利用php教程的http_referer函数来判断用户的来路，这是简单了，
实例

if (isset($_SERVER['HTTP_REFERER'])) {
print "The page you were on previously was {$_SERVER['HTTP_REFERER']}
";
} else {
print "You didn't click any links to get here
";
}
?>

Click me!

下面我们让用户不知道我们的来路处理
实例

]$host = "www.123cha.com";
$referer = "http://".$host;
$fp = fsockopen ($host, 80, $errno, $errstr, 30);
if (!$fp){
echo "$errstr ($errno)
;n";
}else{
$request = "
GET / HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-powerpoint, application/vnd.ms-excel, application/msword, */"."*
Referer: http://$host
Accept-Language: zh-cn
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)
Host: $host
Connection: Close"
."rnrn";

fputs ($fp, "$request");
while (!feof($fp))
{
$res[] = fgets($fp,1024);
}
$html = join("",$res);
fclose ($fp);
$fp = file_put_contents("123cha.html",$html);
echo "done";
}[/code]

这不就行了?

不过很奇怪的是,
www.hao123.com
的页面抓下来是乱码(除了http头),这是为什么?难道是因为用了gzip之类压缩?

[code]$host = "www.zhutiai.com";
$html = file_get_contents("http://".$host);
$fp = file_put_contents("hao123.html",$html);
echo "done";
?>;[/code]

但这样抓的就没问题.

再来分析开始抓的http头
[code]HTTP/1.1 200 OK Date: Wed, 31 Aug 2005 00:59:36 GMT Server: Apache/1.3.27 Cache-Control: max-age=1296000 Expires: Thu, 15 Sep 2005 00:59:36 GMT Last-Modified: Mon, 29 Aug 2005 13:56:00 GMT Accept-Ranges: bytes Connection: close Content-Type: text/html Content-Encoding: gzip Content-Length: 14567[/code]

果然有这句,Content-Encoding: gzip
原来压缩了的,长度14567字节了,
用第二种方法抓,原来没压缩的html是71143字节,原来file_get_contents还可以自动解压缩.

实例二

$host = '127.0.0.1';
$target = '/2.php';
$referer = 'http://www.bkjia.com'; //伪造HTTP_REFERER地址
$fp = fsockopen($host, 80, $errno, $errstr, 30);
if (!$fp){
echo "$errstr($errno)
n";
}
else{
$out = "
GET $target HTTP/1.1
Host: $host
Referer: $referer
Connection: Closernrn";
fwrite($fp, $out);
while (!feof($fp)){
echo fgets($fp, 1024);
}
fclose($fp);
}
?>

另一个2.php文件很简单，只是写上一行读取当前的HTTP_REFERER服务器值的代码即可，如下：

echo "

---

";
echo $_SERVER["HTTP_REFERER"];
?>