PHP: Filter Functions - Manual

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Last updated: Fri, 26 Jan 2007

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# XLI. Filter Functions

# Введение

This extension serves for validating and filtering data coming usually from some insecure source such as user input.

The following filters currently exist, be sure to read the Filter Constants section for information that describes the behavior of each constant:

Таблица 1. Existing filters

ID | Name | Options | Flags | Description
--- | --- | --- | --- | ---
`FILTER_VALIDATE_INT` | "int" | `min_range`, `max_range` | `FILTER_FLAG_ALLOW_OCTAL`, `FILTER_FLAG_ALLOW_HEX` | Validates value as integer, optionally from the specified range.
`FILTER_VALIDATE_BOOLEAN` | "boolean" |  |  | Returns `TRUE` for "1", "true", "on" and "yes", `FALSE` for "0", "false", "off", "no", and "", `NULL` otherwise.
`FILTER_VALIDATE_FLOAT` | "float" |  |  | Validates value as float.
`FILTER_VALIDATE_REGEXP` | "validate_regexp" | `regexp` |  | Validates value against `regexp`, a Perl-compatible regular expression.
`FILTER_VALIDATE_URL` | "validate_url" |  | `FILTER_FLAG_SCHEME_REQUIRED`, `FILTER_FLAG_HOST_REQUIRED`, `FILTER_FLAG_PATH_REQUIRED`, `FILTER_FLAG_QUERY_REQUIRED` | Validates value as URL, optionally with required components.
`FILTER_VALIDATE_EMAIL` | "validate_email" |  |  | Validates value as e-mail.
`FILTER_VALIDATE_IP` | "validate_ip" |  | `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_SANITIZE_STRING` | "string" |  | `FILTER_FLAG_NO_ENCODE_QUOTES`, `FILTER_FLAG_STRIP_LOW`, `FILTER_FLAG_STRIP_HIGH`, `FILTER_FLAG_ENCODE_LOW`, `FILTER_FLAG_ENCODE_HIGH`, `FILTER_FLAG_ENCODE_AMP` | Strip tags, optionally strip or encode special characters.
`FILTER_SANITIZE_STRIPPED` | "stripped" |  |  | Alias of "string" filter.
`FILTER_SANITIZE_ENCODED` | "encoded" |  | `FILTER_FLAG_STRIP_LOW`, `FILTER_FLAG_STRIP_HIGH`, `FILTER_FLAG_ENCODE_LOW`, `FILTER_FLAG_ENCODE_HIGH` | URL-encode string, optionally strip or encode special characters.
`FILTER_SANITIZE_SPECIAL_CHARS` | "special_chars" |  | `FILTER_FLAG_STRIP_LOW`, `FILTER_FLAG_STRIP_HIGH`, `FILTER_FLAG_ENCODE_HIGH` | HTML-escape `'"<>&` and characters with ASCII value less than 32, optionally strip or encode other special characters.
`FILTER_UNSAFE_RAW` | "unsafe_raw" |  | `FILTER_FLAG_STRIP_LOW`, `FILTER_FLAG_STRIP_HIGH`, `FILTER_FLAG_ENCODE_LOW`, `FILTER_FLAG_ENCODE_HIGH`, `FILTER_FLAG_ENCODE_AMP` | Do nothing, optionally strip or encode special characters.
`FILTER_SANITIZE_EMAIL` | "email" |  |  | Remove all characters except letters, digits and `!#$%&'*+-/=?^_`{|}~@.[]`.
`FILTER_SANITIZE_URL` | "url" |  |  | Remove all characters except letters, digits and `$-_.+!*'(),{}|\\^~[]`<>#%";/?:@&=`.
`FILTER_SANITIZE_NUMBER_INT` | "number_int" |  |  | Remove all characters except digits and `+-`.
`FILTER_SANITIZE_NUMBER_FLOAT` | "number_float" |  | `FILTER_FLAG_ALLOW_FRACTION`, `FILTER_FLAG_ALLOW_THOUSAND`, `FILTER_FLAG_ALLOW_SCIENTIFIC` | Remove all characters except digits, `+-` and optionally `.,eE`.
`FILTER_SANITIZE_MAGIC_QUOTES` | "magic_quotes" |  |  | Apply addslashes().
`FILTER_CALLBACK` | "callback" |  | callback function or method | Call user-defined function to filter data.

# Требования

Эти функции всегда доступны.

# Установка

A short installation note: just type

    $ pecl install filter

in your console.

# Настройка во время выполнения

Поведение этих функций зависит от установок в `php.ini`.

Таблица 2. Filter Configuration Options

Name | Default | Changeable | Changelog
--- | --- | --- | ---
filter.default | unsafe_raw | PHP_INI_PERDIR |
filter.default_flags |  | PHP_INI_PERDIR |

Для подробного описания констант PHP_INI_*, обратитесь к документации функции ini_set().

Краткое разъяснение конфигурационных директив.

`filter.default` string

  Filter all $_GET, $_POST, $_COOKIE and $_REQUEST data by this filter. Original data can be accessed through filter_input().

  Accepts the name of the filter you like to use by default. See the existing filter list for the list of the filter names.

`filter.default_flags` integer

  Default flags

# Типы ресурсов

Данное расширение не определяет никакие типы ресурсов.

# Предопределенные константы

Перечисленные ниже константы определены данным расширением и могут быть доступны только в том случае, если PHP был собран с поддержкой этого расширения или же в том случае, если данное расширение подгружается во время выполнения.

`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_DEFAULT` (integer)

  ID of default ("string") filter.

`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 value greater than 127.

`FILTER_FLAG_ENCODE_LOW` (integer)

  Encode characters with ASCII value less than 32.

`FILTER_FLAG_ENCODE_HIGH` (integer)

  Encode characters with ASCII value 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 thousand separator (`,`) in "number_float" filter.

`FILTER_FLAG_ALLOW_SCIENTIFIC` (integer)

  Allow scientific notation (`e`, `E`) in "number_float" filter.

`FILTER_FLAG_SCHEME_REQUIRED` (integer)

  Require scheme in "validate_url" filter.

`FILTER_FLAG_HOST_REQUIRED` (integer)

  Require host in "validate_url" 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.

add a note User Contributed Notes
Filter Functions
user
02-Feb-2007 12:15
`Below is some code using filter API to restrict access to LAN by IPv4 private address range.
These notes may save someone else a little time:
filter_input_array() is useless for running multiple filters on the same key.
No way to chain or negate filters.
<?php
/* Merciful comment! */
function FILTER_NEGATE_HACK($_){ return (bool)!$_; }
function client_is_private_ipv4(){
return (filter_input(INPUT_SERVER, 'REMOTE_ADDR', FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) &&
FILTER_NEGATE_HACK(filter_input(INPUT_SERVER, 'REMOTE_ADDR', FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE));
}
if (! client_is_private_ipv4())
exit('This application is restricted to local network users');
?>`
vojtech at x dot cz
21-Dec-2006 06:38
`Also notice that filter functions are using only the original variable values passed to the script even if you change the value in super global variable ($_GET, $_POST, ...) later in the script.
<?php
echo filter_input(INPUT_GET, 'var'); // print 'something'
echo $_GET['var']; // print 'something'
$_GET['var'] = 'changed';
echo filter_input(INPUT_GET, 'var'); // print 'something'
echo $_GET['var']; // print 'changed'
?>
In fact, external data are duplicated in SAPI before the script is processed and filter functions don't use super globals anymore (as explained in Filter tutorial bellow, section 'How does it work?').`
vojtech at x dot cz
21-Dec-2006 05:13
`Just to note that "server and env support may not work in all sapi, for filter 0.11.0 or php 5.2.0" as mentioned in Filter tutorial bellow.
The workaround is obvious:
Instead of
<?php
$var = filter_input(INPUT_SERVER, 'SERVER_NAME', FILTER_DEFAULT);
?>
use
<?php
$var = filter_var(isset($_SERVER['SERVER_NAME']) ? $_SERVER['SERVER_NAME'] : NULL, FILTER_DEFAULT);
?>`
kevin at oceania dot net
11-Nov-2006 09:34
`Examples of ALL filters and flags here:
http://phpro.org/tutorials/Filtering-Data-with-PHP.html`
philip at php dot net
31-Oct-2006 06:00
`Filter tutorial here:
* http://devzone.zend.com/node/view/id/1113`
add a note
filter_has_var unlink

Last updated: Fri, 26 Jan 2007
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