现在有很多的短网址应用，点击就跳转到缩短之前的网址了，那今天我们就来看一下，PHP如何获取短网址跳转之前的网址，其实也很简单，就是用php的get_headers 函数，
取得Response Headers，之后慢慢分析就行了。
给出具体实现方法：
| 代码如下 |
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$header = get_headers($url, 1);
if (strpos($header[0], ’301′) || strpos($header[0], ’302′)) {
if (is_array($header['Location'])) {
return $header['Location'][count($header['Location'])-1];
} else {
return $header['Location'];
}
} else {
return $url;
}
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实例二
| 代码如下 |
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//
echo get_redirect_url('http://www.111cN.nEt');
//输出结果为：http://code.google.com/android/
function get_redirect_url($url){
$redirect_url = null;
$url_parts = @parse_url($url);
if (!$url_parts) return false;
if (!isset($url_parts['host'])) return false; //can't process relative URLs
if (!isset($url_parts['path'])) $url_parts['path'] = '/';
$sock = fsockopen($url_parts['host'], (isset($url_parts['port']) ? (int)$url_parts['port'] : 80), $errno, $errstr, 30);
if (!$sock) return false;
$request = "HEAD " . $url_parts['path'] . (isset($url_parts['query']) ? '?'.$url_parts['query'] : '') . " HTTP/1.1rn";
$request .= 'Host: ' . $url_parts['host'] . "rn";
$request .= "Connection: Closernrn";
fwrite($sock, $request);
$response = '';
while(!feof($sock)) $response .= fread($sock, 8192);
fclose($sock);
if (preg_match('/^Location: (.+?)$/m', $response, $matches)){
if ( substr($matches[1], 0, 1) == "/" )
return $url_parts['scheme'] . "://" . $url_parts['host'] . trim($matches[1]);
else
return trim($matches[1]);
} else {
return false;
}
}
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