random string

randomstring.php

/*
*   @param $chars ALPHA | NUM | ALPHANUM | HEX | string
*   @param $length number
*   @return $rstring
*/
public function GetRandomString($chars, $length)
    {
        switch ($chars) {
            case "ALPHA":
                $chars = "abcdefghijklmnopqrstuvwxyz";
                break;
            case "NUM":
                $chars = "0123456789";
                break;
            case "ALPHANUM":
                $chars = "abcdefghijklmnopqrstuvwxyz0123456789";
                break;
            case "HEX":
                $chars = "abcdef0123456789";
                break;
            default:
                break;
        }
        $rstring = "";
        $n = strlen($chars);
        for($i = 0; $i < $length; $i++)
        {
            $rstring .= $chars[mt_rand(1,$n) - 1];
        }
        return $rstring;
    }