I found several examples online, but apparently the XenForo templating system doesn't agree with the examples since I get Template Error: Page_Container. I tried inserting the code line in the templateHook call to my chagrin. (ie: after the finding the correct hook: ob_start(), before the main code, and just after $contents .= $pluginContents; ob_clean() or whathaveyou)
I also get fopen permission errors for the cache file and the folder and cache file for writing, even the script itself is set to www-data.www-data and all are given write permissions.
Has anyone gotten a cache system to work for their plugin? Or maybe you leveraged the Zend Framework somehow? If so on either question, please let me know.