用 php 把字串中所有的網址都抓出來

function getUrlsFromString($string){
    $result = preg_match_all('#\bhttps?://[^,\s()<>]+(?:\([\w\d]+\)|([^,[:punct:]\s]|/))#', $string, $matches);

    if( empty($result) ){ // 沒抓到就回傳 0
        return 0;
    }else{
        return $matches[0]; // 抓到回傳 url array
    }
    return $matches;
}

$data = file_get_contents('http://facebook.com');
print_r(getUrlsFromString($data)) ;

Array
(
    [0] => https://www.facebook.com/unsupportedbrowser
    [1] => https://www.facebook.com/unsupportedbrowser
    [2] => https://static.xx.fbcdn.net/rsrc.php/yz/r/KFyVIAWzntM.ico
    [3] => https://static.xx.fbcdn.net/rsrc.php/v3/yB/l/0
    [4] => https://static.xx.fbcdn.net/rsrc.php/v3/yF/l/0
    [5] => https://static.xx.fbcdn.net/rsrc.php/v3/yQ/l/0
    [6] => https://static.xx.fbcdn.net/rsrc.php/v3/y-/l/0
)