Key value store in Perl

I hope this question is still on topic, but recently I found a key-value store programmed in Perl. It was pretty simple, RAM based and I think it had just set and get and also an 'expire' option for keys. I also think it came with as both XS and pure Perl version.

I have been searching for quite a while now and I not sure whether it is o开发者_运维知识库n CPAN or I saw it on GitHub. Maybe someone knows what I am talking about.

It might be helpful in narrowing things down if you could explain what exactly the module does that is special in that regard. If you're looking to implement something with caching in general, I'd point you towards CHI, which is basically a common API with multiple caching drivers.

Do you mean Cache? It can store key/value pairs in a number of places, including shared memory.

It sounds like you are describing Memcached. There is a Perl interface on CPAN.

I've used Tie::Cache for this in the past with excellent results. It created a tied hash variable that exhibits LRU behavior when it grows beyond a configured maximum key count.

my $cache_size = 1000;
use vars qw(cache); %cache = ();
tie %cache, 'Tie::Cache', $cache_size;

From here, you can store hash/value pairs (of course, the value side can be a reference) in %cache and should its size grow to 1000 keys, the LRU keys will be deleted as more are added.

In my usage, I store the right-hand side as an arrayref holding the cached value along with a timestamp of when the entry was cached; my cache reference code checks the timestamp and deletes the key without using it if the entry isn't fresh enough:

sub getCacheMatch {
  my $check_value = shift;
  my $timeout = 600; # 10 minutes

  # Check cache for a match.
  my ($result, $time_cached);
  my $now = time();
  my $time_cached;
  my $cache_entry = $cache{$check_value};
  if ($cache_entry) {
    ($result, $time_cached) = @{$cache_entry};
    if ($now - $time_cached > $timeout) {
      delete $cache{$check_value);
      return undef;
    } else {
      return $result;
    }
  }
}

And I update the cache elsewhere in the code like so:

$url{$cache_checkstring} = [$value_to_cache, $now];