should I allow "." in URL?

When user enters the offer name take that as $offer_name and encode it using base64_encode($offer_name);

$encoded_name = base64_encode($offer_name);

Send this $encoded_name to url...........and if you want to use offer name further decode it using base64_decode($encoded_name);

php codeigniter url web url-masking

if you need the "." you can leave that in urls, if you then use url params to run queries just escape params before to run the query.

Usually i make a 301 redirect to the base_url(); if somenthing wrong with url params.

just my 2 cents

php codeigniter url web url-masking

You can allow "." in URL by adding "." in $config['permitted_uri_chars'] config variable in config.php.

CodeHunter