PHP advanced filter

Use filterDetect whether a number is within a range

The following example uses the filter_var() function to Check whether an INT type variable is within the range of 1 to 200:

<?php
header("Content-type:text/html;charset=utf-8");
$int = 122;
$min = 1;
$max = 200;
if (filter_var($int, FILTER_VALIDATE_INT, array("options" => array("min_range"=>$min, "max_range"=>$max))) === false) {
    echo("变量值不在合法范围内");
} else {
    echo("变量值在合法范围内");
}
?>

Program running result:

The variable value is within the legal range Inside

Detect IPv6 address

★FILTER_VALIDATE_IP The filter validates the value as an IP.

The following example uses the filter_var() function to detect whether a $ip variable is an IPv6 address:

<?php
header("Content-type:text/html;charset=utf-8");
$ip = "2001:0db8:85a3:08d3:1319:8a2e:0370:7334";
if (!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) === false) {
    echo("$ip 是一个 IPv6 地址");
} else {
    echo("$ip 不是一个 IPv6 地址");
}
?>

Program running result:

2001:0db8:85a3:08d3:1319:8a2e:0370:7334 is an IPv6 address

Detect URL - must contain QUERY_STRING (query string)

QUERY_STRING Literal meaning It is the query string. For example, common URL web addresses have xxx.asp?pn=123456? What follows the number is querystring

The following example uses the filter_var() function to detect whether $url contains the query string:

<?php
 header("Content-type:text/html;charset=utf-8");
 $url = "http://www.baidu.com";
 
 if (!filter_var($url, FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED) === false) {
     echo("$url 是一个合法的 URL");
 } else {
     echo("$url 不是一个合法的 URL");
 }
 ?>

Program running result:

http://www.baidu.com is not a legal URL

above The Url URL in the example does not contain QUERY_STRING, so the running result is a negative answer

Remove characters with ASCII values ​​greater than 127

★FILTER_SANITIZE_STRING Filter removes or encodes unwanted characters.

The following example uses the filter_var() function to remove characters with an ASCII value greater than 127 in the string. It can also remove HTML tags:

<?php
$str = "<h1>Hello WorldÆØÅ!</h1>";
$newstr = filter_var($str, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_HIGH);
echo $newstr;
?>

Program running results:

Hello World!

PHP Filter Reference Manual

You can too View the specific application of filters by visiting the PHP Filter Reference Manual on this site.

The reference manual contains a brief description and usage examples of filter parameters!