Question

php 判断来路

下面是我下载页面down.php 的php代码 现在我发现，用迅雷，谷歌浏览器直接打开，就能输出下载文件，一点不起防盗链作用。 现在我想，只允许在我自己站上连接过来的可以直接使用，别的的站过来的，和直接输入这个地址的，跳转到copy.htm页上去。  哥哥姐姐我是菜鸟，不懂php，请帮忙下吧，愁了我好几天了。 看看该修改下面哪里， 我不会啊。。 

Answer 1

PHP中的 $_SERVER["HTTP_REFERER"] 预定义服务器变量可以判断来路。
$_SESSION['HTTP_REFERER']可以获取当前链接的上一个连接的来源地址，即链接到当前页面的前一页面的 URL 地址。
一般用于判断浏览者是从哪里点击链接跳到本页面的，即所说的来路，还可以通过判断来路来防止盗链。
例如：
<?php

$url_array = parse_url($_SESSION['HTTP_REFERER']);
//如果页面的域名不是服务器域名,就连接到登陆窗口
if($_SERVER['HTTP_HOST'] != $url_array["host"]) {
header("location: login.php");
exit;
}

?>

Answer 2

<?php
//通过请求的域名判断
if($_SERVER["SERVER_NAME"]=="你的域名")
{
下载
}
else
{
header("location:copy.htm");
}
?>

Answer 3

<?php
function send_file($file, $speed = 100) {

//First, see if the file exists
if (!is_file($file)) {
die("<b>404 File not found!</b>");
}
//Gather relevent info about file
$filename = basename($file);
$file_extension = strtolower(substr(strrchr($filename,"."),1));
// This will set the Content-Type to the appropriate setting for the file
switch( $file_extension ) {
case "exe":
$ctype="application/octet-stream";
break;
case "zip":
$ctype="application/zip";
break;
case "mp3":
$ctype="audio/mpeg";
break;
case "mpg":
$ctype="video/mpeg";
break;
case "avi":
$ctype="video/x-msvideo";
break;

// The following are for extensions that shouldn't be downloaded
// (sensitive stuff, like php files)
case "php":
case "htm":
case "html":
case "txt":
die("<b>Cannot be used for ". $file_extension ." files!</b>");
break;
default:
$ctype="application/force-download";
}

// Begin writing headers
header("Cache-Control:");
header("Cache-Control: public");
header("Content-Type: $ctype");

$filespaces = str_replace("_", " ", $filename);
// if your filename contains underscores, replace them with spaces

$header='Content-Disposition: attachment; filename='.$filespaces;
header($header);
header("Accept-Ranges: bytes");

$size = filesize($file);
// check if http_range is sent by browser (or download manager)
if(isset($_SERVER['HTTP_RANGE'])) {
// if yes, download missing part

$seek_range = substr($_SERVER['HTTP_RANGE'] , 6);
$range = explode( '-', $seek_range);
if($range[0] > 0) { $seek_start = intval($range[0]); }
if($range[1] > 0) { $seek_end = intval($range[1]); }

header("HTTP/1.1 206 Partial Content");
header("Content-Length: " . ($seek_end - $seek_start + 1));
header("Content-Range: bytes $seek_start-$seek_end/$size");
} else {
header("Content-Range: bytes 0-$seek_end/$size");
header("Content-Length: $size");
}
//open the file
$fp = fopen("$file","rb");

//seek to start of missing part
fseek($fp,$seek_start);

//start buffered download
while(!feof($fp)) {
//reset time limit for big files
set_time_limit(0);
print(fread($fp,1024*$speed));
flush();
sleep(1);
}
fclose($fp);
exit;
}
?>

Answer 4

看下http referer这个能够判断，但一般都可以伪装的。
$_SERVER['HTTP_REFERER']
if(strpos($_SERVER['HTTP_REFERER'],'你域名的部分'){
download
}else{
copy
}