Filtering multi-dimensional POST with PHP filter_input_array

Question

Is there a way to filter/sanitize multi-dimensional POST data with PHP's filter_input_array?

Given a form which results in following POST data:

$_POST[
    'level1a' => [
        'level2a' => [
            'key1' => 'value1',
            'key2' => 'value2'
        ],
        'level2b' => [
            'key1' => 'value1',
            'key2' => 'value2'
        ]
    ],
    'level1b' => [
        'level2a' => [
            'key1' => 'value1',
            'key2' => 'value2'
        ],
        'level2b' => [
            'key1' => 'value1',
            'key2' => 'value2'
        ]
    ]
]

I don't see a way to tell the filter_input_array function that the data to check is nested one level deeper. There seems to be only the flag FILTER_REQUIRE_ARRAY, but no way to tell on which level it needs to check.

Working example with less dimensions:

If it was just a less nested set of data, it would be pretty simple:

$_POST[
    'level1a' => [
        'level2a' => 'value1',
        'level2b' => 'value2'
    ],
    'level1b' => [
        'level2a' => 'value1',
        'level2b' => 'value2'
    ]
]

Could be filtered with:

$args = array(
    'level1a' => array(
        'filter' => FILTER_SANITIZE_STRING, 
        'flags' => FILTER_REQUIRE_ARRAY
    ),
    'level1b' => array(
        'filter' => FILTER_SANITIZE_STRING, 
        'flags' => FILTER_REQUIRE_ARRAY
    )
);
$form_data = filter_input_array(INPUT_POST, $args);

But how to solve it with more nested data? Is there a way without splitting/flattening the POST data?

You can probably fairly easily write a recursive function to run filter_input_array on some data and then recurse to inner arrays. — shevron
– shevron, Commented Sep 10, 2015 at 11:56
I am working on a similar issue right now. I'll let you know what I come up with. — Anthony Rutledge
– Anthony Rutledge, Commented Dec 17, 2015 at 12:54
I might try engineering my HTML form so that it creates only scalars and/or two-dimensional arrays. Since $_POST and INPUT_POST are not the same, flattening $_POST will not have any effect on INPUT_POST. In the pure sense, I think you would want to leave $_POST out of it. My suggestion is for you to flatten your HTML form if at all possible, instead of the input source array. Yes, trickery can be done, but at what cost? Processing time? Maintenance? Documentation? Once you get beyond two dimensions, PHP leaves you to your own devices. :) Notice there is no INPUT_FILES. — Anthony Rutledge
– Anthony Rutledge, Commented Dec 17, 2015 at 13:36
You can try the second idea in this answer stackoverflow.com/a/4995863 — A.J.
– A.J., Commented Jul 27, 2016 at 16:32

ymakux · Accepted Answer · 2016-12-15 04:46:22Z

4

/**
* Trim and filter every value in the nested array
*/
function filter(array &$array)
{
    array_walk_recursive($array, function (&$value) {
         $value = filter_var(trim($value), FILTER_SANITIZE_STRING);
    });

    return $array;
}

/**
* Get filtered POST data
*/
function post(){
  return filter($_POST);
}

answered Dec 15, 2016 at 4:46

ymakux

3,4952 gold badges37 silver badges44 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Filtering multi-dimensional POST with PHP filter_input_array

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related