[Zope] Idea of Caching DTML Methods in Zope

[Oliver Bleutgen]

Jaroslav Lukesh wrote:
> Hi all,
> 
> I have idea about another caching method in Zope. I am very sorry if it
> exist, but I dont know that.
> 
> If I have for example very expensive or manytimes called method, I cannot
> cache it via RAM cache manager, because it gives the same output regardless
> place from where are calling.
> 
> For example, two methods:
> 
> siteroot
> <dtml-var BASE1>/
> 
> localroot
> <dtml-in "PARENTS[3:]">../</dtml-in>
> 
> (3 because I use virtual servers as zoperoot/www/domain )
> 
> So siteroot can be cached via RAM cache manager without no problems,
> because constructing URLs are
> 
> 	<dtml-var siteroot>images/imege.gif
> output will
> 	http://www.domain.com/images/imege.gif
> 
> But localroot could not be cached, because i receive bad locations:
> 
> 	<dtml-var localroot>images/imege.gif
> output will
> 	../../images/imege.gif
> 
> If localroot are cached, then output of that will be same regardless of
> calling directory, it is computed from first access.
> 
> So it is possible to do "dynamic" caching? What I mean, is store all
> localroot objects in context of calling direcotry (or another object).
> 
> I have few hundreds of calling localroot per page and I will be hapy if it
> will have some solution for that. I dont want migrate to siteroot because
> it makes absolute URLs, not relative.
> 
> I know, I could use squid and Accelerated cache manager as reverse cache
> for caching whole pages, but it is not wanted solution (because you cannot
> see immediatelly changes to pages).
> 
> Many thanks for tips or implementation ;-)

Why not do
<dtml-let my_localroot="PARENTS[3:]">
[use my_localroot 100 times]
</dtml-let.

But I suspect this is just because you gave a simplified example.
See, the problem with your idea is more or less exactliy the same a with 
the squid solution: you will not see changes on a page immediatly, as 
the cached method can't really know if the context has changed (in case 
of your local_root thingy, what happens if you have changed the id  of a 
folder higher up?
Actually, because Accelerated Cache Manage can purge pages on the proxy, 
I think the solution you can get with squid is exactly the same as with 
your proposed solution - just some magnitudes faster.

cheers,
oliver