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 the following
The examples in this article describe How to prevent hotlinking in PHP. Share it with everyone for your reference, the details are as follows:
$_SERVER['HTTP_REFERER']
acquisition status
Note $_SERVER['HTTP_REFERER '] may not always be obtained, and can only 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 judgment 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="Example of how to implement anti-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-theft Chain 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 prevent hot links by configuring the server, such as nginx configuration access
( gif|jpg|jpeg|png|bmp|swf) Whitelist of other files
The above is the detailed content of Example of how to implement anti-hotlinking in PHP. For more information, please follow other related articles on the PHP Chinese website!

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。


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