On December 14, 2001 03:04 pm, Perrin Harkins wrote:
> > So our solution was caching in-process with just a hash, and using a
> > DBI/mysql persistent store.
> > in pseudo code
> > sub get_stuff {
> > if (! $cache{$whatever} ) {
> > if !( $cache{whatever} = dbi_lookup()) {
> > $cache{$whatever}=derive_data_from_original_source($whatever);
> > dbi_save($cache_whatever);
> > }
> > }
> > $cache{$whatever}
> > }
>
> That's actually a bit different. That would fail to notice updates between
> processes until the in-memory cache was cleared. Still very useful for
> read-only data or data that can be out of sync for some period though.
>
> > The filesystem based / time sensitive aging is a nice little thing we
>
> should
>
> > put up in CPAN. We've just not done so yet.
>
> How does it differ from the other solutions like Cache::FileCache? Is it
> something you could add to an existing module?
>
Performance,and key structure, semantics. Its mostly different, not
better/worse.
=pod
=head1 NAME
UFMEDIA::CacheOneFile - cache a scalar value in a file on disk
=head1 SYNOPSIS
use UFMEDIA::CacheOneFile;
my $cache = new UFMEDIA::CacheOneFile(
cache_file => '/var/cache/myapp/flurge.cache',
max_age => 30,
refill_sub => sub { recalculate_flurges(31337, 'blue', 42) },
);
my $value = $cache->get_value;
=head1 DESCRIPTION
UFMEDIA::CacheOneFile enables you to cache a single scalar value in a file
on disk. Given a filename under a writable directory, a maximum age, and
a reference to a refill subroutine, a cache object will cache the result
of the refill subroutine in the file the first time B<get_value()> is called,
and use the cached value for subsequent calls to B<get_value()> until
B<max_age> the cach
e file is more than B<max_age> seconds old.
If multiple processes share a single cache file, the first process that
reads the cache file after it has expired will take responsibility for
replacing it with an up-to-date copy. Other processes needing up-to-date
information will wait for this to finish and will then use the new value.
=head1 AUTHOR
Mike Lyons <[EMAIL PROTECTED]>
=head1 SEE ALSO
perl(1).
=cut
> - Perrin
--
Jay "yohimbe" Thorne [EMAIL PROTECTED]
Mgr Sys & Tech, Userfriendly.org
