PHP Filter

PHP Filter extension provides a facility to validate & sanitize data.

This extension is mostly used to validate & sanitize data whenever data comes from unknown & un-trusted sources.

 

Example to validate an email address

<?php

$email_a = 'joe@example.com';
$email_b = 'bogus';

if (filter_var($email_a, FILTER_VALIDATE_EMAIL)) {
    echo "Email address '$email_a' is considered valid.\n";
}

if (filter_var($email_b, FILTER_VALIDATE_EMAIL)) {
    echo "Email address '$email_b' is considered valid.\n";
} else {
    echo "Email address '$email_b' is considered invalid.\n";
}

?>

 

Output

 

Example to validate an IP address

<?php

$ip_a = '127.0.0.1';
$ip_b = '42.42';

if (filter_var($ip_a, FILTER_VALIDATE_IP)) {
    echo "IP address '$ip_a' is considered valid.";
}

if (filter_var($ip_b, FILTER_VALIDATE_IP)) {
    echo "IP address '$ip_b' is considered valid.";
}

?>

 

Output

 

Requirements

No external libraries are needed to build this extension.

 

Installation

The filter extension is enabled by default as of PHP 5.2.0.

To disable the filter extension, use --disable-filter.

Before PHP 5.2 an experimental PECL extension was used, however, the PECL version is no longer recommended or updated.

 

Run-time Configuration

The behavior of these functions is affected by settings in php.ini.

 

Filter Configuration Options

 

Resource Types

This extension has no resource types defined.

 

Predefined Constants

This Filter extension also provided some predefined constants.

In order to use this extension has either been compiled into PHP or dynamically loaded at runtime.

• INPUT_POST (integer)
• POST variables.
• INPUT_GET (integer)
• GET variables.
• INPUT_COOKIE (integer)
• COOKIE variables.
• INPUT_ENV (integer)
• ENV variables.
• INPUT_SERVER (integer)
• SERVER variables.
• INPUT_SESSION (integer)
• SESSION variables. (not implemented yet)
• INPUT_REQUEST (integer)
• REQUEST variables. (not implemented yet)
• FILTER_FLAG_NONE (integer)
  • No flags.
• FILTER_REQUIRE_SCALAR (integer)
  • Flag used to require scalar as input
• FILTER_REQUIRE_ARRAY (integer)
  • Require an array as input.
• FILTER_FORCE_ARRAY (integer)
  • Always returns an array.
• FILTER_NULL_ON_FAILURE (integer)
  • Use NULL instead of FALSE on failure.
• FILTER_VALIDATE_INT (integer)
  • ID of "int" filter.
• FILTER_VALIDATE_BOOLEAN (integer)
  • ID of "boolean" filter.
• FILTER_VALIDATE_FLOAT (integer)
  • ID of "float" filter.
• FILTER_VALIDATE_REGEXP (integer)
  • ID of "validate_regexp" filter.
• FILTER_VALIDATE_URL (integer)
  • ID of "validate_url" filter.
• FILTER_VALIDATE_EMAIL (integer)
  • ID of "validate_email" filter.
• FILTER_VALIDATE_IP (integer)
  • ID of "validate_ip" filter.
• FILTER_VALIDATE_MAC (integer)
  • ID of "validate_mac_address" filter. (Available as of PHP 5.5.0)
• FILTER_DEFAULT (integer)
  • ID of default ("unsafe_raw") filter. This is equivalent to FILTER_UNSAFE_RAW.
• FILTER_UNSAFE_RAW (integer)
  • ID of "unsafe_raw" filter.
• FILTER_SANITIZE_STRING (integer)
  • ID of "string" filter.
• FILTER_SANITIZE_STRIPPED (integer)
  • ID of "stripped" filter.
• FILTER_SANITIZE_ENCODED (integer)
  • ID of "encoded" filter.
• FILTER_SANITIZE_SPECIAL_CHARS (integer)
  • ID of "special_chars" filter.
• FILTER_SANITIZE_EMAIL (integer)
  • ID of "email" filter.
• FILTER_SANITIZE_URL (integer)
  • ID of "url" filter.
• FILTER_SANITIZE_NUMBER_INT (integer)
  • ID of "number_int" filter.
• FILTER_SANITIZE_NUMBER_FLOAT (integer)
  • ID of "number_float" filter.
• FILTER_SANITIZE_MAGIC_QUOTES (integer)
  • ID of "magic_quotes" filter.
• FILTER_CALLBACK (integer)
  • ID of "callback" filter.
• FILTER_FLAG_ALLOW_OCTAL (integer)
  • Allow octal notation (0[0-7]+) in "int" filter.
• FILTER_FLAG_ALLOW_HEX (integer)
  • Allow hex notation (0x[0-9a-fA-F]+) in "int" filter.
• FILTER_FLAG_STRIP_LOW (integer)
  • Strip characters with ASCII value less than 32.
• FILTER_FLAG_STRIP_HIGH (integer)
  • Strip characters with ASCII values greater than 127.
• FILTER_FLAG_ENCODE_LOW (integer)
  • Encode characters with ASCII values less than 32.
• FILTER_FLAG_ENCODE_HIGH (integer)
  • Encode characters with ASCII values greater than 127.
• FILTER_FLAG_ENCODE_AMP (integer)
  • Encode &.
• FILTER_FLAG_NO_ENCODE_QUOTES (integer)
  • Don't encode ' and ".
• FILTER_FLAG_EMPTY_STRING_NULL (integer)
  • (No use for now.)
• FILTER_FLAG_ALLOW_FRACTION (integer)
  • Allow fractional part in "number_float" filter.
• FILTER_FLAG_ALLOW_THOUSAND (integer)
  • Allow a thousand separators (,) in the "number_float" filter.
• FILTER_FLAG_ALLOW_SCIENTIFIC (integer)
  • Allow scientific notation (e, E) in "number_float" filter.
• FILTER_FLAG_PATH_REQUIRED (integer)
  • Require path in "validate_url" filter.
• FILTER_FLAG_QUERY_REQUIRED (integer)
  • Require query in "validate_url" filter.
• FILTER_FLAG_IPV4 (integer)
  • Allow only IPv4 address in "validate_ip" filter.
• FILTER_FLAG_IPV6 (integer)
  • Allow only IPv6 address in "validate_ip" filter.
• FILTER_FLAG_NO_RES_RANGE (integer)
  • Deny reserved addresses in "validate_ip" filter.
• FILTER_FLAG_NO_PRIV_RANGE (integer)
  • Deny private addresses in "validate_ip" filter.
• FILTER_FLAG_EMAIL_UNICODE (integer)
  • Accepts Unicode characters in the local part in the "validate_email" filter. (Available as of PHP 7.1.0)

 

Filter Functions

• filter_has_var — Checks if the variable of the specified type exists

• filter_id — Returns the filter ID belonging to a named filter

• filter_input_array — Gets external variables and optionally filters them

• filter_input — Gets a specific external variable by name and optionally filters it

• filter_list — Returns a list of all supported filters

• filter_var_array — Gets multiple variables and optionally filters them

• filter_var — Filters a variable with a specified filter