filter_var

PHP Filter Function: filter_var
Categories:
Tags:

Support PHP version

  • PHP 5 >= 5.2.0
  • PHP 7
  • PHP 8

Example

IP Address

https://electrictoolbox.com/php-validate-ip-address-filter-var/

Validating an IP address

$ip = "127.0.0.1";
if(filter_var($ip, FILTER_VALIDATE_IP)) {
  // it's valid
}
else {
  // it's not valid
}

Validate an IPv4 IP address

if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
  // it's valid
}
else {
  // it's not valid
}

Validate an IPv4 address, excluding private range addresses

if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_NO_PRIV_RANGE)) {
  // it's valid
}
else {
  // it's not valid
}

Validate an IPv6 address

$ip = "2001:200::";
if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)) {
  // it's valid
}
else {
  // it's not valid
}

Excluding Reserved

if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_RES_RANGE)) {
  // it's valid
}
else {
  // it's not valid
}

Excluding Reserved and Private Ranges

if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)) {
  // it's valid
}
else {
  // it's not valid
}

Combining FILTER_FLAG_IPV4 and FILTER_FLAG_IPV6?

Combining FILTER_FLAG_IPV4 and FILTER_FLAG_IPV6 always return false. So DO NOT combine the IPv4 and IPv6 filter together.

Filter Cheetsheet

Validate filters

ID Flags
FILTER_VALIDATE_BOOLEAN, FILTER_VALIDATE_BOOL FILTER_NULL_ON_FAILURE
FILTER_VALIDATE_DOMAIN FILTER_FLAG_HOSTNAME, FILTER_NULL_ON_FAILURE
FILTER_VALIDATE_EMAIL FILTER_FLAG_EMAIL_UNICODE, FILTER_NULL_ON_FAILURE
FILTER_VALIDATE_FLOAT FFILTER_FLAG_ALLOW_THOUSAND, FILTER_NULL_ON_FAILURE
FILTER_VALIDATE_INT FILTER_FLAG_ALLOW_OCTAL, FILTER_FLAG_ALLOW_HEX, FILTER_NULL_ON_FAILURE
FILTER_VALIDATE_IP FILTER_FLAG_IPV4, FILTER_FLAG_IPV6, FILTER_FLAG_NO_PRIV_RANGE, FILTER_FLAG_NO_RES_RANGE, FILTER_FLAG_GLOBAL_RANGE, FILTER_NULL_ON_FAILURE
FILTER_VALIDATE_MAC FILTER_NULL_ON_FAILURE
FILTER_VALIDATE_REGEXP FILTER_NULL_ON_FAILURE
FILTER_VALIDATE_URL FILTER_FLAG_SCHEME_REQUIRED, FILTER_FLAG_HOST_REQUIRED, FILTER_FLAG_PATH_REQUIRED, FILTER_FLAG_QUERY_REQUIRED, FILTER_NULL_ON_FAILURE

Sanitize filters

ID Flags
FILTER_SANITIZE_EMAIL
FILTER_SANITIZE_ENCODED FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_STRIP_BACKTICK, FILTER_FLAG_ENCODE_LOW, FILTER_FLAG_ENCODE_HIGH
FILTER_SANITIZE_MAGIC_QUOTES
FILTER_SANITIZE_ADD_SLASHES
FILTER_SANITIZE_NUMBER_FLOAT FILTER_FLAG_ALLOW_FRACTION, FILTER_FLAG_ALLOW_THOUSAND, FILTER_FLAG_ALLOW_SCIENTIFIC
FILTER_SANITIZE_NUMBER_INT
FILTER_SANITIZE_SPECIAL_CHARS FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_STRIP_BACKTICK, FILTER_FLAG_ENCODE_HIGH
FILTER_SANITIZE_FULL_SPECIAL_CHARS FILTER_FLAG_NO_ENCODE_QUOTES
FILTER_SANITIZE_STRING FILTER_FLAG_NO_ENCODE_QUOTES, FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_STRIP_BACKTICK, FILTER_FLAG_ENCODE_LOW, FILTER_FLAG_ENCODE_HIGH, FILTER_FLAG_ENCODE_AMP
FILTER_SANITIZE_STRIPPED
FILTER_SANITIZE_URL
FILTER_UNSAFE_RAW FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_STRIP_BACKTICK, FILTER_FLAG_ENCODE_LOW, FILTER_FLAG_ENCODE_HIGH, FILTER_FLAG_ENCODE_AMP

Other filters

ID Flags
FILTER_CALLBACK All flags are ignored

Filter flags

ID Used with
FILTER_FLAG_STRIP_LOW FILTER_SANITIZE_ENCODED, FILTER_SANITIZE_SPECIAL_CHARS, FILTER_SANITIZE_STRING, FILTER_UNSAFE_RAW
FILTER_FLAG_STRIP_HIGH FILTER_SANITIZE_ENCODED, FILTER_SANITIZE_SPECIAL_CHARS, FILTER_SANITIZE_STRING, FILTER_UNSAFE_RAW
FILTER_FLAG_STRIP_BACKTICK FILTER_SANITIZE_ENCODED, FILTER_SANITIZE_SPECIAL_CHARS, FILTER_SANITIZE_STRING, FILTER_UNSAFE_RAW
FILTER_FLAG_ALLOW_FRACTION FILTER_SANITIZE_NUMBER_FLOAT
FILTER_FLAG_ALLOW_THOUSAND FILTER_SANITIZE_NUMBER_FLOAT, FILTER_VALIDATE_FLOAT
FILTER_FLAG_ALLOW_SCIENTIFIC FILTER_SANITIZE_NUMBER_FLOAT
FILTER_FLAG_NO_ENCODE_QUOTES FILTER_SANITIZE_STRING
FILTER_FLAG_ENCODE_LOW FILTER_SANITIZE_ENCODED, FILTER_SANITIZE_STRING, FILTER_UNSAFE_RAW
FILTER_FLAG_ENCODE_HIGH FILTER_SANITIZE_ENCODED, FILTER_SANITIZE_SPECIAL_CHARS, FILTER_SANITIZE_STRING, FILTER_UNSAFE_RAW
FILTER_FLAG_ENCODE_AMP FILTER_SANITIZE_STRING, FILTER_UNSAFE_RAW
FILTER_NULL_ON_FAILURE any FILTER_VALIDATE_*
FILTER_FLAG_ALLOW_OCTAL FILTER_VALIDATE_INT
FILTER_FLAG_ALLOW_HEX FILTER_VALIDATE_INT
FILTER_FLAG_EMAIL_UNICODE FILTER_VALIDATE_EMAIL
FILTER_FLAG_IPV4 FILTER_VALIDATE_IP
FILTER_FLAG_IPV6 FILTER_VALIDATE_IP
FILTER_FLAG_NO_PRIV_RANGE FILTER_VALIDATE_IP
FILTER_FLAG_NO_RES_RANGE FILTER_VALIDATE_IP
FILTER_FLAG_GLOBAL_RANGE FILTER_VALIDATE_IP
FILTER_FLAG_SCHEME_REQUIRED FILTER_VALIDATE_URL
FILTER_FLAG_HOST_REQUIRED FILTER_VALIDATE_URL
FILTER_FLAG_PATH_REQUIRED FILTER_VALIDATE_URL
FILTER_FLAG_QUERY_REQUIRED FILTER_VALIDATE_URL
FILTER_REQUIRE_SCALAR
FILTER_REQUIRE_ARRAY
FILTER_FORCE_ARRAY

Example

Filter email

$email = 'kj@example.com';
// kj@example.com
var_dump(filter_var($email, FILTER_VALIDATE_EMAIL));

$email = 'kj';
// false
var_dump(filter_var($email, FILTER_VALIDATE_EMAIL));

Get just number from the given string

$a = '!a-b.c3@j+dk9.0$3e8`~]\]2';
$number = str_replace(['+', '-'], '', filter_var($a, FILTER_SANITIZE_NUMBER_INT));
// Output is 390382

Reference

Example