Redirect on disallowed characters

I've read all the comments above - but I think you missed the easy way to do this.

Just overload the _filter_uri() function, and do whatever you want:

(Place this file in application/core/MY_URI.php)

// Normally this is not fully uppercase - but for some reason the URI filename isClass MY_URI extends CI_URI{/** * Filter segments for malicious characters * * @access  private * @param   string * @return  string */function _filter_uri($str){    if ($str != '' && $this->config->item('permitted_uri_chars') != '' && $this->config->item('enable_query_strings') == FALSE)    {        if ( ! preg_match("|^[".str_replace(array('\\-', '\-'), '-', preg_quote($this->config->item('permitted_uri_chars'), '-'))."]+$|i", $str))        {            // DO SOMETHING HERE LIKE REDIRECT OR CHANGE THE URL        }    }    // Convert programatic characters to entities    $bad    = array('$',        '(',        ')',        '%28',      '%29');    $good   = array('$',    '(',    ')',    '(',    ')');    return str_replace($bad, $good, $str);}

This is solution I am using on my project:

File: application/core/MY_URI.php

class MY_URI extends CI_URI {    /**     * Filter URI     *     * Filters segments for malicious characters.     *     * @param   string  $str     * @return  void     */    public function filter_uri(&$str)    {        if ( ! empty($str) && ! empty($this->_permitted_uri_chars) && ! preg_match('/^['.$this->_permitted_uri_chars.']+$/i'.(UTF8_ENABLED ? 'u' : ''), $str))        {            return preg_replace('~[^a-zA-Z 0-9%.:_\-,()]+~', '', $str);        }    }}