Having special characters in URLs in CodeIgniter - codeigniter

Question

I want to have URLs like
http://www.example.com/(*.)
but CodeIgniter does not allow me to do that. When I try to access some URLs I get 404 error (and the requested page exists).
I know I can set allowed characters in URL, but I thought about encoding it. However, if I do something like this:
http://www.example.com/<?php echo rawurlencode(string) ?>
or even:
http://www.example.com/<?php echo rawurlencode(rawurlencode(string)) ?>
I still got the 404. Why is that? '%'s are allowed characters, so why it won't work? And what can I do to fix it?

Answer 1

You can allow certain signs through config/config.php and the permitted_uri_chars key.
However, though I'm not fully certain, I do believe these are restricted by default to increase security. As relevant explanation suggests:
/*
|--------------------------------------------------------------------------
| Allowed URL Characters
|--------------------------------------------------------------------------
|
| This lets you specify with a regular expression which characters are permitted
| within your URLs. When someone tries to submit a URL with disallowed
| characters they will get a warning message.
|
| As a security measure you are STRONGLY encouraged to restrict URLs to
| as few characters as possible. By default only these are allowed: a-z 0-9~%.:_-
|
| Leave blank to allow all characters -- but only if you are insane.
|
| DO NOT CHANGE THIS UNLESS YOU FULLY UNDERSTAND THE REPERCUSSIONS!!
|
*/
For instance, what's so neat about the current settings is that you allow few enough uris to parse IDs without risking to have them compromised by '', "" or similiar. Of course there's automatic and manual $this->db->escape(), but this just adds more failsafes.

Answer 2

WHen trying to pass urlencoded strings to the URI it will generate an error if the encoded string has a /, codeigniter will try to parse this as a segment, thus rendering a 404, what you need to use is query strings.
$string = rawurlencode(string)
http://www.example.com/class/method/?string=$string
then on your method
use get
function method()
{
$this->input->get('string');
}

Answer 3

In case you want to have slashes / in the URL, use double raw encoding. For example:
$string = rawurlencode(rawurlencode('/sth/sth'));