I'm attempting to keep a Facebook session alive for as long as the user has the app open. This is done by a simple AJAX call every minute. I'm using the PHP SDK, and calling $facebook->getUser() to get the user's data.
But in spite of this, and even regular activity, the session times out after about 20-30 minutes of use.
The PHPSESSID cookie is configured to expire 30 days after it's set, not 30 minutes, and I'm repeatedly querying the Facebook API every minute. Shouldn't that keep the session alive for as long as the app is open in the browser?