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:

<?php
$header = get_headers($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;
}
?>

实例二,代码如下:

<?php
echo get_redirect_url('https://www.xysoft.cc/');
//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;
    }
}