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';
}
filter_var
(PHP 5 >= 5.2.0, PHP 7, PHP 8)
filter_var — Filtra una variable con el filtro que se indique
Parámetros
-
variable -
Valor a filtrar
-
filter -
El ID del filtro a aplicar. La página Tipos de filtros del manual enumera los filtros disponibles.
Si se omite, se utilizará
FILTER_DEFAULT, que es equivalente aFILTER_UNSAFE_RAW. Esto resultará en que no se realice ningún tipo de filtro de forma predeterminada. -
options -
Array asociativo de opciones o disyunción lógica de flags. Si un filtro acepta opciones, se pueden indicar flags en el campo "flags" del array. Para el filtro "callback" debería pasarse el tipo callable. La llamada de la función de retorno (callback) debe aceptar un argumento, el valor a ser filtrado y debe retornar el valor tras su filtrado/saneamiento.
<?php
// Para filtros que acepten opciones, usar este formato
$opciones = array(
'options' => array(
'default' => 3, // valor a retornar si el filtro falla
// más opciones aquí
'min_range' => 0
),
'flags' => FILTER_FLAG_ALLOW_OCTAL,
);
$var = filter_var('0755', FILTER_VALIDATE_INT, $opciones);
// Para filtros que únicamente acepten flags, se pueden pasar directametne
$var = filter_var('oops', FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
// Para filtros que únicamente acepten flags, también pueden pasarse como
// array
$var = filter_var('oops', FILTER_VALIDATE_BOOLEAN,
array('flags' => FILTER_NULL_ON_FAILURE));
// Filtro "callback2
function foo($value)
{
// Formato esperado: Apellido, Nombre
if (strpos($value, ", ") === false) return false;
list($surname, $givennames) = explode(", ", $value, 2);
$empty = (empty($surname) || empty($givennames));
$notstrings = (!is_string($surname) || !is_string($givennames));
if ($empty || $notstrings) {
return false;
} else {
return $value;
}
}
$var = filter_var('Doe, Jane Sue', FILTER_CALLBACK, array('options' => 'foo'));
?>
Valores devueltos
Retorna los datos filtrados o false si el filtro falla.
Ejemplos
Ejemplo #1 Un ejemplo de filter_var()
<?php
var_dump(filter_var('bob@example.com', FILTER_VALIDATE_EMAIL));
var_dump(filter_var('http://example.com', FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED));
?>El resultado del ejemplo sería:
string(15) "bob@example.com" bool(false)
Ver también
- filter_var_array() - Retorna múltiple variables y opcionalmente las filtra
- filter_input() - Toma una variable externa concreta por su nombre y opcionalmente la filtra
- filter_input_array() - Obtiene variables externas y opcionalmente las filtra
- Tipos de filtros
add a note
User Contributed Notes 38 notes
cabrinosimone at gmail dot com ¶
11 years ago
gt at kani dot hu ¶
11 years ago
I found some addresses that FILTER_VALIDATE_EMAIL rejects, but RFC5321 permits:
<?php
foreach (array(
'localpart.ending.with.dot.@example.com',
'(comment)localpart@example.com',
'"this is v@lid!"@example.com',
'"much.more unusual"@example.com',
'postbox@com',
'admin@mailserver1',
'"()<>[]:,;@\\"\\\\!#$%&\'*+-/=?^_`{}| ~.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.
divinity76 at gmail dot com ¶
7 years ago
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
Steve ¶
6 years ago
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
Andi, info at pragmamx dot org ¶
12 years ago
And this is also a valid url
http://example.com/"><script>alert(document.cookie)</script>
Anonymous ¶
1 year ago
Pay attention:
questionmark in url is also valid
<?php
echo filter_var("http://test???test.com", FILTER_VALIDATE_URL)?"valid":"not valid"; #valid
?>
Anonymous ¶
9 years ago
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.
yactouat at hotmail dot com ¶
5 years ago
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()
mmerlone at gmail dot com ¶
3 years ago
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, $options); // returns 'http://example.com/'
?>
mpyw628 at gmail dot com ¶
6 years ago
I wrote a JavaScript email validator fully compatible with PHP's filter_var() implementation.
mpyw/FILTER_VALIDATE_EMAIL.js: Email validation compatible with PHP's filter_var($value, FILTER_VALIDATE_EMAIL)
https://github.com/mpyw/FILTER_VALIDATE_EMAIL.js
marcus at synchromedia dot co dot uk ¶
12 years ago
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);
}
?>
dale dot liszka at gmail dot com ¶
16 years ago
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'
?>
rschuetz at hmcw dot com ¶
3 years ago
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.
crisp at tweakers dot net ¶
6 years ago
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.
jon dot bertsch at ucop dot edu ¶
15 years ago
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'=> '.')
dale dot liszka at gmail dot com ¶
16 years ago
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|
*/
?>
keevitaja at gmail dot com ¶
12 years ago
please note FILTER_VALIDATE_URL passes following url
http://example.ee/sdsf"f
Robert Vlach ¶
4 years ago
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
$A12345@example.com
!def!xyz%abc@example.com
_somename@example.com
"Abc@def"@example.com
Hardly something I would accept in a live web app in 2020 :-/
Random Guy ¶
10 months ago
Actually, this is not really a helpful comment for a manual (so, don't upvote), but as search engines don't find a lot of occurrences for the error message and especially no helpful hint, it might save somebody some time.
If you're getting an error message like "filter_var(): Unknown filter with ID 2097152" or a different number, you just accidentally mixed up the parameters. So, instead of
<?php
filter_var($ip, FILTER_FLAG_IPV6)
?>
you should try it with
<?php
filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)
?>
and it will work ;) I know, this isn't the most intuitive form you can design a function and it's tempting to throw everything into one param as it is done for regular checks, but, yeah, it is how it is.
remindfwd ¶
1 year ago
Please note that the following will return true, even if the URL is not correct. Because it validates only the domain, subdomain, path and query, not the protocol.
<?php
filter_var( 'http://https://example.com', FILTER_VALIDATE_URL );
?>
Please read more on https://www.php.net/manual/en/filter.filters.validate.php
ajcorrea at gmail dot com ¶
1 year ago
You can use multiple FLAGS to validate an ip address:
//Validade if input is an IPv4 Address:
$_FILTERS = array('flags' => FILTER_FLAG_IPV4);
//Validade if input is an IPv4 address and isn´t a private IP.
$_FILTERS = array('flags' => FILTER_FLAG_IPV4 | FILTER_FLAG_NO_PRIV_RANGE);
//Validade if input is an IPv4 and isn´t a reserved IP.
$_FILTERS = array('flags' => FILTER_FLAG_IPV4 | FILTER_FLAG_NO_RES_RANGE);
//Validade if input is an IPv4, isn´t a private IP and isn´t a reserved IP.
$_FILTERS = array('flags' => FILTER_FLAG_IPV4 | FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE);
filter_var($_input, FILTER_VALIDATE_IP, $_FILTERS);
dakaenev at gmail dot com ¶
10 months ago
As reply of https://www.php.net/manual/en/function.filter-var.php#128235
if you use FILTER_FLAG_PATH_REQUIRED it work correct.
var_dump( filter_var('http://test???test.com/path/?t=1', FILTER_VALIDATE_URL) ); // true
var_dump( filter_var('http://test???test.com/path/?t=1', FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED) ); // false
Guy Sartorelli ¶
1 year ago
Note that filter_var() with FILTER_VALIDATE_URL uses RFC2396 which is obsolete. This means it treats some currently valid characters (such as "_") as being invalid.
In many cases it may be more beneficial to use php parse_url() which uses RFC3986 which is what is currently in effect.
php at maisqi dot com ¶
13 years ago
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.
joe at bloe dot com ¶
10 years ago
"(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."
dyer85 at gmail dot com ¶
16 years ago
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)
)
);
}
?>
dan at spiral8 dot net ¶
8 years ago
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"
alex4home at gmail dot com ¶
11 years ago
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 '
?>
drew_mirage at hotmail dot com ¶
11 years ago
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.
yoanlin93 at gmail dot com ¶
8 years ago
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)
Martin L ¶
12 years ago
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|
Tom ¶
11 years ago
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.)
alice at deviant dot email ¶
8 years ago
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 $dns_check value of true is used, valid will fail. If it is an international domain name, you have to have the php-intl package installed.
Enjoy.
Anonymous ¶
6 years ago
Replying to Andi:
This is NOT a valid URL, as the characters are not encoded
http://example.com/"><script>alert(document.cookie)</script>
This is a valid URL:
http://example.com/%22%3E%3Cscript%3Ealert%28document.cookie%29%3C%2Fscript%3E
joelhy ¶
13 years ago
For those looking for private ip checking, there it is:
<?php
function is_private_ip($ip)
{
return !filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE);
}
?>
drtebi at yahoo ¶
14 years ago
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);
?>
