Back Midas Rome Roody Rootana
  Midas DAQ System  Not logged in ELOG logo
Entry  25 Jan 2021, Thomas Lindner, Suggestion, mhttpd browser caching 
    Reply  25 Jan 2021, Stefan Ritt, Suggestion, mhttpd browser caching 
       Reply  25 Jan 2021, Thomas Lindner, Suggestion, mhttpd browser caching 
    Reply  08 Feb 2021, Konstantin Olchanski, Suggestion, mhttpd browser caching 
       Reply  08 Feb 2021, Stefan Ritt, Suggestion, mhttpd browser caching 
Message ID: 2080     Entry time: 25 Jan 2021     In reply to: 2079     Reply to this: 2081
Author: Stefan Ritt 
Topic: Suggestion 
Subject: mhttpd browser caching 
Let me first explain a bit why caching is there. Once we had the case that someone from 
TRIUMF opened a midas custom page at T2K. It took about one minute (!) to load the page. 

When we looked at it, we found that the custom page pulled about 100 items with individual
HTTP requests from Japan, each taking about one second for the roundtrip. Then we redesigned
the custom page communication so that many ODB entries could be retrieved in one operation,
which improved the loading time from 100s to about 2s.

With the buttons we will have to make the same compromise. If we do not cache anything,
loading the midas status page over the Pacific takes many seconds. If we cache all, any
change on the midas side will not be reflected on the web page. So there is a compromise
to be made. I thought I designed it such that the side menu is cached locally, but when
the user presses "reload", then the full menu is fetched from the server. Of course one
has to remember this, so changing the ELOG URL or other things on the menu require a
reload (or wait a certain time for the cache to expire). So try again if that's working
for you. If not, I can visit it again and check if there is any bug.

If we go the route to disable the cache, better try this to T2K and see what you get before
we commit ourselves to that. Last time TRIUMF people were complaining a lot about long
load times.

Best,
Stefan
ELOG V3.1.4-2e1708b5