学步园

以图片为例。
1、fsockopen方法

$url = “http://www.example.net/xxx/xxx.jpg”;
$t = parse_url($url);
$host = $t['host'];
$file = $t['path'];

$fp = fsockopen($host,80, $errno, $errstr, 30);
if($fp)
{

$header = “GET $file HTTP/1.1/r/n”;
$header .= “Host: $host/r/n”;
$header .= “User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; zh-CN; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1/r/n”;
$header .= “Referer: http://$host/r/n”;
$header .= “Connection: Close/r/n/r/n”;

fwrite($fp, $header);

$jpg = fopen($path . basename($file), “wb”);
while (!feof($fp))
{
$s = fgets($fp,128);
fwrite($jpg,$s);
}
fclose($jpg);

fclose($fp);
}
?>

2、curl方法。需要php中启用curl。来自：http://www.askapache.com/php/curl-multi-downloads.html，我加上了几个选项：REFERER检查等。

set_time_limit(0);
ini_set(’display_errors’,true);//Just in case we get some errors, let us know….

$host = “www.example.net”;
$urls=array(
“http://$host/xxx/xxx.jpg”,
“http://$host/xxx/yyy.jpg”
);

$save_to=’./’;

$mh = curl_multi_init();

foreach ($urls as $i => $url)
{
$g=$save_to.basename($url);
if(!is_file($g))
{
$conn[$i]=curl_init($url);

$fp[$i]=fopen ($g, “wb”);

curl_setopt($conn[$i], CURLOPT_USERAGENT, “Mozilla/5.0 (Windows; U; Windows NT 6.0; zh-CN; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1″);
curl_setopt($conn[$i], CURLOPT_REFERER, “http://$host”);
curl_setopt($conn[$i], CURLOPT_FILE, $fp[$i]);
curl_setopt($conn[$i], CURLOPT_HEADER ,0);
curl_setopt($conn[$i], CURLOPT_CONNECTTIMEOUT,600);
curl_setopt($conn[$i], CURLOPT_FOLLOWLOCATION, 1);
//curl_setopt($conn[$i], CURLOPT_RETURNTRANSFER, 0);
//curl_setopt($conn[$i], CURLOPT_VERBOSE, 0);

curl_multi_add_handle ($mh,$conn[$i]);
}
}

do {
$n=curl_multi_exec($mh,$active);
}
while ($active);

foreach ($urls as $i => $url)
{
curl_multi_remove_handle($mh,$conn[$i]);
curl_close($conn[$i]);
fclose ($fp[$i]);
}

curl_multi_close($mh);
?>