I think as long as you allowed it in ip_allow.config properly, "BAN" method works. 

I think last time the community discussed about this feature, the conclusion is that you can probably achieve similar effect with the regex_revalidate plugin - https://docs.trafficserver.apache.org/en/latest/admin-guide/plugins/regex_revalidate.en.html or the purge remap plugin - https://docs.trafficserver.apache.org/en/latest/admin-guide/plugins/remap_purge.en.html 

I think you should be able to implement the mechanism you mentioned using lua. Although i am not too sure why you want to update cache.config. Since i thought the "ban" is just to invalidate the cache entry once and not indefinitely. 



On Thu, Oct 11, 2018 at 9:35 AM Vaughan, Wendre <wendre.vaughan@soundtransit.org> wrote:

I have ATS 7.1 setup as a reverse proxy for a Drupal-Managed Website.  My Drupal Development Team wants to use a feature called Cache Tags (https://www.drupal.org/docs/8/api/cache-api/cache-tags-varnish ) that is designed specifically for Varnish. 


The Drupal system would send a Request with method ‘BAN’ to the ATS servers expecting the ATS servers to read the X-Cache-Tags headers (a list of pages to not cache) and have ATS do the following:


  1. Purge the ATS cache of any of the items in the X-Cache-Tags list
  2. Dynamically update a list of ‘Never Cache’ to the items in the X-Cache-Tag list.
  3. Remove these four headers from origin responses before sending the response to the requestor:  X-Url, X-Host, X-Cache-Tags, X-Cache-Contexts (can do this with the headers plugin)


So I have a few questions.  Can I setup a method called ‘BAN’ on the ATS servers?  I think I can use the headers plugin and possibly a lua script to do the purging and update the cache.config file.  If I can get the ‘BAN’ method to be accepted by ATS.


I am pretty new to extending ATS with lua.  Any help is appreciated.


Wendre Vaughan

Senior Software Engineer, Operations | Finance & Information Technology | Sound Transit

P: 206.903.7270 | F: 206.398.5223 | e: wendre.vaughan@soundtransit.org


Connect with us

https://www.facebook.com/SoundTransit | https://twitter.com/SoundTransit