学习php简单实现短网址(短链)还原的方法

<?php
$info1 = '亲！暂不能解析此类短网址。';
$info2 = '亲！网址解析失败，请重试。';
$info3 = '<br/><b><a href="';
$info4 = '" target="_blank">立即访问>></a></b>';
$info5 = '亲！不是短网址或无效。';
function unshort($url)
{
global $info1,$info2,$info3,$info4;
 $curl = curl_init();
 curl_setopt($curl, CURLOPT_URL, $url);
 curl_setopt($curl, CURLOPT_RETURNTRANSFER,1);
 curl_setopt ($curl, CURLOPT_USERAGENT, 'Mozilla/8.0 (compatible; MSIE 8.0; Windows 7');
 curl_setopt($curl, CURLOPT_HEADER, 1);
 curl_setopt($curl, CURLOPT_NOBODY, 0);
 curl_setopt($curl, CURLOPT_TIMEOUT, 15);
 curl_setopt($curl,CURLOPT_ENCODING, 'gzip');
 $data = curl_exec($curl);
 if(!empty($data)){
 $message = curl_getinfo($curl);
 curl_close($curl);
 $status = $message['http_code'];
 if ($status == '301' || $status == '302' ){
 $UrlHeader = (get_headers($url,1));
 $unurl = $UrlHeader[Location];
 if(is_array($unurl)) {
 $unurl = $unurl[0];
 $unurl .=$info3.$unurl.$info4;
 return $unurl;
 }
 else {
 $unurl .=$info3.$unurl.$info4;
 return $unurl;
 }
 }
 return $info1;
 }
 return $info2;
}
function adfunshort($url)
{
global $info3,$info4,$info5;
 $c = file_get_contents($url);
 $p = "/url = '(.*)';/isU";
 preg_match($p, $c, $content);
 $unurl = $content[1];
 if($unurl == '') {
 return $info5;
 }
 else {
 $unurl .=$info3.$unurl.$info4;
 return $unurl;
 }
}
?>
<form action="" method="post">
短网址：<input type="text" name="turl" class="inurl" size="26" />
<input type="hidden" name="url_done" value="done" />
<input type="submit" value="提交" class="suburl" />
</form>
<p id="trurl">
<?php
$turl = $_POST['turl']?$_POST['turl']:"";
$url_done= $_POST['url_done']?$_POST['url_done']:"";
if ($url_done == 'done'){
$http = substr($turl,0,7);
 if ($http != 'http://' && $http != 'https:/'){
 $turl = 'http://'.$turl;
 }
 $tturl = substr($turl,0,11);
 if ($tturl == 'http://adf.'){
 $longurl = adfunshort($turl);
 }else {
 $longurl = unshort($turl);
 }echo "短网址 ".$turl." 的真实网址为：<br />$longurl ";
}
?>