Re: [WebMacro-user] Cache templets

[Lane S. <la...@op...>]

Hi Lars,

Caching has been discussed a lot and there is a caching provider 
interface so you can write your own caching implementation. (As I have 
done).

To cache individual objects, you can use a global service model to cache 
individual templates (eg, connection.wmt, statements.wmt, etc.) and 
objects (queryResultReference, queryResultDomain, 
queryResultTransaction, etc). With this kind of a model, you cache both 
the template elements and the results according to memory and 
invalidation events.

I have done all of the above for http://www.opendoors.com

Good luck.

Kindest,

lane

Lars George wrote:

> Hi,
>
> I had a look at OSCache the other day and noticed their Cache Tag 
> support which allows you to wrap a piece of code in a JSP and have it 
> cached for a configurable ammount of time:
>
> http://www.opensymphony.com/oscache/tags.html
>
> Well, I thought, wouldn't that be a cool feature in WebMacro if we 
> could cache a evaluated piece for a certain amount of time? There are 
> a couple of ways to do it of course and even the caching would need to 
> be implemented somehow, but I think it cannot be too difficult and 
> before having a go at it I thought what you guys think of it.
>
> One option would be to specify a Cache Interface class with the 
> necessary functionality and then implement it as required. For 
> instance one could use a special proxy/wrapper class to wrap OSCache 
> into the infrastructure. The classname for the proxy/wrapper class and 
> basic settings could be specified in the WebMacro.properties file.
>
> Then the Eval directive could be enhanced to handle the cache support, 
> eg.
>
>   #eval $listCart using { "cart": $myCart } cache { "timeout": 600, 
> "scope": "session" ... }
>
> using similar parameters as seen above in the OSCache cache tag.
>
> Then all the Eval directive would have to do is check if the cache 
> params are given and a cache proxy class is specified in the settings 
> file and then get the previously evaluated content from the cache or 
> store it there.
>
> Of course, if the WebMacro internal cache is already prepared to 
> handle this sort of extra work, then even better but since I started 
> with OSCache and know that they have all that "scope" stuff already 
> implemented, then why doing it again.
>
> Maybe there is even another way to cache pieces of evaluated template 
> using something like the block code, eg.
>
> #cache { "timeout": ... } #begin
>
> normal template code here
>
> #end
>
> But since I am not fully aware of which is the easier implementation 
> of the two I would love to hear what you guys suggest.
>
> Why all this effort? Well, I started "poluting" the code in a lot of 
> places to cache for instance database records that hardly change so 
> that next time the WebMacro tool which fills the template is called it 
> uses the cached information instead of hitting the database again. It 
> is an obvious choice because it gives the front-end page generator a 
> choice to get fresh or cached data where ever needed. When that 
> happens auto-magically in the backend then there is no control from 
> the presentation layer and the only choice to solve this is to add 
> extra params to the custom WebMacro tool calls which allows to specify 
> this.
>
> I thnk these are more than enough reasons to do it. ;-)
>
> Let me know what you think.
>
> Cheers,
> Lars
>
>
>
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-- 
Lane Sharman
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