Validate filters

Listing of filters for validation
ID Name Options Flags Description
FILTER_VALIDATE_BOOLEAN "boolean" default FILTER_NULL_ON_FAILURE

Returns TRUE for "1", "true", "on" and "yes". Returns FALSE otherwise.

If FILTER_NULL_ON_FAILURE is set, FALSE is returned only for "0", "false", "off", "no", and "", and NULL is returned for all non-boolean values.

FILTER_VALIDATE_EMAIL "validate_email" default   Validates value as e-mail.
FILTER_VALIDATE_FLOAT "float" default, decimal FILTER_FLAG_ALLOW_THOUSAND Validates value as float.
FILTER_VALIDATE_INT "int" default, min_range, max_range FILTER_FLAG_ALLOW_OCTAL, FILTER_FLAG_ALLOW_HEX Validates value as integer, optionally from the specified range.
FILTER_VALIDATE_IP "validate_ip" default FILTER_FLAG_IPV4, FILTER_FLAG_IPV6, FILTER_FLAG_NO_PRIV_RANGE, FILTER_FLAG_NO_RES_RANGE Validates value as IP address, optionally only IPv4 or IPv6 or not from private or reserved ranges.
FILTER_VALIDATE_REGEXP "validate_regexp" default, regexp   Validates value against regexp, a Perl-compatible regular expression.
FILTER_VALIDATE_URL "validate_url" default FILTER_FLAG_PATH_REQUIRED, FILTER_FLAG_QUERY_REQUIRED Validates value as URL (according to » http://www.faqs.org/rfcs/rfc2396), optionally with required components. Beware a valid URL may not specify the HTTP protocol http:// so further validation may be required to determine the URL uses an expected protocol, e.g. ssh:// or mailto:. Note that the function will only find ASCII URLs to be valid; internationalized domain names (containing non-ASCII characters) will fail.

Note:

As of PHP 5.4.11, the numbers +0 and -0 validate as both integers as well as floats (using FILTER_VALIDATE_FLOAT and FILTER_VALIDATE_INT). Before PHP 5.4.11 they only validated as floats (using FILTER_VALIDATE_FLOAT).

When default is set to option, default's value is used if value is not validated.

Коментарии

Автор:
FILTER_VALIDATE_EMAIL does NOT allow incomplete e-mail addresses to be validated as mentioned by Tomas.

Using the following code:

<?php
$email 
"clifton@example"//Note the .com missing
echo "PHP Version: ".phpversion().'<br>';
if(
filter_var($emailFILTER_VALIDATE_EMAIL)){
    echo 
$email.'<br>';
   
var_dump(filter_var($emailFILTER_VALIDATE_EMAIL));
}else{
   
var_dump(filter_var($emailFILTER_VALIDATE_EMAIL));   
}
?>

Returns:
PHP Version: 5.2.14 //On MY server, may be different depending on which version you have installed.
bool(false)

While the following code:

<?php
$email 
"clifton@example.com"//Note the .com added
echo "PHP Version: ".phpversion().'<br>';
if(
filter_var($emailFILTER_VALIDATE_EMAIL)){
    echo 
$email.'<br>';
   
var_dump(filter_var($emailFILTER_VALIDATE_EMAIL));
}else{
   
var_dump(filter_var($emailFILTER_VALIDATE_EMAIL));   
}
?>

Returns:
PHP Version: 5.2.14 //On MY server, may be different depending on which version you have installed.
clifton@example.com
string(16) "clifton@example.com"

This feature is only available for PHP Versions (PHP 5 >= 5.2.0) according to documentation. So make sure your version is correct.

Cheers,
Clifton
2011-01-05 10:00:01
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
FILTER_VALIDATE_EMAIL is discarding valid e-mail addresses containing IDN. Since there are real, live IDNs on the Internet, that means the filtered output is too strict, leading to false negatives.

Punycode-encoded IDN addresses pass the filter correctly; so before checking for validity, it is necessary to convert the e-mail address to punycode.
2011-02-11 10:57:46
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
Notably missing is a way to validate text entry as printable,
printable multiline,
or printable and safe (tag free)

FILTER_VALIDATE_TEXT, which validates no special characters
perhaps with FILTER_FLAG_ALLOW_NEWLINE
and FILTER_FLAG_NOTAG to disallow tag starters
2012-05-06 07:45:29
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
FILTER_VALIDATE_URL does not work with URNs, examples of valid URIs according to RFC3986 and if they are accepted by FILTER_VALIDATE_URL:

[PASS] ftp://ftp.is.co.za.example.org/rfc/rfc1808.txt
[PASS] gopher://spinaltap.micro.umn.example.edu/00/Weather/California/Los%20Angeles
[PASS] http://www.math.uio.no.example.net/faq/compression-faq/part1.html
[PASS] mailto:mduerst@ifi.unizh.example.gov
[PASS] news:comp.infosystems.www.servers.unix
[PASS] telnet://melvyl.ucop.example.edu/
[PASS] http://www.ietf.org/rfc/rfc2396.txt
[PASS] ldap://[2001:db8::7]/c=GB?objectClass?one
[PASS] mailto:John.Doe@example.com
[PASS] news:comp.infosystems.www.servers.unix
[FAIL] tel:+1-816-555-1212
[PASS] telnet://192.0.2.16:80/
[FAIL] urn:oasis:names:specification:docbook:dtd:xml:4.1.2
2012-10-19 17:06:13
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
Regarding "partial" addresses with no . in the domain part, a comment in the source code (in ext/filter/logical_filters.c) justifies this rejection thus:

     * The regex below is based on a regex by Michael Rushton.
     * However, it is not identical.  I changed it to only consider routeable
     * addresses as valid.  Michael's regex considers a@b a valid address
     * which conflicts with section 2.3.5 of RFC 5321 which states that:
     *
     *   Only resolvable, fully-qualified domain names (FQDNs) are permitted
     *   when domain names are used in SMTP.  In other words, names that can
     *   be resolved to MX RRs or address (i.e., A or AAAA) RRs (as discussed
     *   in Section 5) are permitted, as are CNAME RRs whose targets can be
     *   resolved, in turn, to MX or address RRs.  Local nicknames or
     *   unqualified names MUST NOT be used.
2013-03-17 22:22:28
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
Автор:
Rejection of so-called partial domains because of "missing" dot is not following section 2.3.5 of RFC 5321.

It says FQDNs are permitted, and com, org, or va are (well, may be) valids FQDNs. It depends on DNS, not on syntax.

Some TDLs (although few of them) have MX RRs, the for example "abuse@va" is correct.
2013-09-24 11:05:01
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
It's good to remember that using filter_var is primarily for filtering input values when doing boolean logic comparisons. Take the following:

$value = "12";
if(filter_var($value, FILTER_VALIDATE_INT))
{
    // validated as an int
}

The above works as intended, except when $value = "0". In which case filter_var returns a 0, aka false when used as a boolean.

For the correct behavior, do a zero check.

$value = " 0 ";
$filtered = filter_var($value, FILTER_VALIDATE_INT);
if($filtered || $filtered === 0)
{
    // validated as an int
}
2015-03-22 06:18:04
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
Often I see some code like the following:
$value = "12";
if( filter_var($value, FILTER_VALIDATE_INT) )
{
    // validated as an int
}

The above works as intended, except when $value is "0". In the above case it will be interpreted as FALSE.

For the correct behavior,  you have not only to check if it is equal (==) to false, but also identic (===) to FALSE:
$value = " 0 ";
if( filter_var($value, FILTER_VALIDATE_INT)  === FALSE )
{
    // validated as an int
}

I hope, I could help.
2015-03-27 01:09:01
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
Автор:
The description for FILTER_VALIDATE_URL seems incorrect/misleading. "Beware a valid URL may not specify the HTTP protocol" implies a valid URL cannot specify the HTTP protocol. I think "Beware a valid URL need not specify..." would be better.
2015-09-05 23:41:31
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
Note that if using FILTER_NULL_ON_FAILURE as a flag with the FILTER_VALIDATE_BOOLEAN id then NULL is no longer returned if the variable name is not set in the external variable array. It will instead return FALSE. In the description is says that when using the FILTER_NULL_ON_FAILURE flag that ' FALSE is returned only for "0", "false", "off", "no", and ""' an makes no mention of this additional state that can also return false. The behavior is mentioned on the filter_input documentation page under Return Values but that is not overly helpful if one is just looking here.

If FILTER_NULL_ON_FAILURE is not used then NULL is returned when the variable name is not set in the external variable array, TRUE is returned for "1", "true", "on" and "yes" and FALSE is returned for everything else.
2015-11-25 19:18:03
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
FILTER_VALIDATE_EMAIL not only doesn't support whitespace folding and comments. It only checks Addr-spec part of email address. Otherwise it should mark such address as valid: 'Test Example <test@example.com>' because it is valid according to RFC 822.

Also address "test@localhost" should be valid. Which is mentioned in another note.

You can test it with this code:
<?php

$emails 
= array(
   
'Test Example <test@example.com>',
   
'test@localhost',
   
'test@localhost.com'
);

foreach (
$emails as $email) {
    echo (
filter_var($emailFILTER_VALIDATE_EMAIL)) ? 
       
"[+] Email '$email' is valid\n" 
       
"[-] Email '$email' is NOT valid\n";
}
?>

Output for PHP 5.3.21 - 7.0.1 :
[-] Email 'Test Example <test@example.com>' is NOT valid
[-] Email 'test@localhost' is NOT valid
[+] Email 'test@localhost.com' is valid
2016-01-05 14:48:26
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
Автор:
FILTER_VALIDATE_INT first casts its value to string which produces unexpected result for bool and float (https://bugs.php.net/bug.php?id=72490):

<?php

// Prints int(1).
var_dump(filter_var(trueFILTER_VALIDATE_INT));

// ...but this prints bool(false).
var_dump(filter_var(falseFILTER_VALIDATE_INT));

// --------

// Prints bool(false).
var_dump(filter_var(1.1FILTER_VALIDATE_INT));

// ...but this prints int(0).
var_dump(filter_var(0.0FILTER_VALIDATE_INT));

// ...but this again is bool(false).
var_dump(filter_var('0.0'FILTER_VALIDATE_INT));

// Also bool(false).
var_dump(filter_var('-0.0'FILTER_VALIDATE_INT));

?>

Live sample: https://3v4l.org/CZW0W

The docs are not clear on how exactly this casting affects the result for certain input values.
2016-06-30 11:18:02
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
FILTER_FLAG_QUERY_REQUIRED is failing URLs that are encoded e.g.

http://example.com/page.php?q=growing+big

Fails whilst

http://example.com/page.php?q=big

So anything more than one word encoded fails.

Tested on PHP version 7.1
2018-01-30 20:36:33
http://php5.kiev.ua/manual/ru/filter.filters.validate.html
Автор:
since php 7.4 
you can use these 3 beautiful conditions for from validation for validation less, great or in range

<?php
/**
 * less_than_equal_to
 */
$x 50;
if (
filter_var($xFILTER_VALIDATE_FLOAT, ["options" => ["max_range" => 100]]) !== false) {
    echo 
"result : $x is less than OR equal to 100";
} else {
    echo 
"result : $x is NOT less than OR equal to 100";
}
?>
result : 50 is less than OR equal to 100

<?php
/**
 * greater_than_equal_to 
 */
$x 50;
if (
filter_var($xFILTER_VALIDATE_FLOAT, ["options" => ["min_range" => 100]]) !== false) {
    echo 
"result : $x is greater than OR equal to 100";
} else {
    echo 
"result : $x is NOT greater than OR equal to 100";
}
?>
result : 50 is NOT greater than OR equal to 100

<?php
/**
 * less_than_equal_to && greater_than_equal_to
 */
$x 50;
if (
filter_var($xFILTER_VALIDATE_FLOAT, ["options" => ["min_range" => "max_range"=> 100]]) !== false) {
    echo 
"result : $x is in range of 0 to 100";
} else {
    echo 
"result : $x in NOT range of 0 to 100";
}
?>
result : 50 is in range of 0 to 100
2020-04-03 01:17:52
http://php5.kiev.ua/manual/ru/filter.filters.validate.html

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