safe_filename ()

function safe_filename ($fn, $len = 50)

Use this function to create a safe file name. A safe file name is a file name with only alphanumeric characters (A-Z, 0-9), non alphanumeric characters (including space) will be replaced with underscore '_'.

$fn = the original (non-safe) file name.

$len = maximum length of the name (excluding the extension).

Example 1

<?php
require './includes/user_init.php';

$fn = 'tHis is A long % file nam$ with. invalid ch#aracters.txt.doc';
echo safe_filename ($fn);

// output:
// this_is_a_long___file_nam__with__invalid_ch_aracte.doc
?>