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XLI. Filter Functions
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. |
Эти функции всегда доступны.
A short installation note: just type
in your console.
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
Данное расширение не определяет никакие типы ресурсов.
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.
- Содержание
- filter_has_var -- Checks if variable of specified type exists
- filter_id -- Returns the filter ID belonging to a named filter
- filter_input_array -- Gets multiple variables from outside PHP and optionally filters them
- filter_input -- Gets variable from outside PHP 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
 add a note
User Contributed Notes
Filter Functions
fumble1 at web dot de
12-Aug-2007 10:54
I recommend you to use the FILTER_REQUIRE_SCALAR (or FILTER_REQUIRE_ARRAY) flags, since you can use array-brackets both to access string offsets and array-element -- however, not only this can lead to unexpected behaviour. Look at this example:
<?php
$image = basename(filter_input(INPUT_GET, 'src', FILTER_UNSAFE_RAW, FILTER_FLAG_STRIP_LOW));
?>
/script.php?src[0]=foobar will cause a warning. :-(
Hence my recommendation:
<?php
$image = basename(filter_input(INPUT_GET, 'src', FILTER_UNSAFE_RAW, FILTER_REQUIRE_SCALAR | FILTER_FLAG_STRIP_LOW));
?>
Richard Davey rich at corephp dot co dot uk
13-Jun-2007 11:15
There is an undocumented filter flag for FILTER_VALIDATE_BOOLEAN. The documentation implies that it will return NULL if the value doesn't match the allowed true/false values. However this doesn't happen unless you give it the FILTER_NULL_ON_FAILURE flag like this:
<?php
$value = 'car';
$result = filter_var($value, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
?>
In the above $result will equal NULL. Without the extra flag it would equal FALSE, which isn't usually a desired result for this specific filter.
ckroll at rightmedia dot com
08-May-2007 08:02
Beware, the FILTER_SANITIZE_STRING flag functions much like strip_tags, so < will get filtered from input regardless of it's actually part of a tag. We were getting unexepected results with a graphic library we wrote when trying to print < on a dynamic button. The url came in something like ?string=%3C (<) but after filter ran it was empty. To get around this, you could use FILTER_UNSAFE_RAW on that one param.
user
02-Feb-2007 12:15
Below is some code using filter API to restrict access to LAN by IPv4 private address range.
These notes may save someone else a little time:
filter_input_array() is useless for running multiple filters on the same key.
No way to chain or negate filters.
<?php
function FILTER_NEGATE_HACK($_){ 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'); echo $_GET['var']; $_GET['var'] = 'changed';
echo filter_input(INPUT_GET, 'var'); echo $_GET['var']; ?>
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);
?>
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