使用PHP获得从URL的直接下载链接

Question

我需要从php重定向URL直接下载链接。原来的URL

http://www.domain.com/mp3/download.php?id=4760 

这个URL重定向终于我到 http://www.domain.com当我使用的下载链接'http://www.domain.com/mp3/download.php?id=4760。在我的网站上

请你能帮助我。谢谢 ！

Answer 1

/** 
* get_redirect_url() 
* Gets the address that the provided URL redirects to, 
* or FALSE if there's no redirect. 
* 
* @param string $url 
* @return string 
*/ 
function get_redirect_url($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/1.1\r\n"; 
    $request .= 'Host: ' . $url_parts['host'] . "\r\n"; 
    $request .= "Connection: Close\r\n\r\n"; 
    fwrite($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; 
    } 

} 

/** 
* get_all_redirects() 
* Follows and collects all redirects, in order, for the given URL. 
* 
* @param string $url 
* @return array 
*/ 
function get_all_redirects($url){ 
    $redirects = array(); 
    while ($newurl = get_redirect_url($url)){ 
    if (in_array($newurl, $redirects)){ 
     break; 
    } 
    $redirects[] = $newurl; 
    $url = $newurl; 
    } 
    return $redirects; 
} 

/** 
* get_final_url() 
* Gets the address that the URL ultimately leads to. 
* Returns $url itself if it isn't a redirect. 
* 
* @param string $url 
* @return string 
*/ 
function get_final_url($url){ 
    $redirects = get_all_redirects($url); 
    if (count($redirects)>0){ 
    return array_pop($redirects); 
    } else { 
    return $url; 
    } 
}