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Detailed explanation of examples of methods to prevent hotlinking in PHP
- 墨辰丷Original
- 2018-05-19 09:24:531778browse
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 cfba799dd43fce78ec3e9e3d200b7e48
2 directly. Form submitted with Submit or 764a0a970dbc75966e734f5ea597d024 (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. c37f721670919360921ccb8afc9eb479
6． 707ab8d2056c6e1f516d2bf3c9988ff9 or d2eacb9d552db150e90498bcd18784f7Go 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="a.png"/>';
}
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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