PHP从网络下载文件

set_time_limit(0);
// Supports all file types
// URL Here:
$url = 'http://somsite.com/some_video.flv';
$pi = pathinfo($url);
$ext = $pi['extension'];
$name = $pi['filename'];

// create a new cURL resource
$ch = curl_init();

// set URL and other appropriate options
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_HEADER, false);
curl_setopt($ch, CURLOPT_BINARYTRANSFER, true);
curl_setopt($ch, CURLOPT_AUTOREFERER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

// grab URL and pass it to the browser
$opt = curl_exec($ch);

// close cURL resource, and free up system resources
curl_close($ch);

$saveFile = $name.'.'.$ext;
if(preg_match("/[^0-9a-z._-]/i", $saveFile))
    $saveFile = md5(microtime(true)).'.'.$ext;

$handle = fopen($saveFile, 'wb');
fwrite($handle, $opt);
fclose($handle);

PHP