filter_var

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

filter_var使用特定的过滤器过滤一个变量

说明

filter_var ( mixed $value , int $filter = FILTER_DEFAULT , array|int $options = 0 ) : mixed

参数

value

要过滤的内容。注意:标量值在过滤前,会被转换成字符串

filter

The ID of the filter to apply. The Types of filters manual page lists the available filters.

If omitted, FILTER_DEFAULT will be used, which is equivalent to FILTER_UNSAFE_RAW. This will result in no filtering taking place by default.

options

一个选项的关联数组,或者按位区分的标示。如果过滤器接受选项,可以通过数组的 "flags" 下标去提供这些标示。 对于回调型的过滤器,应该传入 callable。 这个回调函数必须接受一个参数(即待过滤的值),并且返回一个在过滤/净化后的值。

<?php
// 对于接受选项的过滤器,请使用此格式
$options = array(
    
'options' => array(
        
'default' => 3// 过滤器失败时返回的值
        // 可以继续写过滤器接收其它选项
        
'min_range' => 0
    
),
    
'flags' => FILTER_FLAG_ALLOW_OCTAL,
);
$var filter_var('0755'FILTER_VALIDATE_INT$options);
// 对于仅接受标志的过滤器,您可以直接将其传递
$var filter_var('oops'FILTER_VALIDATE_BOOLEANFILTER_NULL_ON_FAILURE);
// 对于仅接受标志的过滤器,您还可以将其作为数组传递
$var filter_var('oops'FILTER_VALIDATE_BOOLEAN,
                  array(
'flags' => FILTER_NULL_ON_FAILURE));
// 回调类型过滤器
function foo($value)
{
    
// 预期值: Surname, GivenNames
    
if (strpos($value", ") === false) return false;
    list(
$surname$givennames) = explode(", "$value2);
    
$empty = (empty($surname) || empty($givennames));
    
$notstrings = (!is_string($surname) || !is_string($givennames));
    if (
$empty || $notstrings) {
        return 
false;
    } else {
        return 
$value;
    }
}
$var filter_var('Doe, Jane Sue'FILTER_CALLBACK, array('options' => 'foo'));
?>

返回值

返回过滤后的数据,如果过滤失败则返回 false

范例

Example #1 一个 filter_var() 的示例

<?php
var_dump
(filter_var('bob@example.com'FILTER_VALIDATE_EMAIL));
var_dump(filter_var('http://example.com'FILTER_VALIDATE_URLFILTER_FLAG_PATH_REQUIRED));
?>

以上例程会输出:

string(15) "bob@example.com"
bool(false)

参见

User Contributed Notes

mmerlone at gmail dot com 21-Sep-2021 02:03
Be aware that FILTER_FLAG_PATH_REQUIRED is happy with a single slash (/), so:

<?php
$options
= array('flags' => FILTER_FLAG_PATH_REQUIRED);
filter_var('http://example.com', FILTER_VALIDATE_URL, $options); // returns false
filter_var('http://example.com/', FILTER_VALIDATE_URL, $options); // returns 'http://example.com/'
?>
rschuetz at hmcw dot com 22-Apr-2021 06:59
I cannot confirm what yactouat said. As of PHP 7.3, 0 will not be filtered out with FILTER_VALIDATE_INT. It correctly returns 0, not false. Of course you have to check the return value with an identity operator. Otherwise you cannot distinguish between 0 and false.
marcelo dot espindola at gmail dot com 20-Dec-2020 03:56
To remove multiple consecutive spaces replacing just one:

preg_replace('/\s\s+/', ' ', $value);
Robert Vlach 08-Apr-2020 06:33
I won't recommend using this function to validate email addresses on a normal website. The problem is that in accordance with RFC 3696 (Application Techniques for Checking and Transformation of Names) the following email addresses would be considered as valid:

customer/department=shipping@example.com
$A12345@example.com
!def!xyz%abc@example.com
_somename@example.com
"Abc@def"@example.com

Hardly something I would accept in a live web app in 2020 :-/
yactouat at hotmail dot com 18-May-2019 02:47
While getting familiar with filter_var( $var, FILTER_VALIDATE_INT ), I found interesting that 0 will be filtered out and therefore wont be considered as an int. Hope that helps someone not to be stuck ;)

N.B.: if you need to accept 0's, you could use is_int()
Steve 15-Oct-2018 01:47
The note from "hek" about HTML5 having patterns thus alleviating the need to filter in PHP is completely wrong:  You still must filter input on the server side.  The HTML5 form inputs are client-side, meaning they are completely under the user's control.  Only when you receive the data in PHP is it server-side and under your control.  Once the data is under your control, then you must filter/sanitize it properly.

This is true regardless of server-side language.  I would encourage the moderators to remove the note from "hek" because it will mislead people with horrible consequences.

Steve
Anonymous 06-Sep-2018 07:31
Replying to Andi:

This is NOT a valid URL, as the characters are not encoded

http://example.com/"><script>alert(document.cookie)</script>

This is a valid URL:

http://example.com/%22%3E%3Cscript%3Ealert%28document.cookie%29%3C%2Fscript%3E
mpyw628 at gmail dot com 22-Jul-2018 10:40
I wrote a JavaScript email validator fully compatible with PHP's filter_var() implementation.

mpyw/FILTER_VALIDATE_EMAIL.js: Email validation compatible with PHP's filter_var($value, FILTER_VALIDATE_EMAIL)
https://github.com/mpyw/FILTER_VALIDATE_EMAIL.js
ccbsschucko at gmail dot com 15-Jun-2018 12:59
<?php
   
class Sanitizer {
       
/**
        * @param str => $email = email a ser sanitizado
        */
       
public static function email($email){
            return
filter_var($email, FILTER_SANITIZE_EMAIL);
        }

       
/**
        * @param str => $valor = valor a ser sanitizado
        * @param bol => $allow_accents = permitir acentos
        * @param bol => $allow_spaces = permitir espa?os
        */
       
public static function alfabetico($valor, bool $allow_accents = true, bool $allow_spaces = false){
           
$valor = str_replace(array('"', "'", '`', '′', '¨'), '', trim($valor));
            if(!
$allow_accents && !$allow_spaces){
                return
preg_replace('#[^A-Za-z]#', '', $valor);
            }
            if(
$allow_accents && !$allow_spaces){
                return
preg_replace('#[^A-Za-zà-?à-?]#', '', $valor);
            }
            if(!
$allow_accents && $allow_spaces){
                return
preg_replace('#[^A-Za-z ]#', '', $valor);
            }
            if(
$allow_accents && $allow_spaces){
                return
preg_replace('#[^A-Za-zà-?à-? ]#', '', $valor);
            }               
        }

       
/**
        * @param str => $valor = valor a ser sanitizado
        */
       
public static function alfanumerico($valor, bool $allow_accents = true, bool $allow_spaces = false){
           
$valor = str_replace(array('"', "'", '`', '′', '¨'), '', trim($valor));
            if(!
$allow_accents && !$allow_spaces){
                return
preg_replace('#[^A-Za-z0-9]#', '', $valor);
            }
            if(
$allow_accents && !$allow_spaces){
                return
preg_replace('#[^A-Za-zà-?à-?0-9]#', '', $valor);
            }
            if(!
$allow_accents && $allow_spaces){
                return
preg_replace('#[^A-Za-z0-9 ]#', '', $valor);
            }
            if(
$allow_accents && $allow_spaces){
                return
preg_replace('#[^A-Za-zà-?à-?0-9 ]#', '', $valor);
            }
        }

       
/**
        * @param str => $valor = valor a ser sanitizado
        */
       
public static function numerico($valor){
            return
preg_replace('/\D/', '', $valor);
        }

       
/**
        * @param str => $valor = valor a ser sanitizado
        */
       
public static function integer($valor){
            return (int)
$valor;
        }

       
/**
        * @param str => $valor = valor a ser sanitizado
        */
       
public static function float($valor){
            return (float)
$valor;
        }

       
/**
        * @param str => $valor = valor a ser sanitizado
        */
       
public static function money($valor){
           
$valor = preg_replace('/\D/', '', $valor);
            if(
strlen($valor) < 3){
               
$valor = substr($valor, 0, strlen($valor)).'.00';
                return (float)
$valor;
            }
            if(
strlen($valor) > 2){
               
$valor = substr($valor, 0, (strlen($valor)-2)).'.'.substr($valor, (strlen($valor)-2));
                return (float)
$valor;
            }
        }

       
/**
        * @param str => $valor = valor a ser sanitizado
        */
       
public static function url($valor){
           
$valor = strip_tags(str_replace(array('"', "'", '`', '′', '¨'), '', trim($valor)));
            return
filter_var($valor, FILTER_SANITIZE_URL);
        }
    }
   
// ex:
   
var_dump(Sanitizer::numerico('bgusybd458ad8964sdfsd'));
   
// 4588964
?>
crisp at tweakers dot net 09-Jan-2018 10:31
Note that only using FILTER_VALIDATE_URL to validate url's input may result in XSS:

$url = 'javascript://%0Aalert(document.cookie)';

if (filter_var($url, FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED)) {
    echo '<a href="' . $url . '">click</a>';
}

You should at least additionally check the actually used scheme.
divinity76 at gmail dot com 22-Jun-2017 11:00
note that FILTER_VALIDATE_BOOLEAN tries to be smart, recognizing words like Yes, No, Off, On, both string and native types of true and false, and is not case-sensitive when validating strings.

<?php
$vals
=array('on','On','ON','off','Off','OFF','yes','Yes','YES',
'no','No','NO',0,1,'0','1','true',
'True','TRUE','false','False','FALSE',true,false,'foo','bar');
foreach(
$vals as $val){
    echo
var_export($val,true).': ';   var_dump(filter_var($val,FILTER_VALIDATE_BOOLEAN,FILTER_NULL_ON_FAILURE));
}
?>

outputs:
'on': bool(true)
'On': bool(true)
'ON': bool(true)
'off': bool(false)
'Off': bool(false)
'OFF': bool(false)
'yes': bool(true)
'Yes': bool(true)
'YES': bool(true)
'no': bool(false)
'No': bool(false)
'NO': bool(false)
0: bool(false)
1: bool(true)
'0': bool(false)
'1': bool(true)
'true': bool(true)
'True': bool(true)
'TRUE': bool(true)
'false': bool(false)
'False': bool(false)
'FALSE': bool(false)
true: bool(true)
false: bool(false)
'foo': NULL
'bar': NULL
alice at deviant dot email 02-May-2016 12:19
Many people, myself included, have found that the FILTER_VALIDATE_EMAIL does not actually properly work.

Below is a wrapper that I believe validates every legal routable address.

<?php

/*******************************************
 *
 * These are the function
 *
 *  check_username is called by check_email
 *  - it compensates for bugs in the php
 *    filter_var function.
 *  - returns boolean
 *
 *  check_email is the function to use.
 *  First argument is string, address to
 *    check
 *  Second argument is optional boolean,
 *    whether or not to use DNS to validate
 *    the domain name. Defaults to true
 *  Returns boolean
 *
 */
 
function check_username($uname) {
 
//Only UTF-8 addresses are legal
 
if (iconv('UTF-8', 'UTF-8', $input) != $input) {
      return
FALSE;
  }
 
//replace all characters above U+007F with letter U for simplicity of checking
 
$uname = preg_replace('/[\x{007F}-\x{FFFF}]/u', 'U', $uname);
 
 
//remove comments - only legal in format (comment) at beginning or end of username
 
$s[] = '/^\([^\)]*\)/'; $s[] = '/\([^\)]*\)$/';
 
$uname = preg_replace($s, '', $uname);
 
//make sure we have something left
 
if(strlen(trim($uname)) == 0) {
    return
FALSE;
  }
 
// check for legal dot usage
 
if(substr_count($uname, '..') > 0) {
    return
FALSE;
  }
 
// convert \\ and \" to an A for simplicity
 
$s[] = '/[\\\][\\\]/';
 
$s[] = '/\\\"/';
 
$uname = preg_replace($s, 'A', $uname);
 
// check for illegal use of quotes
 
if(preg_match('/[^.]+"[^.]+/', $uname)) {
    return
FALSE;
  }
 
// compensate for characters legal when in quotes
 
$uname = preg_replace_callback('/"(.*)"/', function ($m) {
   
$s[]="/[ \(\),\:;<>@\[\] ]/";
    return
preg_replace($s,'Q',$m[1]);
    },
$uname);
 
// check what we have left with filter_var
 
return filter_var($uname . '@example.org', FILTER_VALIDATE_EMAIL);
}

function
check_email($email, $dns_check=true) {
 
$array = explode('@', $email);
  if(
count($array) < 2) {
    return
FALSE;
  }
 
$domain = end($array);
 
array_pop($array);
  if(
function_exists('idn_to_ascii')) {
   
//php filter no workie with unicode characters
   
$domain = idn_to_ascii($domain);
  }
 
$ipcheck = preg_replace(array('/^\[ipv6\:/i', '/^\[/', '/\]$/'), '', $domain);
  if(
filter_var($ipcheck, FILTER_VALIDATE_IP)) {
   
// it's an IP address
   
if(! filter_var($ipcheck, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)) {
      return
FALSE;
    }
  } else {
   
// it's a domain name
    //   php bug - FILTER_VALIDATE_EMAIL doesn't like naked TLD
   
if(! filter_var('user@a.' . $domain, FILTER_VALIDATE_EMAIL)) {
      return
FALSE;
    }
    if(
$dns_check) {
      if(!
dns_get_record($domain)) {
        return
FALSE;
      }
    }
  }
 
//now check legal username
 
return check_username(implode('@', $array));
}
?>
It evaluates the address in two parts, first evaluating the host and if that legal it then evaluates the user name.

If there is a DNS problem *and* the default $dns_check value of true is used, valid will fail. If it is an international domain name, you have to have the php-intl package installed.

Enjoy.
buttflattery at gmail dot com 18-Jan-2016 03:15
FILTER_VALIDATE_URL validates a url like http://www.
amy at anvilzephyr dot com 10-Jan-2016 08:14
It might be wise to trim or sanitize (FILTER_SANITIZE_EMAIL) your email variable before validating to remove spaces:
filter_var(trim($email), FILTER_VALIDATE_EMAIL)
Ant 14-Dec-2015 02:20
Note: filter_var with filter=FILTER_VALIDATE_URL used parse_url function
dan at spiral8 dot net 08-Dec-2015 02:23
Here's a simple test using filter_var with FILTER_VALIDATE_URL.
(If you're using file_get_contents after this you will run into a problem, I was using: PHP 5.5.12 (cli))

<?php
$url
= 'a://google.com';

$result = filter_var($url, FILTER_VALIDATE_URL);

if(
$result){
    echo
'Valid URL'.PHP_EOL;
}

var_dump($result);
?>

The result is:
Valid URL
string(14) "a://google.com"
yoanlin93 at gmail dot com 22-Nov-2015 06:34
Some boolean conversions:

<?php
var_dump
(filter_var('oops', FILTER_VALIDATE_BOOLEAN, array('flags' => FILTER_NULL_ON_FAILURE)));
// NULL

var_dump(filter_var('false', FILTER_VALIDATE_BOOLEAN, array('flags' => FILTER_NULL_ON_FAILURE)));
// bool(false)

var_dump(filter_var('true', FILTER_VALIDATE_BOOLEAN, array('flags' => FILTER_NULL_ON_FAILURE)));
// bool(true)

var_dump(filter_var(0, FILTER_VALIDATE_BOOLEAN, array('flags' => FILTER_NULL_ON_FAILURE)));
// bool(false)

var_dump(filter_var(1, FILTER_VALIDATE_BOOLEAN, array('flags' => FILTER_NULL_ON_FAILURE)));
// bool(true)

var_dump(filter_var('TRUE', FILTER_VALIDATE_BOOLEAN, array('flags' => FILTER_NULL_ON_FAILURE)));
// bool(true)

var_dump(filter_var('', FILTER_VALIDATE_BOOLEAN, array('flags' => FILTER_NULL_ON_FAILURE)));
// bool(false)

var_dump(filter_var('FALSE', FILTER_VALIDATE_BOOLEAN, array('flags' => FILTER_NULL_ON_FAILURE)));
// bool(false)
Anonymous 04-Nov-2015 11:20
FILTER_VALIDATE_URL allows:

filter_var('javascript://comment%0Aalert(1)', FILTER_VALIDATE_URL);

Where the %0A (URL encoded newline), in certain contexts, will split the comment from the JS code.

This can result in an XSS vulnerability.
joe at bloe dot com 13-Jul-2014 03:04
"(comment)localpart@example.com"
is an invalid E-Mail address per RFC5322 (Appendix A.6.3):
"Also, the comments and white space throughout addresses, dates, and message identifiers are all part of the obsolete syntax."
george at NOSPAM dot crownvalleysoftware dot com 30-Apr-2014 10:08
In the options, "logical disjunction" means "or" - for example:
filter_var($somestring ,FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_LOW | FILTER_FLAG_STRIP_HIGH);
Tom 18-Nov-2013 10:23
It is important to note that though the data type of the first parameter of the function is stated as "mixed", this is only one half of the truth.

While it accepts any data type, the first parameter will always be cast to string before being validated or sanitized.

It seems that this function was designed strictly to be used on user input strings. For example: from an online-form. When using it for anything other than that, you may see issues. So read the documentation very carefully!

Especially note that there is an (to date) unresolved issue (#49510) concerning the Boolean filter while using the FILTER_NULL_ON_FAILURE flag. Note that both (string) FALSE and FALSE are not recognized as boolean values and will return NULL (not FALSE as you might expect).

I thus personally suggest that (to date) the best way to take the filter_var()-functions beyond their original purpose (and allow future extension and customization) is to wrap them in your own classes. This will allow you to work-around unexpected behavior on non-string input and add your custom checks, or back-port filters or sanitizers that may be added in later versions of PHP.
(Especially since PHP currently still lacks filters and sanitizers for some of the more exotic HTML5 input types, like "color". Thus there actually is a chance that we may see a need for custom filters or backports at some point in the future.)
CertaiN 01-Aug-2013 10:35
E-mail validator function that supports IPv6 and checking length.
This also supports Japanese old feature phone E-mail address by sending second argument $strict as FALSE.

<?php

function validate_email($email, $strict = true) {
   
$dot_string = $strict ?
       
'(?:[A-Za-z0-9!#$%&*+=?^_`{|}~\'\\/-]|(?<!\\.|\\A)\\.(?!\\.|@))' :
       
'(?:[A-Za-z0-9!#$%&*+=?^_`{|}~\'\\/.-])'
   
;
   
$quoted_string = '(?:\\\\\\\\|\\\\"|\\\\?[A-Za-z0-9!#$%&*+=?^_`{|}~()<>[\\]:;@,. \'\\/-])';
   
$ipv4_part = '(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])';
   
$ipv6_part = '(?:[A-fa-f0-9]{1,4})';
   
$fqdn_part = '(?:[A-Za-z](?:[A-Za-z0-9-]{0,61}?[A-Za-z0-9])?)';
   
$ipv4 = "(?:(?:{$ipv4_part}\\.){3}{$ipv4_part})";
   
$ipv6 = '(?:' .
       
"(?:(?:{$ipv6_part}:){7}(?:{$ipv6_part}|:))" . '|' .
       
"(?:(?:{$ipv6_part}:){6}(?::{$ipv6_part}|:{$ipv4}|:))" . '|' .
       
"(?:(?:{$ipv6_part}:){5}(?:(?::{$ipv6_part}){1,2}|:{$ipv4}|:))" . '|' .
       
"(?:(?:{$ipv6_part}:){4}(?:(?::{$ipv6_part}){1,3}|(?::{$ipv6_part})?:{$ipv4}|:))" . '|' .
       
"(?:(?:{$ipv6_part}:){3}(?:(?::{$ipv6_part}){1,4}|(?::{$ipv6_part}){0,2}:{$ipv4}|:))" . '|' .
       
"(?:(?:{$ipv6_part}:){2}(?:(?::{$ipv6_part}){1,5}|(?::{$ipv6_part}){0,3}:{$ipv4}|:))" . '|' .
       
"(?:(?:{$ipv6_part}:){1}(?:(?::{$ipv6_part}){1,6}|(?::{$ipv6_part}){0,4}:{$ipv4}|:))" . '|' .
       
"(?::(?:(?::{$ipv6_part}){1,7}|(?::{$ipv6_part}){0,5}:{$ipv4}|:))" .
   
')';
   
$fqdn = "(?:(?:{$fqdn_part}\\.)+?{$fqdn_part})";
   
$local = "({$dot_string}++|(\"){$quoted_string}++\")";
   
$domain = "({$fqdn}|\\[{$ipv4}]|\\[{$ipv6}]|\\[{$fqdn}])";
   
$pattern = "/\\A{$local}@{$domain}\\z/";
    return
preg_match($pattern, $email, $matches) &&
        (
            !empty(
$matches[2]) && !isset($matches[1][66]) && !isset($matches[0][256]) ||
            !isset(
$matches[1][64]) && !isset($matches[0][254])
        )
    ;
}

?>
gt at kani dot hu 21-Jun-2013 02:31
I found some addresses that FILTER_VALIDATE_EMAIL rejects, but RFC5321 permits:
<?php
foreach (array(
       
'localpart.ending.with.dot.@example.com',
       
'(comment)localpart@example.com',
       
'"this is v@lid!"@example.com',
       
'"much.more unusual"@example.com',
       
'postbox@com',
       
'admin@mailserver1',
       
'"()<>[]:,;@\\"\\\\!#$%&\'*+-/=?^_`{}| ~.a"@example.org',
       
'" "@example.org',
    ) as
$address) {
    echo
"<p>$address is <b>".(filter_var($address, FILTER_VALIDATE_EMAIL) ? '' : 'not')." valid</b></p>";
}
?>
Results:

localpart.ending.with.dot.@example.com is not valid
(comment)localpart@example.com is not valid
"this is v@lid!"@example.com is not valid
"much.more unusual"@example.com is not valid
postbox@com is not valid
admin@mailserver1 is not valid
"()<>[]:,;@\"\\!#$%&'*+-/=?^_`{}| ~.a"@example.org is not valid
" "@example.org is not valid

The documentation does not saying that FILTER_VALIDATE_EMAIL should pass the RFC5321, however you can meet with these examples (especially with the first one). So this is a note, not a bug report.
drew_mirage at hotmail dot com 18-Jun-2013 07:14
One key thing to remember about filtering integers is that the value for the option max_range must be less than or equal to the value of PHP_INT_MAX.

filter_var($someVariable, FILTER_VALIDATE_INT, array('options' => array('min_range' => 1, 'max_range' => SOME_VALUE_GREATER_THAN_PHP_INT_MAX)));

This will fail even if $someVariable is a valid integer in the expected range.

This can show up when you are attempting to validate a potential key for an unsigned MySQL INT type (whose maximum value is 4294967295) on a 32-bit system, where the value of PHP_INT_MAX is 2147483647.
cabrinosimone at gmail dot com 02-Apr-2013 03:19
Pay attention that the function will not validate "not latin" domains.

if (filter_var('уникум@из.рф', FILTER_VALIDATE_EMAIL)) {
    echo 'VALID';
} else {
    echo 'NOT VALID';
}
alex4home at gmail dot com 10-Jan-2013 12:18
Keep in mind that FILTER_VALIDATE_EMAIL will validate the email address according to standards.
However, giving the fact that organizations are free to restrict the forms of their own email addresses, using ONLY this filter can you a lot of bounces.

gmail, yahoo, hotmail, aol have special rules

For example :
<?php

$email_a
= '0hot\'mail_check@hotmail.com';
if (
filter_var($email_a, FILTER_VALIDATE_EMAIL)) {
    echo
"This (email_a) email address is considered valid.";
  
//reported as valid
}

//there can be no  "0hotmail_check@hotmail.com"
//because hotmail will say "Your email address needs to start with a letter. Please try again." even if you remove the '
?>
marcus at synchromedia dot co dot uk 03-Sep-2012 09:13
It's very likely that you actually want to detect all reserved ranges, not just private IPs, and there's another constant for them that should be bitwise-OR'd with it.
<?php
function is_private_ip($ip) {
    return !
filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE);
}
?>
Martin L 27-Jul-2012 10:35
FILTER_SANITIZE_EMAIL header injection test.

<?php
$InjString
= "\r\n|\n|%0A|%0D|bcc:|to:|cc:|Content-Type:|Mime-Type:|";
echo
filter_var($InjString, FILTER_SANITIZE_EMAIL);
?>

||%0A|%0D|bcc|to|cc|Content-Type|Mime-Type|
Andi, info at pragmamx dot org 23-May-2012 06:07
And this is also a valid url

http://example.com/"><script>alert(document.cookie)</script>
keevitaja at gmail dot com 28-Jan-2012 08:05
please note FILTER_VALIDATE_URL passes following url

http://example.ee/sdsf"f
joelhy 06-Jul-2011 02:44
For those looking for private ip checking, there it is:
<?php
 
function is_private_ip($ip)
{
     return !
filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE);
}
?>
php at maisqi dot com 27-May-2011 07:11
FILTER_VALIDATE_URL does not support internationalized domain name (IDN). Valid or not, no domain name with Unicode chars on it will pass validation.

We can circumvent this with a home grown solutions, but C code is C code, so I've gone for the code bellow, which builds on filter_var().

<?php
$res
= filter_var ($uri, FILTER_VALIDATE_URL);
if (
$res) return $res;
// Check if it has unicode chars.
$l = mb_strlen ($uri);
if (
$l !== strlen ($uri)) {
   
// Replace wide chars by "X".
   
$s = str_repeat (' ', $l);
    for (
$i = 0; $i < $l; ++$i) {
       
$ch = mb_substr ($uri, $i, 1);
       
$s [$i] = strlen ($ch) > 1 ? 'X' : $ch;
    }
   
// Re-check now.
   
$res = filter_var ($s, FILTER_VALIDATE_URL);
    if (
$res) {    $uri = $res; return 1;    }
}
?>

The logic is simple. A non-ascii char is more than one byte long. We replace every one of those chars by "X" and check again.

An alternative will be to punycode the URI before calling filter_var(), but PHP lacks native support for punycode. I think my approach is effective. Please e-mail me if you think otherwise or see room for improvement.
drtebi at yahoo 24-Nov-2009 11:55
Notice that filter_var with FILTER_VALIDATE_EMAIL does not work if you are trying to get a String from an XML document e.g. via xpath.

I often use XML files as configuration files and use a function that returns a string from the config file via xpath. While this worked fine before 5.2.11, it doesn't anymore (and shouldn't, since it's an XML Element, not a String).

To overcome this problem, $variable can be type-casted:

<?php
$variable
= fancyXmlGetFunction('from');
filter_var((String) $variable, FILTER_VALIDATE_EMAIL);
?>
jon dot bertsch at ucop dot edu 24-Mar-2009 07:49
Here's an actual example of the filter syntax with a flag since there doesn't appear to be a one liner for this anywhere:

'hours' => array('filter'=>FILTER_SANITIZE_NUMBER_FLOAT, 'flags' => FILTER_FLAG_ALLOW_FRACTION, 'options'=> '.')
dyer85 at gmail dot com 03-Nov-2008 02:00
Note that when using FILTER_VALIDATE_INT along with the FILTER_FLAG_ALLOW_HEX flag, the string "2f", for example, is not validated successfully, because you must use the "0x" prefix, otherwise, it treats the data as base 10.

The range options are also smart enough to recognize when the boundaries are exceeded in different bases.

Here's an example:

<?php

$foo
= '256';
$bar = '0x100';
var_dump(validate_int($foo)); // false, too large
var_dump(validate_int($bar)); // false, too large

function validate_int($input)
{
  return
filter_var(
   
$input,
   
FILTER_VALIDATE_INT,

   
// We must pass an associative array
    // to include the range check options.
   
array(
     
'flags'   => FILTER_FLAG_ALLOW_HEX,
     
'options' => array('min_range' => 1, 'max_range' => 0xff)
    )
  );
}

?>
dale dot liszka at gmail dot com 09-Jul-2008 10:15
Here is how to use multiple flags (for those who learn better by example, like me):

<?php
echo "|asdf".chr(9).chr(128)."_123|";
echo
"\n";
// "bitwise conjunction" means logic OR / bitwise |
echo filter_var("|asdf".chr(9).chr(128)."_123\n|" ,FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_LOW | FILTER_FLAG_STRIP_HIGH);

/*
Results:
|asdf    ?_123|
|asdf_123|
*/
?>
dale dot liszka at gmail dot com 09-Jul-2008 09:54
Using the FILTER_CALLBACK requires an array to be passed as the options:

<?php
function toDash($x){
   return
str_replace("_","-",$x);
}

echo
filter_var("asdf_123",FILTER_CALLBACK,array("options"=>"toDash"));
// returns 'asdf-123'
?>
John 26-Jul-2007 12:35
I managed to get this to work with PHP 5.1.6 on CentOS 5 with minor difficulty.

1) Download the PECL filter package
2) Extract the tarball
3) phpize the directory
4) ./configure
5) make
6) filter-0.11.0/logical_filters.c:25:31: error: ext/pcre/php_pcre.h: No such file or directory
7) find / -name php_pcre.h
8) Make sure php-devel is installed
9) Edit filter-0.11.0/logical_filters.c and replace "ext/pcre/php_pcre.h" with the absolute path of php_pcre.h
10) make
11) make install
12) add "extension=filter.so" to php.ini
13) Restart Apache
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