User Defined Filter

Константи, описані нижче — визначені цим розширенням, тож доступні, коли розширення скомпільовано як частина PHP або динамічно підключене під час виконання.

FILTER_CALLBACK (int)

This filter delegates the filtering to a user defined function. The callable is passed via the options parameter as the value associated to the 'options' key.

The callback should have the following signature:

function callback(string $value): mixed

value

The value that is being filtered.

Зауваження:

The value returned by the callback will be the value returned by the invoked filter function.

Приклад #1 Example of using FILTER_CALLBACK to validate a login name

<?php
function validate_login(string $value): ?string
{
    if (strlen($value) >= 5 && ctype_alnum($value)) {
        return $value;
    }
    return null;
}

$login = "val1dL0gin";
$filtered_login = filter_var($login, FILTER_CALLBACK, ['options' => 'validate_login']);
var_dump($filtered_login);

$login = "f&ke login";
$filtered_login = filter_var($login, FILTER_CALLBACK, ['options' => 'validate_login']);
var_dump($filtered_login);
?>

Поданий вище приклад виведе:

string(10) "val1dL0gin"
NULL

Зауваження:

As of PHP 8.1.25 and 8.2.12, the structural flags FILTER_REQUIRE_ARRAY, FILTER_FORCE_ARRAY and FILTER_REQUIRE_SCALAR apply to this filter, and FILTER_NULL_ON_FAILURE changes how such a structural failure is reported. In earlier versions all flags were ignored. Filter specific flags are always ignored, and since the return value of the callback is the result, the callback itself cannot fail: no flag turns a false returned by the callback into null or an exception.