Bolt Full Page Cache

Bolt Full Page Cache sits in front of Magento's cache.

When dealt a cached result it does not load Magento at all. No Magento files, events or profiler are executed.

The hole punching is set the in the admin configuration : Admin -> Configuration -> Bolt

Bolt FPC will add the header X-Cached-By: Bolt to the response to the page.

Details

Bolt will be injected before the Magento runs, checking the index.php file you can see the included bolt file.

Hole Punching

Hole Punching Docs

Debugging Bolt

Bolts core files where the caching and checks will be located in the lib folder root of your web directory.

The file for a majority of file handling with cached files will be located in lib/Fishpig/Bolt/Cache/File.php

Bolt will check the cache key and load the file if possible if not then attempt to save it after it's been loaded by magento. - The hole punching will affect this. - Custom observers can be made to avoid the bolt caching saving take place.