[Zope-PAS] RFC: PAS caching

[Jens Vagelpohl]

Hi guys,

I'm going to work on caching for PAS and have thought about a couple 
different architectural models to do so. I've come to a model I 
personally like and wouldn't mind some comments.

Basically, I am proposing an architecture that works a little bit like 
ZCacheable in that you instantiate cache managers and associate objects 
(in this case plugins) with them. Obviously there are only a few plugin 
types where it makes sense to cache anything. Since the "cacheable" 
plugins have varying interfaces there would be specific cache manager 
objects for each of them, and only the appropriate plugin can be 
associated with them.

The plugins would cache based on keys that reflect the arguments to the 
given method that is used to retrieve data and allow to set parameters 
such as cache duration and knobs to invalidate the cache.

The caches require some cooperation from the plugins so that the 
methods that provide cacheable data would try to locate and consult an 
appropriate cache first, just like index_html in some basic OFS types 
now consults ZCache_get before computing a result. The interfaces 
itself would not be affected, just the implementations (which I would 
handle myself, too).

What do you think?

jens

---------------

Jens Vagelpohl			jens at zetwork.com
Software Engineer			Zope - done medium rare
Zetwork GmbH				http://www.zetwork.com/