How to determine whether PHP is a remote file

function chk_remote_file_exists($url) {
    $ch = curl_init(); 
    $timeout = 10; 
    curl_setopt ($ch, CURLOPT_URL, $url); 
    curl_setopt ($ch, CURLOPT_HEADER, 1); 
    curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1); 
    curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout); 
    $contents = curl_exec($ch);
    if (preg_match("/404/", $contents)) {
        return false;
    }
    return true;
}
$url = 'http://www.lvxing1788.com/lvxing.html';
var_dump(chk_remote_file_exists($url));
exit;