title: Magento FPC and $_SESSION object
body: <p>How to use a cache when you have content depending on SESSION variable?
  Does it work with Varnish-like cache? Does it require FPC?</p>
  
  <p>let me explain.
  My customers can select their model of Car (manufacturer, model, year), once selected this is stored in SESSION object.
  (Of course every product is linked to a list of Cars in the back end.)</p>
  
  <p>The thing is, on the frontend, There is a module that automatically filters the products according to the Car selected by the customer.</p>
  
  <p>I'm not only talking about a user that would search for a product by entering a keyword on the search bar.
  I'm also talking about the category pages.
  When the customer visits the website, clicking on a category, then the list of products within this category is filtered too!
  So while the customer navigates, he only see compatible products with his car.</p>
  
  <p>I failed to use VARNISH because of this (VARNISH is based on url only, and the selected Car is not part of every url...).</p>
  
  <p>That's why I'm wondering if there is any concept of Cache that would take into account SESSION variables?</p>
  
  <p>thanks,
  Rod</p>