EE - FPC and Category item count

Question

A customer of ours has reported a "bug" that their live site works differently from the staging environment. What they see is that when a user selects "all" products on a category page, then changes categories, the selection reverts to the default number of items per page items on live but stays at "all" products on staging.

What we found was that the live site had Full Page Cache (FPC) enabled and the staging site had it disabled. Once FPC was enabled on staging server, we were able to replicate the issue in that environment. Checking further, this happens on all of our EE sites and I guess I had never tested/noticed it before.

I understand that FPC is storing a version of the page as generated with the default parameters, but, is there any way to generate the non-cached behavior without using a new URL that includes the show parameter?

Thanks

Answer 1

Category filtering is initially applied by URL argument, but when this is done the filter selections are also stored in the users session. When the user navigates to another category after applying filtering, the filter selection stored in the session is used to filter the category and you don't see any URL arguments. The EE FPC is not taking this session data into account when loading category cached content and is purely caching by URL.

If you want this to work using the standard EE FPC then you will need to have it customised to consider this session stored filter data.

Alternatively you may want to consider Evolved Caching which is a much more complete caching solution which, amongst many other benefits, does consider this session stored filter data (and yes it does work under EE).