unlink
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.
XLI. Filter Functions
Introduction
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:
Table 93. 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. |
Requirements
No external libraries are needed to build this extension.
Installation
A short installation note: just type
$ pecl install filterin your console.
Runtime Configuration
The behaviour of these functions is affected by settings in php.ini.
Table 94. Filter Configuration Options
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| filter.default | unsafe_raw | PHP_INI_PERDIR | |
| filter.default_flags | PHP_INI_PERDIR |
For further details and definitions of the PHP_INI_* constants, see the Appendix I, php.ini directives.
Here's a short explanation of the configuration directives.
- 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
Resource Types
This extension has no resource types defined.
Predefined Constants
The constants below are defined by this extension, and will only be available when the 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_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.
Table of Contents
- 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 NotesFilter Functions
ckroll at rightmedia dot com
08-May-2007 03:02
08-May-2007 03:02
user
02-Feb-2007 08:15
02-Feb-2007 08:15
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)!$_; }
function client_is_private_ipv4(){
return (filter_input(INPUT_SERVER, 'REMOTE_ADDR', FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) &&
FILTER_NEGATE_HACK(filter_input(INPUT_SERVER, 'REMOTE_ADDR', FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE));
}
if (! client_is_private_ipv4())
exit('This application is restricted to local network users');
?>
vojtech at x dot cz
21-Dec-2006 02:38
21-Dec-2006 02:38
Also notice that filter functions are using only the original variable values passed to the script even if you change the value in super global variable ($_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 01:13
21-Dec-2006 01:13
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
12-Nov-2006 05:34
12-Nov-2006 05:34
Examples of ALL filters and flags here:
http://phpro.org/tutorials/Filtering-Data-with-PHP.html
philip at php dot net
01-Nov-2006 02:00
01-Nov-2006 02:00
Filter tutorial here:
* http://devzone.zend.com/node/view/id/1113