Replace preg_replace() with `e` modifier with call of preg_replace_callback() to fix the invalid character count in a serialized string

Question

How can I update this code :

$data = preg_replace('!s:(\d+):"(.*?)";!e', "'s:'.strlen('$2').':\"$2\";'", $array);

with the preg_replace_callback function?

Thanks.

Answer 1

preg_replace_callback() is very similar to preg_replace(), except parameter 2 is a callable function that takes $matches as a parameter. Don't forget to remove the /e modifier, since we aren't executing anything.

$array = array(
    's:1:"test";',
    's:2:"one more";',
);

$data = preg_replace_callback('!s:(\d+):"(.*?)";!', function($matches) {
    $string = $matches[2];
    $length = strlen($string);
    return 's:' . $length . ':"' . $string . '";';
}, $array);

print_r($data);
// Array ( [0] => s:4:"test"; [1] => s:8:"one more"; )