This is a sandbox project, which contains experimental code for developer use only.
Node access approach to first click free feature.
This module allows to access content (nodes) to visitors of given roles (e.g. anonymous) just once when they come from Google or any external domain. When they click on the website to access other content, they'd get an access denied.
This module uses node access, so anything that does not pass through node access checks will be visible.
This module will deny access to any request that is not a "First Click Free" action (first visit), so you definitely need a way to grant your permissions accordingly, Content Access is recommended, also R4032login is advised in order to redirect the users to the login page on 403 errors.
See First click free module for a hook_boot approach.
More info or First Click Free