Re: Cached pages

On Mon, Apr 04, 2016 at 05:16:54PM +0100, Nick Warne wrote:
> Hi Jorge,
> 
> On 04/04/16 13:00, Jorge Arellano Cid wrote:
> >>Usually shift+[refresh] drops the cache and gets the new page, but the only
> >>way I get get dillo to do this is exit, and restart (no big deal with a 0.02
> >>second start-up time :) )
> >>
> >>Ideas?
> >
> >   Strange, I just tested this trivial cgi script and a simple reload
> >does the trick (button press or Ctrl-r). Does it work for you?
> 
> OK, basically on the html page with the form you enter some letters/words...
> hit submit (or 'process' in my case) and the perl CGI produces the results
> and the time taken.
> 
> Now, if if you use the same words on the index page, dillo doesn't run the
> CGI, but produces the previous cached page - sure, a reload works, but that
> doesn't seem logical.

  Logic depends upon the considered facts.


> Firefox doesn't do this, it runs the CGI each time, which is what I would
> expect on something that produces dynamic content.

  Cache policy is not trivial (e.g. check idempotency in HTTP).

  For  instance,  if  you decide to try to reload whenever it may
seem  useful,  you  start  having  problems when users go offline
(i.e.  intermitent internet connections). BTW,  that's how we got
"offline mode"; Good&Simple right? Hmmm, no. Unfortunately it was
nearly  impossible  to  teach  the  proverbial grandma when to go
offline  and  when  online.  Power users started to complain they
were  not  able  to  go  back and forward fast on already visited
pages,  and  that  pages  dissappeared. Why, the browser issued a
reload  every  time, cleaning the cache, and guess what, websites
used the opportunity to refresh advertisement.

  At  some  point there were cache directives served in HTTP, but
they  got  abused  by advertising again (i.e. always reload means
more  money).  And  some  sites decided to serve their pages with
always  reload  directives,  even some decided to issue automatic
reloads  after  a  certain a mount of time (more clicks/visits on
the stats, more money for payed advertisingt, etc...).

  One  of  the  reasons why people love to have many open tabs is
that  since  the  reload  mess inception (and some other stuff as
custom navigation), it became hard to tell whether you'll be able
to see the same page again by going back and forward. So tabs are
a solution to the new problem.

  As  you  may  see  from  this short sample, a cache policy must
consider lots of cases.


-- 
  Cheers
  Jorge.-