[mp1] Serving cached content first, then refreshing

[Jean-Michel Hiver <jh...@mkdoc.com>]

Hi List,


Thanks to help on the list I have writtent the CPAN module
MKDoc::Apache_Cache [1].

At the moment when a cached document has expired from the cache, the
module does the following:

* refresh the cache

* send the newly cached content


I would like make an option so that the reverse could be done, i.e.

* send the expired cached content immediately.

* refresh the cache if it needs to be refreshed and if no other process
  currently does it.


However I am not sure how to go about it... Maybe with a cleanup handler
which would recompute the content and refresh the cache?

Then I have another problem. What if another cleanup handler closed the
database connection before my cleanup handler is executed? It would be
impossible to refresh the content under these conditions.

If I do register a cleanup handler, how can I make sure that it will be
the first cleanup handler to be executed?


Any other ideas?
Cheers,

[1] http://search.cpan.org/~jhiver/MKDoc-Apache_Cache/lib/MKDoc/Apache_Cache.pm
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Jean-Michel Hiver
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Re: [mp1] Serving cached content first, then refreshing

[Perrin Harkins <pe...@elem.com>]

On Thu, 2004-02-05 at 08:12, Jean-Michel Hiver wrote:
> However I am not sure how to go about it... Maybe with a cleanup handler
> which would recompute the content and refresh the cache?

Bingo!

> Then I have another problem. What if another cleanup handler closed the
> database connection before my cleanup handler is executed?

Don't do that.  Why would you close the connection?

> If I do register a cleanup handler, how can I make sure that it will be
> the first cleanup handler to be executed?

In my experience, you can't reliably control the order that they run
in.  If you need multiple things done in a certain order, have one
cleanup handler that does several things in the order you require.

- Perrin


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