Backend DevelopmentPHP TutorialDetailed explanation of examples of methods to prevent hotlinking in PHPDetailed explanation of examples of methods to prevent hotlinking in PHP
This article mainly introduces the method of anti-hotlinking in PHP, and analyzes the related technologies and specific implementation techniques involved in PHP anti-hotlinking in the form of examples. Friends in need can refer to it
The details are as follows:
$_SERVER['HTTP_REFERER'] acquisition situation
Note $_SERVER['HTTP_REFERER'] may not always be obtained, only It can be obtained under the following circumstances:
1. The circumstances under which HTTP_REFERER can be obtained are as follows:
1. Use
2 directly. Form submitted with Submit or (POST or GET)
3． Form submitted using Jscript (POST or GET)
2. The following situations cannot be obtained:
1. Link from Favorites
2. Click "Home" or the customized address
3. Use Jscript's location.href or location.replace()
4． Directly enter the address
5 in the browser.
6． or Go to
7． Use XML to load the address
strrpos Function explanation:
strrpos - Calculate the position of the last occurrence of the specified string in the target string
Description
int strrpos (string $haystack, string $needle [, int $offset = 0])<br>Returns the last occurrence of needle in string $haystack Numeric location.
| $haystack | Find in this string. |
| $needle | If needle is not a string, it will be converted to an integer and treated as a sequential value of characters. |
Return value
Returns the position where needle exists. If not found, returns FALSE.
Hot link determination code: asd.php
<?php
//防盗链技术
//先判断是否获取到 $_SERVER['HTTP_REFERER'] 变量
if(isset($_SERVER['HTTP_REFERER'])){
//判断$_SERVER['HTTP_REFERER']是不是以http://localhost/开始的
if(strpos($_SERVER['HTTP_REFERER'],"http://localhost")==0){
echo '<img src="/static/imghwm/default1.png" data-src="a.png" class="lazy" / alt="Detailed explanation of examples of methods to prevent hotlinking in PHP" >';
}
else{
header("Location:warning.php");//跳转页面到warning.php
//echo $_SERVER["HTTP_REFERER"];
}
}
else {
header("Location:warning.php");
}
?>
warning.php
<html> <b>倒链</b> </html>
Anti-hotlink verification code
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> </head> <body> <a href="http://localhost/wml/asd.php" rel="external nofollow" >验证防盗链</a> </body> </html>
The above is the understanding principle
Generally configure the server to prevent hotlinking, such as nginx configuration access
(gif|jpg|jpeg|png|bmp|swf) White list of other files
The specific configuration can be searched on Baidu
Related recommendations:
NginxAnti-hotlinkingAnd Nginx access control and Nginx parsing php configuration
How about PHP Implementanti-hotlinkdetailed explanation
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