The basic idea of ​​PHP anti-hotlinking method and the setting method of anti-hotlinking protection_php tips

Hot links refer to content that the service provider itself does not provide services. It uses technical means to bypass other beneficial end-user interfaces (such as advertisements) and provide other service providers' services directly to end users on its own website. content to deceive end users’ browsing and click-through rates. The beneficiary provides no or very few resources, while the real service provider receives no benefit. Preventing hotlinking is an important task for every website developer.

Doing a good job of preventing hotlinking can reduce a lot of pressure on the website server. Here we share a method to implement anti-hotlinking in PHP:

General download steps: Search -> Output the search results list -> Enter the software details page -> Click the download button -> Open the download page -> Click download to start downloading

My method is to make an article on the download page

First define a $key=sdkfjwojf32413 in the public file of the website, which is equivalent to a key

Generate a random number on the download page: $certcode = '84615354' (the generated number is different every time you open it)

Then use the above two variables and the ID of the software to generate an md5() encrypted string

Then generate the real download address of the software: file.php?id=5&codekey=ksfjwofsdkfsf

The id here is the number of the software. You can find the software address from the database based on it $codekey=md5($id.$certcode.$key)
Then save the certcode into the session,

Get the codekey and id from the parameters of file.php, then get the $key from the public file, and then get the $certcode from the session

Verify the codekey to see if it is correct. If it is incorrect, exit, otherwise proceed as follows

1. Delete the session (opening this address again will be invalid)

2. Read the software address from the database, then read the software content, and output (use PHP's file reading method to output the software content to be downloaded instead of directly giving him the address to download)

If you want to download, you must open your own download page and open the address from your download page to download, and the download address is different every time because the random numbers generated are different

Even if your download address is connected to other places, it cannot be downloaded.

Extended reading (specific implementation):

1. Simple anti-leeching

$ADMIN[defaulturl] = "http://www.vvschool.cn/404.htm";//盗链返回的地址
$okaysites = array("http://www.vvschool.cn/","http://www.siyizhu.com"); //白名单
$ADMIN[url_1] = "http://www.vvschool.cn/temp/download/";//下载地点1
$ADMIN[url_2] = "";//下载地点2，以此类推

$reffer = $HTTP_REFERER;
if($reffer) {
$yes = 0;
while(list($domain, $subarray) = each($okaysites)) {
if (ereg($subarray,"$reffer")) {
$yes = 1;
}
}
$theu = "url"."_"."$site";
if ($ADMIN[$theu] AND $yes == 1) {
header("Location: $ADMIN[$theu]/$file");
} else {
header("Location: $ADMIN[defaulturl]");
}
} else {
header("Location: $ADMIN[defaulturl]");
}?>

How to use: Save the above code as dao4.php. For example, if the validatecode.rar I used for testing is in my site, use the following code to represent the download link.

File name?site=1&file=file

2. Server anti-hotlinking

3. Anti-leeching methods for software downloads

//放置下载软件的根目录相对于当前脚本目录的相对目录
$fileRelPath = "../../software";
//例外允许连接的网址，注意:自身域名不需要填入,设定为肯定可以下载,
// 空字符串("")表示直接输入网址下载的情况
$excludeReferArr = array("www.wreny.com", "wreny.com");
chdir($fileRelPath);
$fileRootPath = getcwd() ."/";
$filePath=$HTTP_GET_VARS["file"];
$url=parse_url($_SERVER["HTTP_REFERER"]);
if($url[host]!=$_SERVER["HTTP_HOST"] && !in_array($referHost, $excludeReferArr)){
?>

In fact, there are many anti-leeching methods. Here is just a general idea for reference:

(1) IIS anti-leeching, using ISAPI_Rewrite, can be used as a solution to anti-leeching under Windows;

(2) Anti-hotlinking of pictures, adding watermarks to pictures. Although hotlinkers can achieve their goals, they are also promoting their own websites.

The above is the basic idea and setting method of PHP anti-hotlinking. I hope it will be helpful to everyone's learning.