PHP 5.4.33 Released


(PHP 5 >= 5.2.0)

filter_inputGets a specific external variable by name and optionally filters it


mixed filter_input ( int $type , string $variable_name [, int $filter = FILTER_DEFAULT [, mixed $options ]] )





Name of a variable to get.


The ID of the filter to apply. The Types of filters manual page lists the available filters.


Associative array of options or bitwise disjunction of flags. If filter accepts options, flags can be provided in "flags" field of array.

Return Values

Value of the requested variable on success, FALSE if the filter fails, or NULL if the variable_name variable is not set. If the flag FILTER_NULL_ON_FAILURE is used, it returns FALSE if the variable is not set and NULL if the filter fails.


Example #1 A filter_input() example

$search_url filter_input(INPUT_GET'search'FILTER_SANITIZE_ENCODED);
"You have searched for $search_html.\n";
"<a href='?search=$search_url'>Search again.</a>";

The above example will output something similar to:

You have searched for Me &#38; son.
<a href='?search=Me%20%26%20son'>Search again.</a>

See Also

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User Contributed Notes 11 notes

ss23 at ss23 dot geek dot nz
4 years ago
Note that this function doesn't (or at least doesn't seem to) actually filter based on the current values of $_GET etc. Instead, it seems to filter based off the original values.
['search'] = 'foo'; // This has no effect on the filter_input

$search_html = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_SPECIAL_CHARS);
$search_url = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_ENCODED);
"You have searched for $search_html.\n";
"<a href='?search=$search_url'>Search again.</a>";

If you need to set a default input value and filter that, use filter_var on your required input variable instead
anthony dot parsons at manx dot net
7 years ago
FastCGI seems to cause strange side-effects with unexpected null values when using INPUT_SERVER and INPUT_ENV with this function. You can use this code to see if it affects your server:
foreach (
array_keys($_SERVER) as $b ) {
var_dump($b, filter_input(INPUT_SERVER, $b));
foreach (
array_keys($_ENV) as $b ) {
var_dump($b, filter_input(INPUT_ENV, $b));
If you want to be on the safe side, using the superglobal $_SERVER and $_ENV variables will always work. You can still use the filter_* functions for Get/Post/Cookie without a problem, which is the important part!
akshay dot leadindia at gmail dot com
1 year ago
The beauty of using this instead of directly using filter_var( $_GET['search'] ) is that you don't need to check if( isset( $_GET['search'] ) ) as if you pass that to filter_var and the key is not set then it will result in a warning. This function simplifies this and will return the relevant result to you (as per your options set) if the key has not been set in the user input.

If the type of filter you are using also supports a 'default' argument then this function will also stuff your missing input key with that value, again saving your efforts
3 months ago
This function provides us the extremely simple solution for type filtering.

Without this function...
if (!isset($_GET['a'])) {
$a = null;
} elseif (!
is_string($_GET['a'])) {
$a = false;
} else {
$a = $_GET['a'];
$b = isset($_GET['b']) && is_string($_GET['b']) ? $_GET['b'] : '';

With this function...
= filter_input(INPUT_GET, 'a');
$b = (string)filter_input(INPUT_GET, 'b');

Yes, FILTER_REQUIRE_SCALAR seems to be set as a default option.
It's very helpful for eliminating E_NOTICE, E_WARNING and E_ERROR.
This fact should be documented.
travismowens at gmail dot com
4 years ago
I wouldn't recommend people use this function to store their data in a database.  It's best not to encode data when storing it, it's better to store it raw and convert in upon the time of need.

One main reason for this is because if you have a short CHAR(16) field and the text contains encoded characters (quotes, ampersand) you can easily take a 12 character entry which obviously fits, but because of encoding it no longer fits.

Also, while not as common, if you need to use this data in another place, such as a non webpage (perhaps in a desktop app, or to a cell phone SMS or to a pager) the HTML encoded data will appear raw, and now you have to decode the data.

In summary, the best way to architect your system, is to store data as raw, and encode it only the moment you need to.  So this means in your PHP upon doing a SQL query, instead of merely doing an   echo $row['title']  you need to run htmlentities() on your echos, or better yet, an abstract function.
Maksym Karazeev
5 years ago
Just a tip.

Note how to setup default filter for filter_var_array

When I tried to use filter_var_array and didn't mentioned all array indexes in definition it filtered it with some filter and broke values so using this tip corrected everything

= array_map(create_function('', 'return array("filter"=>FILTER_UNSAFE_RAW);'), $input);
west {:a7} jsausa {:d0t}~ com
1 year ago
It's worth noting that the names for variables in filter input obey the same rules as variable naming in PHP (must start with an underscore or letter).  We were allowing users to build custom forms but hashing the names to prevent them from putting arbitrary content into the dom.  Turns out the hash function occasionally produced entirely numeric values for the field name... which doesn't work with filter_input but worked fine if you read directly from $_GET, $_POST, or $_REQUEST.  A workaround is to always prefix an underscore to the field name.
chris at chlab dot ch
2 years ago
To use a class method for a callback function, as usual, provide an array with an instance of the class and the method name.

class myValidator
  public function
// return username or boolean false

$myValidator = new myValidator;
$options = array('options' => array($myValidator, 'username'));
$username = filter_input(INPUT_GET, 'username', FILTER_CALLBACK, $options);
descartavel1+php at gmail dot com
5 months ago
contrary to what is stated here on the comments on thow to use the options for filters, there is no range option or default... in fact, there is not much option AT ALL. It is not mentioned in the manual anywhere, and the provided code on that comment does nothing with php-5.4.4..

(GET, 'p', FILTER_VALIDATE_INT, array('options'=>array('default'=>5, 'min_range'=>0, 'max_range'=>9)) );
// ?p=30 => 30
// ?p="123" => 123
// ?p=-23 => -23
// ?p=asdf => null
Stefan Weinzierl
7 months ago
Here is an example how to work with the options-parameter. Notice the 'options' in the 'options'-Parameter!

=array('options'=>array('default'=>5, 'min_range'=>0, 'max_range'=>9));

$priority=filter_input(INPUT_GET, 'priority', FILTER_VALIDATE_INT, $options);

$priority will be 5 if the priority-Parameter isn't set or out the given range.
med dot k1987 at yahoo dot com
4 years ago
Does anybody know how to prevent FILTER_SANITIZE_SPECIAL_CHARS from converting the line breaks (\n) into (&#10;).
I'm developing a simple commenting system for my website and I found that the php filter converts \n to &#10; so when using nl2br() there are no line breaks.
help please.
thanks :)
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