How to rebuild a cached page when it expires? I'm using views caching after reading this great Q&amp;A and getting good results. I have to keep the expiration short because I'm showing the "last comment" in the view and those changes often.

I'm thinking about using views content cache to expire the cache every time a comment is added. Or cache actions to do it with rules.

What I would like to do is rebuild the cache immediately after it expires? I read that boost module offers that but I need a solution for authenticated visitors (already use Varnish for anonymous).

The cache graceful module seems to offer that but only has 20 installs (plus requires a couple of other modules).

Are there any other solutions that allow expiring a cache and "warming" it up right away?
If you know what functions need to run in order to warm a cache, checkout httprl. httprl_queue_background_callback() is the function to look into using. Simple example of calling watchdog in the background http://drupalcode.org/project/httprl.git/blob/24a88acd2180191d0b54696e577f14615e37302d:/README.txt#l268

In terms of graceful varnish cache clears this has a good example: https://www.varnish-cache.org/trac/wiki/VCLExampleGrace Example of it in use: http://groups.drupal.org/node/63203