I'm working on a Facebook Platform application that runs in iframe mode, and I'm having trouble understanding how to navigate between pages within the app.

Let's say the first page that is loaded within the iframe at my canvas URL is one.html. Within that page, there is a link to two.html that just changes the source of the iframe and doesn't reload the Facebook chrome. When I do this, all the Facebook fb_sig_* query string parameters that Facebook passes to the original page aren't included, and so two.html has no awareness of the connection to Facebook and no ability to make API calls to generate the content for the page.

One possible solution would be to manually extract all the Facebook parameters from one.html and append it to the link to two.html myself. This seems really ugly and I figured there had to be a cleaner way. For reference, my application is written in Perl and uses the WWW::Facebook::API module as a client library. I didn't see anything in it that I can use to easily reconstruct the Facebook parameters for use with links in iframe apps.

Another possible solution would be to store all the Facebook parameters in a session on my server on the first page load, and just use the values in that session on subsequent page views. But what happens if the data I've stored no longer matches what Facebook would have sent if it were a completely new request (i.e. something in the user's Facebook session changed)?

Is there something obvious I'm missing? What is the standard approach to navigating between pages within an iframe app? Facebook's documentation is atrocious and I haven't been able to find anything that clearly explains how this works. I also realize this wouldn't be an issue with an app using FBML instead of an iframe, but my understanding is that iframe apps are now encouraged over FBML apps, though again this seems ambiguous since so much of Facebook's documentation is outdated and contradictory.