＼/＼?)|'. // 如果含有文件对文件部分进行校验
'(＼/[0-9a-zA-Z_!~＼*＼'＼(＼)＼.;＼?:@&=＼+＼$,%#-＼/]*)?)$/';

if(!preg_match($patern, $url)) {
die( '您输入的URL格式有问题，请检查！');
}
}

$url = "https://www.111cn.net ";
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_NOBODY, true);
$result = curl_exec($curl);
if ($result !== false)
{
$statusCode = curl_getinfo($curl, CURLINFO_HTTP_CODE);
if ($statusCode == 404)
{
echo "URL Not Exists"
}
else
{
echo "URL Exists";
}
}
else
{
echo "URL not Exists";
}