Question

I am trying write a PHP function that returns a random string of a given length. I wrote this:

<?
function generate_string($lenght) {
    $ret = "";
    for ($i = 0; $i < $lenght; $i++) {
        $ret .= chr(mt_rand(32,126));
    }
    return $ret;
}

echo generate_string(150);
?>

The above function generates a random string, but the length of the string is not constant, ie: one time it is 30 characters, the other is 60 (obviously I call it with the same length as input every time). I’ve searched other examples of random string generators, but they all use a base string to pick letters. I am wondering why this method is not working properly.

Thanks!

Answer 1

Educated guess: you attempt to display your plain text string as HTML. The browser, after being told it’s HTML, handles it as such. As soon as a < character is generated, the following characters are rendered as an (unknown) HTML tag and are not displayed as HTML standards mandate.

Fix:

echo htmlspecialchars(generate_string(150));