从字符串获取URL

一段时间以来，我一直在寻找使用PHP从字符串中获取URL的代码.我基本上是试图从消息中获取一个缩短的URL，然后稍后执行HEAD请求以查找实际的链接.

For a little while now I've been searching for a code to get URL's out of a string using PHP. I'm basically trying to get a Shortened URL out of a message, and then later do a HEAD request to find the actual link.

任何人都有从字符串返回URL的代码吗?

Anyone have any code that returns URLs from strings?

谢谢.

编辑Ghost Dog:

以下是我正在解析的示例:

Here is a sample of what I am parsing:

$test = "I am testing this application for http://test.com YAY!";

这是我得到的解决问题的答案:

And here is the response I got that solved it:

$regex = '$\b(https?|ftp|file)://[-A-Z0-9 &@#/%?=~_|!:,.;]*[-A-Z0-9 &@#/%=~_|]$i';

preg_match_all($regex, $string, $result, PREG_PATTERN_ORDER);
$A = $result[0];

foreach($A as $B)
{
    $URL = GetRealURL($B);
    echo "$URL<BR>";    
}


function GetRealURL( $url ) 
{ 
    $options = array(
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_HEADER         => true,
        CURLOPT_FOLLOWLOCATION => true,
        CURLOPT_ENCODING       => "",
        CURLOPT_USERAGENT      => "spider",
        CURLOPT_AUTOREFERER    => true,
        CURLOPT_CONNECTTIMEOUT => 120,
        CURLOPT_TIMEOUT        => 120,
        CURLOPT_MAXREDIRS      => 10,
    ); 

    $ch      = curl_init( $url ); 
    curl_setopt_array( $ch, $options ); 
    $content = curl_exec( $ch ); 
    $err     = curl_errno( $ch ); 
    $errmsg  = curl_error( $ch ); 
    $header  = curl_getinfo( $ch ); 
    curl_close( $ch ); 
    return $header['url']; 
} 

有关详细信息，请参见答案.

See Answer for the Details.