解析百度搜索结果链接的url，获取真正的url

转载于：https://www.cnblogs.com/xcsn/p/4678304.html

百度输入关键词搜索出现的列表页，点击目标链接，然而跳转的时候却是百度地址，经过百度解析，才真的跳到目标页面。

解决办法：模拟请求，得到真正的地址。

<?php
$url = "http://www.baidu.com/link?url=nS2MGJqjJ4zBBpC8yDF8xDh8vibi1lVeE7gGr9UONBu";

$info = parse_url($url);
$fp = fsockopen($info['host'], 80,$errno, $errstr, 30);
fputs($fp,"GET {$info['path']}?{$info['query']} HTTP/1.1
");
fputs($fp, "Host: {$info['host']}
");
fputs($fp, "Connection: close

");
$rewrite = '';
while(!feof($fp)) {
    $line = fgets($fp);
    if($line != "
" ) {
        if(strpos($line,'Location:') !== false) {
            $rewrite = str_replace(array("
","
","Location: "),'',$line);
        }
    }else {
        break;
    }
}
var_dump($rewrite); //结果显示：string(22) "http://www.google.com/" 
?>

将http://www.baidu.com/link?url=nS2MGJqjJ4zBBpC8yDF8xDh8vibi1lVeE7gGr9UONBu解析为http://www.google.com/