Sometimes it is important for a site to not provide direct access to certain pages except you are a legitimate user.
This is the case for instance when you want to prevent that robots access certain pages and retrieve information in behalf of users that in reality did not access the site.
Leting the users or robots have direct access to pages can cause some type of loss to the site, like for instance not exposing the users to advertising on which the site depends.
This class provides a solution that consists on adding special tokens to links that can be verified on each page to determine whether the user accessed the page following legitimate links. With this verification, the site may refuse to serve the usual content.
This class is meant to generate obfuscated HTML links in a way that is possible to detect whether the a page was accessed following a real link or went directly to a given page.
This way the class can be used to disallow users to freely navigate in a site without going through the intended pages, preventing direct access to pages eventually bookmarked during a previous access to the site.