php获得网址跳转之后的网址

我们在获取其他网站的图片或视频地址的时候，有时会遇到对方的网站地址为了安全或是防盗链，而做了跳转。我们看一下下面的例子：

访问此网址：

http://mas.prd.am-img.com/2012/08/13/A4SELFAA0011144/3.jpg

直接跳转到：

http://ta.img.cn.amgbs.com/mas/2012/08/13/A4SELFAA0011144/3.jpg

这个时候我们要怎么解决这个问题呢？利用get_headers函数，读取：Location值。废话就不多了，看以下代码：

我们先看一下get_headers函数能获取那些信息。

<?php
$url = "http://mas.prd.am-img.com/2012/08/13/A4SELFAA0011144/3.jpg";
print_r(get_headers($url));
?>

显示的效果为：

Array
(
    [0] => HTTP/1.1 302 Moved Temporarily
    [1] => Server: nginx/1.0.10
    [2] => Date: Thu, 30 Aug 2012 17:59:50 GMT
    [3] => Content-Type: text/html
    [4] => Content-Length: 161
    [5] => Connection: close
    [6] => Location: http://ta.img.cn.amgbs.com/mas/2012/08/13/A4SELFAA0011144/3.jpg
    [7] => HTTP/1.1 200 OK
    [8] => Date: Thu, 30 Aug 2012 17:59:50 GMT
    [9] => Server: PWS/8.0.9.3
    [10] => X-Px: ht h0-s1003.p0-foc.cdngp.net
    [11] => Cache-Control: max-age=300
    [12] => Expires: Thu, 30 Aug 2012 18:02:47 GMT
    [13] => Age: 123
    [14] => Content-Length: 217344
    [15] => Content-Type: image/jpeg
    [16] => Last-Modified: Mon, 13 Aug 2012 08:49:02 GMT
    [17] => Connection: close
)

最终代码：

<?php
function isfile($url)
{
    $isfile = get_headers($url);
    $result = str_replace("Location: ","",$isfile[6]);
    return $result;
}
$url = "http://mas.prd.am-img.com/2012/08/13/A4SELFAA0011144/3.jpg";
echo isfile($url);
?>