How to set up anti-leeching in PHP_PHP tutorial-PHP Tutorial-php.cn

Hotlinking refers 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 directly upload content to its own website. End users provide service content of other service providers to defraud end users of their browsing and click-through rates. The beneficiaries provide no resources or very few resources, while the real service providers receive no benefits. 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 php anti-hotlinking method:

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 not correct, exit. Otherwise, perform the following operations

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

<ol class="dp-c">
<li class="alt"><span><span class="vars">$ADMIN</span><span>[defaulturl] = </span><span class="string">"http://www.vvschool.cn/404.htm"</span><span>;//盗链返回的地址  </span></span></li>
<li>
<span class="vars">$okaysites</span><span> = </span><span class="keyword">array</span><span>(</span><span class="string">"http://www.vvschool.cn/"</span><span>,</span><span class="string">"http://www.siyizhu.com"</span><span>); //白名单   </span>
</li>
<li class="alt">
<span class="vars">$ADMIN</span><span>[url_1] = </span><span class="string">"http://www.vvschool.cn/temp/download/"</span><span>;//下载地点1  </span>
</li>
<li>
<span class="vars">$ADMIN</span><span>[url_2] = </span><span class="string">""</span><span>;</span><span class="comment">//下载地点2，以此类推 </span><span> </span>
</li>
<li class="alt"><span> </span></li>
<li>
<span class="vars">$reffer</span><span> = </span><span class="vars">$HTTP_REFERER</span><span>;  </span>
</li>
<li class="alt">
<span class="keyword">if</span><span>(</span><span class="vars">$reffer</span><span>) {  </span>
</li>
<li>
<span class="vars">$yes</span><span> = 0;  </span>
</li>
<li class="alt">
<span class="keyword">while</span><span>(list(</span><span class="vars">$domain</span><span>, </span><span class="vars">$subarray</span><span>) = each(</span><span class="vars">$okaysites</span><span>)) {  </span>
</li>
<li>
<span class="keyword">if</span><span> (</span><span class="func">ereg</span><span>(</span><span class="vars">$subarray</span><span>,</span><span class="string">"$reffer"</span><span>)) {  </span>
</li>
<li class="alt">
<span class="vars">$yes</span><span> = 1;  </span>
</li>
<li><span>}  </span></li>
<li class="alt"><span>}  </span></li>
<li>
<span class="vars">$theu</span><span> = </span><span class="string">"url"</span><span>.</span><span class="string">"_"</span><span>.</span><span class="string">"$site"</span><span>;  </span>
</li>
<li class="alt">
<span class="keyword">if</span><span> (</span><span class="vars">$ADMIN</span><span>[</span><span class="vars">$theu</span><span>] AND </span><span class="vars">$yes</span><span> == 1) {  </span>
</li>
<li>
<span>header(</span><span class="string">"Location: $ADMIN[$theu]/$file"</span><span>);  </span>
</li>
<li class="alt">
<span>} </span><span class="keyword">else</span><span> {  </span>
</li>
<li>
<span>header(</span><span class="string">"Location: $ADMIN[defaulturl]"</span><span>);  </span>
</li>
<li class="alt"><span>}  </span></li>
<li>
<span>} </span><span class="keyword">else</span><span> {  </span>
</li>
<li class="alt">
<span>header(</span><span class="string">"Location: $ADMIN[defaulturl]"</span><span>);  </span>
</li>
<li><span>}?> </span></li>
</ol>

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How to use: Save the above code as dao4.php. For example, the validatecode.rar I used for testing is in my site http://vvschool.cn/temp/download, and the following code is used to represent the download connection.

File name?site=1&file=file

2. Server anti-hotlinking

3. Anti-leeching methods for software downloads

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

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In fact, there are many anti-hotlinking methods. Here is just a general idea for reference: ⑴ IIS anti-hotlinking, using ISAPI_Rewrite, can be used as a solution to anti-hotlinking under Windows; ⑵ Picture anti-hotlinking, Although hotlinkers can achieve their goals by adding watermarks to images, they are also promoting their own websites.